The increase in population and living standards, as well as global warming and heatwaves due to climate change, have created a challenge to meet the cooling demand in buildings. In this study, the cooling requirement for a multifamily building through simulations in a future city district in central-Sweden was determined. Different air supply set point  strategies, window to floor ratio and building rotations were employed to minimize the cooling requirements. The building was modelled so as to meet the Nearly Zero Energy Building (NZEB) requirements. Window to floor ratio of 10% with a piecewise proportional controller for supply temperature was depicted as appropriate for the building. A 45° rotation of the building increased the cooling demand. The cooling demand of the building increased by employing the extreme climate condition, as a representative for future climate, with factors 3.8 and 6.4 for cooling set points 25°C and 27°C for window to floor ratio 10%. This implies the need for a resilient building to withstand future climate conditions. The requirement to update the climate files was also used for decision making in the design process and building regulation. 

The changes in climate and the expected extreme climate conditions in the future, given the long life span of the buildings have pushed the design limits. In this study, the changes in primary energy use (PEPET), total energy use and CO2 emission were investigated for a prototype residential building. The building fulfils nearly zero energy building (NZEB) characteristics, imposed by the Swedish building regulations. Different cooling technologies and various typical meteorological year (TMY) climate files assembled for different periods, as well as automatic shading were investigated. The assembled TMY files advocated for the present (2001-2020) and mid-future (2041-2060) period using the CORDEX data. Different cooling methods and set-points (24-28°C) were defined to evaluate the cooling energy requirement changes.

It was discovered that the freely available typical climate file fails to cover the induced changes in climate and its extreme implications on the building. The required cooling energy use increased from 1.7-5.8 times the freely available climate file, when using the projected TMY and the extreme climate files.

Addition of automatic shading system reduced cooling energy up to 75% within the studied cooling methods and set-points. Moreover PEPET and CO2 emission also decreased for the studied cooling methods, climate and weather files.

In this study, the performance of different cooling technologies from energy and economicperspectives were evaluated for six different prototype residential Nearly Zero Energy Buildings(NZEBs) within a planned future city district in central Sweden. This was carried out by assessingthe primary energy number and life cycle cost analysis (LCCA) for each building model and coolingtechnology. Projected future climate file representing the 2050s (mid-term future) was employed.Three cooling technologies (district cooling, compression chillers coupled/uncoupled with photovoltaic (PV) systems, and absorption chillers) were evaluated. Based on the results obtained fromprimary energy number and LCCA, compression chillers with PV systems appeared to be favorableas this technology depicted the least value for primary energy use and LCCA. Compared to compression chillers alone, the primary energy number and the life cycle cost were reduced by 13%, onaverage. Moreover, the district cooling system was found to be an agreeable choice for buildingswith large floor areas from an economic perspective. Apart from these, absorption chillers, utilizingenvironmentally sustainable district heating, displayed the highest primary energy use and life cycle cost which made them the least favorable choice. However, the reoccurring operational cost fromthe LCCA was about 60 and 50% of the total life cycle cost for district cooling and absorption chillers,respectively, while this value corresponds to 80% for the compression chillers, showing the high netpresent value for this technology but sensitive to future electricity prices.

The study investigates the impact of improved synthetic amorphous silica, specifically developed aerogel-based insulating coatings, Quartzene (Qz), on energy efficiency in buildings across cold and warm climate zones. Simulations were conducted on various coatings and thicknesses for exterior and interior wall surfaces, as well as roofs. These were evaluated using a prototype residential building under dynamic thermal conditions. Wall coatings were analyzed, including a base plaster and a mixture with 10%Wt aerogel-based Quartzene. Additionally, three roof coating samples were tested: Qz 12.5%Wt, TiO2 3.3%Wt, and a blend of aerogel-based mixtures and TiO2. Mixtures containing Qz exhibited the lowest thermal conductivity (0.05 W/(m·K)) and high short-wave reflectance (up to 0.93 μm), impacting transmission loads, time lag, and decrement factor. Energy savings of up to 11% were observed in warm climates when implementing the coatings (unaged performance). Overall, the coated surfaces increased time lag and reduced decrement factor compared to uncoated surfaces. Aerogel-based coatings showed enhanced effectiveness in lowering transmission loads.