Due to the fact that efficiency of PV panels decreases by approximately 0.5%/K, possibilities to stabilize the temperature on the panel's surface are considered in this paper. The aim of this investigation is to determine the transition temperature of PCM layer that allows avoiding rapid temperature fluctuations on the PV back surface. To meet the stated goal, dynamic simulations of thermal and electrical performance of PV/PCM panels were carried out using ESP-r software. Based on the obtained results, it can be concluded that additional PCM layer on the back side of PV panel can effectively increase the efficiency of electricity production with PCM transition temperature about 20°C.

Purpose The purpose of this paper is to investigate the potential of the experimental building integrated photovoltaic (BIPV) façade to cover net energy use in the adjacent office room. Electricity generated by PV panels was intended to cover the energy demand for the mechanical ventilation and the supplementary lighting. Analyses were performed for two orientations of the façade (east and west) and two occupancy profiles considering one or two employees per one office room. Design/methodology/approach The study was conducted by carrying detailed numerical analyses of energy produced by the BIPV façade and its consumption in adjacent office room. Calculations of energy generated by PV panels were made using simulation programme ESP-r. Advanced model, used in analyses, take into account dependence of the main electrical parameters of photovoltaic cell from temperature. Findings The findings reveal that energy generated by photovoltaic panels during transitional and cooling seasons is sufficient for lighting and ventilation requirement. However during winter months BIPV facade can cover energy demand only for ventilation. Originality/value The paper provides an original analysis of experimental BIPV façade system as a source of on-site produced renewable energy to cover energy demand in offices building under certain climate conditions. The results reported in presented paper shows the potential of BIPV facades and display this potential in a context of building net energy balance.

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The main goal of this study is to develop the new external thermal insulation composite system (ETICS) by integration of flexible photovoltaic (FPV) and encapsulated phase change materials (PCM). This work is the first step of the international project En-ActivETICS and concerns mainly material selection and systems integration issues. The paper presents a complete solution of façade component which integrates thermal insulation, heat storage and electricity generation - En-ActivETICS that combines ETICS technology with a self-supporting flexible photovoltaic elements. This system will be applicable for both masonry or concrete constructions and it is a new step in the development of building facade technology allowing to achieve a component classified to the group of functional material. In the paper, the formulation of basic principles of En-ActivETICS as well as an overview of existing materials and technologies is presented. Finally, the initial concept of the system is described. The main features of that system is using an elastic, high heat capacity and frost resistant adhesive joining flexible PV with thermal insulation.

The main goal of the paper was to numerically analyse the risk of overheating of the Energy Activated External Thermal Insulation Composite System (En-ActivETICS) as an example of Building Integrated Photovoltaics (BIPV). The analyses were conducted with the coupled power flow method (thermal and electrical) for 20 European cities. All locations were analysed considering the local climate in the context of building performance simulation as well as electricity production. The obtained results allowed for the determination of the risk of overheating, which can influence system durability, accelerated thermal ageing, and overall performance. It was revealed that the risk of overheating above 80 °C is possible in almost all locations; however, the intensity considerably differs between southern and northern Europe. The effect of latent heat storage for better thermal stabilization and overall performance was determined numerically for all locations. Finally, the improved solution with a phase change material (PCM) layer beside the PV panel was proposed individually for specific climatic zones, considering the required heat capacity. The maximum panel temperature for improved En-ActivETICS does not exceed 85 °C for any location.