Search

The building sector plays an important role in the global climate change mitigation objectives. The reduction of CO2 emissions and energy consumption in the building sector has been intensively investigated in the last decades, with solar thermal energy considered to be one of the most promising solutions due to its abundance and accessibility. However, the discontinuity of solar energy has led to the study of thermal energy storage to improve the thermal performance of solar thermal systems. In this review paper, the integration of various types of phase-change materials (PCMs) in transpired solar collectors (TSC) is reviewed and discussed, with an emphasis on heat transfer enhancements, including nanomaterials. Thermal energy storage applied to TSC is studied in terms of design criteria, materials technologies, and its impact on thermal conductivity. This review highlights the potential of nanomaterial technology integration in terms of thermal performance improvements. The utilization of nanomaterials in solar walls holds the potential to significantly enhance their performance. The integration of diverse materials such as graphene, graphite, metal oxides, and carbon nanoparticles can pave the way for improving thermal conductivity. [ABSTRACT FROM AUTHOR]

The number and coverage of climate change mitigation policies have increased in the past twenty years, but important policy adoption gaps remain. To analyse sectoral climate policy in the G20 over time (2000–2019), we compiled a dataset of climate change mitigation-relevant policies and identified 50 key policy options that constitute a comprehensive sectoral climate policy package. Approximately half of these policy options are not widely adopted. Adoption is particularly low for policies that aim to: phase out coal and oil and mandate energy reductions in electricity and heat supply; reduce industrial process emissions and incentivise fuel switch in industry; design urban planning strategies for retrofits; and support the use of renewable energy for cooking and heating/cooling purposes in buildings. Policies to remove fossil fuel subsidies and support carbon dioxide removal also need substantial improvement. However, many policy adoption gaps exist as the coverage of at least one policy option could be improved in each sector. Policy adoption gaps leave at least one-tenth of the G20's emissions completely uncovered. Filling these gaps is fundamental to realize the full mitigation potential of existing policy options and to advance the transition towards global net zero greenhouse gas emissions. Mitigation-related policy options can be presented as a matrix by sector to shed light on what constitutes a comprehensive climate policy package; looking across sectoral climate policies helps to unpack and clarify the status of adoption. Policy adoption gaps exist in all sectors. Increasing the sectoral coverage of climate policies will help to ensure that all relevant sectoral emissions and mitigation areas are considered in national mitigation efforts. Even if an increase in policy coverage alone does not ensure emission reductions, the absence of policy coverage indicates that emissions can still be further reduced and that a portion of global emissions remain uncovered by policies. Despite the observed increase in the number and coverage of climate policies, slow progress towards reducing global emissions and meeting the collective Paris climate goals calls for more comprehensive climate change mitigation policies. Filling policy adoption gaps presents a concrete strategy to improve sectoral, national and global climate policy. [ABSTRACT FROM AUTHOR]

Jevons Paradox has fundamental implications on sustainable development and the UN Sustainable Development Goals (SDGs). The paradox states that technological improvements aiming to increase the energy efficiency risk causing a rebound effect, and an increase in demand, production, and resource exploitation. Third world countries undergoing early-stage technological development may be particularly vulnerable, but it is also relevant in complex economic systems, where policymaking on climate and energy building on insufficient knowledge and attention to rebound effects can impair the desired outcome in terms of climate change mitigation, resource use and sustainable development. [ABSTRACT FROM AUTHOR]

High-resolution maps of the urban heat island (UHI) and building energy consumption are relevant for urban planning in the context of climate change mitigation and adaptation. A statistical–dynamical downscaling for these parameters is proposed in the present study. It combines a statistical local weather type approach with dynamical simulations using the mesoscale atmospheric model Meso-NH coupled to the urban canopy model Town Energy Balance. The downscaling is subject to uncertainties related to the weather type approach (statistical uncertainty) and to the numerical models (dynamical uncertainty). These uncertainties are quantified for two French cities (Toulouse and Dijon) for which long-term dense high-quality observations are available. The seasonal average nocturnal UHI intensity is simulated with less than 0.2 K bias for Dijon, but it is overestimated by up to 0.8 K for Toulouse. The sensitivity of the UHI intensity to weather type is, on average, captured by Meso-NH. The statistical uncertainty is as large as the dynamical uncertainty if only one day is simulated for each weather type. It can be considerably reduced if 3–6 days are taken instead. The UHI reduces the building energy consumption by 10% in the center of Toulouse; it should therefore be taken into account in the production of building energy consumption maps. [ABSTRACT FROM AUTHOR]

Curbing the increasing carbon emissions from residential and commercial buildings would be of great importance for achieving China's NDC (Nationally Determined Contributions) target. However, studies on city-level emission pathways and mitigation strategies aiming at building sector are still far from sufficient, especially for regions in Central China. Considering the large potential for further building energy demand increase within this area, this study focuses on Hubei, one of the first batch low-carbon pilot provinces to investigate the possibility of earlier emission peak and reduction potentials by prefecture-level city. When downscaling provincial energy use and emissions estimated from local government plans and academic research, statistical data was applied to exploring the relationship between building energy consumption and socioeconomic variables, then spatial allocation factor could be generated after combining with projections of grid-level GDP and population. Results show that by replacing coal and natural gas (NG) that are currently the main heating & cooking energy sources with more electricity and renewable energy, emissions from the building sector would peak around 2025, which is especially true for three major big cities with higher emission growth rate due to population and urban expansions. Moreover, when considering additional improvement on building energy efficiency, provincial reductions burden would be more evenly distributed among cities. It is implied that by formulating tiered mitigation policies for cities at various economic development levels, including decarbonization of energy structure and improvement of energy efficiency, more cities would peak their emissions from the building sector before 2030. This analytical framework innovatively create a multi-city platform for the simulation of building sector mitigation pathway to facilitate cities' low-carbon development. Image 1 • A spatial downscaling framework was developed for building energy consumption and emission projections on city-level. • Building sector mitigation potential for a low-carbon region with limited supporting data was quantified with this method. • Emission pathway and reduction contribution of the building sectors of multiple cities were estimated. • Electrification and greater renewable energy use in buildings would make emissions peak earlier for more developed cities. • Further building energy efficiency improvement helps increase the mitigation contribution from the less developed cities. [ABSTRACT FROM AUTHOR]

COP21 led to an agreed target of keeping the increase in global average temperature well below 2 °C compared to pre-industrial levels. Due to its high potential for decarbonisation, the building stock will have to contribute a reduction of at least 85-95% in greenhouse gas (GHG) emissions until 2050. Policy-driven scenario analysis is, therefore, important for assisting policy makers who are called upon to develop a corresponding framework to achieve those targets. The research questions of this paper are (1) Do long-term scenarios (in particular those labelled as ambitious) of energy demand in buildings reflect the COP21 target? (2) If not: What are reasons for the gap in terms of scenario assumptions, in particular, regarding the policy framework in the corresponding scenarios? The method builds on following steps: (1) analysis of GHG-emission reduction in scenarios from the policy-driven, bottom-up model Invert/EE-Lab; (2) compare scenarios among each other and analyse if they are in line with Paris targets; (3) discuss possible explanations for any gaps and the implications on future modelling work and policy making. Results show that scenarios labelled as being "ambitious" for several EU MSs achieve GHG-emission reductions of 56-96% until 2050. However, just 27% of these ambitious scenarios achieve reductions above 85%. The reason is that policies for most of the modelled scenarios were developed together with policy makers and stakeholders, who—for different reasons—were not willing to go beyond a certain stringency in the modelled instruments. In particular, this was the case for regulatory instruments, which show to be essential for achieving ambitious climate targets. [ABSTRACT FROM AUTHOR]

Background: Driven by climate change mitigation, EU countries are committed to improve energy efficiency of their building stock by implementing the energy performance of buildings directive (EPBD). Should higher energy efficiency result in better indoor environmental quality (IEQ), this policy could also be seen as an opportunity to improve public health across Europe.Objectives: This paper focuses on the assessment of the effects of energy retrofits on occupant satisfaction with IEQ and health in multifamily buildings.Methods: Data on occupant satisfaction with IEQ and health were collected from the occupants of 39 Finnish and 15 Lithuanian multifamily buildings (an average of five apartments per building, one adult per apartment) both before and after energy retrofits (such as improving thermal insulation, windows, heating and/or ventilation systems). Parallel to the data collected from the occupants, data on several IEQ parameters, including temperature, temperature factor, and air change rate, were collected from their apartments. Moreover, data from seven Finnish and five Lithuanian non-retrofitted control buildings were collected according to the same protocol.Results: Occupant satisfaction regarding indoor temperature was associated with both retrofit status (OR 5.3, 95% CI 2.6-11.0) and measured IEQ parameters (indoor temperature OR 1.4 per 1 °C increase, temperature factor OR 1.1 per 1% increase, and air change rate OR 5.6 per 1/h increase). Additional positive associations were found between retrofit status and occupants reporting absence of upper respiratory symptoms (OR 1.8, 95% CI 1.1-2.9) as well as not missing work or school due to respiratory infections (OR 4.1, 95% CI 1.2-13.8), however, these associations were independent of the measured IEQ parameters.Conclusions: There seems to be a strong subjective component related to the observed changes in occupant satisfaction with IEQ and health as a result of energy retrofitting in buildings. Further studies are needed to verify the actual mechanisms, as well as possible long term effects. [ABSTRACT FROM AUTHOR]

The interpretation of the energetic signature of a city, taken as an integrated urban energy system, has been attempted in this study. Instead of the customary bottom-up approach, we successfully identified an average gray-box dynamic model by inversion of measured hourly system load and weather data. The third-order lumped-parameter thermal network model is derived by applying energy conservation principles to major nodes representing buildings, paved surfaces and urban canopy. This powerful data-driven approach offers deep insights into the thermo-physical properties of the built structures as well as the coupling of buildings and the urban microclimate. In particular, the Urban Heat Island (UHI) intensity has been determined to be close to 2 °C while the corresponding electricity cooling load penalty is 12%. [ABSTRACT FROM AUTHOR]

Increasingly compact high density urban development in cities has allowed urban heat island effect to take root and increase the energy consumption of commercial buildings to cool its interior. Although the extensive use of glass façade has allowed these buildings to harness daylight to light up the building interior, it has also allowed substantial solar energy to enter and heat up the building. This is especially critical in hot and humid tropical regions, where reducing solar heat gain, while minimizing heat loss are equally important. The evaluation of glass performance is often conducted using active measurement, which make use of known radiant source. However, this type of setup cannot be applied for testing under non-controlled weather. Though a passive test procedure can be conducted under actual weather conditions using the outdoor test chamber, it is not suitable for a large-scale testing and fast on-site characterization. In addition, this test is limited to the fabricated glazing and thus could not predict potential issues in the design stage. Advances in simulation techniques have enabled building professionals to evaluate the glass façade of a building at the design phase. However, the typical simulation tools are unable to integrate the high performance glazing description, which is generated thanks to advances in coating technology, using the existing glass models. Furthermore, these tools are often lack of local weather models that plays an important role in accurately assess the solar heat gain admitted into the building. This paper provides useful information on different high performance glass façades and assesses their applicability for green building in a tropical country like Singapore. The research effort encompasses an improvement in the methodology used to predict solar irradiance through building glass that incorporates seamlessly the advanced glass models into the solar irradiance simulation. In addition, this will show how to effectively estimate the actual sky behavior via a measured data-based optimization process. A comparison of the simulation results with the measurements from an outdoor climatic test chamber under tropical climate will be performed. An assessment based on the typical glass performance metrics (e.g. U-value and Solar-Factor) together with measured energy savings obtained with the use of different high performance glass façade compared to clear float glass as a control will also be presented. [ABSTRACT FROM AUTHOR]

Recently high reflective materials such as high reflectance paint for wall and solar control film or Low-E glass for window are utilized as a building façade aiming for reducing the cooling load of the buildings. From a view point of the direction of reflected rays, almost half of the energy goes upward due to diffuse reflection in case of paint, meanwhile most of energy goes down to the ground due to specular reflection by the glass. This leads to deterioration of thermal environment of surrounding buildings, and is one of causes of urban heat island. Retro-reflective façade materials are promising candidates for mitigation of urban heat island. The authors successfully developed a new type of transparent solar control window film Albeedo that selectively reflects near-infrared rays towards the sky. The film has a saw-tooth microstructure with a spectrally-selective reflection layer. This microstructure is able to reflect infra-red rays toward the sky. The upward reflectance of the film is measured by our custom made spectroscope. Firstly, the sample is placed in a large scale integrating sphere. Then, solar energy absorptive materials are arranged under the sample to absorb the transmitted component and positioned where the downward reflection goes to. Finally, a halogen lamp irradiates the sample at an incident angle of 60° as a light source. The result of the upward reflectance of near-infrared is about 33%. We also conducted field test measurements to evaluate the energy savings of the interior of the building and the degree of reflection of the exterior. [ABSTRACT FROM AUTHOR]

This paper uses an example of an architect designed and occupied suburban house in the temperate climate of Perth, Western Australia to demonstrate how climatic design and low-technology active systems can deliver thermal comfort in average climatic conditions. However when thermal conditions are more extreme acceptable temperature ranges may not be met. Thermal monitoring in the house over eight days of extreme temperatures in summer and winter shows that acceptable temperature ranges may not be met in winter. During extreme winter conditions south facing rooms fall below comfort conditions by up to 3 K in the late night and early morning. The conclusion drawn is that in naturally ventilated buildings personal and psychological behavioral adaptation must go hand-in-hand with climatic design. This behavioral adaptation may become more important in the future if current climatic extremes become the new normal. [ABSTRACT FROM AUTHOR]

Building energy performance (BEP) is an ongoing point of reflection among researchers and practitioners. The importance of buildings as one of the largest activators in climate change mitigation was illustrated recently at the United Nations Framework Convention on Climate Change 21st Conference of the Parties (COP21). Continuous technological improvements make it necessary to revise the methodology for energy calculations in buildings, as has recently happened with the new international standard ISO 52016-1 on Energy Performance of Buildings. In this area, there is a growing need for advanced tools like building energy models (BEMs). BEMs should play an important role in this process, but until now there has no been international consensus on how these models should reconcile the gap between measurement and simulated data in order to make them more reliable and affordable. Our proposal is a new generation of models that reconcile the traditional data-driven (inverse) modelling and law-driven (forward) modelling in a single type that we have called law-data-driven models. This achievement has greatly simplified past methodologies, and is a step forward in the search for a standard in the process of calibrating a building energy model. [ABSTRACT FROM AUTHOR]

The paper draws from the general literature on energy efficiency and historic buildings to explain the importance and potential of user-driven energy efficiency in historic buildings. It is the first review that places the user as a central object of study in the research field of historic buildings and energy efficiency. Relevant interdisciplinary topics and research results that make up the core of the field are presented and discussed in relation to user behaviour and its impact on energy consumption. The paper also investigates how user behaviour aspects can be integrated in a procedural approach to energy refurbishment in historic buildings. Research and experience from the building stock in general clearly shows how a user's awareness and behaviour, such as choice of temperature, zone heating and controlled airing, can have a significant effect on energy demand yet have no physical impact on the building. However, this has not received enough attention with regards to the historic building stock, where many physical energy efficiency measures can have negative impacts on the historic qualities of the building. Modification of user behaviour can therefore be a way not only to reduce energy demand but also to minimise the physical impact of increasing energy efficiency on historic buildings. The paper concludes that the current research agenda on historic buildings and energy efficiency has broken much ground but remains focused more on technical solutions than bottom-up user perspectives. Two main topics are identified as key barriers and future research fields: First, energy performance modelling is identified as a general barrier to developing sustainable strategies that promote user impact in historic buildings. Accurate energy modelling of historic buildings is a complex field reliant on the thermal interplay between user-building and building-district. Improved knowledge and intensified research is necessary to avoid distorted energy modelling results and unwanted rebound effects. Practical tools also require that the modelling can be used for trade-off scenarios where other sustainability aspects such as cultural heritage and economy are weighed in. Second, awareness raising in order to foster a deeper understanding and knowledge about the construction, system and cultural heritage values of a building is proposed as a key ingredient and driver for improved and sustainable energy behaviour. The paper argues that while user-driven energy efficiency represents an important resource for fostering less energy-demanding and less intrusive interventions in historic buildings, there are no guarantees for achieving the planned level of energy efficiency without taking into account user behaviour and the actual operation and energy performance of the historic building. To do this without risking negative consequences, improved decision-making processes are needed on policy, building and user level. An interdisciplinary bottom-up approach to energy refurbishment is presented. The essence of the model is that users and residents should always play a central role in the decision-making process because the well-being of the historic building will always depend on its day-to-day users, and vice versa. [ABSTRACT FROM AUTHOR]

Global climate change and energy crises have increasingly impeded the sustainable development of society and economy. With an accelerated process of urbanization and improved standards of living, China has become the largest carbon emitter in the world and therefore has great responsibility and great potential to mitigate global carbon emissions. Accordingly, as the largest source of emissions in China, Chinese buildings should also decrease carbon emissions towards this goal. However, until now, there has been no clear and comprehensive understanding of the carbon emissions in this sector. To fill this gap, we survey the current and future situation. Firstly, we estimate the controlled ceiling of building carbon emission, splitting from the overall reduction goal in China. Then we develop a comprehensive carbon-calculating methodology, the China Building Carbon Emissions Model, using a bottom-up approach, and assess the building carbon emissions based on official statistics. On the basis of that, scenario analysis is used to predict the future trend of carbon emissions in China's building sector. According to our analysis, it is critical to simultaneously control floor space, energy consumption and energy structure to limit the growth of carbon emissions in the building sector. Finally, some relative policy suggestions are also discussed. [ABSTRACT FROM AUTHOR]

• Hybrid bottom-up model to integrate geo-referenced and synthetic stock models. • Demonstrate multi-scale and long-term transitional workflow for commercial building stock. • Identify drivers and determinants of energy usage in the commercial building stock. • 32% cumulative performance gap if concurrent consideration of physical and technical factors is disregarded. • Introducing the unit block concept to determine minimum viable requirements. For energy modelling of commercial building stock (CBS), several methodologies were developed focusing on technology alternatives and retrofits for climate change mitigation, but they often have limitations to involve a differentiated description of practices and policies across a range of scales and sectors. This paper presents a novel hybrid model by integrating spatial and synthetic modelling approaches to facilitate the concurrent consideration of multiple building-oriented elements. The model is further implemented on Japanese building stock to demonstrate multi-scale and long-term framework for energy modelling of CBS. The results indicate the following findings: the scale choice introduces significant variability in energy consumption estimation with a relative error of 10–17% mainly depending on building geometry and plug loads; the long-term model exhibits a higher scale-bounded uncertainty in terms of energy saving potential that varies by 2–3 times when a non-representative scale is applied; disregarding physical and technical factors results in a cumulative performance gap of up to 32%; and the accuracy and extent of the model across the stock are more sensitive to technical factors, such as building system stock dynamics and the heterogeneity of HVAC systems, than physical factors. The model provides a multi-tier framework using spatial intelligence building stock approach to develop long-term energy efficiency monitoring strategies for CBS. [ABSTRACT FROM AUTHOR]

In order to tap the energy saving and climate mitigation potential of buildings, transaction costs of implementing energy efficient technologies need to be better understood and ultimately reduced. The objective of this paper is to identify and analyze the nature and scale of transaction costs resulting from the application of the passive house concept in energy efficient renovations. Related conceptual choices are also discussed. This study explores learning strategies as a potential to reduce transaction costs. It focuses on transaction costs borne by building owners and building developers in the planning and implementation phases of a passive house-oriented renovation in Sweden. Results reveal three main sources of transaction costs: due diligence, negotiations and monitoring. The analysis shows that transaction costs are non-negligible and for individual cost sources the scale can be three times higher than for conventional renovations. To reduce transaction costs, various learning strategies such as study visits, demonstration projects, new forms of meetings and new channels of (written) information were found. These strategies have the potential to half transaction costs of future renovation projects. [ABSTRACT FROM AUTHOR]

The intensification of the Urban Heat Island effect (UHI) is a problem that involves several fields, and new adequate solutions are required to mitigate its amplitude. The construction sector is strictly related with this phenomenon; in particular, roofs are the envelope components subject to the highest solar irradiance, hence any mitigation strategy should start from them and involve their appropriate design process. For this purpose, cool materials, i.e. materials which are able to reflect a large amount of solar radiation and avoid overheating of building surfaces have been deeply analyzed in the last years both at building and urban scales, showing their benefits especially in hot climates. However, green roofs also represent a possible way to cope with UHI, even if their design is not straightforward and requires taking into account many variables, strictly related with the local climatic conditions. In this context, the present paper proposes a comparison between cool roofs and green roofs for several Italian cities that are representative of different climatic conditions. In search of the most effective solution, the answers may be different depending on the perspective that leads the comparison, i.e. the need to reduce the energy consumption in buildings or the desire to minimize the contribution of the UHI effect. [ABSTRACT FROM AUTHOR]

Due to its significant carbon footprint and cost-effectiveness for upgrades, the commercial property sector is important for climate change mitigation. Although barriers to energy system changes, such as funding, financing and information, are well recognized, Energy Star property owners and managers are successfully overcoming these barriers and instigating energy efficiency upgrades, renewable energy installations, and behavior and management programs. To examine the decision-making process that leads to energy performance improvements, a national survey of property owners and management organizations of buildings that earned an Energy Star score of 75 or higher was conducted. The extent to which energy upgrades were considered strategic investments motivated by environmental sustainability or corporate social responsibility, or financial investments motivated by payback period or return-on-investment criteria, was contingent upon the property type and type of energy project. Environmental sustainability was found to be an important motivation for energy projects in office spaces in general, but in the case of smaller office spaces was often combined with motivations for corporate social responsibility. Energy projects on education properties were motivated by financial investment. Building envelope and mechanical efficiency upgrades were considered financial investments, while renewable energy, green roofs, and water conservation technologies were considered environmental sustainability initiatives. [ABSTRACT FROM AUTHOR]

• Method was established to model building stock composition in adopted technologies. • Stock model can estimate the baseline development of building stock. • Building stock energy models can be constructed to use building stock data. • The Japanese technology deployment trend can significantly reduce CO 2 emissions. • Efficiency measures help avoid the increase in electricity demand by electrification. A significant improvement in the building stock energy efficiency is imperative to mitigate climate change. Building stock energy models (BSEMs) that employ reference building models are useful for mitigation analysis. However, most existing BSEMs developed for commercial building stock focus on limited building systems and energy conservation measures, and technology deployments are suggested based on simple vintage-driven scenarios. These approaches are insufficient, particularly for regions where improvements to building insulation performances can have a modest impact. This study aims to establish a BSEM framework to overcome this issue and to validate the framework via its application to the Japanese commercial building stock. The framework develops statistical models for estimating the selection probabilities of system alternatives and utilizes them to disaggregate building stocks. A reference building model is developed for each stock segment. The results show that this approach facilitates the use of multiple technological options considering various factors that affect technological deployments, and it also helps estimate the baseline development of building stocks. Furthermore, the developed model well represents the observed distributions in energy use intensity and estimates the aggregated energy consumption of building stocks with a reasonable accuracy. The baseline development was estimated to reduce the CO 2 emission by 18% by 2030 from 2013. Efficiency measures can help avoid the increase in electricity demand caused by electrifying the heat source of heating, ventilating, and air-conditioning and water heating systems. The framework could help extend the scope of BSEM application because BSEM development is not information intensive. [ABSTRACT FROM AUTHOR]

Many newly built, energy-efficient terraced houses are characterised by high indoor air temperatures and thermal comfort issues, because these state-of-the-art houses were designed and built without considering the warming climate conditions in the summer. As a result, many of these residential buildings are at risk of overheating and require careful implementation of passive cooling design systems when retrofitting. This study reviews the overheating risk and energy effectiveness of six passive design strategies tested and implemented in an innovative terraced house located in southeast London during the long-term heatwaves experienced in both the UK and continental Europe in the summer of 2018. A quantitative research methodology is employed based on an extensive monitoring campaign conducted to measure environmental conditions, including indoor air temperature, relative humidity and CO 2 of each occupied space in a prototype base-case building. In the subsequent phase of the research, retrofit strategies were investigated by modelling and simulation using the Integrated Environmental Solutions (IES) software suite for data validation. The preliminary results of the modelling and simulation confirmed the survey findings of high levels of occupant discomfort and relatively high cooling loads. The internal operating temperatures of the simulated rooms remained high throughout the day and night during the long-term heatwaves, ranging from a minimum of 24.7 °C to a maximum of 32.1 °C. The results highlight significant deviations in the estimated energy consumption of the base-case building as well as in the energetic and environmental indexes of the passive cooling design strategies. The study will contribute to the strategic design of retrofit interventions to effectively reduce cooling energy consumption by considering occupants' thermal comfort, thermal adaptation and energy use. Graphical abstract to this article can be found online at – The Graphical abstract illustrates the adopted and developed comprehensive methodological design approach for the study. [Display omitted] [ABSTRACT FROM AUTHOR]

One of the major anthropogenic sources of greenhouse gases is the operation of building stock. Improving its energy efficiency has the potential to significantly contribute to achieving climate change mitigation targets. The purpose of this study was to roughly estimate such potential for the operation of the national building stock of Czechia to steer the national debate on the development of related national plans. The estimation is based on a simplified energy model of the Czech building stock that consists of sub-models of residential and nonresidential building stocks, for which their future energy consumptions, shares of energy carriers and sources, and emission factors were modeled in four scenarios. Uncertainties from the approximation of the emission factors were investigated in a sensitivity analysis. The results showed that the operation of the Czech building stock in 2016 totaled 36.9 Mt CO2, which represented 34.6% of the total national carbon dioxide emissions. The four building stock scenarios could produce reductions in the carbon dioxide emissions of between 28% and 93% by 2050, when also considering on-side production from photovoltaics. The implementation of the most ambitious scenario would represent a drop in national CO2 yearly emissions by 43.2% by 2050 (compared to 2016). [ABSTRACT FROM AUTHOR]

• Methodology for determining the energetically optimal walls U-value was presented. • Importance of considering future energy consumption in design of buildings was shown. • Future-oriented design demonstrated a reduction of the insulation carbon footprint. • The importance of considering microclimatic features in the design of dwellings was shown. In the context of climate change, it is difficult to maintain the energy performance of houses, especially in countries with building codes that regulate the maximum allowed amount of energy that a building can consume. For this reason, there is a need for a review of building standards and adaptation to the context of energy performance in planning future projects. The objective of this research was to ascertain the thermal transmittance of external walls for single-family homes and to establish the energetically optimal thickness of thermal insulation by using an energy simulation to maintain heating energy consumption in conditions of climate change while following the state regulations in the Los Ríos region of Chile. It was demonstrated that for each time period and in each geographical location of the region the optimal U-value of the external walls is different. For a house to have a heating energy consumption corresponding to 90 kWh/m2/year, it must have an optimal average U-value of the walls of 0.49 ± 0.11 W/m2K (year 2006 in the study region); however, for the period 2035–2050, this value is expected to reach 0.78 ± 0.14 W/m2K. In addition, it was shown that designing the house with an energy performance perspective of 15 years helps to reduce the carbon footprint of the use of thermal insulation in the walls by 20%. The results obtained demonstrate the importance of considering the effects of future climate change in the housing design process in terms of both energy and environmental. [ABSTRACT FROM AUTHOR]

Building energy use is becoming increasingly important in China. Despite a rapid growth in recent years, energy use intensity in China is still relatively low compared to other advanced economies; thus, there is still substantial room for it to increase as living standards and industrial services are improved. It is therefore important to focus on the future development of building energy use by considering new trends in the building and energy sectors, as well as the role of occupant behavior. This study uses the China Building Energy Model (CBEM) to model China's building energy consumption and carbon emissions up to 2050 for different scenarios based on these considerations. The results indicate that building energy use will be 80% higher than the current situation if the strategies of the 13th Five-Year Plan are maintained and approximately 10% higher if stronger strategies toward energy efficiency are employed. Carbon emissions are predicted to peak around 2020 to 2035. The contributions of key strategies in different subsectors are also discussed. This research suggests that, through the use of suitable strategies and policies, energy use and carbon emissions in China's building sector can achieve the combined goals of energy revolution and climate change mitigation. • China's building energy consumption and carbon emissions up to 2050 were modeled. • China's building energy use will be 10%–80% higher under different scenarios. • The contributions of key strategies in different subsectors were discussed. • China's building sector is able to develop sustainably with suitable strategies. [ABSTRACT FROM AUTHOR]

The growing concern about global climate change extends to different professional sectors. In the building industry, the energy consumption of buildings becomes a factor susceptible to change due to the direct relationship between the outside temperature and the energy needed to cool and heat the internal space. This document aims to estimate the energy consumption of a Minimum Energy Building (MEB) in different scenarios—past, present, and future—in the subtropical climate typical of seaside cities in Southern Spain. The building energy consumption has been predicted using dynamic building energy simulation software tools. Projected climate data were obtained in four time periods (Historical, the 2020s, 2050s, and 2080s), based on four emission scenarios defined by the Intergovernmental Panel on Climate Change (IPCC): B1, B2, A2, A1F1. This methodology has been mathematically complemented to obtain data in closer time frames (2025 and 2030). In addition, different mitigation strategies have been proposed to counteract the impact of climate change in the distant future. The different energy simulations carried on show clearly future trends of growth in total building energy consumption and how current building designers could be underestimating the problem of air conditioning needs in the subtropical zone. Electricity demand for heating is expected to decrease almost completely, while electricity demand for cooling increases considerably. The changes predicted are significant in all scenarios and periods, concluding an increase of between 28–51% in total primary energy consumption during the building life cycle. The proposed mitigation strategies show improvements in energy demands in a range of 11–14% and they could be considered in the initial stages of project design or incorporated in the future as the impact of climate change becomes more pronounced. [ABSTRACT FROM AUTHOR]

• A numerical model is developed to study indoor thermal conditions during heat waves. • Moisture buffering can have an important influence on the indoor thermal conditions. • Pre-cooling before the start of a heat wave can lower indoor temperature moderately. • Moisture-desorption cooling has a large potential in reducing indoor heat stress. Urban areas are increasingly impacted by the urban heat island effect, especially during heat waves. In the context of improving energy efficiency in buildings, passive and energy-efficient cooling methods are needed for reducing indoor heat stress and lowering building energy consumption during heat waves. In this study, a whole building simulation model that includes both moisture and heat transport in wall envelopes and indoor environment is developed. An analytical solution and two test cases are used to validate the developed model. The developed model is applied to study indoor thermal conditions in urban areas in Zurich, Switzerland in a hot summer. The results show that indoor temperature could not be accurately simulated when moisture transport in the wall envelopes is neglected. Due to the urban heat island effect, night ventilation is not sufficient to cool down the indoor environment during the heat wave in the urban area. The potential of precooling before the heat wave and moisture-desorption cooling from hygroscopic materials have been studied to reduce indoor heat stress in the urban area. The average operative temperature during the heat wave can be reduced by 0.43 °C by precooling before the start of the heat wave, whereas desorption cooling from hygroscopic materials could reduce the average operative temperature during heat waves by 1.31 °C. A combination of these two mitigation measures could lead to enhanced passive cooling effect. There is a large potential of using desorption of hygroscopic material to reduce heat stress during heatwaves, while minimizing energy consumption of buildings. [ABSTRACT FROM AUTHOR]

• Real historic buildings with artworks are examined. • Indoor environment, thermal comfort and energy performance were assessed. • The indoor environment is simulated and validated with on-site measurements. • Future indoor climate conditions were predicted for a 2050 scenario. • Future climate change will increase cooling demand. Climate change will affect the indoor temperature of historic buildings, impacting the preservation of artworks and the thermal comfort of users, and possibly leading to increased energy consumption. These buildings generate more emissions than new buildings and in most European countries, preservation principles take precedence over energy efficiency and the reduction of emissions. This research is a key topic for the mitigation of climate change and proposes a method for assessing the impact of climate change on the preservation of artworks, thermal comfort, and energy consumption. An experimental method was followed, combining analytical formulations, on-site measurements, and Heating, Ventilation and Air Conditioning systems in order to identify the adequate hygrothermal parameters for historic buildings. The climate change scenario predicted for 2050 was based on projected temperature variation. The case studies were Baroque churches, historic buildings located in the south of Europe. Data obtained from a monitoring campaign carried out in these churches was used to validate dynamic simulation models. The churches analysed showed an increase in cooling demand and a decrease in heating demand. Furthermore, in order to ensure human comfort and the preservation of artworks, it was necessary to implement active systems in operation for 12-hour periods. These results suggest an energy overconsumption, as the energy consumption for human comfort and artwork preservation was 50% higher than the energy consumption of active systems for the preservation of valuable historic objects. In addition, the annual energy consumption decreases for future scenarios for 2050 in the case of artwork preservation and thermal comfort, but increases by almost 15% for the preservation of works of art due to higher level relative humidity. Before historic buildings can be adapted, it is essential to understand the influence of the future climate on their design, construction, and environmental conditions. [ABSTRACT FROM AUTHOR]

Heat is a growing concern in cities around the word, especially in the face of climate change. Because buildings are an important component of the built environment vis-à-vis both energy use and heat resiliency in cities, we explored their climate mitigation and adaptation potential. Specifically, we investigated how design decisions interact with regard to three heat-related factors—namely, energy use/CO 2 emissions, passive survivability, and heat rejection to the urban climate. We selected an archetypical building as our test case, created various design permutations, and used whole-building simulations to analyze their performance. Our simulations show that permutations of the building with a smaller carbon footprint also emit less heat to ambient air and had a better passive survivability. However, we also noted potential trade-offs (e.g., where ventilation is inadequate, increasing insulation levels for energy efficiency may hurt passive survivability). Based on our findings, we argue that, at least at a policy level, it is imperative to take advantage of the synergies, and their collective benefits. Moreover, building regulations or incentive programs should look beyond energy as the sole performance metric of interest and consider passive survivability as well as thermal interactions with urban climate. Image 1 • Buildings can improve urban heat resiliency via three different mechanisms. • We simulated all three in 1300 permutations of a multi-family residential building. • Results show a synergy; buildings with passive survivability emit less GHG & heat. • Trade-offs also exist between climate adaptation & mitigation and should be avoided. • The resiliency measures tested increase costs at the individual building level. [ABSTRACT FROM AUTHOR]