Analysis and selection criteria of photovoltaic panels for DHW

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