Investigation and optimization of the use of flat plate collectors with different designs in various energy systems

Heating, cooling, and power requirements of residential buildings are of fundamental importance in terms of energy management. The increasing energy demand has made the use of renewable energy sources increasingly significant. The combined use of renewable energy sources and waste heat is considered a highly efficient alternative to optimize the energy performance of residential buildings. This hybrid approach contributes to ensuring energy supply security and supports achieving sustainability goals by reducing the carbon footprint. In this study, solar energy-supported heating, cooling, and power generation systems capable of operating under low solar radiation conditions were analyzed. In the first phase of the study, a solar energy-supported single cooling system (GDAS) was designed. In the second phase, a hybrid heating and cooling system (GDHIS) was developed. In the final phase, a hybrid heating, cooling, and power generation system (GDHISG) was introduced. Cooling needs during the summer were met using a single-stage absorption cooling system, while heating requirements during the winter were provided by a solar energy-assisted natural gas boiler. Additionally, the waste heat from the boiler and cooling systems was utilized for power generation using thermoelectric generators (TEGs). The TEGs were placed on a heat exchanger filled with phase change material. As a result of the Net Present Value analysis in the examined systems, the designs with the highest NPV are the systems with vacuum tube collector (ETC). NPV value for designs with ETC was calculated as 6726.13 US$ for GDAS, 3941.49 US$ for GDHIS and 29.84 US$ for GDHISG. Exergy efficiency for designs with ETC was determined as 2.39% for GDAS, 4% for GDHIS and 4.93% for GDHISG. 209.77 m3 of natural gas was saved in the GDHIS system using ETC. A total annual electricity production of 138. 53 kW was determined in TEG. It has been calculated that the designed systems will provide 15890.2 kg CO₂ emission savings for the GDAS system, 16005.6 kg for GDHIS and 17696.82 kg for GDHISG based on lignite fuel at the optimal points.