Thermoeconomic and sustainability analysis of a compact, unglazed solar air heater with cetearyl alcohol-based thermal energy storage assembly

Abstract

Solar energy is actively applied in both thermal and electrical practices. This experimental study examines the performance of a solar air heater consisting of PVT collectors and a cetearyl alcohol-based thermal energy storage unit integrated into the back of the collector. Contrary to conventional ones, alternative thermal energy storage material has been put forward, and its suitability in PVT collectors has been investigated. Three different configurations of equipment were assembled: a PVT (a conventional thermal-photovoltaic system without any modifications), a FTS/PVT (thermal-photovoltaic system with modifications such as finned and thermal energy storage unit), and a TS/PVT (thermal-photovoltaic system with modification only over thermal energy storage unit), and later the three of them were experimentally analyzed under the conditions of low and high airflow rates. Energy and exergy analyses were conducted on each designed system. A cost analysis was also carried out on each PVT. According to the findings, the maximum thermal energy efficiency occurred while using the TS/PVT system under 2.3 m/s air flow rate conditions. In other words, under this airflow rate condition, the biggest average thermal energy efficiency value was 67.24 %, achieved by TS/PVT, followed by FTS/PVT with 64.68 % and PVT standing at the end of the list with 60.19 %. Yet the maximum thermal exergy efficiency was attained at an airflow rate of 1.7 m/s, and the average thermal exergy efficiencies at this air flow rate were found as 14.30 %, 15.88 %, and 11.38 % for PVT, FTS/PVT, and TS/PVT, respectively. Considering the data, the sustainability analysis of each system was studied in terms of the sustainability index values. It can be ultimately reported that the performance of solar air heaters can be enhanced with such modifications, and cetearyl alcohol can be used as an alternative thermal energy storage material in PVT systems.