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Data availability: Data will be made available on request. ; Copyright © 2023 The Author(s). Urban settings and climate change both impact on energy use and thermal comfort inside buildings. This paper first presents a study of changes in energy demand in residential buildings considering the overlapping effect of climate change and urban heat island intensity in two European locations; Cadiz (Spain) and London (United Kingdom), representing temperate and hot European climates and moderate and dense urban settings. Future-urban weather files were generated and simulations were run considering energy demand and indoor thermal comfort. In hot climate regions such as the one of Cadiz, future climate will increase the cooling demand and the additional impact of the UHI leads to a further increase of up to +28% of total energy demand compared to the current climate without considering urban effects. Future-urban weather conditions will be detrimental also for buildings in London, where the annual energy demand is predicted to increase by up to the 16% if future climate and urban effects are included. This is due to a higher increase in cooling demand compared to the reduction for the heating need. The paper also presents a method to take into account microclimatic conditions in naturally ventilated buildings, especially the effect of wind variations around the building which impacts natural ventilation rates. Air and surface temperature and wind speeds were studied using ENVImet and the resulting microclimatic conditions were used as inputs to the EnergyPlus Airflow Network model for the calculation of the building ventilation rates. It was found that ventilation rates are reduced (in comparison to meteorological weather files) and this reduction impacts negatively on internal operative temperatures. A thermal comfort analysis was carried out indicating that the selection of a suitable weather file and microclimatic conditions is essential for more accurate predictions of internal thermal comfort and will assist in ...

Materials science offers solutions that when are combined can offer important energy savings in the building sector. In this study, high reflectance coating and thermal storage capacity are combined with the aim of improving energy efficiency in buildings. For this issue a multifunctional pigment having a phase change material adsorbed on its surface and a high total solar reflectance has been manufactured. The total solar reflectance of the pigment will make the paint to reflect the sunlight radiation in the infrared part of the spectrum reducing the amount of absorbed radiation. This high reflection provides a surface level effect as is a passive stimulus-responsive solution that acts with sunlight radiation. On the other hand, the thermal storage capability provides a bulk level effect as is passive stimulus-responsive solution acting by temperature changes, making it possible to use constructive materials as a thermal energy storage media. The preparation process is described and the pigment is characterized conveniently. The thermal performance of corresponding pigmented coatings was evaluated by an experiment simulation in which different boxes were covered with the coating containing the multifunctional pigment and traditional pigmented coating on their tops. The indoor air temperature and the interior temperature of the substrate were measured obtaining differences of 4–5°C. European Union Seventh Framework Programme, FP7-NMP-2010-Small-5 (under grant agreement no 280393) Dpto. Educación, Política Lingüística y Cultura of the Basque Goverment, IT-630-13 Ministerio de Ciencia e Innovación, MAT2013-42092-R Engineering and Physical Sciences Research Council, EP/I003932

Abstract Our study proposes to analyze from a social practice and behavioural economics perspective the factors that influence a mismatch between energy behaviour and retrofit efficacy in the context of social housing. Retrofit interventions not only have the potential of improving energy efficiency of buildings, but they also change the context in which individuals live, therefore improving their wellbeing at home. However, the surrounding social context might suggest some context-specific practices and cognitive biases that negatively influence energy behaviour, creating a gap between expected and actual energy performance. Addressing the context-specific practices and cognitive biases is especially necessary when it comes to social housing. Social housing neighbourhoods are not only low-energy efficient, but also socially vulnerable. This context might shape specific practices and make salient specific cognitive biases which require special consideration within an energy retrofit program. The ambition of this study is to understand the context-specific practices and cognitive biases that characterize the pre-refurbishment phase of a retrofit program and to identify the ones that can be used as behavioural and social levers to enhance retrofit efficacy. To this aim, we analyze the results of a questionnaire administered to the tenants of a social housing district through the lenses of social practice theory and behavioural economics. Our results show that analysing tenants’ behaviour through an interdisciplinary social science approach allows to identify a range of context-specific variables that can be used as levers to align behaviour to retrofit interventions.

Solar energy has been widely introduced in the building market to provide electricity, heating and domes-tic hot water for a sustainable development. However, the low-density and the mismatch between energysupply and demand make appropriate its combination with thermal energy storage (TES) systems. Theintegration of these technologies (solar thermal and TES) in the building design is a key aspect to reduceenergy consumption. Latent heat storage using phase change materials (PCM) presents an advantage incomparison to conventional sensible heat storage systems due to the required volume. In this context,an innovative system that integrates PCM inside the structural horizontal building component is pre-sented in this paper. The slab consisted of a prefabricated concrete element with 14 channels filled withmacro-encapsulated PCM which is used as a storage unit and a heating supply. In order to melt the PCMthe system is coupled to a solar air collector. The prototype is tested in an experimental facility locatedin Puigverd de Lleida (Spain) where its thermal performance is evaluated under real weather conditions.This study demonstrates the high potential of the concrete slab on reducing the energy consumptioncompared to a conventional heating system. The work partially funded by the Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER), ENE2015-64117-C5-3-R (MINECO/FEDER), and ULLE10-4E-1305). The authors wouldlike to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123) and thecity hall of Puigverd de Lleida. This project has received fundingfrom the Eurpean Commission Seventh Framework Programme(FP/2007-2013) under Grant agreement Nº PIRSES-GA-2013-610692 (INNOSTORAGE) and from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 657466 (INPATH-TES). Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan dela Cierva, FJCI-2014-19940.

The need to achieve energy efficiency standards in new and existing buildings has triggered both research and design practice aimed at reducing their carbon footprint and improving their indoor comfort and functionality conditions. In this view, a dedicated scientific effort has to be spent while dealing with historical architectures needing to preserve their key testimonial knowledge into the society. Therefore, tailored retrofit strategies have been investigated and implemented without compromising their architectural value, especially when new uses are foreseen in those buildings. This review classifies different examples of the use of energy efficiency approaches and the integration of renewable energies in historical buildings, including solar and geothermal energy, and the use of heat pumps and other high-efficiency Heating Ventilation and Air Conditioning systems. Prof. Luisa F. Cabeza would like to acknowledge the Spanish Government for the funding PRX17/00221, that allowed her to visit University of Perugia during 6 months. Prof. Cabeza would like to thank the Catalan Government for the quality accreditation given to their research group (2017 SGR 1537). GREA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. The project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curiegrant agreement No 712949 (TECNIOspring PLUS) and from the Agency for Business Competitiveness of the Government of Catalonia.

Historic buildings built before 1945 make up a significant part of the building stock in the European Union. They also contribute to the greenhouse gas emissions due to high energy consumption. However, policy makers and building owners are facing “building energy efficiency-heritage value” dilemma when, on the one hand it is important to preserve a building’s heritage value and on the other hand, energy consumption should be reduced significantly. Internal insulation is one of the energy efficiency measures that can be applied. However, this is one of the most challenging and complex energy efficiency measures due to changes in boundary conditions and hygrothermal behaviour of the wall, especially in cold climate. We aimed to study the thermal behaviour of two internal insulation materials applied to historic masonry building in a cold climate. We carried out long term in-situ measurements of heat flux and temperature for internal insulation with aerogel and vacuum insulation panels (VIP) in the case study building in the historic quarter of Riga, Latvia. The original walls are made of 51 cm thick calcium silicate bricks. They were poorly maintained and heavily damaged by moisture before energy efficiency renovation. After renovation the external surface of walls was painted with self-cleaning, water repellent hydrophobic facade paint. The energy efficiency renovation also included insulation of floor and roof, change of windows, new ventilation and air heat pump installation. The analysis of the thermal behaviour show that the masonry part of the wall is exposed to freezing risk for a significant number of days during the winter. Calcium silicate bricks are very sensitive to freeze-thaw damage therefore we carried out computer simulation for the assessment of hygrothermal behaviour. Results show that the calcium silicate masonry part of the internally insulated wall in cold climate leads to exposure to freeze-thaw damage if the moisture content of the brick is higher than the capillary saturation. This process strongly depends on unfavourable outdoor conditions for wall types with and without water repellent hydrophobic paint.