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Thermal mass, a pivotal element in a building's performance, functions as an indoor thermal buffer. While literature underscores its advantages, the enduring impact of thermal mass amid climate change remains uncertain. This study methodically assesses thermal mass effects in 21 Iranian cities across contemporary and future climates, juxtaposing heavyweight and lightweight constructions. The EPSAP algorithm, a generative building design method, created a dataset of two-story single-family houses. Cooling and heating demands were evaluated in EnergyPlus, accounting for current and future system design efficiencies. Future climates were simulated using EC-Earth3 model estimations for the SSP5-8.5 scenario in 2050 and 2080 timeframes. The findings reveal that the energy efficiency advantage of heavyweight over lightweight buildings will diminish by up to 0.60 kW·h·m−2 in 2050 (40 % less than the present-day climate difference between constructions) and 0.93 kW·h·m−2 in 2080 (63 %) for cities in central and southern regions. The performance differences between constructions will sometimes be null, making thermal mass negligible. Conversely, only three cities in Northern Iran exhibit an opposing trend for mid to very-high thermal transmittances. Regarding building geometry, heavyweight construction correlates strongly with indexes related to building compactness, while lightweight construction aligns more with glazing-related indexes. However, as climates warm or we move towards warmer regions, discernible differences between lightweight and heavyweight constructions vanish for both shape- and glazing-related indexes. In conclusion, although the use of thermal mass will be less effective, building design professionals will have greater latitude for innovative construction and design solutions. • Thermal mass will have a lower energy benefit as global warming settles in Iran. • Adequate envelope thermal transmittances enhance thermal mass energy benefits. • Heavyweight construction has a higher correlation with shape-related indexes. • Lightweight construction has a higher correlation with glazing-related indexes. • In the future, no difference is found between constructions' geometry indexes. [ABSTRACT FROM AUTHOR]

Even though global warming is expected to raise the energy demand in office buildings, most energy analyses and design studies neither consider its impacts nor adaptive energy solutions. This study evaluates the effects of future climate on the energy demand of an office building in Portugal and proposes mitigation measures to improve its energy performance and environmental sustainability. The study simulates the energy demand of the building in 2055 and 2090 under different future scenarios using data from the latest climate model experiments, considering systems, envelopes, and operations interventions, and assesses the potential of photovoltaic panels to meet the energy demand. The results show that the interventions may reduce electric energy consumption between 16 % and 25 %, and the photovoltaic panels can meet 23 %–59 % of the total demand, depending on the scenario and the year. However, storage technology and equipment efficiency must evolve favorably to reach low energy. The findings reveal if a building designed and optimized for the current climate will remain optimal in the future and demonstrate the benefits of applying cleaner production and sustainable consumption principles to the office building sector. The study provides valuable insights for practitioners and policymakers. [Display omitted] • The impact of future scenarios on an office building's energy demand is assessed. • Alternative measures are analyzed to improve energy performance in 2055 and 2090. • The electric demand may be reduced by up to 16 %–25 % in the future. • The impact of the climate scenario may be significant. • PV panels may reduce the purchased electric energy by around 23–59 % in the future. [ABSTRACT FROM AUTHOR]

Highlights • The U-value impact on the thermal performance of residential buildings was analyzed. • 192000 buildings were randomly generated and evaluated using dynamic simulation. • Six geometry-based indexes were correlated with the buildings performance. • Higher U-values can decrease energy consumption in lower latitudes. • Higher and wider U-value intervals increase the geometric freedom for lower latitudes. Abstract Contrarily to what happens in northern European countries, buildings in the Mediterranean region are prone to overheating. Consequently, it is important to better understand the role that the thermal transmittance of the building envelope elements has on air-conditioning consumptions. This paper analyzes the effect of different U -values on building design in the Mediterranean area. 192 000 residential buildings were randomly generated for sixteen distinct locations and the energy consumption was assessed for each. It was found that in northern Mediterranean locations, as U -values decreased, energy consumption also decreased. However, in warmer climates, low thermal transmittances tended to significantly increase energy consumption. Hence, the lower the latitude, the higher the U -values should be, in order to prevent increasing the cooling demands. Additionally, geometry-based indexes were correlated with the building's energy performance. For high U -values, it was found that bigger buildings worsen the energy performance and larger windows tended to improve it. For low U -values, bigger north-facing windows were beneficial. There is an adequate interval of values for which the geometry has a lower impact, which is wider and higher for lower latitudes, thus meaning that not only does the building performance improve but architects are also freer to explore alternative designs. [ABSTRACT FROM AUTHOR]

This paper presents a study on the application of lightweight steel framed (LSF) construction systems in hot climate. A generative design method created 6010 houses, with random geometry and random roof and exterior wall types with different insulation levels, and EnergyPlus was used to evaluate the energy consumption for air-conditioning of each building. The main goals were to determine which geometric variables correlate with the energy performance, and to provide some guidelines to foster efficient LSF buildings in hot climates. By correlating six geometry-based indexes with the energy consumption for each construction element type group, it was verified that roofs do not show significant correlation, while exterior walls presented weak to moderate positive correlation with the building volume, very weak to weak negative correlation with the relative compactness, no correlation with the shape coefficient, moderate to strong negative correlation with the window-to-floor, window-to-wall, and window-to-exterior surface ratios. The results also show that buildings with larger windows and greater level of insulation have better energy performance. No significant difference of energy performance was found between different LSF construction systems with equivalent thermal resistance. [ABSTRACT FROM AUTHOR]

Mathematical morphing of historical weather data to match the projected climate change scenario is a commonly used method to generate future weather files for building energy simulation. It is known for preserving the local weather characteristics, which is particularly important when designing or analyzing high-performance buildings. Researchers may use one of the available morphing tools. Unfortunately, current tools use future climate data from outdated climate models with lesser accuracy, coarser spatial resolution, and fewer climate scenarios than recent models. In addition, these tools are closed, preventing others from adding corrections, updating, and developing them further. This paper presents an open-source, cross-platform, and state-of-the-art morphing tool that generates future hourly weather data for the whole building performance simulation. The novel tool is applied to a real-case office building in Coimbra, Portugal. In the SSP5-8.5 scenario, simulations show thermal energy needs and electricity use will reduce by 60% in 2050 and 77% in 2080 for heating and will increase by 67% in 2050 and 121% in 2080 for cooling. As a result, the building's global electricity consumption will increase by 24% in 2050 and by 53% in 2080. The study is extended to other locations in Europe, concluding that the total HVAC energy needs will remain constant or even decrease in heating-dominated climates, mainly due to the significant drop in the heating demand in the future. • A new future weather morphing research tool is presented. • It uses the latest data from the CMIP6 experiments (EC-Earth3). • The open-source code promotes research transparency and scientific discovery. • The tool overcomes issues and implementation closedness from other tools. • An application to a real-case office building shows the impact of climate change. [ABSTRACT FROM AUTHOR]

• Ideal U -values for 2050 climate projection in the Mediterranean region are determined. • Current well insulated buildings are not prone to overheating in the future. • In the future, ideal U -values are similar or even lower than current ones. • Casablanca is the only location presenting an overheating risk. • The increase of cooling demand will overcome the heating demand decrease. One of the effects of climate change is global warming, which will increase cooling demand in buildings. However, scientific literature does not show consensus on the risk of highly insulated buildings being prone to overheating. This paper presents a statistical comparison of two synthetic datasets for current and future climates in sixteen Mediterranean locations. The weather data for the 2050 climate projection was generated by 'morphing' current weather data. The buildings were created using a generative design method to produce random geometries and random U -values for the envelope elements. Energy performance was evaluated using dynamic simulation. In addition to the expected general increase in cooling demand (up to 137 %) and a smaller reduction in heating demand (up to 63 %), the results demonstrate that the ideal U -values used in the current climate in almost all of the locations will not cause overheating. In several cases, the decrease of the U -values is even recommended for Podgorica, Valencia, Tunis, Malaga, Larnaca, and Alexandria, as the reduction of heating demand compensates the increase of cooling demand. Casablanca was the only location showing an increase in the ideal U -values, thus presenting risk of overheating if using current ideal U -values. [ABSTRACT FROM AUTHOR]

Efficient ventilation is an effective method for reducing thermal loads inside buildings, thus decreasing cooling energy consumption. This is especially relevant in warmer climates. Therefore, it is important to better understand the role that different ventilation parameters play on air-conditioning consumptions. This study analyzes the effect of three different ventilation parameters – air flow rate, minimum indoor temperature and indoor-outdoor temperature difference – on the energy performance of buildings in the Mediterranean region. A set of 500 residential building geometries was randomly generated and the energy consumption for different combinations of ventilation parameters was assessed in sixteen distinct locations. Results suggested that the ventilation specifications that minimize air-conditioning energy consumption fall within similar values for all the evaluated locations: ventilation rates of at least 10 air changes per hour, a minimum indoor temperature for ventilation slightly below the building's cooling setpoint, and a low indoor-to-outdoor temperature difference. It was also found that, in lower latitudes, the buildings' energy performance tended to become similar, thus reducing the impact of their geometry and orientation. These results may help building practitioners to infer the most adequate ventilation strategies to implement, since this study is not limited to specific ventilation methods. • The ventilation impact on energy performance of residential buildings was analyzed. • 500 buildings were randomly generated and evaluated using dynamic simulation. • Similar ventilation specifications can be used for all the evaluated locations. • Ventilation rates of at least 10 ACH show to be the most adequate. • In lower latitudes, geometry and orientation are less impacting on energy performance. [ABSTRACT FROM AUTHOR]

• Datasets of low and high thermal mass with random U -values are compared. • Low thermal mass buildings have lower and wider range of ideal U -values. • High thermal mass buildings demand more cooling energy. • Buildings with high thermal mass consume lesser heating energy in warmer climates. • Thermal mass impacts differently the energy consumption along the U -value scale. High thermal mass construction is commonly used to reduce cooling energy consumption during the summer period as a passive design strategy in the Mediterranean region. Although being a generalized design practice, the benefit to the building performance is not fully consensual within the scientific community. This work explores the influence of thermal transmittance on the energy efficiency of buildings with different thermal mass levels. Hence, a statistical comparison of the buildings' annual energy consumption for air-conditioning is carried out based on two synthetic datasets with high and low thermal mass and varying thermal transmittance for opaque and transparent elements. In addition to climate location, the results demonstrate that thermal transmittance has varying impact on the contribution of thermal mass. The locations presenting such behavior were Marseille (−0.99% to +3.89%), Istanbul (−0.73% to +4.21%), Valencia (−1.31% to +4.97%), Algiers (−2.32% to +3.81%), Malaga (−3.95% to +6.21%), Casablanca (−5.66% to +6.96%), and Tel Aviv (−1.81% to +5.44%). These findings demonstrate that the influence of thermal mass is more complex than previously thought and levels should be chosen in relation with the thermal transmittance value. [ABSTRACT FROM AUTHOR]

This paper critically reviews the role of performance-based generative design in fast prototyping of buildings, describes the methodology of an automated generative layout design to produce complete building solutions, and presents a case study of multi-story buildings in urban context. The proposed approach evolves the building design solutions by interacting with the city 3D geometry and evaluates the energy consumption for air-conditioning. The building designs take into consideration urban geometric constraints and objectives, such as alignment with surrounding buildings, urban lot area, and relative and absolute position of the generated elements. During the evaluation process, the urban context is considered for casting shadows and reflecting solar radiation. The case study consists of six alternative 15-story buildings located in the city of São Paulo (Brazil), having commercial areas on the ground floor and two apartments per story on the remaining floors. The results show that, despite having similar apartments in every story, the urban context has a relevant impact on the buildings' energy performance. The difference between the apartments' best and worst energy performing stories ranges from 9% to 12% (ignoring the outlier story located in the first level), depending on the building solution. The results also show that the most energy efficient apartments' story is not located in the top or bottom floors, but rather at an intermediate level. • Urban context is added to an automatic floor plan generation procedure. • Alternative 15-story buildings are generated with residential and commercial spaces. • Energy consumption for air-conditioning is evaluated for every apartment. • Shadows and reflections from surroundings are evaluated during dynamic simulation. • Stories' energy performance vary from 9% to 12% despite having similar geometry. [ABSTRACT FROM AUTHOR]

The climate will become hotter, and buildings will perform differently as outdoor conditions evolve. If the lowest energy demand is desired, it is crucial to determine the ideal thermophysical properties of the envelope over the buildings' life span. However, the scientific literature is still scarce in providing a compelling answer. Therefore, this study (i) determines ideal thermal transmittance values (U -values) for present-day and future climates, (ii) determines to what extent the thermophysical properties will need to change to remain ideal, (iii) identifies different trends of U -values over time, (iv) establishes a relationship between outdoor air temperatures, cooling and heating setpoints, and ideal U -values, and (v) proposes a set of design strategies according to each trend. The EPSAP generative design method was used to create a large dataset of residential buildings with random geometries and U -values to evaluate their energy demand for heating and cooling in EnergyPlus. The thermal performance of each building was evaluated for 30 locations in Brazil for the current period and two future timeframes (2050 and 2080). The Future Weather Generator tool was used to morph today's typical meteorological weather to match the EC-Earth3 data for the SSP5–8.5 scenario. Although climate change has a similar relative impact, its consequences differ over time in each location. The ideal U -values have different trends in different regions: (a) remaining unchanged in the future, (b) changing from being the highest possible to the lowest of the analyzed range in 2050 or 2080, and (c) being mid-range values in the present and with similar or lower values in the future climate. The impact on the thermal loads of maintaining the present-day ideal U -values also varies significantly in the future timeframes, from being nil to representing an increase reaching 30 % in 2050 (∆ 2.94 MW·h ± 0.06 MW·h) and 57 % in 2080 (∆ 6.05 MW·h ± 0.09 MW·h). Therefore, building design professionals need to use different strategies according to each region and consider how climate evolves during the lifetime of the building. • Ideal U -values in present-day and future climates in Brazil are determined. • The trend of the ideal U -values varies according to each region. • A relation between U -values and outdoor temperatures and HVAC setpoints was found. • A fast procedure is presented to determine the trend of the ideal U -values over time. • For each trend, building design strategies are proposed. [ABSTRACT FROM AUTHOR]