Nano and Biotech Based Materials for Energy Building Efficiency

This chapter starts with an overview of the unsustainable energy consumption which is due to fast population growth and related greenhouse gas emissions. The case of energy efficiency building is introduced. A short analysis of the ambitious European nearly zero-energy building (NZEB) target is presented. Shortcomings of current materials concerning energy building efficiency are reviewed. Examples of promising nano- and biotech-based materials for energy building efficiency are briefly covered. A book outline is presented.

Nowadays in many countries, the building sector is the largest energy consumer and one of the best ways to reduce energy demand of buildings is the reduction in heat losses through the envelope. In this scenario, insulating materials with aerogels have growing interest and new applications such as insulating aerogel-based renderings are in development. This chapter deals with the analysis of superinsulating applications for building envelope such as aerogel-incorporated concrete- and aerogel-based renders. After an overall analysis of the market trend for these innovative systems, the rendering compositions, the physics, thermal, acoustic, and hygrothermal properties of aerogel-based renders are discussed. In situ applications of the new developed render are analyzed and the potential of the investigated materials is highlighted, by considering experimental measurements in Sect. 2.4. Finally, a comparison with traditional solutions and the future trends are considered.

The chapter deals with the potential of highly energy-efficient windows with silica aerogel for energy saving in buildings. Aerogel is a low-density nanostructured porous material with very low thermal conductivity (about 0.018 W/m K for translucent granular aerogel at room temperature) and excellent acoustic insulation. It is ideal for energy saving in buildings, also due to its good optical transparency. The characteristics of the raw material (silica aerogel for windows: monolithic and translucent granular) are illustrated with general information about the production process, the main chemical and physical properties, and a market overview; then, nanogel windows are discussed and thermal, visual, and acoustic performance are highlighted. A useful worldwide market overview about the commercial products and the main manufactures is also included. Finally, a state-of-the-art review of nanogel windows in building applications is discussed: the potential of the investigated solutions is described by both experimental results and simulation models of the aerogel windows performance, referring to different case studies. Future research, market trends, and costs are also discussed.

This chapter outlines the state of the art of the thermochromic glazings that are able to provide energy efficiency by letting in more solar energy at a low temperature than at a high temperature, thereby leading to diminished need for space cooling. Thermochromic technology employs VO₂-based materials as thin coatings or nanoparticle composites. For coatings, suitable switching between conditions with high and low solar energy throughput at low and high temperature, respectively, can be achieved by replacing some of the vanadium atoms by tungsten, and luminous transmittance can be enhanced by the addition of some magnesium. Antireflection (AR) coatings can give further improvements. By going to nanoparticle composites with VO₂ dispersed in a transparent host, it is possible to combine high luminous transmittance with large modulation of solar energy transmittance. This modulation ensues from plasmonic absorption in metallic-like VO₂ nanoparticles. Thermochromic glazings are not yet (2015) available as products, but the rapid development during recent years has led to performance limits that appear very interesting for practical applications. Energy modeling of buildings with thermochromic glazings points at very substantial savings. A further development may be to integrate thermochromic nanoparticles in laminated electrochromic devices.

Can photosynthesis of leaves evolve glass into a photoactive energy system? To create a transculent material that emulates the chemical reaction cycle of leaves by endothermic principles as a metabolic cycle for thermal conductance heat targeting. The evolution of glass envelopes into a photoactive adsorption layer, at an integrated multiscale level, in response to climatic regionalization. Nature’s biological systems are living multifunctional mechanical information systems of chemical composition. They have the ability to learn and adapt to changing climatic conditions by self-regulation of solar adsorption, to achieve thermal management. These self-programmable controls of adaptive material performance will progress the surfaces of a skyscraper, from being a mere material entity to a dynamic one. This response to real-time performance change by the hour, season and weather conditions is exothermic management of a glass material as an energy flow cycle. The transformation of glass envelopes into a dynamic energy system that responds to the environment and contributes to the planet’s energy needs. This chapter focuses on the use of an optically transparent, thermal energy adsorbing glass composite that is in the conceptual phase. Progression of this has just entered the laboratory testing of the first phototype composite.

This chapter presents a method to evaluate the performance and to support product development of adaptive micro- and nanobased material and technologies, integrated into buildings. In the first section, an introduction to adaptive building concepts is provided, followed by an overview of adaptive micro- and nanomaterials for building envelope integration in the second part. The role of building simulation in the development of innovative adaptive materials and technologies is discussed in the third section, together with the limitations and challenges of predicting by means of computation the performance of adaptive materials. The most advanced methodologies and the characteristics of the tools to support product development for building-integrated adaptive materials and technologies are presented in the fourth section. Finally, a case study is described to demonstrate and illustrate some of the potential of those methodologies, consisting in the evaluation of the performance of future generation adaptive glazing.

Vacuum insulation panels (VIP) represent a state-of-the-art high-performance thermal insulation solution. The pristine non-aged centre-of-panel thermal conductivity value for a VIP can be as low as 0.002–0.004 W/(mK) depending on the core material. Normally, declared average values accounting for thermal bridge effects and ageing during e.g. 25 years are to be given, typical an effective thermal conductivity value between 0.007 and 0.008 W/(mK) for VIPs with fumed silica cores. VIPs enable highly insulated solutions for building applications, both for the construction of new buildings and for the renovation of existing buildings, and may hence be a measure to reduce the energy usage in buildings without having to employ very thick building envelopes. This study gives a state-of-the-art review of VIP products found available on the market today and explores some of the future research possibilities for these products. The application of nanotechnology is regarded as a promising pathway for achieving and improving both vacuum and non-vacuum based high-performance thermal insulation materials. During the last years, VIPs have been utilized with success for building applications in increasing numbers, where one of the main driving forces is the increased focus on e.g. passive houses, zero energy buildings and zero emission buildings. Thus, VIPs are now in the early market stages as a building product. The implementation of VIPs in various building constructions has lead to an increased interest in the utilization of this product, both in new and refurbished constructions. Even though there is not enough data to conclude the effect over a lifetime of a building yet, the immediate result in decreased energy usage can be seen. However, the challenges of guaranteeing a set of lifetime expectancy, along with high costs, are some of the major reasons why VIPs are met with a certain scepticism in the building industry. Aiming to give better quality assurance for the users, make further advances in VIP envelope technologies and the development of VIP core materials, along with a further cost reduction, represent crucial aspects for VIPs to become a competing thermal insulation solution for buildings.

Energy efficiency in buildings is a vital factor to be addressed in every stages of development of building envelopes, since buildings consume almost one-third to one-quarter of energy being produced globally. In the spectrum of techniques available to cater the building cooling and heating load demands, there has been a continuous quest toward latent thermal energy storage (LTES) systems for achieving energy redistribution requirements in buildings. The interesting fact about the LTES systems relies on the phase change materials (PCMs) being used to store and release heat energy depending upon the thermal load demand. A step ahead, the utilization of nanomaterials paves the way for accomplishing enhanced thermal performance of such PCMs on a long run. This chapter is exclusively dedicated to provide better understanding of a variety of nanomaterial-based PCM composites for thermal energy storage and energy efficiency in buildings. This is an ever-growing as well as emerging field of interest to wide scientific and engineering communities globally. The nucleus of this chapter is focused on the enhancement of thermal energy storage capabilities of NanoPCM composites which would contribute for achieving improved energy efficiency in buildings.

Cool materials represent an interesting and acknowledged solution able to produce a threefold benefit: the reduction of cooling energy needs in buildings, the mitigation of the urban heat island phenomenon, the counterbalance of global warming trend at larger scale. In fact, they are environmentally friendly and relatively cost-effective materials characterized by high solar reflectance and infrared thermal emittance properties. Therefore, they are helpful to mitigate the urban microclimate by decreasing air and surface temperature when applied over building envelopes, i.e., roofs and walls, and urban paving surfaces. This chapter will discuss about the key research contributions to the development and testing of such cool materials’ effectiveness with a specific focus on the material engineering and characterization. More in details, the recent nanoscale developments will be addressed and the main applications of cool materials will be discussed in order to provide quantitative and quantitative assessment of the effectiveness of such technology for building energy efficiency.

This chapter shows the potential of the architectural integration of semi-transparent photovoltaic (STPV) systems for improving the energy efficiency of buildings. The research presented focuses on developing a methodology able to quantify the building energy demand reduction provided by these novel constructive solutions. At the same time, the design parameters of the STPV solution are analyzed to establish which of them have the greatest impact on the global energy balance of the building, and therefore which have to be carefully defined in order to optimize the building operation. In summary, this work contributes to the understanding of the interaction between STPV systems and buildings, providing both components manufacturers and construction technicians, valuable information on the energy-saving potential of these new construction systems and defining the appropriate design parameters to achieve efficient solutions in both new and retrofitting projects.

Organic photovoltaics is now reaching a more mature stage and new applications are emerging to its direct use as active elements into buildings. This chapter illustrates the more recent developments of organic photovoltaic technology focussing on the description of semitransparent devices integrated into glazing systems for energy efficiency in buildings. It describes briefly the fundamental functioning principles of Hybrid and Organic (HOPV) devices that includes Dye Sensitized Solar Cells (DSC), polymeric cells as well as new emerging technologies, followed by a description of the actual studies carried on building integrated HOPV. Last section presents some showcases of HOPV integrated into buildings.

In this chapter, the sustainable development of rigid polyurethane foams for heat-insulating applications is described. Firstly, the most important aspects as the use of bio-based and environmentally friendly components in the formulations of polyurethane systems as well as requirements for heat insulating of buildings are presented. Next, the complex mechanism of heat transport in porous materials is discussed including the influence of cell structure on the thermal conductivity of final rigid polyurethane foams. In the two last parts of this chapter, the most important components used in various methods of polyurethane foam synthesis are described. Moreover, the effects of bio-components and foaming conditions on the cell structure and physical mechanical properties of rigid polyurethane foams are discussed.

Petrochemical-based plastics that are used in building construction produce hazardous non-biodegradable wastes after demolition of the buildings or temporal constructions that create logistics and disposal problems. Recent investigations on bio-based plastics reveal opportunities for a new and sustainable construction material made from the renewable organic sources that due to biodegradability can be left in soil or composted after demolition because of biodegradability. Bioplastics also have the potential to lead to the rise of new building materials with low-embodied energy, thus contributing to energy building efficiency. However, the current cost of pure bioplastics is higher than the cost of petrochemical plastics. To improve the cost efficiency of bioplastics, inexpensive raw materials are needed. Potential feedstocks for bioplastics production include negative-, zero- or low-cost by-products of acidogenic fermentation, pyrolysis oil from lignocellulosic biomass and waste, organic fractions of municipal solid waste, reject waters, primary and secondary sludges from wastewater treatment plants, to mention a few. Cost reduction can be achieved through cost-efficient fermentation technologies based on continuous and septic cultivation of mixed bacterial cultures and production of crude composite bioplastics as construction material with low-embodied energy.

The increasing interest about reaching a zero net balance energy building has mainly been focused on issues such as insulation, facades and smart and productive envelopes, and mechanical systems, that is, on the operational energy saving. Nevertheless, recent studies prove that the construction stage of a building is responsible for a significant amount of the total energy consumed by the same along its life. There are several open research lines starting from the interest in the embodied energy, and we may summarize the main ones in the following: scientific criteria to decide the material with less impact; improvements in the production of existing materials; advanced, intelligent, and composite materials, etc. Within these lines, it has taken special importance that related to bio-inspired materials. The work carried out by our team has investigated in the geometric patterns of the natural forms instead of the before-mentioned lines, and it has investigated how the physical configuration of the matter contributes to its reduction. Our work analyses how nature organizes its bearing systems and how nature uses the minimum energy possible, having developed, along millions of years, strategies to reach the most efficient, lightweight, and cooperative systems. Our work deals about how nature reaches the appropriate embodied energy lightening material in its structural forms at all scales, macroscopic and microscopic using emptiness. The tree’s vascular bundle structure, the cellulose cell morphology, and the bird’s pneumatic bone constitution show how vacuum or emptiness is as important as matter in structural resistance and stability. Application of this knowledge can be done for building technologies, with procedures to reduce weight and structural material as a way of saving energy.

There is a high demand of energy consumption due to the increasing population, industrial expansion, and development plans. However, the increasing cost of energy and the negative impact on the environment by energy production plants have resulted in the need to find means to substantially reduce energy consumption. Buildings are one of the main factors contributing to the world energy consumption. About two-thirds of the total energy is used for the buildings. It is essential to reduce energy consumption of buildings by finding more effective thermal insulation materials. Cellulose is a green, cheap, and abundant material with low thermal conductivity. Its combination with aerogel structure forms a novel and effective heat insulation material known as cellulose aerogel. Cellulose aerogels can be fabricated from bacterial cellulose, wood/paper pulps, or cellulosic wastes. The aerogels become water-repellent after being treated with silane reagents via a chemical vapor deposition (CVD) method. They show highly porous structures with good flexibility, high stability, and extremely low thermal conductivities. These characteristics make them promising for thermal insulation applications.

Microalgae are a potential candidate as a feedstock for biofuels and bioproducts in addition to remediate flue gas streams and wastewater. On an industrial scale, algae are grown in photobioreactors of which there are currently three styles: open, closed, and algal film. Open photobioreactors have the lowest capital cost, but suffer from lower productivity and contamination issues, while closed photobioreactors have high capital cost, but culture conditions are easier to control. Algal film photobioreactors are still in the developing phase, but show promise in reducing downstream processing costs due to their high algal biomass concentration. Algae are used to produce fuel products such as biodiesel, biocrude, ethanol, and biogas as well as producing high-value-added products. There are challenges with growing algae for fuel products associated with the high capital cost and processing costs of algae. To mitigate the high capital costs, building-integrated photobioreactor is a promising solution since the photobioreactor can serve multiple functions such as dissipating heat and removing CO₂ from the flue gas stream. In these applications, closed photobioreactors are the most promising since they have a wide range of configurations and culture control.

The research presented addresses the production of biomass in architectural facade, making these facades photobioreactors, PBRs, of micro algae cultivation. These aquatic microorganisms and simple structures grow from the process of photosynthesis and absorption of CO₂. The integration of what up to now was an industrial system in the architectural envelope opens new and interesting alternatives to renewable energies. We present different cases of PBRs on façades, with both new construction and renovation or energy-efficient rehabilitation. In all the examples, currently under development, it has sought a central objective economic feasibility and energy productivity. The designs range from simple and easily standard proposals done with existing materials in the market and economic assembly, to unique designs, with manufacturing singled out, which bring high representative value. The entire catalog of architectural design solutions is accompanied by industrial systems similar to those described for operation as PBR. In the study costs of façades transformed into PBRs are compared to standard façades achieving highly competitive values at a certain scale factor. Other factor developed is the increase of thermal regulation in the interior of a building because of the isolation produced by the inclusion of architectural PBRs and circulating water with microorganisms in the constructive elements of the models. Again the results open a promising future to this new concept of facades increasing both passive and active energetic values.