In this paper, a standalone photovoltaics-thermal solar panel is modelled using the TRNSYS simulation engine. Based on this, it was explored how such a system can be comprised of thermal and electrical storage components to provide electricity and hot water for a dwelling in a warm location in Europe. Furthermore, it was investigated how, by cooling the temperature of the solar cells, the electrical power output and efficiency of the panel was improved. The performance of the system was also studied, and the amount that the solar panel was able to convert the solar energy into electricity was investigated. Through this, we discovered that when the temperature of the panel was reduced, on average, by 20%, the electrical power output increased by nearly 12%. Moreover, it was demonstrated that the modelled system can provide hot water under different solar radiation conditions and during all seasons of the year.

Swimming pools are used around the world for recreational, rehabilitation and physical activity. From an energy and environmental standpoint, grey water as a waste thermal potential of swimming pools is a valuable heat source produced continuously in extensive, measurable and large quantities. The main objective of this article is to analyse the feasibility of proposed grey water heat recovery (GWHR) system from the showers and backwater from swimming pool filters for an indoor pool located in recreation centre in Poland. Analysis, calculations and results were obtained and discussions of water and energy consumption were carried out for the mentioned indoor swimming pool on the basis of real measurements case study for water flow rate, water temperature in swimming pools and showers. The results ensure a significant potential of energy savings by using the proposed GWHR system, which allows to reduce the energy demand by 34% up to 67% for pool water preheating and domestic hot water (DHW). The environmental impact of proposed GWHR system was analysed and calculated by using Common Air Quality Index. Environmental results are illustrated and discussed specially for the reduction of CO₂, NO_X, SO_X emissions and dust and ensure a significant reduction of these pollutants in range of 34% to 48%.

The article presents different aspects of application of copper pipes in water supply system, which have importance on properly work of installation and people health safety. The article analyses the water flow velocity criteria and their influence on the operation of the installation. It is particularly dangerous for copper pipes to exceed the permissible water flow velocity, as this results in corrosive processes. It is also not recommended that the flow velocity be too low, as it affects the development of biofilm and multiplication of bacteria.

The energy demand for heating the halls buildings is high. The impact on this may have the technology of production, building construction and technology requirements (HVAC systems). The isolation of the external partitions, the location of the object in relation to the surrounding buildings and the degree of the interior insolation (windows and skylights) are important in the context of energy consumption. The article discusses the impact of external conditions, wind and sunlight on energy demand in the industrial hall. The building model was prepared in IDA ICE 4.0 simulation software. Model validation was done based on measurements taken in the analyzed building.