Thermal efficiency of a solar power system in a collective residential structure based on performance tests

Abstract

Here, we evaluated the efficiency of a solar domestic hot water system in a dormitory in Rzeszow. Radiance exposure was analyzed based on information obtained from an online database (the meteorological station in Rzeszow-Jasionka). The mean seasonal and annual solar irradiation of a flat surface and surfaces inclined at 30°, 45°, and 60° from the horizontal plane in Rzeszow were determined. The mean monthly irradiation was compared with that in selected European cities based on the Photovoltaic Geographical Information System meteorological database. The thermal solar panel area and final consumption of solar energy in Poland from 2005 to 2014 are also presented. The characteristics of the analyzed building, distribution of the inhabitants, and consumption of hot water from 2009 to 2014 are described. The heat demand was determined by hot water consumption per day per person based on hot water consumption metering and heat metering. The solar energy conversion efficiency was determined after the solar thermal collectors were installed in the building. The relation of the heat demand calculated based on the thermal energy utilized to heat water per person and heat metering for heating water was also analyzed. We also present a method of calculating the annual (stratified by month) ratio of solar energy utilization. Energy savings for the building were calculated. Improvements that could further increase the solar energy efficiency and shorten the investment payback period are proposed.