The Analysis of Efficiency and Investment Profitability of a Solar Water Heating System in a Multi-Family Building

The study analyses the efficiency of a Solar Water Heating (SWH) system, potential financial savings and investment profitability. The analysis pertaining to the amount of energy generated by the collectors had been performed for the multi-family building within the span of two years. The efficiency of the system was determined by comparing the amount of energy from solar radiation incident on the surface of the collectors to the amount of energy generated by the collectors and fed to the existing Domestic Hot Water (DHW) system. The amount of energy generated by the collectors was approx. 70 GJ per year, at the efficiency of the SWH system equalling 36%. The best time for the operation of the system was the period from April to September, during which the share of generated for DHW amounted to 78%. It is reflected in the decreased consumption of gas by 6% throughout the year. Furthermore, based on the data about the efficiency and energy yield of the set of collectors, as well as data on insolation, the analysis was performed to determine the installation and operation costs and the depreciation period of the investigated SWH system