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The article discusses the issue of selecting power of photovoltaic panels for heating domestic hot water (DHW). It is indicated that the price of installation is several times lower than a couple of years ago. The authors present a method of selecting system power depending on DHW installation’s heating requirements and the building’s energy consumption. This algorithm allows for central heating requirements that are crucial in case of heating a building with solid fuel appliances. The described selection method uses heating power details obtained while drawing up Energy Performance Certificates, or the so-called heating degree-days, which enable to precisely determine the heating requirements in individual days of the year and select appropriate power of PV installation for the building’s energy performance. In addition, the authors have calculated the heating losses occurring in different elements of installation and showed their influence on the system’s power selection. The last part discusses the possibility of integrating PV installation used for heating DHW with the building’s central heating system, in order to use the energy surplus.

The article presents the analysis of the performance of a concentrating collector in the heating system of a residential building. Air was used as the working fluid. The heating requirements of the building were determined for each day of the year. The amount of direct irradiation reaching the absorber’s surface on all the days of the year was determined with the use of hourly meteorological data for Wroclaw, shared by the Ministry of Infrastructure and Growth. It was assumed that the collector is equipped with a tracking system working in one axis. Calculations and comparisons were made for the amount of solar irradiation for three values of the receiver’s inclination angle: β1=60°, β2=90° and β3=30°. Statistical method was used in order to determine the optimum inclination of the mirror and the amount of flowing air. This method involves creating a plan of experiment with three levels of changeability for two input factors. In the last stage, the amount of heat obtained from the installation during all the days of the year was analysed. The gains were juxtaposed on the diagram with the building’s heat demand. The analysis has shown that the heat requirements can be met only partially.

The article presents the results of the test of a heat storage filled with chamotte brick. The air parameters were used as the basis for determining the heat stream represented by a working medium, which was then compared with the stream accumulated in the material filling the deposit. Additionally, heat streams were shown for individual segments of the deposit. The efficiency of heat accumulation was determined for each of them. They showed that the efficiency of accumulation process was highest in the deposit’s first segments and the lowest in the last segments, where the air was the coldest. The dynamics of the efficiency’s shift was different for each of the observed segments. In the area closest to the inlet of hot air, the dynamics of the process of heat accumulation decreased the fastest and after one hour only a slight increase of efficiency was visible in the function of time. In the accumulation material placed closest to the outlet, the process of absorbing heat was very fast, starting from the 20th minute before the tests were completed. The smallest changes in the process’ character, throughout the whole time of testing, were recorded in the middle layer.