Towards Low and Positive Energy Buildings

Europe has undergone rapid warming in recent years, resulting in frequent and intense heat waves during the past two decades. This warming trend in Europe has resulted in prolonged periods of extreme heat and amplified the atmosphere’s ability to retain water vapor. Consequently, the growing capability of moisture retention leads to more intense rainfall and storms, increasing the likelihood of more frequent flood events. These interlinked events shed light on the intricate relationship between human activities, the emission of greenhouse gases (GHG), and the dynamics of climate change, revealing its complex nature. Considering these developments, the costs associated with adapting various structures, ranging from residential homes to educational institutions and healthcare facilities, alongside fortifying flood defenses, exhibit an upward trajectory across all climate scenarios when contrasted with scenarios void of climate change impacts (with high confidence). Additionally, this accelerated warming trend has implications for the durability of materials such as wood, plastic, stone, paint, and renders, which are susceptible to degradation caused by solar radiation and hygrothermal conditions. Circular economy and energy efficiency in buildings are essential for achieving sustainability and climate mitigation. The circular economy model promotes a more responsible use of natural resources and their associated environmental impacts, with long-term strategies that preserve buildings and formulate resilient solutions with proper maintenance. Likewise, energy efficiency in the construction sector can reduce energy consumption and emissions, achieving a good balance between passive and active solutions. For example, in the EU-27, in 2021, 27% of GHG emissions came from the energy sector, 23% from industry, 14% from the residential and commercial sectors, and 3% from waste. This chapter explains the impact of climate change in Europe and the potential effects on the built environment, demonstrating how circularity and energy efficiency in buildings serve as strategies for achieving climate change adaptation and increasing sustainability. To provide a clearer understanding of these principles, the text also presents several illustrative examples.

The lurking climate-related challenges have fostered the adoption of measures to cut off energy consumption across the building sector, a main contributor to the overall greenhouse gas emissions. The Passivhaus (PH) standard has become a canonical benchmark across the EU for achieving the nearly-zero-energy building milestone. The foundation of the PH standard resides in achieving a heating demand below 15 kWh/m²·yr, by minimising heat losses, while preserving an elevated indoor air quality. In this research, the design and execution of a non-residential building, according to the PH standard, is presented. The site features a bioclimatic design, and the Passive House Planning Package tool is utilised during the design and execution phases to estimate the thermal transmittance of the building envelope, quantify thermal bridges, and calculate energy demands, all of which complied with the PH criteria. Blower door tests are performed post-execution, and the resulting air renovation rates are consistent with an airtight structure, according to the PH standard. Budgetary considerations are also presented. A comparison between the expected and final expenditure provides a useful guideline for attaining better cost-effectiveness in future PH projects.

The techno-economic assessment of energy efficiency in a university teaching building was conducted to analyse the feasibility of investments in energy optimization improvements within this educational environment. This evaluation focused not only on reducing energy consumption but also on optimizing available energy resources. The methodology involved an energy analysis, performance simulations, and a detailed economic analysis, considering initial, operational costs, and benefits throughout the building's lifecycle. The results aim to identify whether the implementation of efficient lighting systems, adequate insulation, and renewable energy sources can generate significant economic savings and a notable reduction in energy consumption in the teaching building. Additionally, the optimization of climate control systems was highlighted as a key opportunity, and the positive influence of incentive policies and financing in promoting energy efficiency in educational settings was acknowledged. It was concluded that investments in energy efficiency are beneficial both economically and environmentally for university buildings, contributing to long-term sustainability and the reduction of operational costs.

This chapter analyzes the safety conditions in battery rooms for renewable energy installations, focusing on sizing, ventilation, and classification according to the ATEX directive. For this purpose, the applicable European regulations are used as a reference to determine the classified areas according to fire and explosion risks, as well as the required safety distance and ventilation. An example application for a 24-V lead-acid battery is presented. The chapter also discusses safety measures for battery rooms that produce hydrogen and oxygen during the charging process, with reference to the technical reference specifications for determining the required hazard distance and ventilation openings. Graphical results are provided for the different battery types and voltages analyzed. Finally, it is concluded that the measures established by the new European application standard need to be adapted to comply with current legislation.

Residential buildings account for a significant share of the total energy consumption in the European Union (EU). With the European Commission estimating that 75% of Europe’s building stock is energy inefficient, renovation of existing buildings is crucial to help reduce global energy consumption and CO₂ emissions. This study provides insight into the energy performance of the residential building stock in the most populated city of Andalusia, Seville. The data contained in 45,920 energy performance certificates (EPC) of dwellings were processed and analysed according to the type of dwellings (single-family dwellings and individual dwellings in multi-family blocks), construction period, and their district location. The results obtained revealed that most of the dwellings have a poor energy performance rating (with approximately 66% classified under label E). The districts with the highest percentages of dwellings with the worst-energy performance (EPC “G” and “F”) are D4 Cerro-Amate district (36%) and D2 Macarena district (34%). The bottom-up approach used in this study provides useful information to assess the energy performance of Seville’s residential buildings on the urban scale. These findings can help define renovation strategies and public energy policies targeting districts having buildings with poor energy performance.

This chapter delves into the critical issue of adaptive thermal comfort in tropical countries, with a particular focus on contexts such as Vietnam, where a thriving economy is bringing new lifestyles associated with more energy-dependent air conditioning systems. On-site monitoring and a survey distributed to residents were used to collect information on indoor environment and adaptive comfort. Overall, our main results show that indoor temperatures of about 28 °C and relative humidity of 75% can be comfortable for the majority of residents and that air conditioners are rarely used. In conclusion, our findings emphasize the importance of developing thermal comfort models adapted to local conditions and cultural backgrounds.

Scientific research has identified different adaptive behaviours that influence thermal comfort in buildings. Depending on factors such as ventilation mode, building type, or occupant age, those user actions are diverse and include air conditioning and fan usage, window and/or door opening, curtain and/or blind usage, cloth adjustment, and beverage drinking, among many others. Especially in the Mediterranean summer climate, façade openings are likely to be a direct inflow of hot air. Focusing on the case study of a residential building with a robust envelope, this chapter aims to assess the impact of keeping windows open on indoor temperature and relative humidity.

The Galapagos Islands are the world’s second-largest marine reserve, declared a World Heritage Site in 1978 by UNESCO, and are located in a hot and humid climate zone. Their fragile ecosystem is susceptible to the adverse effects of global warming. The increase in ambient temperature can lead to a rise in the energy requirement to achieve thermal comfort in the residential sector, mainly made up of naturally ventilated dwellings. Several studies have been developed for Ecuador regarding the impact of passive strategies in naturally ventilated dwellings on the continent, but no studies have been conducted in the Archipelago. In this sense, the present study aims to evaluate the vulnerability of a naturally ventilated house in the Galapagos, using adaptive models based on temperature and thermal stress index based on temperature and humidity. The results showed adequate levels of thermal comfort, according to UNE-EN 16,798–1:2020. However, the heat index revealed that for approximately 40% of the time the dwelling was occupied, the occupants were highly vulnerable (32 °C < HI < 52°), increasing the likelihood of heat cramps, heat exhaustion, and heat stress.

This chapter addresses the critical issue of soil waterproofing, often overlooked despite its significant environmental impact. Soil waterproofing, primarily caused by sealing materials like asphalt and concrete, disrupts natural soil functions, exacerbating land degradation and water consumption. The study focuses on the city of Alcala de Guadaíra, where 90% waterproof soil has led to numerous problems since 1900, including floods and landslides. The research proposes solutions at both private and public levels, emphasizing sustainable urban drainage systems (SUDS) and private building interventions. These solutions involve intermediate storage on private properties, functioning as energy rooftops utilizing water as an energy source. The findings underscore the potential of public–private cooperation in managing urban rain, highlighting its effectiveness in preventing and mitigating floods.

This chapter aims to evaluate the feasibility of supplying a building in Seville with photovoltaic (PV) energy to meet its heating, ventilation, and air conditioning (HVAC) and domestic hot water (DHW) needs according to the standards set by the Spanish Technical Building Code (CTE). Using the PVGIS calculator, it was found that complete energy supply could be achieved from December to March, with excess energy generated, but PV production falls short in the other months. Additionally, the study assesses HVAC and DHW energy consumption under various climate scenarios (RCP2.6, RCP4.5, and RCP8.5) for the years 2050 and 2100, revealing a slight decrease in heating demand and a significant increase in cooling demand due to climate change. The chapter also explores the potential of using higher efficiency PV panels available in the market to bridge the gap identified, comparing these findings with the current CTE specifications. This analysis highlights the need to reformulate the CTE to promote the construction of nearly zero-energy buildings and examines the implications of climate change on future energy consumption patterns.

This chapter explores the application of geographic information systems (GIS) to analyse and project urban heat islands (UHIs) in the Yucatan Peninsula. Currently, UHIs are a significant problem in developing cities, especially in regions with tropical climates. The chapter presents a detailed methodology to detect UHI's presence and temporal growth from the processing and treatment of satellite images supported by climatological data measured in situ. Take the City of Francisco de Campeche case study, which has witnessed remarkable urban growth in the last decade and is estimated to continue in subsequent years. The surface temperature of the city and the vegetation index are analysed, and it is observed that it is possible to correlate both phenomena and indicate the increase in temperature associated with it. For the case study, the increase was 1.4 °C. Finally, the chapter presents proposals for mitigating the increase in temperature in the peninsular city based on reforestation and how these are linked to previous studies.

The impact of tourism on the behavioural patterns of residential occupants can be significant. Noise generated by tourist activities may restrict the resident ability of adaptation during hot periods (e.g. limiting opening windows). This issue can be even more severe in future climate change scenarios. In this context, the aim of this study is to analyse the impact of restricted natural ventilation practices on sleeping thermal comfort. The analysis focused on the summer period (e.g. July and August) when natural nocturnal ventilation can effectively cool residential spaces. A case study of a dwelling in the Albaicín neighbourhood of Granada was selected for this purpose. Simulations were conducted for both current and future scenarios based on representative concentration pathways (RCP 2.6, RCP 4.5, and RCP 8.5). The thermal comfort of the dwelling was assessed using the PMV model adapted for the night-time conditions. The findings indicate that limiting natural night ventilation leads to an increase in hours of thermal discomfort. For all future scenarios, the values obtained indicate that the percentage of hours of sleeping thermal discomfort is higher compared to the current scenario.