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This paper reviews innovative building envelope technologies that can improve total building energy efficiency and reduce greenhouse gas emissions. The building envelope has a significant impact on energy and thermal performance, making various technologies like phase change materials, aerogel, and active and adaptive systems essential for enhancing the building envelope’s energy efficiency. Phase change materials reduce energy consumption by lowering peak heating and cooling loads, improving thermal comfort. Paraffin wax is considered the most dependable phase change material for building envelopes, as it can decrease energy consumption for heating and cooling. Study shows that active PCM thermal energy storage system can reduce room temperature by 6.8 °C in summer. Aerogel, in comparison, is recognized for its exceptional insulation capabilities and low density that minimize heat transfer and boost thermal insulation in buildings. Silica aerogel’s outstanding feature is its capacity to offer thermal performance that surpasses traditional insulation materials by 2–4 times, thereby delivering substantial energy savings of up to 35 %. Active and adaptive systems, such as smart windows and kinetic facades, enable real-time control of building envelope performance, improving energy efficiency and indoor comfort. Smart windows can lead to annual energy savings up to 35.9 kWh/m2 compared to traditional windows, and kinetic facades can reduce cooling loads for buildings up to 21 %. The review assesses various adaptive facade solutions for their suitability in diverse climate zones, versatility in application and energy efficiency. Despite the existence of some limitations and challenges, such as high costs and insufficient understanding of their long-term performance, the continuous development and deployment of these technologies can still yield a significant contribution to improving building energy efficiency and mitigating greenhouse gas emissions.

In recent years, the demand for energy-efficient technological solutions in the building sector has risen significantly worldwide. The exploitation of phase change material as a medium for thermal energy storage in building envelopes has increased due to its superior properties. There is still a knowledge gap to cover in the way to the effective solar thermal energy storage in the building envelope – to enhance the heat transfer, to reduce the heat loss, etc. This paper deals with the optimisation of heat transfer using a solar concentrator (Fresnel lens). This study examines the effect of Fresnel lens focal point location on heat transfer in a dynamic solar facade prototype that stores thermal energy in phase change material. Nine different setups (solar façade compositions) were tested in the laboratory – two parameters with three alternatives each. Testing conditions simulate the relevant Northern Europe climate. By changing the air gap configuration and location of the Fresnel lens focal point, the heat transfer to phase change material was observed by measuring temperatures in the phase change material container using five thermocouples. The results show the improved thermal performance in test modules with larger cone diameter by 7.2 % and Fresnel lens focal point positioning closer to the back of the phase change material container by 5.4 %.

Finding the generic hygrothermal properties of historical brick for application in Heat Air and Moisture (HAM) simulation programs such as Delphin, Wufi, etc., is the main objective of this paper. In this paper hygrothermal properties and Delphin simulation results of 40 different historical brick samples from the 17th to 20th Century, were used. The clustering results of hygrothermal properties were cross-examined with the results of clustering results of Delphin simulation data. Six and three clusters were found to be optimal, accordingly for Hygrothermal properties and Delphin results data groups. After cross-examination, a total of 9 combined clusters were recognized, with two dominant clusters containing 67.5 % of all samples (30 and 37.5 %), four of the clusters had only one sample in them, and other clusters had two, three, and four samples in them. Additionally, all the resulting clusters were compared with the brick sample groups that were created based on the description of the brick: color, material type, and year of manufacturing.

Energy communities are paving the way for new cooperation opportunities related to energy consumption and energy production. Individuals unite in energy communities to reduce the costs related to energy consumption. Although previous work has mainly focused on energy exchange inside the community. This work aims to investigate the Pareto-optimal solutions to the transformation of a historical district into an energy community. For energy efficiency and production measure calculation, a system dynamics model is developed. Multiobjective differential evolution optimization method is employed for the evaluation of energy efficiency and production measures with a focus on net present value, self-sufficiency, annual emission reduction, and specific heat consumption. The optimization target functions can be increased at a cost in net present value. Replacement of household appliances and windows enables significant energy demand reductions while maintaining positive net present value. Electricity production from photovoltaic panels offers an additional pathway to increase selfsufficiency share while maintaining positive net present value.

Buildings are linked to a significant untapped energy saving potential, accounting for 40 % of European Union’s (EU) final energy and 36 % of CO2 emissions. Energy efficient building envelopes plays the key role to achieve decarbonization of the EU’s building stock by 2050. Active building envelopes are emerging and novel trend offering the paradigm shift in perception of building enclosures. Paper presents study of active solar façade containing phase change material for energy storage. Study seeks for optimisation of solar façade module by introducing dynamic component and variating in the composition of module itself to ensure faster energy harvesting and minimise the heat losses at discharging phase. Comparative tests were carried out in laboratory, in controlled heating and cooling conditions to evaluate impact of dynamic component. The dynamic component has reflective inner coating that focuses solar radiation on the element in heating phase and aerogel insulation filling in the blades that decreases heat loss in the cooling phase. Varying components in the design were used– thickness of aerogel insulation, Fresnel lens and width of concentrating cone diameter. Wide range of phase change material average temperature was observed 24 °C in setups with full aerogel filling to 50 °C in setup Fresnel lens. Average temperature in phase change material was reached higher in all setups with dynamic component compared to identical setups without dynamic component. Temperature differences were in the range from 1 °C in aerogel filled setups till 6 °C in setups with Fresnel lens.

The study presented in this paper is a continued research of preceding tests of small-scale passive solar wall module to explore 1) the behaviour of solar wall module in various setups for an extended 48-hour period of time, and 2) the performance of solar module with and without fine metal wires as heat exchange enhancers. Eight different solar wall module setups were assembled and tested in a precisely controlled environment. The study reassures observations and conclusions made in previous research and provides new conclusions. Modules that can harvest more solar radiation in the charging phase are exposed to higher heat losses at the discharge phase to the external environment. Module setups that reach stable heat flow fast and respectively melt PCM volume effectively, create a problem of not managing to harvest more of the available solar radiation.

The EU 2030 climate package calls for raising energy efficiency, increasing usage of RES and decreasing the carbon footprint. There are stringent requirements for new buildings, but the energy efficiency potential in the existing building stock is still not fully explored. The latest trend in urban energy efficiency is the Positive Energy Block (PEB) strategies for new developments. It includes raising building energy efficiency, optimizing energy flow and implementing renewable energy sources (RES). Transforming all existing blocks in a city centre to a PEB would radically change the pattern of energy supply and consumption. European cities have historic centres with great architectural and cultural value. Any urban regeneration strategies must respect and preserve historic values. This paper describes double multi-criteria analysis evaluating urban blocks from both the energy efficiency and cultural heritage perspective with the goal to select the sample block for a “Smart urban regeneration – transition to the Positive Energy Block” case study. Proposed criteria for multi-criteria analysis to evaluate cultural heritage, liveability and energy efficiency potential describes specific qualities of the urban block. The obtained results show that blocks with higher cultural value show less energy efficiency potential and vice versa. It is recommended to apply cultural value and liveability qualities in the Smart urban regeneration process to those blocks with high energy efficiency potential.

The study presented in this paper is a continuation of small-scale passive solar wall module testing to evaluate: 1) the impact of phase change material embedded in building envelope on indoor air temperature in comparison to reference wall insulated with mineral wool 2) the impact of Fresnel lens on heat transfer processes in designed module compared to PMMA acrylic glass. Six different solar wall modules and a reference wall module were built and tested in a laboratory under controlled conditions. Compared to previous studies, changes in the experimental setup were made - solar radiation intensified, simulated outdoor temperature adjusted. The study shows explicitly the phase change melting processes in different modules tested, describing the differences between modules and impact of Fresnel lenses and insulation solutions. Room temperature with solar wall modules after the full cycle of charging and discharging latent and sensible energy (24 h) is higher than in the reference wall. Two of 3 of the proposed solar wall modules with Fresnel lens are more effective than modules with PMMA.

Energy consumption in historic building stock is high compared to current energy efficiency standards. The heritage value of the façade and the limited space on the external surface in densely populated urban streets limit the application of external insulation. Internal insulation can be applied instead. However, it is considered to be a riskier technology due to moisture-related damage. In addition to mold growth and wood rot, frost damage should be considered in cold climates. This study aims to assess the impact of a vapor-open capillary-active calcium silicate internal insulation system with and without adhesive glue on the hygrothermal behavior of masonry from various historic bricks in cold climates by performing numerical simulations in the software Delphin. Test results of hygrothermal properties of 40 historic brick samples were used in numerical experiments to assess the impact of a brick type, the quality of the application of calcium silicate (with or without adhesive), and the impact of cold climate on the hygrothermal behavior. Results show that temperature behavior is similar to all wall types whereas a large difference is observed in moisture behavior. The application of adhesive glue tends to reduce moisture spikes caused by rain events when compared to the same samples without adhesive. Findings only partly correspond to other studies on factors affecting moisture behavior. [ABSTRACT FROM AUTHOR]

To meet the 2050 EU decarbonization goals, there is a need for new and innovative ideas to increase energy efficiency, which includes reducing the energy consumption of buildings and increasing the use of on-site renewable energy sources. One possible solution for achieving efficient thermal energy transition in the building sector is to assign new functionalities to the building envelope. The building envelope can function as a thermal energy storage system, which can help compensate for irregularities in solar energy availability. This can be accomplished by utilizing phase change materials as the energy storage medium in the building envelope. In this paper, two phase change materials with different melting temperatures of 21 °C and 28 °C are compared for their application in a dynamic solar building envelope. Both experimental and numerical studies were conducted within the scope of this study. The laboratory testing involved simulating the conditions of the four seasons through steady-state and dynamic experiments. The performance of the phase change materials was evaluated using a small-scale PASLINK test stand that imitates indoor and outdoor conditions. A numerical model of a small-scale building envelope was created using data from laboratory tests. The purpose of this model was to investigate how the tested phase change materials perform under different climate conditions. The experimental findings show that RT21HC is better at storing thermal energy in the PCM and releasing it into the indoor area than RT28HC. On the other hand, the numerical simulation results demonstrate that RT28HC has an advantage in terms of thermal storage capacity in climates found in Southern Europe, as it prevents overheating of the room. [ABSTRACT FROM AUTHOR]

Energy communities are widely studied from various perspectives, especially in the context of geopolitical events of recent years, when humanity is faced with the need for urgent solutions to mitigate climate change and alleviate the crisis of energy resources. Although citizens' interest in the use of renewable resources has gradually grown, energy policy support measures for more active participation of society in the implementation of energy efficiency measures are still being implemented with variable success, especially through mutual agreement. Serious games are a rapidly growing tool for awareness and collaboration on a single platform for gamers seeking solutions to energy resource optimization issues. The main focus of the article is on the opportunities offered by a newly developed simulation tool for promoting the development of energy communities and the experience gained by its users. The tool's description and simulation results provide new information and knowledge for those working in the serious gaming field. The proposed solution promotes the development of new methods (tools) for decision-making processes based on serious games. This study uses a multi-player simulation tool to enable the modelling of scenarios for energy efficiency measures for apartment building block residents and energy community target goals for decision-making decisions. User experience and game mechanics were tested on a pre-selected group. The results indicate positive feedback, including a practical application for both energy community and professionals, and provide valuable recommendations for further research and improvement of the tool. [ABSTRACT FROM AUTHOR]