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About this book

This book provides insights on a broad spectrum of renewable and sustainable energy technologies from the world’s leading experts. It highlights the latest achievements in policy, research and applications, keeping readers up-to-date on progress in this rapidly advancing field. Detailed studies of technological breakthroughs and optimizations are contextualized with in-depth examinations of experimental and industrial installations, connecting lab innovations to success in the field. The volume contains selected papers presented at technical and plenary sessions at the World Renewable Energy Congress, the world's premier conference on renewable energy and sustainable development. Held every two years, the Congress provides an international forum that attracts hundreds of delegates from more than 60 countries.

Table of Contents

Frontmatter

Metereology 2014

Frontmatter

1. Estimation of Global and Diffuse Horizontal Irradiance in Abu Dhabi, United Arab Emirates

This chapter presents empirical regression models for estimating the monthly average daily global horizontal irradiance in the capital city of Abu Dhabi, United Arab Emirates (UAE), based on the measurement data of 9 years. It also addresses selected models available in the literature for the estimation of diffuse horizontal irradiance and their correlation to measured data. The effect of atmospheric turbidity, due to humidity, sandstorms, and aerosols, on the solar irradiance is also addressed.

Hassan A. N. Hejase, Ali H. Assi

2. Time Series Prediction of Renewable Energy: What We Can and What We Should Do Next

We summarize our recent developments of time series prediction for renewable energy. Given the past parts of high-dimensional time series for renewable energy outputs, we can predict their multistep future in real time with confidence intervals. We also proposed a way to evaluate the closeness in the high-dimensional space for improving the prediction, and an index showing when the prediction is more likely to fail. In addition, it is straightforward to apply the proposed framework to predict the electricity demands. Therefore, we can generate information necessary to consider efficient unit commitments for a case where more renewable energy resources are installed.

Yoshito Hirata, Kazuyuki Aihara, Hideyuki Suzuki

3. Linear and Nonlinear Modeling for Solar Energy Prediction for Zone, Region and Global Areas

Solar energy data provides information on the sun’s potential at a location during a specific time period. These data are very important for designing and sizing solar energy systems. Due to the high cost and installation difficulties in solar measurement, solar energy data are not always available. Therefore, there is a demand to develop alternative ways of predicting solar energy data. Here, we present linear and nonlinear models for global and diffuse solar radiation. The various models have been tested in different areas. These areas are classified as zone, region and global. The zone and region models were found to be accurate and could be used to predict solar radiation, which is a really interesting achievement. However, the global models had a high percent error. Three statistical values were used to evaluate the developed models, that is, root mean square error, the mean absolute percentage error (MAPE), and mean bias error.The results found the nonlinear models to be more accurate than the linear models—when calculating the solar energy in Malaysia using the nonlinear model, the MAPE was 6.4 %; however, when using the linear models, the MAPE was 7.3 %.

Hudhaifa Mazin, Hussein A. Kazem, Hilal A. Fadhil, S. A. Aljunid, Qutaiba M. Abdulmajeed, Miqdam T. Chaichan

4. Shortest Term Solar Energy Forecast

Due to the strong growth in photovoltaics (PVs), forecasting is gaining importance. At present, most forecasts are based on numerical weather prediction (NWP) models without cloud assimilation. These models lack the ability to forecast the exact position of clouds, which is needed for single-point forecasts. Nowcasting methods, based on current information about cloud positions, provide an opportunity to enhance solar forecasts. Here, we review two of four existing methods—sky camera and satellite image-based methods. Sky cameras are still at an early stage of development and much work is currently being performed. Uncertainties are in the range of 25 % for 30 s data and up to 10 min ahead. Satellite image-based methods have been in use for several years. It is possible to show that a simplified approach using NWP-based cloud vectors leads to similar accuracy as using cloud vectors based on multiple images. Satellite-based methods enhance forecasts by 30–40 % compared to NWP forecasts for forecast horizons of 15 min to 4 h. We also briefly discuss simple post-processing and aggregation methods.

Jan Remund, Daniel Klauser, Stefan C. Müller

R. Integration 2014

Frontmatter

5. Photovoltaic-Integrated Buildings in Florence and Lucca, Italy: Case Studies

When using the integrated approach, solar systems become part of the general building design. In fact, they often become regular building elements. This is due to the fact that integrating solar systems into the building envelope is often a necessity if the systems are to be economically feasible. The solar elements cannot be separate elements that are added after the building, or at least the architectural design of it, is complete. Rather, they must replace other building elements, thereby serving dual functions and reducing total costs.The following case studies depict a coming-of-age of building-integrated photovoltaics (PVs).These PV elements are specially designed for glass shading devices. The PVs will serve as shading elements for areas protected by the new system.The overhanging shading roof provides adequate shade in the summer and allows for useful solar heat gain in the winter. These factors combined should help to keep the building’s running costs to a minimum. In conclusion, the simulations and testing at the design stage show that the overall environmental strategy will reduce the building’s running costs while optimizing visual and thermal comfort.Integrating PVs into the architectural design offers more than cost benefits; it allows the creation of an environmentally friendly energy-efficient building.The systems consist of crystalline PV modules integrated with a semi-transparent module. We also present an example of PV modules in thin films.

Lucia Ceccherini Nelli

6. 50—Energy Efficiency in Retrofitting a European Project for Training on Renewable Energy Solutions (REE_TROFIT)

REE_TROFIT (www.reetrofit.eu) project (founded by the EU Commission in the Intelligent Energy Europe (IEE) program) aims to contribute to solve the shortage of local qualified and accredited retrofitting experts, as foreseen in the Energy Performance of Buildings Directive (EPBD) and its recast—and as indicated by various European countries in an assessment by the European Commission (EC)—for increasing the energy performance of the existing building stock. REE_TROFIT will use the in-house know-how and experiences of participants in carrying out vocational courses on innovative eco-building technologies. REE_TROFIT project defines best practices for institutionalization and implementation of vocational courses on renewable energy (RE) solutions and energy efficiency (EE) in retrofitting, setting up, and implementing a large-scale educational scheme and by fostering exchange of knowledge and best practices among stakeholders.One of the major milestones of REE_TROFIT project is to raise awareness in the regional, national, and European policy-makers for the full implementation of the EPBD and its recasts. Additionally, during its lifespan, it intends to define an exploitation strategy for assuring the sustainability of training beyond the project duration and increases the local retrofitting markets.The REE_TROFIT (newsletters: http://www.reetrofit.eu/content.php?p=nlt) training scheme is founded on an innovative educational model specifically targeted for the building professionals; the adopting REE_TROFIT training model offers the following attractive features:Flexibility: is applicable in contexts with different regulatory frameworks: climate, landscape restrictions, qualification levels of learners, etc.Transferability: is capable of responding to local training needs through methodologies and tools transferable at European level.Innovation: is accessible, affordable, and capable of overcoming the problems encountered during the previous training program experimented in the partnering countries.Modularity: offers different training programs which are composed of independent, closed, domain-specific modules that may be activated according to the different training needs.Brevity: offers training courses with a short duration, which are decomposed in shorter training tracks in order to ease the attendance of the targeted professionals.Plurality: different training methods, tools, and media might be used in the training process in order to consider the needs of the trainees and to guarantee effectiveness.

Lucia Ceccherini Nelli

7. Nuclear Power: A Promising Backup Option to Promote Renewable Penetration in the French Power System?

The general 3X20 European directive proposes renewable penetration goals. In France, 27 % of the electricity is to be produced by renewable resources by 2020, and this share will be continuously growing until 2050. Among these resources, some—such as wind and solar—are not dispatchable, which trigger challenges to maintain the reliability target level of the power system, both in the short and long term. Wind and solar are expected to contribute to about 12 % of the French electricity production by 2020 and according to voluntaristic scenarios they could contribute to over 50 % of the total electricity production by 2050.The increase of the non-dispatchable renewable share in the power system modifies the residual demand (which is equal to the demand minus non-dispatchable renewable production) pattern to a more power ramping and higher variation in amplitudes. To keep the system balanced, backup options are numerous, though scarcely considered exhaustively in power systems modeling. Besides peaking unit production—such as gas turbines—which is usually the preferred option, storage, demand (or supply) curtailment, interconnections, and baseload (nuclear for instance) power modulation should also be considered, particularly in such a context of high non-dispatchable renewable penetration.In the French context of significant production of nuclear power, nuclear modulation is investigated as a feasible opportunity to facilitate renewable energy penetration. Available capacity is assessed based on realistic scenarios and through the use of residual load duration curves. The load modulation impact on the nuclear levelized cost of electricity is estimated, and nuclear backup option is compared to gas on economic and environmental terms. Gas backup is more competitive than nuclear in each of the studied scenarios, but including a carbon tax could change the trends (as low as € 20/tonCO2 in some cases). This advocates for such incentives to avoid the effective greenhouse gas release. Nuclear backup would be all the more competitive than power plants used are amortized.

Camille Cany, Christine Mansilla, Pascal Da Costa, Gilles Mathonnière, Jean-Baptiste Thomas

8. Impact of Integrated Hybrid PV/Wind Generation on Harmonic Power Flow in Medium-Voltage Grid

The renewable energy sources such as wind energy or solar energy play an increasingly significant role as electric supply resources and as an integral part of the electrical grid. The negative influences on the power quality of renewable energies derive mainly from two typical characteristics of renewable sources: their randomly varying availability which can lead to frequency variation, to grid instability, and to a total or partial loss of load power supply and the presence of a static converter as output interface of the generating plants that introduces voltage and current harmonics into the electrical system that negatively affect the system power quality. As the availability of wind varies in a different manner than the sun radiation does, the hybrid wind/photovoltaic (PV) generation may increase the resultant availability and consequently reduce the negative impact on power quality of the voltage and current of the host network. One of the many aspects of power quality is the harmonic content of voltages and currents. Harmonics can be analyzed in either the frequency domain or in the time domain with post-processing using Fourier analysis. This chapter uses the Power Factory software to carry out the analysis of harmonics in the integrated power system in the frequency domain. The analysis comprises harmonic power flow including harmonic power flow according to International Electrotechnical Commission (IEC) 61000-3-6 and flicker analysis according to IEC 61400-21. Harmonic load flow calculates actual harmonic indices related to voltage or current distortion and harmonic losses caused by harmonic sources (usually nonlinear loads such as current converters). In the harmonic power flow calculation, the program carries out a steady-state network analysis at each frequency at which harmonic sources are defined. The flicker analysis performs the calculation of long- and short-term flicker disturbance factors introduced by wind turbine generators.The effect of renewable units on the host grid depends, among other things, on the grid topology. Therefore, this impact on the power quality is studied using a typical medium-voltage (20 kV) distribution network. The test grid is a 20-bus distribution system including 12 transformers, 7 cables, 7 × 20 kV buses, 6 × 0.69 kV buses, 7 × 0.4 kV buses, and 5 general loads. A wide range of simulations have been carried out, and the simulation results have been thoroughly discussed, and very important findings have been concluded. The conclusions would be a useful aid for planning and operation of renewable integration in medium-voltage distribution systems.

Ali Hamzeh, Abbas Sandouk

9. Implementation and Validation of Energy Conversion Efficiency Inverter Models for Small PV Systems in the North of Brazil

The increasing amount of distributed photovoltaic (PV) system components into distribution networks involves the development of accurate simulation models that take into account an increasing number of factors that influence the output power from the distributed generation systems. The modeling of PV system components in power systems and the relative control architecture is an important part of the introduction of a relevant quantity of renewable energy to the future development of the smart grid. Therefore, it is essential to have proper validated models to help operators perform improved studies and be more confident with the results. We present two energy conversion efficiency inverter models developed for two small PV systems using the Jantsch inverter models (Jantsch, Schmidt, Schmid, Results of the concerted actions on power conditioning and control. XI European Photovoltaic Solar Energy Conference, Swiss, 1992) and Sandia inverter model (King, Gonzalez, Galbraith, Boyson,Performance model for grid-connected photovoltaic inverters, Sandia National Laboratory Report, New México, 2007). The component models were implemented in MATLAB software and the simulation results were compared, firstly, with the datasheet values of the inverter Xantrex GT2.8-NA-240/208 UL-05 model and then with the microinverter Enphase® Energy (M215) model. To confirm the strong dependency on ambient conditions and to validate the simulation models, operation data from two small PV systems using the Xantrex and Enphase Energy inverters located in the north of Brazil were used and statistical analysis and comparison of the results was performed.

Luís Monteiro, Igor Finelli, André Quinan, Wilson N. Macêdo, Pedro Torres, João T. Pinho, Eduardo Nohme, Bruno Marciano, Selênio R. Silva

10. Mitigation Measures to Minimize Adverse Impacts of Renewable Energy Integration

The intermittent nature of renewable energy (RE) sources, in particular solar and wind energy, has an impact on system operations including voltage and frequency, harmonics and power quality (PQ) in general, and influences the overall performance of the power network as well as the distribution network (DN). Hence, integration of large-scale RE into the DN is one of the biggest challenges today.Therefore, this study initially investigates the potential impacts, in particular, voltage regulation, reactive power compensation, current and voltage harmonics causes due to large-scale integration of RE into the Berserker Street Feeder, Frenchville substation under Rockhampton distribution network (DN), Central Queensland, Australia. Finally, to reduce the level of impacts observed, energy storage system and STATCOM devices (both optimised) were developed and integrated into the network that ensures a smooth power supply to the customers. Results show that integration of both optimised STATCOM and energy storage enhances the overall power quality of the Rockhampton power network as it enhances voltage regulation and improves power distribution and transformer utilisation and reduces total harmonic distortion of the power network.

GM Shafiullah, Amanullah MT Oo, Alex Stojcevski

Policy 2014

Frontmatter

11. Smart Grid and Intelligent Office Buildings: Virtual Power Plants—The Basis for the Optimal Use of Renewable Energy Sources

Electricity energy generation and its supply through electricity networks are mainly organized in a top-down, centralized manner. Energy consumption can be predicted quite accurately at a high level, and this forms the basis for prescheduling the production by large power plants. Only few actors are involved in the generation, trade, and transportation of electricity, but this is changing rapidly. The increasing share of decentralized renewable energy conversion in combination with the new types of consumers will drastically alter the operation of electricity systems. Office buildings will become a potential source of energy flexibility which can be offered to the grid as a virtual power plant (VPP). In order to minimize uncertainty in the balance between energy supply and demand, it is necessary to develop realistic user behavior, installations behavior, and smart grid interaction. Monitoring the needs and preferences of users is necessary to predict future states of the demand for the smart energy systems (SES; e.g., based on weather forecasts and user behavior). The consumer of energy can become a producer due to the decentralized renewable energy conversion. To control this dynamic and interactive process automated prosumer support is needed to optimize interaction between offices and the smart grid. The chapter describes the first steps towards such systems.

Kennedy Aduda, Wim Zeiler, Gert Boxem

12. Survey of Renewable Electricity Tariffs in Iran

The protective tariff policy, investment and guaranteed purchase of electricity through renewable energy sources are some of the most important tools in Iran for developing electricity production. Here, we measure and compare the marginal cost of electricity production through renewable electricity in Iran, and survey the renewable electricity tariff policy in Iran. To have balanced development in renewable energy resources, researchers have calculated and recommended different tariffs for different technologies, i.e., solar thermal, wind and small hydropower. All our research measurements were performed using COMFAR software.

A. Kaabi Nejadian, Faramarz Separi, Mehdi Barimani Varandi, Mohamad reza Khaje Samakoosh

13. Transitions to a Post-carbon Society: Scenarios for Western Australia

Pathways towards a post-carbon society are being explored across all levels of government, within the scientific community and society in general. This chapter presents scenarios for cities and regions in Australia after the Age of Oil, particularly the energy-intensive state of Western Australia (WA). It argues that a post-carbon WA would ideally use technological and wider social choices to reduce carbon emissions close to zero. It focuses on policy requirements, institutional and governance arrangements and socio-technical systems to provide an industry-focussed renewable energy development plan that will help to balance ongoing and past emissions and lead to a low-carbon society.

Martin Anda, Martin Brueckner, Yvonne Haigh

14. Future Indian Programme in Renewable Energy

India is the world’s fourth largest economy as well as the fourth largest energy consumer, importing 80 % of its oil, 18 % of its gas and now even 23 % of its coal. As the Indian economy continues to grow, so will its energy consumption. India’s total energy demand, which was nearly 700 Mtoe in 2010, is expected to cross 1500 Mtoe by 2030. This is likely to increase India’s dependence on energy imports from 30 % in 2010 to an unsustainable figure of over 50 % by 2030.

Pradeep Chaturvedi

15. Solar and Wind Energy–Present and Future Energy Prospects in the Middle East and North Africa

The countries of the Middle East possess an enormous potential for the development of renewable energy resources. This region of the globe captures a plentiful amount of direct sunshine, which in turn creates both wind and solar energy. Tapping into this potential will dramatically reduce fossil fuel dependency, and thus create a cleaner environment and new platforms of socio-economic growth. Although previous attempts to evaluate this renewable energy potential have been small in scale and scattered, they have demonstrated an encouraging outlook for the entire region and lead to the contention that there is a sufficient amount of renewable energy to meet all of these countries’ energy needs. This chapter examines future renewable energy exploitation goals for Middle Eastern and North African (MENA) countries and explains how solar and wind resource assessment and site selection models, along with strong governmental involvement, can create success or failure in emerging renewable markets.

Abdul Salam Darwish, Sabry Shaaban

16. The Pugwash UK 2050 High Renewables Pathway

Making use of the UK Department of Energy and Climate Change (DECC) 2050 Pathways Calculator, in 2013 the British Pugwash group produced a report with three basic UK scenarios: High Nuclear, High Renewables and an Intermediate pathway. This chapter summarises the conclusions from the high renewables scenario, in which around 80 % of UK energy will be supplied from renewables by 2050, with full grid balancing, at a slightly lower cost and with lower emissions than for the Pugwash High Nuclear and Intermediate scenarios. Export of surplus electricity could earn around £ 15 billion p.a., or if a ‘power to gas’ conversion route was adopted an extension to near 100 % renewables was considered possible.

David Elliott, David Finney

17. The Role of Renewable Energy Sources in Solving Energy and Water Problems of Mediterranean Sea Islands

According to the Amsterdam Treaty, declaration No. 30, “…insular regions suffer from structural handicaps linked to their island status, the permanence of which impairs their economic and social development”. Considering the above, the present work aims to present different aspects of the current energy and water situation in Mediterranean Sea islands, using as case studies two representative French and Greek island regions. To this end, common problems as well as differences that call upon the elaboration of more case-specific solutions are identified. Accordingly, emphasis is given on future prospects for renewable energy sources and the role of integrated, hybrid solutions including energy storage and desalination aspects.

D. Zafirakis, Gilles Notton, Chr. Darras, M. L. Nivet, E. Kondili, J. K. Kaldellis

18. Bias in Energy Statistics—A Review of Misinformation About Sustainable Energy

Some previous reviews of predictions of energy supply have shown how official statistics have tended to underplay the contribution of renewable energy to future needs. This chapter is based on a range of examples of bias within information regarding energy use, fossil fuel reserves and comparisons of energy sources. Some of these relate to the presentation of statistics in a way that misinforms, often through visual information in graphs and charts. Other biases relate to future predictions and lack of transparency regarding assumptions made. However, as shown in this chapter, even short-term predictions often turn out to be incorrect, and there is evidence that this is often due to biased use or interpretation of statistics. Some of the biases relate to prices, others to growth rates and implied limits to diffusion of sustainable energy technologies. In some cases it is possible to show in retrospect how statements promoting conventional energy over renewable sources have not in fact proved to be correct. Of course, some examples of bias in promotion of renewable energy sources also exist.This chapter reviews examples of how energy statistics have been used to give bias (whether accidentally or deliberate) to conventional energy technologies over sustainable ones and identifies methods to assist in a critical evaluation of information sources.

Arthur A. Williams

19. Equipment for Technical Education in the Field of Energy and Environment

GUNT Hamburg is a leading manufacturer of technical equipment for engineering education. In order to promote possible technical solutions for global challenges from climate change and progressive resource depletion, the 2E division of GUNT concentrates on didactic equipment for the field of energy and environment. The close interconnection between the fields of renewable energy, energy efficiency, and environmental technologies is a fundamental aspect of the 2E concept as indicated in the scheme below. Among the environmental technologies, the water treatment field is of special importance since it is crucial for the conservation of the human habitat. The objective of 2E is to integrate the principles of sustainability into the field of technical training. A carefully thought-out spectrum of teaching and research equipment covering high-didactic demands for the energy and environment sector has been developed.This contribution gives an overview of the structure of the 2E curriculum, summarizes the basic didactical and technical concepts, and gives short examples of selected training units from different subject areas. The didactical concept of the development of a 2E technical training unit emphasizes the key training aspects from practice and theory with a special focus on sustainable engineering. The scope of typical experiments ranges from the commissioning and operation of important system components to the calculation and optimization of the essential key performance indicators. The energy efficiency of a process or a system is among the most important and meaningful key figures. Thus enabling the students to perform appropriate measurements for a step-by-step analysis of parameters affecting the energy efficiency is a predominant objective when preparing the instructional material.As a typical example of this concept, our experiments in the field of photovoltaic (PV) energy conversion are presented in detail. The ET 250 trainer enables measurements on typical PV modules by means of a basic electrical circuit. Current, voltage, temperature, and irradiation intensity can be measured using a preconfigured measurement unit. Knowledge gained from these experiments serves as a fundament to understand details such as the function of maximum power point tracking systems which are typical in modern PV installations.In the next step of our PV course, methods and practical components to compensate temporal fluctuations in the energy demand and offer are investigated. To cover the associated learning objectives, we developed the ET 255 trainer. The ET 255 provides a built-in PV simulator besides PC-based measurement and analysis software. Thus the effect of varying irradiation on the behavior of systems components such as grid-connected inverters or stand-alone charge regulators can be investigated during a laboratory course without being hampered by actual weather conditions.At the end of this contribution, some remarks on new 2E developments are given. In the biomass energy field, the laboratory biogas plant CE 642 was successfully commissioned for two customers. In the field of energy from sea waves, our ET 270 was completed which provides a laboratory system based on the principle of an oscillating water column (OWC).

Kristian Boedecker

20. The Development of Renewable Energy in Russia

The beginning of the twenty-first century has been marked by quick growth of renewable energy sources market in the world, especially, in Europe. In Russia this market is extremely small; big energy projects with the application of renewable energy sources are absent. The present chapter provides the data on the potential of renewables in Russia; the analysis of the factors affecting the application of renewable energy sources.In 2012 the Russian government took a number of steps for the development of renewable energy, first of all, photovoltaics (PV), wind energy, and small hydropower. The chapter analyzes these measures and data on the quantity of installations of PV, wind energy, and small hydroelectric power stations. The information on a number of projects of renewable energy sources use in houses, urban facilities is provided. The additional initiatives promoting the use of renewable energy in Russia are offered.

Sergey Karabanov, Pavel Bezrukikh, Evgeny Slivkin, Dmitry Suvorov

21. Future Energy Without Oil and Fossil Fuel

Problems caused by global warming due to carbon dioxide released from combusting fossil fuels are now generally accepted. Fossil fuels are a finite resource that will start to run out during this century, we have, for example, around 40 years of oil supply at current usage rates. It is shown in the chapter that world can run successfully without fossil fuel sources using the current technology.

John Lowry

22. Problematic Integration of Fatal Renewable Energy Systems in Island Grids

The islands are often not or partially connected to continental networks and manage their own energy supplies in reaching alone the supply/demand balance and in assuring the quality of the delivered electricity. The low consumption and the lack of interconnections induce energy costs higher than in other regions. The islands are good locations for using new technologies of energy production and storage. For increasing their security, they often prefer to use indigenous sources as renewable ones but the intermittence and stochastic character of these “fatal” energy sources make them more difficult to control and manage and more again in small island networks. Most islands have good renewable energy (RE) resources which are underused in comparison with their real potential. A particular attention is paid to the problem induced by the renewable energy sources (RES) utilization in an island electrical grid on the electrical management.

Gilles Notton

23. Renewable Energy Development in Africa: Issues, Challenges and Prospects

The solar radiation climatology of Africa is such that more than half of the continent has solar radiation intensities of more than 7000 kWh/m2/day. The hydropower resource of the continent is huge especially in the central and eastern parts of the continent with the Grand Inga of Democratic Republic of Congo alone of having a potential of about 50,000 MW. There is a significant geothermal potential along the East African Rift Valley spanning Djibouti, Ethiopia, Kenya and Tanzania. High-wind potentials exist along the coastal and mountainous parts of the continent. Biomass in the form of fuelwood is the dominant fuel in the household sector in the whole continent and most especially in the tropical zones. Biodiesel from Jatropha is gaining more recognition in many African nations.The optimal utilization of the renewable energy resources of Africa will call for a continent-wide increase in energy access in order to uplift the continent’s socioeconomy. This will in turn call for the practical elimination of the challenges bedevilling the sector. This can be done through the adoption of strong political will by African national governments to drive renewable energy development. There is also the need for sound policies and plans as well as institutional and legal frameworks in addition to the enthronement of pragmatic capacity building in renewable energy technologies.

Abubakar S. Sambo

24. Perspectives for Renewable Energy in Europe

Challenges on the Way Towards a Stable and Reliable Policy Framework Until and Beyond 2020

The Renewable Energies Directive (RED) of the European Union (EU), enacted in 2009, which established a binding target of a 20 % share of renewables for the EU and differentiated binding targets for each Member State by 2020, is facing significant implementation challenges. It appears that, due in part to a range of policy adaptations in the interim, the EU and many of its Member States will fail to achieve the targets. A European Commission-supported consortium of scientists and European and national renewable energy associations tasked with tracking progress towards the established targets has developed policy recommendations that would enable the EU and all Member States to achieve or even overshoot their 2020 targets. In order to get back on track, and succeed in 2020 and beyond, the consortium has developed an overarching six-point recommendation, highlighting the need for policy stability, and a focus on the key sectors of transportation and heating and cooling, among other pressing concerns.

Rainer Hinrichs-Rahlwes

25. Examination of Energy Usage of Electrical House Applications in Terms of Energy Efficiency

This study evaluates the energy utilization efficiency of the Turkish residential-commercial sector (TRCS) and electrical house applications in 2011 by using energy and exergy analyses. Of the total energy input, 28.15 % was produced in 2011, while the rest was obtained by imports. In 2011, 34.47 % of Turkey’s total end-use energy was consumed by the residential-commercial sector. Annual fuel consumptions in space heating, water heating, and cooking activities as well as electrical energy used by appliances are determined for the period 2000–2011. It is clear from this figure that the energy efficiencies in the years studied range from 57.05 to 65.53 %, while the exergy efficiencies vary from 8.02 to 10.07 %. In addition, researches on EHA efficiency indicated an efficiency of 81 % for the first law of thermodynamics and 22 % for the second law of thermodynamics.

Zafer Utlu, Hasan Saygin

26. The Role of Decentralized Energy for Widening Rural Energy Access in Developing Countries

Decentralized energy (DE) is an inevitable part of universal energy access, particularly in developing countries. It is not just an absolute solution for widening energy in off-grid rural areas but it is important for remote and deprived areas connected to the centralized electricity network those suffer from inefficient energy due to the high grid network losses. Moreover, it covers waste and resource management, carbon and energy efficiency, and socioeconomic sustainability which can integrate sustainable consumption and production into the business models. Modern bioenergy in the form of biomass, ethanol, biodiesel, or biogas has the highest potential mainly because the technology is mature and is a relatively easy competitive substitute for fossil fuels. Despite many advantages and benefits of DE in rural areas, there are important barriers which prevent the increase of access to modern energy services; all of them are associated with social, technical, managerial, and institutional issues. This chapter states a record of DE statement in the world by emphasis on the present barriers. Therefore, to tackle these barriers, a holistic approach which covers the whole dimensions of a DE model is needed. In this regard, this interdisciplinary model should be flexible and should consider the benefits of all stakeholders, including national and international authorities, private sectors, developers, investors, small and medium enterprises, and local communities.

S Ghazi

27. Renewables Are to Save Fuel

All countries, especially the biggest fuel consumers, want to save fuel. Fuel efficiency improvements have had significant success but renewables are also an option to save fuel and they are making great strides: operating wind power capacity overtook nuclear power in the middle of 2014.China, the USA and India are leading the way, not only in the amount of coal they are burning (nearly three quarters of the total) but also in installing wind power (over half the total) and other renewables to save coal.If additional capacity were needed to stop the UK’s lights going out, cheap plant would be needed to cover just the peaks, not a capital intensive plant like wind or solar or nuclear. In fact, no new capacity can be justified because there is plenty of spare including plant that has been mothballed. Subsidies for new plant such as wind and solar and possibly nuclear are justified by their fuel saving.A 20 % minority of countries, including all the European Union (EU) and some other Organisation for Economic Co-operation and Development (OECD) countries, are prepared to limit their emissions of greenhouse gases to tackle the dangers of global warming as set out by the Intergovernmental Panel on Climate Change (IPCC) but most countries are not. They regard the dangers of global warming as of secondary importance to their own prosperity.One of the most feared dangers, as promulgated by the media, is that the ice caps will melt and we shall all be inundated. They are excited to see the sea ice melting in the Summer but they forget that it refreezes in the Winter and in any case in accordance with Archimedes’ principle, floating ice does not change the water level when it melts. The IPCC predict sea level rises of around 0.4 m over the next 100 years, which seem very moderate and unfrightening for governments when compared with the tidal ranges of many metres that they experience around the world every 12 h.So carbon abatement to tackle global warming does not provide a strong case for installing renewables but the urgent need to save costly fuel imports strongly supports the huge expansion of renewables that we see today.

Donald Swift-Hook

28. Renewable Energy Against an Oil and Gas Background: Challenges, Drivers, and Case Studies

Renewable energy (RE) development has always been a difficult proposition in oil- and gas-rich countries. Since it has not been the main economic driver for these countries, inadequate emphasis has been placed in this area. But most countries have realized that fossil fuel reserves are exhaustible and that in order to ensure future sustainable development, more importance must be attached to developing indigenous renewable sources of energy.In an oil and gas backdrop, huge challenges are being faced on an ongoing basis. Therefore, much more effort has to be placed on education and sensitization programs. The average person is more concerned with his present economic status and therefore pays less attention to the future benefits that can be derived from using RE technologies.Ensuring sustainable socioeconomic development is challenging in societies where substantial subsidies continue to be placed on fossil fuel electricity generation as opposed to green technologies. But governments are fast realizing that their economies will not be sustained when oil and gas reserves are reducing. Emphasis is being placed on international cooperation to intensify RE project development.Many oil- and gas-rich countries are now moving toward a “Green Energy Revolution.” Some classic examples include Abu Dhabi’s carbon-neutral Masdar City, Qatar’s Solar Schools’ project, and Saudi Arabia’s solar heating plant in Riyadh. The Caribbean Community is also moving toward a 50 % RE in its energy mix. Even Trinidad and Tobago, a net exporter of natural gas, is forging ahead with its plans to develop RE technologies, in particular solar and wind energy.The goal is therefore to improve overall economic advantage and accelerate the transition from fossil fuels to sustainable technologies for future environmental preservation.

Indra Haraksingh

29. Development of an Optimisation Model for the Evaluation of Alternative Energy and Fuel Supply Chains

Energy and fuel supply chains (SCs) and their optimisation not only in techno-economic terms but also accounting for environmental and social implications imbedded in each supply chain option render a very interesting research topic, especially in areas with limited energy resources and areas where strict air quality limitations apply. Considering that the aim of this chapter is to present a developed methodology and the assorted modelling tool for the optimisation of alternative SCs considering sustainability dimensions in the design and operation on top of technical limitations. To evidence that a small-scale power planning problem will be assessed, that is, an isolated consumer, Milos island in Greece, for a specific timeframe, proofing the implementation possibilities and flexibility of the model to change over different optimisation targets and limitations applicable in each specific energy decision strategy.

Christiana Papapostolou, Emilia M. Kondili, John K. Kaldellis

PV 2014

Frontmatter

30. An Innovative Dynamic Model for the Performance Analysis of a Concentrating Photovoltaic/Thermal (CPV/T) Solar Collector

A zero-dimensional dynamic model has been developed in order to simulate both electrical and thermal performance of a real concentrating photovoltaic/thermal (CPV/T) solar collector, namely the Absolicon X10 PVT prototype. This model calculates the instantaneous average temperatures of the main components of the system by handling a system of nonlinear differential equations, obtained via the application of the first law of thermodynamics, which is introduced in a MATLAB routine. Input parameters of the model include all the values characterising both the weather conditions and the main physical, geometrical and dimensional properties of the collector. Model validation was performed, firstly, via a steady-state simulation according to the EN 12975 standard in order to compare the thermal efficiency provided by the model with the solar collector efficiency curve. The difference among these values was constantly limited around 1 %. As a second step, the model was verified in a daily transient simulation by using the experimental data collected during the tests carried out at the ENEA Portici Research Centre, where an Absolicon X10 PVT collector is currently in operation. The measured and simulated thermal and electric yields were compared, thus achieving the confirmation that model can provide estimations consistent with the expected results.

Giuseppe Fiorenza, Giovanni Luigi Paparo, Felice Apicella, Nicola Bianco, Giorgio Graditi

31. A Key Player Towards a Sustainable Energy Mix

The energetic issues are on the top of the political agenda in many countries for environmental reasons, for its driving role in all the economic sectors, and for the energetic independence concerns. These problems are stressed by the increasing weight of renewable intermittent power sources in the global mix. In particular, due to its high potential and the strong national policy support it beneficiated, solar photovoltaic energy is now a key player in the world energy mutation and the way it is integrated into the global mix should be carefully performed.To deeply understand the way the solar energy can penetrate and transform the forthcoming energy framework, we adopted a three-level strategy to provide some answers to the following questions: (i) How can we situate the photovoltaic power role in future energy mixes? (ii) Due to its main drawback, intermittency, could we provide an optimal design of a system combining storage devices? (iii) What is the efficiency of the incentive policies that are or have been implemented to accelerate its deployment?That is why, in a first part, the peculiar position of the solar photovoltaic energy in the energy mix is analyzed. After recalling the general issues of future global energetic mixes, we propose a brief description of the different photovoltaic technologies and their promising evolutions in terms of technical improvements and cost reductions. Then, we describe the fast growing photovoltaic market and its consequences both on the electricity mix and the industry sector.In the second part, we investigate the problematic of integrating such intermittent energy in the electricity mix, by developing a multi-criteria optimization methodology that simulates a system composed of photovoltaic panels and storage devices. Applications on a real case in the Cirque de Mafate (L’île de la Réunion, France) are provided to illustrate the interest of our method.Finally, we question the efficiency of different public supports to the photovoltaic technologies in the most relevant countries. We focus on correlating the installed power capacity with the spent public money and the electricity prices.In these works, we put into relief the necessity to consider energy issues through the prism of technical basis. Indeed, solutions that cannot be efficient should not be implemented in the system. However, a solely technical treatment of energy challenges is obviously insufficient, since energy is core point for the economy, for the citizen and so for the politician. Such a combined approach needs to remain anchored on concrete data close to the reality of the technical devices and keeping in mind the financial feasibility of the proposed solutions, when designing a new energy landscape and thus a new societal model.

Sophie Avril, Christine Mansilla, Pascal da Costa, Jean-Claude Bocquet

32. On-Grid Photovoltaic Water Pumping Systems for Agricultural Purposes: Comparison of the Potential Benefits Under Three Incentive Schemes

Electricity self-consumption represents a key issue to shorten the photovoltaic (PV) systems’ payback period (PBP). To achieve high self-consumption rates, load control or storage systems are commonly used. Water pumping for irrigation is an interesting application that can largely increase the share of PV electricity self-consumption. The main objective of this chapter is to analyze the potential benefits of on-grid photovoltaic water pumping (PVWP) systems compared to those of conventional PV installations without water pumping. Three countries with different incentive schemes for PV installations have been studied: China with feed-in tariff, Italy with investment subsidies and net metering, and Sweden with tax reduction, investment subsidies, and green certificates. Wheat, maize, and potatoes have been chosen as reference crops to investigate the feasibility of PVWP systems as they are some of the most irrigated crops in China, Italy, and Sweden, respectively. The results show that the grid-connected PVWP systems lead to a lower PBP, between 1 and 2 years, compared to PV installations without pumping. Owing to the low cost of electricity and feed-in tariffs, China presented the longest PBP. The PVWP systems in Italy have the shortest PBP mostly due to the more favorable incentive scheme compared to China and Sweden. The PBP of PVWP systems in Sweden is extremely affected by the uncertainty to benefit of the investment subsidies.

Pietro Elia Campana, Alexander Olsson, Chi Zhang, Sara Berretta, Hailong Li, Jinyue Yan

33. Enhancement in Conversion Efficiency by Surface Modification of Photoanode for Natural Dye-Sensitized Solar Cell

To avoid the negative effects of current energy systems on environmental pollution and global warming, research have been focused on renewable energy sources for the future. Among the renewable energy sources, solar cells have attracted a great interest as a solution to this problem. As a result, the conversion of solar energy into different forms has been the core of research for the past few years. The conventional solid state silicon-based solar cells, though highly efficient, are yet to become popular for mass applications as they are highly expensive. Therefore, developing low-cost devices for harvesting solar energy is most desirable. Dye-sensitized solar cells (DSSCs) have been considered as one of the most promising photovoltaic technologies because they are generally made from inexpensive components and have a simple designed structure. Numerous metal complexes and organic dyes have been utilized as sensitizers so far; the highest efficiency of DSSCs sensitized by ruthenium complex and osmium complex compounds absorbed on nanocrystalline TiO2 reached 11–12 %. The major drawbacks of ruthenium are its rarity, high cost and the complicated synthesis of ruthenium complexes. The natural dyes anthocyanin/betacyanin obtained from fruits, flowers and leaves can be easily extracted by simple procedures and their cost-effectiveness, non-toxicity and complete biodegradation; therefore, the use of natural dyes in DSSCs has been a major focus of research. Among various wide-bandgap semiconducting oxides, nanocrystalline TiO2 (ns-TiO2) is the most suitable material for the photoanode of DSSC but TiO2 can utilize only 6 % of the total solar irradiation in photocatalysis. Doping with metal oxides has been considered a promising way for improving the photocatalytic efficiency of ns-TiO2. The increased photoactivity of CuO–TiO2 may be attributed to the improvement of the light absorption properties and the slowdown of the recombination between the photoexcited electrons and holes during the photoreaction. We have studied the performance of DSSCs sensitized with anthocyanin pigments extracted from black grapes. The solar cell was assembled using CuO–TiO2 thin film on ITO-coated glass with anthocyanin dye, liquid electrolyte system with LiI: I2 as a redox couple. The obtained solar conversion efficiency was 4.8 % using an irradiation of 100 mW/cm2.

Mridula Tripathi, Priyanka Chawla

34. Study of Trap Density Effect on Current Voltage Characteristics of SubPc and C60 Organic Semiconductors for Photovoltaic Application

Our work is focussed on the effect of trap density on the current density−voltage characterization of organic active layers chloro(subphthalocyaninato)boron (SubPc) or fullerene (C60), in which SubPc and C60 were applied as the donor and acceptor materials, respectively. The results show that at high voltage ( > 0.17 V) the trap density affected J−V dramatically. Our results are in good agreement with those by Holmes et al. (Adv Funct Mater 22:617–624, 2012)

Mebarka Daoudi, Nesrine Mendil, Zakarya Berkai, Abderrahmane Belghachi

35. PV Cell and Module Degradation, Detection and Diagnostics

With crystalline silicon photovoltaic (PV) modules being in the market for over three decades, investigation into usual causes and extent of module degradation after prolonged exposure in field conditions is now possible. Degradation phenomena vary significantly between cells, modules and installations, giving rise to different power degradation rates reported. The main defects observed in the field-aged PV modules include EVA browning, degradation of the antireflective coating, delamination between the glass-encapsulant and the cell-encapsulant interfaces, humidity ingress, corrosion of busbars and contacts, shunt paths, cracks/micro-cracks in the cell, damage of the glass and the back sealing and bypass diode failure. This study presents severe degradation effects observed in PV modules operating outdoors for over 20 years. In many of the cases investigated, different defects were found to coexist within the same cell or module, leading to more severe effects of optical/physical, thermal and electrical degradation phenomena, significantly reducing the PV power output. Other modules that exhibited extensive optical/physical degradation showed milder degradation in performance. Detection of module degradation was carried out in this study first through visual inspection and I-V curve analysis. Further, nondestructive diagnostic techniques were used such as infrared thermography for the identification of hot spots and these were seen to be mainly linked to resistive busbars and contacts and electroluminescence imaging for the identification of shunts and other defects. The detection, diagnosis and monitoring of such defects is of great importance for a deeper understanding of the complex ageing mechanisms that take place after prolonged PV exposure in field conditions, and the identification of underlying causes, assisting the early identification of defects and the extension of the energy life of PV systems.

Eleni Kaplani

36. Practical Identification of the Photovoltaic Module Parameters

As the amount of the energy radiated to the earth by the sun exceeds the annual energy requirement of the world population, making use of this inexhaustible energy source for our everyday electricity requirement is the great challenge of the present and the future. The generation of electric energy from the sun via photovoltaic (PV) generation is one of the most appropriate candidates in this manner. For PV applications, the accurate simulation of the PV module performance, which is an important point in the accurate design of these systems, depends mainly on the electrical parameters of the PV module (series resistance, reverse saturation current, short-circuit current temperature coefficient, and ideality factor). Also, the knowing of the effect of the ageing on the PV module performance after a certain period requires an accurate identification of these parameters. This chapter presents accurate methods to get the PV module electrical parameters depending on practical measurements for its current–voltage (I–V) characteristics under different operating conditions (different solar radiation intensity and module temperature) using an accurate data acquisition system. Then, the chapter compares the theoretical performance of the PV module using the identified parameters with the measured curves to arrive at the accurate determination of the PV module parameters.

E. T. El Shenawy, O. N. A. Esmail, Adel A. Elbaset, Hisham F. A. Hamed

37. Experimental Results of Computer Monitoring of PV-based Energy System

Renewable energy emerges as a cleaner and sustainable alternative for generating electricity. This chapter proposes development of an experimental monitor and control scheme for stand-alone photovoltaic (PV) systems. The proposed system comprises a set of PV panels, a number of storage batteries, a charge controller, DC/AC inverter to feed electrical load, and a backup generator. A monitoring and control unit was designed and implemented to operate the system using a specially developed computer program based on LabVIEW software. The main task of the proposed scheme is to manage and protect the batteries from over discharging that may destroy batteries. To do so, the developed control scheme disconnects the load from PV and battery system, using switching control, when state of charge (SOC) of batteries falls to 35 % or less, and switching on a petrol engine/AC generator unit. The control panel that employs a USB data acquisition card (DAQ) connected to the PC was built, installed, operated, and calibrated with the system. The cost of generated electricity was not taken into consideration as the system is built on experimental scale. Results of the study indicate a significant decrease in the battery useful capacity with higher discharged current (load requirements). It is also possible to use the I-V curves to identify the batteries SOC, particularly at low SOCs to protect the batteries when SOCs are lower than 35 %. A significant output is the possibility for continuous, through monitoring of the system performance setting an accurate archive of generated power, battery performance, effect of electrical load, and control of the backup generator to ensure the continuity of electrical load supply.

Kamal Abed, Ahmed Bahgat, Mervat Badr, Mahmoud El-Bayoumi, Ayat. Ragheb

38. New Renewable Energy Promotion Approach for Rural Electrification in Cameroon

Rural electrification in Cameroon was in the past planned by the Government through the Ministry of Water and Energy. This issue was addressed through grid extension using three-phase medium voltage, a single wire earth return solution, or off-grid thermal plants for remote localities. Because the architecture of the electricity grid is radial isolated, this leads to many technical problems and a limited rate of electrification, especially in remote areas. The country learned a lot from failures and realized that the rural electrification solutions were yet to come. In order to really tackle the rural electrification problem, a dedicated Agency for Rural Electrification was created, bringing new approaches.Given the cost of fossil fuel in the country, thermal plants are very expensive from the operating and maintenance point of view, leading to high cost of electricity, especially in places with low income and poor communication and infrastructures. Grid extension is constructed with specially treated wooden poles with limited life expectancy. It hence requires power lines with frequent maintenance under the threat of bushfire. Furthermore, there is high voltage drop due to very long distances and heavy lightning problems during the rainy season. On the other hand, Cameroon has huge hydro, biomass, and solar potential, allowing the country to envisage the development of these sources of renewable energy in most remote areas.In order to address the issue, the Rural Electrification Agency has launched a new approach since 2009 based on the promotion of renewable energy to electrify the rural areas. This is based on the recommendation of the World Bank which has provided initial funds to subsidy the initial investment costs. Objective criteria have been set up to ensure promotion of solar hybrid energy and micro hydro in remote areas, including capacity building of all stakeholders. The study is based on the institutional reforms of the sector, the previous rural electrification programs, and the ongoing organization and projects in the framework of renewable energy promotion.

Joseph Kenfack, Olivier Videme Bossou, Joseph Voufo, Samuel Djom, Nicolas Crettenand

39. Photovoltaics and the Energy System: Adaptation of Layout and Load

In the foreseeable future sustainable electrical energy systems should be capable of handling 100 % renewable energy across electrical distribution grids. Due to the recent drop in the price of photovoltaic (PV) systems, PVs will play a major role in the global renewable energy portfolio. The technical implications of this energy transition from fossil fuels to renewables are manifold and will affect all sectors of electricity supply (generation, transmission, distribution, operation management), and consequently lead to a new system design. The major challenge facing the effective integration of PVs into the grid is variable generation as a result of positioning to the sun, weather conditions and load level. Here, we address generation issues by suggesting that PV power plants be adapted to load requirements to achieve peak power output during periods of high demand using azimuth and tilt angle modifications, thermal conditioning of PV modules, smart site selection and a combination of complementary energy sources. Moreover, we also address several possibilities regarding load management such as load shifting, inducements, load adaptation and appropriate market design. A brand new, non-technical method is to shift the holiday season; this has the potential to achieve the most effective results for a small cost within the shortest time period.

Stefan Krauter

40. Evaluation of the Characteristics of the PV Module Considering Effects of Real Climatic Conditions

The photovoltaic (PV) model is used in a simulation study to validate the system design of a PV system. This work presents the modeling and the simulation of the PV module using the Matlab environment taking into consideration the measurements carried out under real working conditions in Tetouan (northern Morocco). The model is developed based on the mathematical model of the PV module. A particular PV module is selected for the analysis of the developed model. The three-dimensional profile of solar radiation used in this work is presented. The output current and power characteristic curves, which highly depend on some climatic factors such as solar radiation and temperature, are obtained by simulation for the selected module and discussed. The instantaneous power production characteristics of the 12 months of the year are presented and interpreted.

H. Yatimi, E. Aroudam

41. Temperature Dependence of Carrier Mobility in SubPc and C60 Organic Semiconductors for Photovoltaic Applications

Carrier mobility is an important parameter in determining device performance in optoelectronics. Here, we study the charge carrier mobility of C60 and SubPc neat layers for different temperatures calculated in darkness. The results show that temperature affects the disorder energy (σ) of organic semiconductors; when the temperature is < 289 K, this parameter is around 0.03 eV and it is double when the temperature is > 289 K. In these conditions, the mobility of electrons and holes are around 0.14 and 10−7 Cm2/Vs, respectively. Our results are in good agreement with experimental data reported by Pandey et al., Adv Funct Mater 22:617–624. 2012)

Nesrine Mendil, Mebarka Daoudi, Zakarya Berkai, Abderrahmane Belghachi

42. An Assessment on the Impact of the Solar Spectrum on Different PV Materials in Sunny Sites by Using Different Time Scales

This chapter is addressed at analyzing how the performance of some photovoltaic (PV) materials is influenced by the solar spectrum distribution according to the months of the year. Spectral responses of four different PV technologies—amorphous silicon, cadmium telluride, copper indium diselenide, and monocrystalline silicon—have been used to develop this study. Spectra and incident global irradiance were scanned at 5-min intervals in two inland sunny sites located in Spain during a 12-month experimental period. Regarding the results, it was concluded that amorphous silicon and cadmium telluride PV modules undergo the highest differences of monthly spectral gains over the year. Much slighter seasonal variations of these gains are perceptible in the other two considered PV technologies. Specifically in the two locations analyzed, spectral gains range from approximately − 12 % (January) to around 2 % (June) for the amorphous silicon (a-Si) PV module while such gains range from values close to 0 % (April to September, inclusive) to values slightly lower than − 2 % (December) for the copper indium diselenide (CIS) and monocrystalline silicon (m-Si) PV module. Prevailing “red-rich” and “blue-rich” spectra in winter and summer, respectively, could explain these results.

G. Nofuentes, M. Alonso-Abella, M. Torres-Ramírez, F. Chenlo

43. Optimizing Photovoltaic Water Pumping Systems for Developing Countries Through the Addition of a Novel Induced-flow Subsystem

Water supply and sanitation in developing countries represents an issue responsible for millions of deaths each year. Despite the recent advances in photovoltaic (PV) water pumping systems, high set-up costs, lack of local expertise and reliability issues have prevented many people from benefiting from this potentially life-saving technology. This is particularly unfortunate given that PV pumps have been shown to be cheaper than conventional diesel pumps over the product lifetime. This research has been undertaken to reduce these high implementation costs and other stability issues by developing the theory towards a self-regulating, sustainable pumping system based on the use of an additional flow subsystem modelled on a DC boost-converter circuit from power electronics.Initial experimental results demonstrate a good proof of concept. Using an induced-flow test rig, based on the use of a high-speed ON/OFF valve, oscillations in the flow through the system have been observed as having waveforms which are in line with those anticipated from theory. Additionally, a boost in output pressure was seen as the active time (or duty cycle) of the valve was increased to achieve flow to greater pumping heads and increased output flow with improved efficiency. In conclusion, these results reveal a potential to develop a one-size-fits-all, sustainable PV pumping system based on a centrifugal pump. Ultimately, this could offer a cheaper and more reliable supply of a resource, which is vital to any developing community: clean water.

N. Davies, T. D. Short, A. Hassan

44. Power Converters and Control of Grid-Connected Photovoltaic Systems

Photovoltaic (PV) installations have had an exponential growth mainly due to the governments and utility companies that support programs that focus on grid-connected PV systems (Haeberlin H (2001) Evolution of inverters for grid-connected PV systems from 1989 to 2000, in Proceedings of the 17th European Photovoltaic Solar Energy Conference, pp. 426–430. Munich). In an effort to use solar energy effectively, a great deal of research has been done on the grid-connected PV generation systems. Out of the total PV power installed in the Europe, 98.7 % are grid-connected PV systems and 1.3 % are off-grid PV systems. Therefore, in grid-connected PV systems, the inverter which converts the output direct current (DC) of the solar modules to alternating current (AC) is receiving increased interest in order to generate power to utility. A key consideration in the design and operation of inverters is how to achieve high efficiency with power output for different power configurations. The requirements for inverter connection include maximum power point, high efficiency, control power injected into the grid, and low total harmonic distortion of the currents injected into the grid. Consequently, the performance of the inverters connected to the grid depends largely on the control strategy applied. Many topologies are used for this purpose.An overview of power inverter topologies and control structures for grid-connected PV systems are presented. The first section describes the various configurations for grid-connected PV systems and power inverter topologies. The following sections report and present control structures for single-phase and three-phase inverters. Some solutions to control the power injected into the grid and functional structures of each configuration are also proposed.

L. Hassaine

45. Monitoring and Diagnostics of Photovoltaic Power Plants

Photovoltaic (PV) systems should be monitored in order to control their production and detect any possible faults. Different possibilities exist for data analysis. Some perform it yearly, analyzing the performance of the PV system over a significant time period of operation and comparing it with similar systems. This shows that a system is performing poorly, but it has the disadvantage that it cannot be used to explain the causes of this underperformance. Others use high-resolution monitoring (minutely to hourly intervals) to analyze the performance of the system; with this higher resolution, a fault diagnosis procedure can be executed. These systems can detect general faults like constant energy losses, total blackout, and short-time energy losses, and the best can also detect shading; however, they cannot identify the exact cause. With the introduction of distributed maximum power point tracking (DMPPT) systems—power optimizers and micro-inverters—a new level of PV system monitoring is possible. Since these systems require the monitoring of the modules’ operating voltage and current (for the maximum power point tracking (MPPT) algorithm), the use of voltage and current sensors for each module is at no extra cost. It is only necessary to add a communication module since it is not directly incorporated in the DMPPT board.Based on the use of such appliances, a wireless sensor network (WSN) that allows monitoring, at panel level, the efficiency of PV panels has been proposed; nodes of the WSN, which are installed on each PV module, are equipped with voltage, current, irradiance, and temperature. Acquired data are then transferred to a management center which is in charge of estimating efficiency losses and correlated causes at the level of the single module.This research has been further developed in this chapter. The authors propose the possibility of using the DC/DC converter inside the system for MPPT. It allows to span the PV module voltage within a certain range, to measure a partial current–voltage (I-V) curve under the assumption that failures can be detected mostly by the parameter variation of RS, RSH, and diode factor η in the I-V curve based on equivalent circuit equation. These parameter variations should be calculated from I-V curve variation. The failure pattern would be presumed from the parameter variations caused by I-V curve variation, if the field data were accumulated. Due to the fact that I-V is partially available, new algorithms, analytical and metaheuristic, for parameter identification have been developed.The calculated parameters are used not only to detect long-term faults (e.g., aging, soling, delamination, and so on), but also to build an I-V curve reference when an impromptu fault happens (e.g., shading, breakdown diode, and so on).An experimental hardware and software (in LabVIEW/MATLAB environment) setup has been realized, so many measurement campaigns have been done. The proposed algorithms for parameter identification have been checked against real outdoor conditions. The chapter contains several graphs and charts which explain the relationship between I-V curve shapes and type of faults. A full literature survey will also be included in this study.

Giuseppe Marco Tina, Fabio Cosentino, Cristina Ventura

46. AC Power Short-term Forecasting of a Thin-film Photovoltaic Plant Based on Artificial Neural Network Models

Solar and PV forecasts for time horizons ranging from a few minutes ahead to several days ahead are generally significant for planning the operations of power plants which convert renewable energies into electricity. With the increasing penetration of photovoltaic (PV) power systems into the grid, the problems caused by the fluctuation and intermittence of PV power output are gaining interest. The power output fluctuations impact the power system’s stability. For this reason, an accurate forecast of PV production is necessary to consider PVs a reliable energy source.Different techniques can be used to generate solar and PV forecasts, depending on the forecast horizon—very short‐term forecasts (0–6 h ahead) perform best when they make use of measured data, while numerical weather prediction models are essential for forecast horizons beyond approximately 6 h.The aim of this study is to evaluate models for PV AC power short-term forecast using different artificial intelligence-based techniques and using ahead values of solar radiation and ambient temperature as data sources for forecasting. The data refer to a 1-kWp experimental micromorph silicon modules plant located at ENEA Portici Research Centre in southern Italy. A large dataset consisting of data measured every 5 min and acquired from 2006 to 2012, is used for the training/testing of the artificial neural networks (ANNs) proposed here. The AC power production evaluation is based upon data measured by a commercial inverter used for plant connection to the grid. This kind of inverter allows acquisition of operative data during their functioning hours, which are usually the central hours of the day. Therefore, when commercial inverters are used to acquire data, the use of ANNs is the best method for forecasting.In order to verify the effectiveness of the forecast data, measured and predicted data have been compared and the errors have been calculated by means of the relative mean bias error, the relative root mean square error and the correlation coefficient. Experimental data are reported to demonstrate the potentiality of the adopted solutions and to compare the different techniques proposed here. Furthermore, an algorithm that allows classification of a day as variable, cloudy, slightly cloudy or clear has been used for verification as forecast uncertainty depends on the meteorological conditions.

Giuseppe Marco Tina, Cristina Ventura, Giovanna Adinolfi, Sergio Ferlito, Giorgio Graditi

47. Digital Signal Processor-Based Power Management System Implementation for a Stand-Alone Microgrid on a Small Island in Korea

This chapter presents a power management system (PMS) for the control of a stand-alone microgrid that was installed in Mara Island’s microgrid system in Korea. Most stand-alone microgrids can control or confine the start, stop, or output of each distributed generator using the energy management system, but these functions cannot guarantee stability against disturbances that occur transiently and unexpectedly due to their reliance on communications. Therefore, Mara Island’s microgrid system developed and applied a PMS that does not rely on communications to secure the stability of the transient system. The PMS controls controllable active and reactive power, particularly that of energy storage systems, for the controllable active power of a diesel engine. First, we performed a controller hardware-in-the-loop simulation to verify the PMS performance. The microgrid system was modeled in a real-time digital simulator, connecting the PMS designed by a digital signal processor. Second, the PMS was installed in Mara Island’s microgrid system in Korea, which includes a photovoltaic power generation system, a diesel engine, a battery energy storage system, and the PMS. These systems are connected to a 380-V, one-feeder distribution subsystem. The loads of the microgrid usually vary from 40 to 120 kW. The results show that the proposed PMS helps to improve the stability of the stand-alone microgrid. The stability and utilization of the system can be increased by utilizing the PMS in accordance with the purpose of the microgrid system.

Chul-Sang Hwang, Jong-Bo Ahn, Jin-Hong Jeon, Gyeong-Hun Kim, Eung-Sang Kim, Minwon Park, In-keun Yu

48. Techno-Economic Assessment of Photovoltaic Systems in Oman: Review Article

Here, we present a review of the feasibility of photovoltaic (PV) systems in Oman. Different PV system configurations, for example, stand-alone and grid connected, have been reviewed and discussed for Oman. The effects of environmental parameters were taken into consideration when evaluating the performance of the PV systems. The systems were evaluated in terms of technical and economic criteria. The outcome of this work is deemed important since the cost of energy of PV systems was found to be cheaper than the cost of energy generated by fossil fuel without government subsidies. Furthermore, the technical and economic evaluation showed that the grid-connected PV system is feasible and promising in Oman. This study contains worthwhile information for those interested in PV system investment in Oman and the neighboring hot weather countries.

Hussein A Kazem

49. The Photovoltaic Project of Sudan to Reach More than One Million Homes: An Exercise in Policy Making, Finance, Strategies, Education and Sustainability

Sudan is enjoying the highest incidence of solar power in the world, and has a surface area of 1,890,000 km2. Electricity from fossil fuel and hydro sources reaches 34 % of the total population—covering 57 % of the urban and 16 % of the rural population. There are plans to reach 95 % of the urban population by 2016. Despite this plan, however, no more than 28 % of the rural population can be covered. This is a clear challenge for the implementation of renewable energy sources.A project for the promotion of solar energy was launched in 2001 comprising workshops, exhibitions and lectures. Implementation started in the following years resulting in a photovoltaic (PV) electricity supply reaching 7000 families in the rural areas. 150 healthcare units, schools, water supply, groceries and village cultural clubs were served. By 2005/2006 these efforts had succeeded in supplying electricity to 1000 villages, including in-house equipment for the service units.A target was set to supply PV electricity to 1,100,000 homes in the rural areas over the following 20 years. The scheme was launched in 2012 in the most northerly States.The work is perceived as a case study in the field of implementation, covering policy making, finance, strategies, education and sustainability of a PV electricity supply for rural areas.A novel feature is the launch of a project called ‘Barrier Removal to Secure PV Market Penetration in Semi-Urban Sudan’. The approaches used to carry out the various activities were discussed and evaluated and found to be highly effective for achieving the objectives.The socio-economic impacts were clearly noticed from the start.The success encouraged the project workers to fulfill the challenge of securing PV electricity for more than one million homes.

Anwar El-Hadi

50. Enhanced Performance of Dye-sensitized Solar Cells Aided by Olive-shaped ZnO Nanocrystallite Aggregates as the Light-scattering Layer

Olive-shaped ZnO nanocrystallite aggregates were synthesized for dye-sensitized solar cells (DSSCs). The submicron-sized hierarchical nanostructure is composed of highly crystalline ZnO nanoparticles about 20 nm in diameter and has an overall dimension of approximately 150 × 300 nm. An economical and environment-friendly aqueous solution method was developed to synthesize the olive-like aggregate. This template-free self-assembly method involved the mixing of zinc nitrate and sodium hydroxide aqueous solutions at a low temperature (80 °C) and aging the mixture for a particular length of time. We employed a low-temperature (150 °C for 1 h) thermal treatment process for the fabrication of bilayer photoelectrode, with commercial ZnO nanoparticles (~ 20 nm) as the underlayer and submicron-sized structures as the light-scattering overlayer. The N719-sensitized DSSCs containing the aggregate overlayer reached a power conversion efficiency of 4.4 %, 33 % higher than that attained by DSSCs incorporating large solid particles (200–500 nm) as the scattering layer. The enhanced overall conversion efficiency of aggregate-based cells was correlated with a prominent increase in the short-circuit current density. Optical and dye-loading investigations show that this improvement can be attributed to the dual functionality of the olive-shaped nanocrystallite aggregates, which have excellent light-scattering ability to enhance photon capture while providing a large surface area for sufficient dye adsorption.

Wei-Chen Chang, Hung-Shuo Chen, Wan-Chin Yu

51. Better Than Optimum: Integrated. The Integration of Renewable Energy in Architecture as an Optimization Factor

This chapter presents the importance that the embodied energy of the support material of a photovoltaic installation can have in relation to the energy produced and, therefore, in relation to other efficiency factors in the design of photovoltaic installations. The importance of these costs cannot be neglected in the overall system efficiency.The monitoring of photovoltaic panels after a few years of operation under real conditions demonstrates that a good integration of photovoltaic systems in constructive elements, even if their inclination or orientation is not the recommended one, may be better than just overlapping them in an optimal position. The embodied energy of the added constructive materials used when the system is not integrated may be more than the loss of production as a result of a nonoptimal photovoltaic modules disposal.This chapter illustrates the potential that architectural design applied to photovoltaic modules integration could represent, based on the experience of the photovoltaic pergola built in 2004 at the Forum esplanade in Barcelona. The ultimate goal is to consider the architectural design as another, important parameter when sizing photovoltaic systems, together with the orientation, tilt, temperature and other parameters regularly used.

H. Coch, C. Pardal, A. Pagès-Ramon, A. Isalgué, I. Crespo

ST 2014

Frontmatter

52. Heat Removal Factor of an Unglazed Photovoltaic Thermal Collector with a Serpentine Tube

Heat removal factor (F R ) is a vital parameter in determining the thermal efficiency of a photovoltaic thermal (PVT) system. As a main factor of thermal performance, F R represents the ratio of the actual heat transfer to the maximum yield of heat transfer. In this study, F R of an unglazed PVT with serpentine tube collector was determined, with focus on the flat-plate thickness of the flat-plate serpentine tubes. Thermal modeling was used to estimate the overall heat losses of the unglazed PVT. The highest F R value of 0.88 was obtained in the 0.015-m-thick flat plate, followed by 0.84 in the 0.010-m-thick flat plate. The difference in F R between the two designs was only 4.54 %, which can be considered within the acceptable range for the flat-plate thickness. This consideration was based on an economic point of view and the handling issues of PVT systems.

M. A. M. Rosli, Kamaruzzman Sopian, Sohif Bin Mat, M. Yusof Sulaiman, E. Salleh

53. An Experimental Investigation of Solar-Assisted Heat Pump Combined with A Latent Heat Storage

The building sector is one of the leading sectors in energy consumption. For this reason, utilizing renewable energy sources in building air conditioning systems has significant importance. Taking advantage of using heat storage systems integrated with renewable energy-sourced air conditioning systems makes it possible to benefit from cyclic renewable sources, such as solar energy, for longer periods of time. In this way, increasing solar fraction and decreasing dependency on fossil fuels in heating systems will be possible.In this study we present an experimental analysis of a hybrid heating system in Istanbul. Analyses are performed according to the first and second law of thermodynamics using real data obtained from a prototype structure built as part of a project. The main components of the system are solar collectors, latent heat storage (LHS) as a low-temperature heat source, and a heat pump. Furthermore, a buffer tank placed in the system provides a continuous supply of hot water to a wall heating cycle. By storing input and output heat from the heat pump, a significant reduction in consumption of compressor energy was achieved.During the testing period an average of 0.895 kW energy was gained from solar collectors, of which 0.77 kW was stored in LHS. As a result, the charging time (average 402 min) of LHS was far higher than the discharging time (97.8 min). A large amount of heat was transferred to the heat pump and average coefficient of performance (COP) of the heat pump was calculated as 4.38 for the whole testing period.On average, 2.42 kW of exergy destruction took place during the experiment. Solar collectors and heat pumps are promising components in terms of exergy destruction; showing 1.15 and 1.09 kW, respectively, in our study. A high percent of heat loss took place from the heat pump (1.83 kW), followed by the accumulator-wall heating cycle (0.42 kW). On the contrary, the highest breakdown of exergy loss occurred in the accumulator-wall heating cycle (0.28 kW).The discharging energy efficiency of LHS is high throughout all system components. Furthermore, the heat pump showed a significant efficiency of 78 %. The exergy efficiency of system components investigated during the discharging period was similar (approximately 32 %). However, the efficiency of solar collectors and charging of LHS was 2.3 and 7 %, which is relatively low.Our study results indicate that the performance of solar collectors and LHS units in terms of energy is adequate; however, the system seems open to improvement in terms of exergy. Increasing the total surface area of solar collectors can contribute to an improvement of system performance. In this prototype, the total area of the solar collectors was 3.24 m2. As a result of simulations, if the collector area is increased to 10 m2, a significant amount of excess storable energy will be gained which will increase solar fraction in winter months.

Devrim Aydın, Zafer Utlu

54. Experimental Study of Modified Absorption Cooling Systems by Adding Ejector–Flash Tank Unit

In this study, an absorption cooling system with and without ejector–flash tank units is proposed by testing an experimental rig at Universiti Kebangsaan Malaysia in Bangi, Malaysia. A combined ejector–flash tank unit with absorption cooling system has been designed and installed. The major components of the system consist of the generator, ejector, condenser, flash tank, evaporator, absorber, and solution heat exchanger. Experimental results show that the COP of the absorption cooling systems with and without an ejector–flash tank unit was, respectively, 0.87 and 0.64 under the same operating conditions. In addition, the cooling effect in the former also increased, which may be caused by the improvement in the quality of ammonia entering the evaporator. This study revealed the possibility of optimizing the performance of absorption cooling systems through the addition of ejector–flash tank units.

Ranj Sirwan, Kamaruzzman Sopian, Mohammed Al-Ghoul

55. Temperature Prediction for an Integrated Solar Collector with Spherical Phase-Change Material

Phase-change material (PCM) systems play a particularly important role during off peak periods in improving thermal storage systems. In this study, we aim to predict output temperature in integrated solar heating using a radial basis function rural network (RBFNN). First, we present a brief PCM numerical model including geometrical and operational parameters and discuss the effect of this parameter on the output temperature. The working fluid temperature is uniformly distributed and equal to collector output temperature. The learning data is theoretical, generated by using a standard solar collector integrated with 95 PCM modules. The RBFNN model has three input nodes representing spherical size, duct length and number of balls and two output nodes representing the first and last layer PCM temperatures. Simulation result shows the predicted PCM temperatures at the first and last layer closely match the analytical data from computational fluid dynamics.

Fatah O. Alghoul, Kamaruzzman Sopian, Mohammed Al-Ghoul, Shahrir Abdullah, Mohammed Sheldin, Adnan M

56. Design of Various Hybrid Single-Pass Photovoltaic–Thermal (PV/T) Solar Collector

In this chapter, five different designs of hybrid photovoltaic–thermal (PV/T) solar collectors are fabricated and their performance are evaluated. All designs are based on the concept of single-pass collector. Designs of heat exchangers for the collectors include honeycomb, stainless steel wool, V-groove, ∇-groove, and rectangular groove. The advantages of the collectors are their capability to generate both electricity and heat simultaneously. The objective of this study is to compare the performance of all PV/T collectors. All systems were tested at irradiance of ~ 800 W/m2 with mass flow rate spanning from 0.01 to 0.13 kg/s.

Mohd. Yusof Hj. Othman, Faridah Hussain, Kamaruzzman Sopian, Baharuddin Yatim, Hafidz Ruslan

57. Optimizing Solar Hot Water Systems (Closed Systems) for Air-Conditioning Cycles in TRNSYS

Parallel and series solar hot water systems (closed systems) were simulated and optimized. The system is designed to supply the required heat for solar air-conditioning cycles such as heat generators in ejector cycle, absorption cycle generator, regenerator in liquid desiccant cycle and regenerating absorbent of the desiccant wheel, and solid desiccant cycle. A model of solar hot water system was simulated in TRNSYS and then, based on solar fraction, the components of the system were optimized. For optimization of the cycle, the dynamic performance of the system in supplying the required temperature for a cycle of Three Tons Refrigeration was analyzed under different situations. The results were compared with the experimental results to obtain consistency. The effects of the parameters of the system, supplied heat capacity, the energy used by the heater, and the effect of the environment were surveyed regarding feasibility of achieving higher solar energy. Finally, the solar hot water system was optimized for Bushehr city. The results showed that the optimization of the solar system is influenced by environmental parameters such as radiation intensity, dry bulb temperature, relative moisture; the way the system is utilized (residential and institutional); the term of operation of the system; and, most importantly, the set point of the auxiliary hot water system. The optimized system was featured as follows: solar fraction: 0.5, area of collector: 86 m2, angle of collector: 31°, set point of the auxiliary hot water system: 75°C, capacity of tank: 4 m3, solar collector discharge: 0.25 kg/s, and mass discharge rate of the thermal converter: 0.2 kg/s.

A Kaabi Nejadian, Ali Mohammadi, Behnoosh Bakhtiari Heleyleh

58. Analytical Model Development for Efficient Solar Desalination System (SDS)

Supply of adequate quantities of fresh potable water is one of the most serious problems confronting human, especially when we know that one third of the world population are suffering from water shortage and it is expected to reach two thirds in the near future. Therefore, desalination, as a non-conventional water resource, has become one of the most interesting alternative water sources to partially face the freshwater scarcity in the near future. This chapter presents a parametric study to simulate for an optimal design of a transportable solar desalination system (SDS) in order to achieve maximum thermal performance. The study reveals that changing the solar intensity, reflector parabolic height and width, evaporation area, wind velocity, saline water depth, and absorbing tube shape changes the unit productivity.

Bassam A. Noaman, Ahmed F. Elsafty

59. A Model to Estimate Ambient Conditions and Behavior of the Airflow Inside a Solar Chimney

This chapter presents models to estimate the environmental conditions and the behavior of the airflow within a prototype of a small-scale solar chimney located in Belo Horizonte, Brazil. A correlation from the literature for diffuse radiation, based on clearness index and global radiation, was evaluated. A model from the literature was used to estimate the ambient temperature of the device. The results of both parameters were compared with the experimental data. An energy balance was applied to find the heat interactions between the ground, airflow, coverage, and environment, based on the estimated incident solar radiation and ambient temperature. Literature correlations were used to estimate the convective heat transfer coefficients. Consolidated correlations were then applied to estimate the mass airflow rate and outlet temperature of the airflow inside the prototype. The results were compared with the experimental data for 4 days in autumn and good agreements were found. The model was then used to estimate the airflow parameters for 1 year. The analysis performed was transient, with results provided for each hour of the day, for 365 days. These results showed good accordance with the experimental data. The greater differences were found in the mass flow rate at night.

Janaína Oliveira Castro Silva, Tauane Shaisly Fernandes, Sérgio de Morais Hanriot, Antônia Sônia Alves Cardoso Diniz, André Guimarães Ferreira, Cristiana Brasil Maia

60. Comparative Investigation of Solar Photovoltaic (PV) and Photovoltaic/Thermal (PV/T) Systems by both Laboratory and Field Experiments

Photovoltaic (PV) semiconductor degrades in performance due to temperature rise. Therefore, a super thin-conductive thermal absorber was developed to retrofit the existing PV panel into a photovoltaic/thermal (PV/T) panel with multiple benefits including dual outputs of increased electricity and additional hot water, and potential savings in installation cost and space. The thermal absorber regulates the PV temperature by creating trade-off between PV efficiency and thermal output. This chapter presents the parallel comparative investigation of the PV and the PV/T panels through laboratory and field experiments. The laboratory evaluation consisted of one PV and one PV/T panel, while the overall field system involved 15 stand-alone PV panels and 15 retrofitted PV/T panels. The total electric installation capacity of the field system was around 6 kWp, and all the PV or PV/T panels were connected to the national grid through an electric inverter. The laboratory testing results demonstrated that this PV/T panel could achieve an electrical efficiency of PV cells at about 16.8 % (about 5 % increase), and produce an extra amount of heat with thermal efficiency of nearly 65 % under standard testing conditions. The nominal mass flow rate of the working fluid is recommended at 50 Lh−1m−2. The thermal absorber was measured at an extremely low pressure drop of less than 20 Pa. The field-testing results indicated that the hybrid PV/T panel could essentially improve the electrical return of PV panels by nearly 3.5 % in practice, and meanwhile increase the overall energy output (both electricity and heat) by nearly 324.3 %. Such synergetic integration of PV and thermal absorber not only results in improved PV efficiency but also generates more energy per unit area when compared with stand-alone PV panel. To replace with conventional electric water heating system, the 15 PV/T panel’s payback periods were estimated at less than 5 years and the corresponding CO2 emission reduction was about 440 t throughout their life span of 25 years. Further opportunities and challenges in the built environment were discussed from aspects of different PV/T stakeholders to accelerate the development of such technology. It is expected that such a dedicated technology could become a significant solution to yield more electricity, offset heating load freely and reduce carbon footprint in contemporary energy environment.

Xingxing Zhang, Jingchun Shen, Xudong Zhao, Ying Xu, Benno Nibeler

61. Performance of a Recirculating-Type Solar Dryer

A novel recirculation-type integrated solar collector drying chamber solar dryer has been designed, constructed, and tested. The solar dryer comprises a feed hopper, a centrifugal blower, a pneumatic conveyor, and a transparent structure acting as drying chamber containing a hopper with a vortex at the top. The transparent structure has a dimension of 3 m in diameter and height of 3 m. The blower used has a capacity of maximum 1 kW, 220 V, and a supplying air velocity of 30.3/s. A series of tests were conducted outdoors where solar radiation was available. A test with 104 kg of rough rice indicated that the drying time required to reduce the moisture content (m.c.) of rough rice from 28.4 % wb to the final m.c. of 14.3 % wb was 5 h. During the test, the drying temperature was kept constant at 50.1 °C and the relative humidity (RH) was 21.73 %. The required power for the pneumatic conveyor was 581 W, with a total energy input of 210.7 MJ, including LPG and solar radiation. The resulting drying efficiency was 22.4 % with specific energy of 15.2 MJ/kg of water evaporated. Another test using 200 kg with initial m.c. of 27.6 % wb of rough rice has shown that the required drying time to achieve the final m.c. of 14.3 % was 8 h. During the test, the drying temperature was kept constant at 46.9 °C, and the RH was 21.7 %. The drying efficiency was 31.7 % with specific energy of 10.7 MJ/kg of water evaporated. By knowing the amount of rough rice retained in the receiving hopper and the rate of recirculation, it was possible to measure the drying time of each cycle until the drying process completed. By using the sphere model, we were able to estimate the drying curve, where it was found that a good agreement exists between the theoretical and experimental data using the value of drying constant k = 2.75 (1/hr) and M e of 7 % db. As the drying time increased toward the end of drying process, it was observed that the variation in rough rice m.c. became smaller and smaller and was better than that found in the previous study.

Yefri Chan, T. M. Nining Dyah, Kamaruddin Abdullah

62. Thermo-Energy Transfer Optimization of a Solar Distiller with Energy Storage Under Bou-Ismail Climatic Conditions

Seawater desalination techniques are sustainable, but their use is limited in rich countries. However, in recent years, the capacity of desalination stations has greatly increased and production costs by m3 experienced a sharp decline. Seawater and brackish water desalination using solar energy witnesses a growing interest in some developing countries. Solar distillation is a technically feasible, simple, profitable, and operational method for the production of freshwater. This thermal process is a key to future water problems in the water poorest regions, namely arid and isolated sites in southern Algeria as it permits to desalinate brackish water and treated wastewater reuse concentrated salt. The aim of this study is to evaluate the effect of temperature and the internal components of solar still on its operation. An experimental examination of a solar distiller performance is realized and designed by a team of research of UDES. The daily instantaneous and global yield will be examined to show the temperatures’ influence on the different distiller elements as well as on the quantity of distillate produced. Also, a comparison of different geometries with energy storage has been undertaken in order to study the influence of geometry on the production of distilled water.

Randha Bellatreche, Dalila Belhout, Maamar Ouali, Djamila Zioui, Zahia Tigrine, Hanane Aburideh, Sarah Hout

63. Solar Thermal Collectors with Low and High Concentration

This chapter describes the performance analysis of different concentrating technologies through experimental and numerical modeling activities. Two solar thermal systems with different designs and, accordingly, different concentration ratios have been studied. The first solar device is a stationary compound parabolic concentrator (CPC) collector: it is provided with truncated or full CPC reflectors and evacuated tubes. Each evacuated tube is composed of an outer glass envelope and a glass absorber with selective coating in thermal contact, via absorber fin, with a U-shaped channel for the liquid flow. The second system is a parabolic trough concentrator (PTC) with two-axis solar tracking: the primary optics consists of a segment of parabolic cylinder which concentrates the direct normal irradiance (DNI) on a linear receiver. In this system, two types of flat receivers have been tested. One receiver has been designed for thermal energy extraction, and it consists of a canalized roll-bond plate provided with a semi-selective coating. The other receiver has been designed for cogeneration of electricity and heat (CPVT), and it is equipped with triple-junction photovoltaic cells, which are actively cooled by an aluminum roll-bond heat exchanger. The performance of the described collectors has been experimentally characterized at the Solar Energy Conversion Laboratory of the University of Padova (45.4°N, 11.9°E), Italy. The collectors have also been mathematically modeled, and the numerical data have been validated against the experimental measurements.

Matteo Bortolato, Ahmed Aboulmagd, Andrea Padovan, Davide Del Col

64. Building-Integrated Solar Thermal Systems

With buildings accounting for 40 % of primary energy requirements in the EU and the implementation of the Energy Performance of Buildings Directive, developing effective energy alternatives for buildings is imperative. The increasing role for renewables implies that solar thermal systems (STSs) will have a main role as they contribute directly to the heating and cooling of buildings and domestic hot water. Meeting building thermal loads will be primarily achieved through an extensive use of renewables, following standard building energy-saving measures. These systems are typically mounted on building roofs with no attempt to incorporate them into the building envelope creating aesthetic challenges, space availability issues, and envelope integrity problems. This chapter aims to give a survey of possible solutions of STS integration on the building roofs and façades. The advantages of integration are quantified, and suggestions are given to address the possible problems created.

Soteris A. Kalogirou

65. Experimental Study on Regenerator Performance of a Solar Hybrid Liquid Desiccant Air-Conditioning System

This chapter presents an experimental study on the performance of the liquid desiccant regenerator of a hybrid solar air-conditioning system. Lithium chloride (LiCl) solution is used as the working desiccant material. The effects of air temperature, air humidity ratio, and solution temperature on the performance of the regenerator are disused. The experimental results showed that the moisture removal rate (MRR) and effectiveness of the regenerator increase slowly as a function of the air inlet temperature. It was found that the MRR and effectiveness increased about 0.79 and 1.1 %, respectively. The moisture removal rate decreased with increasing air inlet humidity ratio and increased with desiccant inlet temperature.

Sohif Bin Mat, Kamaruzzman Sopian, M. Yusof Sulaiman, Abdulrahman Th. Mohammad, Abduljalil A. Al-abidi

66. Integration of Concentrated Solar Power Plant and Coal-Fired Power Plants for Block Size of 100 MW

Development of renewable energy sources has not reached a stage where it can completely replace the conventional power plants. However, renewable energy technologies like wind energy, solar photovoltaic or concentrated solar plant (CSP) can join hands with conventional power plants to address the energy crisis and develop themselves to make this replacement possible in near future. This chapter explores the possibility of integrating CSP with coal power plant (CPP) for reducing the installation cost of CSP, which in turn would also reduce coal consumption and carbon emission from coal plants. Moreover, it would also boost up the implementation of different government renewable energy policies.Based on the proposed technique in the chapter, CSP can be installed in existing coal power plants (CPP). Auxiliary drives in coal power plant consume approximately 8 % of total power generation in CPP. These auxiliary drives can run on the thermal energy provided by CSP. Important concerns like identification of land in coal plant for CSP installation, total land requirement, process of installation and integration of CSP with CPP are elaborated in this chapter.This chapter also investigates the advantages and challenges for the integration of CPP and CSP. CSP is more effective in regions where direct normal irradiation (DNI) is more than 1900 kWh/m2/year which limits the use of suggested integration method. On the other hand, availability of power block for CSP would result in significant cost reduction in CSP plant installation. Moreover, cost required for resources like man power for operation and maintenance would be reduced considerably. These plants would not be dependent on any kind of power purchase agreement; hence, it would encourage CSP project developers for new installations all over the world.

Pankaj Deo

67. Indoor Experimental Investigations of Two Different Static 3-D Solar Concentrators

Designs and experimental investigations of two different hyperboloid (elliptical hyperboloid concentrator (EHC) and circular hyperboloid concentrator (CHC)) solar concentrators have been reported in this chapter. Indoor tests have been carried out for the two prototypes of solar concentrators. In order to estimate the temperature of the surface area of the receiver tubes for process heat applications, thermal imaging analysis has been carried out and also presented in this chapter. It was observed that the outlet temperature of 93 °C is obtained for the EHC solar concentrator and the outlet temperature of 60 °C is obtained for the CHC solar concentrator, respectively. Indoor experimental temperature distribution of the receiver was carried out for two types of receivers. Temperature measurement was carried out under ‘flow’ and ‘no flow’ conditions. Both the EHC and CHC systems were tested and their concentration ratio was found to be 20×. In order to estimate the temperature distribution along the receiver, thermal imaging camera and FLIR Tools software were used to obtain the temperature variation along the receiver at three points. Under ‘no flow’ conditions, stagnation temperatures were measured at three points ( represented as T1, T2 and T3) located on the receiver surface.

Imhamed M. Saleh Ali, K S Reddy, Tapas K Mallick

68. Effect of Isothermal Dehumidification on the Performance of Solar Cooling System in Tropical Countries

In recent years, due to the increasing price of energy, and also a high portion of the energy used by conventional air conditioning systems in tropical countries, solar desiccant cooling systems have been identified as energy-efficient cooling systems. The significant impact of the dehumidification process on the performance of a solar cooling system as well as on the thermal comfort condition is because of hot and humid outdoor conditions, and also high latent heat loads of buildings in tropical countries. In this study, to evaluate the isothermal dehumidification effect on the performance of the solar desiccant cooling system, the coefficient of performance (COP) and the zone temperature and humidity ratio of two simulated models (one stage and two stage) of the solar desiccant cooling system have been compared. The Transient Systems Simulation (TRNSYS) modeling validation is carried out by data measurement of a one-stage solar desiccant cooling system which was installed in the technology park of Universiti Kebangsaan Malaysia (UKM) in Malaysia. The capacity of cooling load and also the sensible heat ratio of the zone were 1 ton and 0.25, respectively.The comparison results between one-stage and two-stage desiccant cooling systems show that under the same operation conditions (regeneration temperature and outdoor conditions) the COP of one-stage and two-stage models were 0.50 and 1.06, respectively, while the supply air of the two-stage model could handle the latent and sensible loads. Therefore, it was achieved that the isothermal dehumidification is a great method to improve the COP of the solar desiccant cooling system, and also indoor comfort conditions in tropical countries.

M. M. S. Dezfouli, Kamaruzzman Sopian, Sohif Bin Mat, K. S. M. Sahari

69. Heat-Driven Heat Pumps—The Future of Domestic Heating in Europe?

There have been many attempts to commercialize and introduce heat-driven (particularly gas-fired) heat pumps over three decades. There are now three domestic systems on the market [Robur, Vaillant and Viessmann], with others under development.The different types are reviewed, the markets assessed, and the barriers to wider uptake are discussed. Other options for future heating systems proposed within the UK are a range of electric heat pump developments and fuel cell/micro-CHP units. Moving to an all-electric decarbonised electricity grid is shown to require a vast investment to perhaps triple the capacity of the electricity infrastructure and whilst possible in the long term cannot secure the emission reductions essential in the medium term. The case is proposed for a mixed heating solution with both gas-fired and electric heat pumps, also hybrids being used well in the 2040s. New-build houses will be almost exclusively electric and will need integration with advanced storage to supply domestic hot water. Older properties with higher heat loads will either use hybrid electric heat pump—gas boiler systems or gas-fired heat pumps. The proposed mix, whilst not being the minimal emission route, is much more affordable and a pragmatic solution to domestic heating.

R. E. Critoph

70. Implementation of a CSP Plant for Localized Energy Supply at Populated Zones in the North of Chile

Chile is nowadays facing a complicated energy situation characterized by an energy matrix dominated by fossil sources, unclear energy policies, and rising prices, which causes loss of competitiveness of the national industry and an inefficient electricity grid. These variables, among others, make the national electric system to be characterized by its high economic, environmental, and social costs, for which nonconventional renewable energies (NCRE), such as solar, are seen as a possible solution in the medium term, considering the existing high levels of radiation in certain geographical areas.This chapter seeks to determine technical and economic feasibility of implementing a central tower concentrated solar power (CSP) plant, technology currently under development for the conversion of solar radiation into electricity, assessing the total supply of a populated zone. To carry out this study, implementation of energy efficiency (EE) measures in certain areas (domestic consumption, industrial, commercial, public services, and transport) will be considered. In terms of the electricity distribution system, the plant will be connected via a substation directly to the populated area under consideration. In other words, CSP design and operation is based on localized supply. This grid connection at distribution level reduces cost and provides secure electricity supply. All these aspects will be part of a business model that, carrying a private and social project evaluation, could make a joint venture between the Chilean state and private companies. Analysis of this model led to the need of the Chilean State to take part on clean and efficient energy investments and the importance of sustainable energy for both actors as an alternative to face a future that is expected to be increasingly dependent on energy consumption.The systematical and massive implementation of the innovative measures presented in this chapter for populated areas with appropriate technologies for different meteorological and geographical conditions may contribute to mitigate the growth of the main national electricity grids, reduce losses associated with electric power transmission, diminish unnecessary energy consumption, and therefore decrease environmental impacts associated to them.Finally, noteworthy is the importance of the new developments achieved through innovation and the opportunities resulting from the reduction in costs through scaling of the industry and constructions that could significantly reduce capital investments required for implementation of these kinds of projects.

José M. Lobo, Hugo Osorio, M. Pilar Gárate

71. Solar Thermal Polygeneration System for Cooling, Fresh Water, and Domestic Hot Water Supply: Experimental Analysis

The demands for space air-conditioning and clean drinking water are relatively high in Middle East countries. A sustainable and innovative approach to meet these demands along with the production of domestic hot water is discussed in this chapter. A solar thermal polygeneration (STP) system is designed and developed for the production of chilled water for air-conditioning using absorption chiller, pure water with membrane distiller, and domestic hot water by heat recovery. The STP system has four major components: (i) evacuated tube collector field, (ii) 10TR absorption chiller, (iii) air-gap membrane distillation units, and (iv) heat exchangers integrated together to operate in four different modes for complete solar cooling, cogeneration of pure water and domestic hot water, trigeneration of cooling, pure water and domestic hot water, and cogeneration of cooling and pure water. Experiments on different modes and the analyzed results show the advantages of combined operation through effective utilization of heat lost in the process operation.

Gowtham Mohan, Uday Kumar N. T., Manoj Kumar P., Andrew Martin

72. Solar Thermal Systems for Zero-Energy Buildings: Perspectives and Challenges

The implementation of energy-efficiency measures as well as the integration of renewable energy systems, on the move towards the zero (or nearly zero)-energy building is certainly a challenging task. This is even more the case, when buildings are to operate in conditions with increased cooling demand, as it happens in the Eastern Mediterranean, the Middle East and North Africa. The aim of a zero-energy building cannot be achieved without a truly integrated energy design approach, by a combination of two major tools: (a) avoiding, postponing or reducing the generation of heating and cooling loads, by applying the basic principles of building physics and (b) using alternative, renewable sources and systems to produce the heating and refrigeration necessary.Understanding the requirements of the user and providing adequate solutions remains the single most important prerequisite, if the design had to be successful and just a simple academic exercise. Targeted, interdisciplinary postgraduate courses are needed, with curricula focusing on the utilization of state-of-the-art technology, but also with the holistic approach in the core of their educational attitude, in order to provide architects and engineers with the expertise needed.

Agis M. Papadopoulos

73. Experimental Investigation of the Effect of Solar Collector’s Inclination Angle on the Generation of Thermosiphonic Flow

Cyprus is currently the leading country in the world with respect to the application of solar water heaters for domestic applications, with more than 93 % of the houses equipped with such a system. The great majority of these solar water heaters are of the thermosiphonic type. Currently, the knowledge about the parameters affecting the ‘thermosiphonic phenomenon’ is rather poor while on an international level (International Organization for Standardization, ISO, and Comité Européen de Normalisation CEN committees) there is no standard available to test thermosiphon solar collectors. The deeper understanding of the ‘thermosiphonic phenomenon’ and the identification of the key parameters affecting it is the main aim of a research project currently in process in Cyprus.In this chapter, the experimental results of the research project are presented. Specifically, a special test rig was set up and equipped with all the sensors necessary to measure all the parameters that are most likely to affect the ‘thermosiphonic phenomenon’. All tests were conducted according to ISO 9459-2:1995(E). The system was able to operate in various weather and operating conditions and could accommodate the change of inclination of the collector. During the experimental procedure, three different inclination angles of the solar collector were tested in order to evaluate their effect on the generation of thermosiphonic flow. The thermal performance of the collector was calculated both in thermosiphonic operation and also according to EN12975-2:2006 in order to determine the thermal performance at a flow and operation conditions specified by the standard. Finally, a series of correlations were attempted using the experimental results for the thermosiphonic operation of the collector which are the following: (i) the temperature difference of the water at the outlet and the inlet of the collector (ΔT) with solar global radiation, (ii) the water mass flow with the solar global radiation and (iii) the water mass flow with the temperature difference of the water at the outlet and the inlet of the collector. The results of the data analysis showed that the examined parameters were well correlated and also the optimum inclination angle in terms of the highest thermosiphonic flow generation was that of 45°.

G. P. Panayiotou, S. A. Kalogirou, G. A. Florides, G. Roditis, N. Katsellis, A. Constantinou, P. Kyriakou, Y. Vasiades, T. Parisis, A. Michaelides, J. E. Nielsen

74. Performance Improvement in a BIST Water Collector: A Parametric Study

A flat-plate solar collector with high building integration was designed and prototyped. The experimentations showed that the performances of this solar collector can be improved. A numerical thermal model, developed in Matlab® environment using a finite difference model, was validated. Then, a modelling of the complete solar domestic hot water system (solar collector + water storage + piping) was realized. The performance of this system was calculated for various solar collector configurations such as the number and the position of the water pipes, air layer thickness, fluid flow rate, etc. Several solar fractions were used to implement this optimization procedure. An optimized solar collector structure is finally presented.

Gilles Notton, Christian Cristofari, Fabrice Motte, Jean-Louis Canaletti

75. Performance Evaluation of a Novel Solar Industrial Wastewater Treatment Unit for Reuse

In the present study, a novel solar industrial wastewater treatment unit (NIWWTP) was designed, constructed, and tested under actual meteorological conditions of Greater Cairo, Egypt. Nonconventional treatment and decontamination of highly polluted wastewater such as solar degradation is the new approach and currently the focus of intense investigations due to their potential for revolutionary technological applications in the twenty-first century. Industrial wastewater is considered as chemically polluted water that causes most of water-borne diseases. The pollution potential of textile dyes has been primarily prompted due to concerns regarding their possible toxicity and carcinogenicity. Color is the first contaminant to be recognized in wastewater and has to be removed before being discharged into water bodies or on land. This is mainly due to the fact that many dyes are made from known carcinogens and other aromatic compounds. Photocatalytic degradation of dyestuffs from aqueous synthetic sample as well as from real textile wastewater representing industrial color-containing wastewater from a textile company will be used in this study to investigate the performance efficiency of the system under investigation for color removal and decontamination of pollutants. Results showed that the treated water was colorless, with minimum chemical contaminates and pathogenically decontaminated. Experimentally, the system was affected by meteorological conditions such as ambient temperature, wind speed, solar radiation intensity, pollutant concentration in wastewater, quantity of water exposed, and water contact time in the system. The use of solar energy for the water treatment process will provide good potential of using renewable energy on a large scale for a nonconventional wastewater treatment plant using clean energy in the coming decades.

Hamdy El-Ghetany, M. Hamdy El-Awady

76. Theoretical and Experimental Investigations of Solar Heating Systems Under Specified Output Conditions of Hot Water

The theoretical analysis discussed in this work is a suitable mathematical tool by which the performance of the proposed collector can be predicted. The obtained experimental results coincide with the obtained theoretical data from a devised computer program. Controlled output temperature can be obtained from the proposed system. The performance of the tested collector under the proposed intermittent flow conditions is superior to that of the conventional thermosyphone flow collector.

W. Tadros, M. Saadeldin, S. A. Hassan

77. Thirty-Five Years of Experience with Research, Promotion and Use of Solar Cookers to Save Conventional Fuels and Reduce Carbon Emission

Since 1979, the author has designed, studied and used various models of solar cookers—from thermal food warmer in 1979, to PV multi-voltage cooker in 2010 and to single-axis tracker for solar cookers in 2012. Besides publishing the results in technical journals and national and international conferences, these have been promoted through lectures in communities, educational and cultural centres, TV, radio, newspapers, workshops and seminars in Costa Rica and many other countries. For one of the models of solar cooker, the author got a patent in 1984.In the present work, different models and some promotional activities, especially at educational institutes, to warm the lunch for students are mentioned.

Shyam S. Nandwani

78. Development of an Efficient Low- and Medium-Temperature Vacuum Flat-Plate Solar Thermal Collector

Production of heat accounts for over half of our overall primary energy consumption in domestic and industrial applications. Despite the great scope for deployment of solar thermal collectors to provide low- and medium-temperature heat, there is relatively little uptake of this technology. The requirements for heat provision are studied, and the desired characteristics of potential solutions considered. Application areas are discussed in addition to the potential for system integration. An assessment is made of the shortcomings of solar thermal collectors and the requirements for new technologies suggested. This leads to a design approach for a collector that is effective across a range of applications and provides further supplementary benefit for system or building integration.A vacuum flat-plate (VFP) solar thermal collector is proposed as a solution to the requirements for domestic and industrial heat at the low- to medium-temperature range. VFP solar thermal collectors have several potential advantages over other collector types: they may deliver heat efficiently at 150–250 °C, and they may be made much thinner than the existing collectors, offering new application opportunities in industrial process heat and for building integration. VFP collectors achieve this by combining the optical properties of flat-plate (FP) collectors with the heat loss characteristics of evacuated tubes. This chapter considers the development of a micro/mini-channel absorber plate and vacuum enclosure for a VFP collector.

G. S. F. Shire, R. W. Moss, P. Henshall, F. Arya, P. C. Eames, T. Hyde

79. Analytical Modelling of Integrated Solar Drying System

The drying of fruit and vegetables is a subject of great importance. Dried fruit and vegetables have gained commercial importance, and their growth on a commercial scale has become an important sector of the agricultural industry. However, food drying is one of the most energy intensive processes of the major industrial process and accounts for up to 15 % of all industrial energy usage. Due to increasingly high electricity prices and environmental concern, a dryer using traditional energy sources is not a feasible option anymore. Therefore, an alternative/renewable energy source is needed. In this regard, an integrated solar drying system that includes highly efficient double-pass counter flow v-groove solar collector, conical-shaped rock-bed thermal storage, auxiliary heater, the centrifugal fan and the drying chamber has been designed and constructed. Mathematical model for all the individual components as well as an integrated model combining all components of the drying system has been developed. Mathematical equations were solved using MATLAB program. This paper presents the analytical model and key finding of the simulation.

M. A. Karim, Zakaria Mohd. Amin

80. Ejector Chillers for Solar Cooling

Ejector chillers are being studied at Department of Industrial Engineering of Florence (DIEF) since 2000, both theoretically and experimentally. This chapter discusses the application of solar-powered chillers in air conditioning and details the fundamental parameters. This technology is not far from being a technically feasible alternative to commercially available single-stage absorption chillers, but obviously a huge effort is still needed to improve its performance and gain access to the market.

Adriano Milazzo, Federico Mazzelli

81. Modelling Conical Rock-Bed Solar Thermal Storage Tank

An important application of solar thermal storage is for power generation or process heating. Low-temperature thermal storage in a packed rock bed is considered the best option for thermal storage for solar drying applications. In this chapter, mathematical formulations for conical have been developed. The model equations are solved numerically for charging/discharging cycles utilizing MATLAB. Results were compared with rock-bed storage with standard straight tank. From the simulated results, the temperature distribution was found to be more uniform in the truncated conical rock-bed storage. Also, the pressure drop over a long period of time in the conical thermal storage was as low as 25 Pa. Hence, the amount of power required from a centrifugal fan would be significantly lower. The flow of air inside the tank is simulated in SolidWorks software. From flow simulation, 3D modelling of flow is obtained to capture the actual scenario inside the tank.

M. A. Karim, Zakaria Mohd. Amin

82. Reducing Biomass and the Use of Kerosene for Cooking in Indonesia to Support the Global Efforts to Reduce CO2 Emission

We discuss Indonesia’s efforts in poverty alleviation within the context of national energy. The statistical data regarding provincial poverty lines, the number of people who live below this line, the energy type used by low-income families and the gender situation are given. Several approaches to energy provision for firewood consumers are described in the global context. It started with a field research initiative until the formation of a national program for socio-economic development including World Bank involvement. Various demands such as electricity development, overcoming climate change disasters and infrastructure reconstruction led to funding scarcity. We describe ideas/initiatives to obtain funding by showing the benefits of reducing CO2 emission. The estimated annual global costs of adapting to climate change and the Cancun Agreement are briefly described within the funding scarcity context.

Herliyani Suharta, A. M. Sayigh

83. The Solar Greenhouse: A Strategy for Energy Savings in Social Housing in Milan

The recently updated Lombardy Region law no. 39/2004 and the new Milan city building code stimulate more and more the use of passive climate control strategies to reduce thermal energy consumption. Solar greenhouse is one of the strategies promoted by regulations both for new and retrofit buildings.This chapter compares solar greenhouse regulation requirements (orientation, natural ventilation, openings, shading devices, etc.) with the Milan city public housing policies and programmes. In particular, it focuses on the large public building stock produced between the post-second war period and the 1980s, which has a very low energy performance and therefore high retrofit potential.Both the regional law and the building code consider greenhouse retrofitting by closing balconies or integrating building elements, such as the “loggia”. The solar greenhouses are feasible only if they reach at least a 10 % energy savings, calculated in accordance with the UNI EN ISO 13790/2008 (energy performance of buildings—calculation of energy use for space heating and cooling).The closing of balconies and loggias, especially in social housing, is an action that has often been made to increase the space available in the residence. However, the closing is often individual unauthorized action followed by subsequent amnesty and payment, which legalizes the increased volume and the facade change, independently by any energy performance evaluation.The consequence of individual uncontrolled actions is the change of facades, which often radically modify the visual impact of the residential complex, out of any facade image of the entire building.This chapter analyses a case study of a 1940–1950s social housing building in Milan.The selected case is a linear building with a mix 1/2/3-bedroom flats which have the requirements of the legislation to implement the bioclimatic greenhouses. Over the years, many flats became private property and many of the loggias were closed actually becoming real bioclimatic greenhouses. This chapter specifies the actual energy savings and takes into account the potential visual impacts that would occur with an action controlled and bound by guidelines provided by the local authorities and by the Lombardy public housing company (Aler).

Valentina Dessi’

84. Solar-Assisted Ultra-supercritical Steam Power Plants with Carbon Capture and Storage

This chapter focuses on the evaluation of the potential benefits arising from the integration of concentrating solar systems into coal-based ultra-supercritical (USC) power plants with post-combustion CO2 capture (PCC). In order to offset the efficiency penalty introduced by CO2 removal, the USC-PCC plant was integrated with a concentrating solar field with direct steam generation based on parabolic trough and linear Fresnel collectors. The performance of the solar-assisted USC-PCC power plant was evaluated by means of specifically developed simulation models by using data sets for a typical meteorological year for the sites of Cagliari (Sardinia, Italy) and the North Western Australia Coast. A preliminary cost analysis was also carried out.

Giorgio Cau, Daniele Cocco, Vittorio Tola

85. A Modular Linear Fresnel Reflecting Solar Concentrator for Low-Enthalpy Processes

One of the aims of solar-thermal engineering is to develop ‘medium temperature collectors’ in the range of 70–250 °C that are suitable for applications such as cleaning, drying, evaporation, distillation, pasteurization, sterilization and cooking, as well as applications with low-temperature heat demand and high consumption rates (domestic hot water, space heating and swimming pool heating), and heat-driven refrigeration and cooling. In this work, we present an applied research on the development of a modular linear Fresnel reflecting solar concentrator (MLFRC) for heating water and steam generation at low enthalpy in the temperature range of 70–110 °C. We present a simple mathematical method to determine the distance among the reflecting elements and the angle for each one in order to avoid shading between the elements during the period of operation. We designed a non-imaging CPC cusp-type collector with a cylindrical receiver as a secondary concentrator. We also evaluated the thermal performance of MLFRC according to the Standard ANSI/ASHRAE 93:2003.

O. A. Jaramillo, J. O. Aguilar, R. Castrejón-García, N. Velázquez

86. Exergetic, Environmental and Economical Analysis of a Cogeneration Plant Connected to a District Heating Network.

Based on actual operational and economic data of an existing Rankine cycle cogeneration plant connected to a district heating network, a detailed economic and exergetic evaluation is carried out in order to study the influence of the network temperature level of the cogeneration plant efficiency, namely the sum of the electrical and thermal efficiency.

K. Sartor, P. Dewallef

87. Investigation on the Thermal Characteristics of a Bi-fluid-Type Hybrid Photovoltaic/Thermal (PV/T) Solar Collector

Known as a photovoltaic/thermal (PV/T) solar collector, this type of hybrid solar collector involves the integration between conventional PV cells and a solar thermal component. Up to now, the research in this field has tended to focus on either air or water as the working fluid. When both water and air are utilised under the same PV/T solar collector, it is seen as more appealing due to its space-saving design and range of potential applications. Known as a bi-fluid-type PV/T solar collector, this type of hybrid system is the subject of this research. For collector optimisation purposes, thermal modelling is considered important and hence, 2-dimensional (2-D) steady-state energy balance equations are derived to model the bi-fluid PV/T system during the simultaneous mode of fluid operation. However, when the fluids are to be operated simultaneously, the equations are not solvable analytically, and hence the numerical method is employed. Following this, the common useful thermal characteristic parameters of the collector, that is, the collector efficiency factor Fʹ, heat removal F R and also the overall heat transfer loss coefficient U1 cannot be determined analytically. Nevertheless, these quantities can be evaluated experimentally and graphically through computer simulations using the derived 2-D steady-state analysis. Theoretically, using the results obtained from the modelling, suitable curves are plotted of which the values of FR for the hybrid solar collector during independent mode of fluid operation for water and air and for bi-fluid configuration are computed as 0.59, 0.71 and 0.82 respectively. Meanwhile, at zero reduced temperature, the predicted thermal efficiencies are at 42.8, 51.3 and 59.2 % respectively. Experiments are then performed for steady-state analysis under the solar simulator at the Solar Energy Research Lab UiTM Perlis, Malaysia. The results obtained are found to be in good agreement with the values predicted by the mathematical model. From this study it can be concluded that the utilisation of both water and air as the working fluid under the same hybrid solar collector is seen as promising in order to optimise solar energy utilisation. The validated 2-D steady-state analysis is very useful in order to predict the collector performance under the influence of important environmental and design parameters. This study contributes as the starting platform in a research on a bi-fluid-type hybrid PV/T solar collector covering both theoretical and experimental studies.

Hasila Jarimi, Mohd Nazari Abu Bakar, Norain A. Manaf, Mahmod Othman, Mahadzir Hj Din

88. A Modified Solar/Gas Thermodynamic Hybridization Scheme in ISCC Plants for Reducing the Air-Cooled Condenser Power Consumption

The cooling systems for most existing and under construction integrated solar combined cycle (ISCC) power plants are based on air-cooled condensers (ACCs). This condensing technology limits the cycle efficiency and requires additional power consumption to run fans. The present study aims at investigating the thermodynamic feasibility of replacing the conventional bottoming steam cycle by a binary cycle, which is based on the coupling between an air bottoming cycle (ABC) and organic Rankine cycle (ORC). The advantage of the novel solar/gas thermodynamic hybridization scheme is that the ABC gets rid of the condensing process, and the ORC is more efficient for recovering heat at low/medium temperatures. The study is based on making some thermodynamic modifications on the first Algerian ISSC power plant, which is used as a reference case study. The thermodynamic simulations performed by the flow sheet software Cycle-Tempo demonstrate that the new proposed thermodynamic layout can reduce the condenser (CD) heat duty and power consumption by about 20 %. The study analyzes the sensitivity of the performance of the new thermodynamic concentrating solar power (CSP) conception applied to air temperature and heat transfer fluid (HTF) mass flow rate.

Fouad Khaldi, Mounir Aksas

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