TY - JOUR N2 - A domestic hot water (DHW) system has been modernized in a multi-family house, located in the southeastern part of Poland, inhabited by 105 people. The existing heating system (2 gas boilers) was extended by a solar system consisting of 32 evacuated tube collectors with a heat pipe (the absorber area: 38.72 m2). On the basis of the system performance data, the ecological effect of the modernization, expressed in avoided CO2 emission, was estimated. The use of the solar thermal system allows CO2 emissions to be reduced up to 4.4 Mg annually. When analyzing the environmental effects of the application of the solar system, the production cycle of the most material-consuming components, namely: DHW storage tank and solar collectors, was taken into account. To further reduce CO2 emission, a photovoltaic installation (PV), supplying electric power to the pump-control system of the solar thermal system has been proposed. In the Matlab computing environment, based on the solar installation measurement data and the data of the total radiation intensity measurement, the area of photovoltaic panels and battery capacity has been optimized. It has been shown that the photovoltaic panel of approx. 1.8 m2 and 12 V battery capacity of approx. 21 Ah gives the greatest ecological effects in the form of the lowest CO2 emission. If a photovoltaic system was added it could reduce emissions by up to an additional 160 kg per year. The above calculations take also emissions resulting from the production of PV panels and batteries into account. L1 - http://journals.pan.pl/Content/116269/PDF-MASTER/05-Olczak-i-inni.pdf L2 - http://journals.pan.pl/Content/116269 PY - 2020 IS - No 1 EP - 74 KW - photovoltaic panel KW - reduction of CO2 emission KW - evacuated tube collector with heat pipe A1 - Olczak, Piotr A1 - Olek, Małgorzata A1 - Kryzia, Dominik PB - Instytut Gospodarki Surowcami Mineralnymi i Energią PAN VL - vol. 23 DA - 2020.04.07 T1 - The ecological impact of using photothermal and photovoltaic installations for DHW preparation SP - 65 UR - http://journals.pan.pl/dlibra/publication/edition/116269 T2 - Polityka Energetyczna - Energy Policy Journal ER -