Techno-economic-environmental analysis of a PVT-based solar combined cooling, heating, and power system

The growing adoption of solar energy in the residential sector plays a pivotal role in advancing sustainable energy practices, reducing carbon dioxide emissions, and enhancing energy independence. This study examines the novel integration of photovoltaic-thermal (PVT) technology with a diffusion absorption refrigeration (DAR) cycle in a solar combined cooling, heating, and power (S-CCHP) system. A transient model is developed, along with economic and environmental assessments, to simulate energy performance, highlighting the use of heat from the PVT system to drive cooling without using electricity during summer months. For comparison, systems using conventional photovoltaic (PV) and solar thermal (ST) technologies are also analysed under different configurations, both with and without battery storage. As a case study, the system is designed for application in Berlin, Germany, and the results show that the PVT-based system can supply 68% of domestic hot water demand and 48% of appliance electricity use, but only 12% of space heating due to the limited temperature output of the PVT collectors. Importantly, while the DAR system achieves full coverage of space cooling demand in summer, it relies heavily on auxiliary thermal energy input, underscoring a key area for system improvement. The economic analysis indicates net present values of approximately €7800 for PVT, €11,300 for ST, and €23,600 for PV, with corresponding payback periods of 21.0, 16.5, and 6.9 years. In terms of environmental performance, the PVT-based system achieves the highest carbon dioxide emission reduction at 2658 kg/year, followed by the PV (1904 kg/year) and ST (1781 kg/year) systems. The sensitivity analysis highlights the critical role of battery integration, especially under high grid electricity prices. In conclusion, the PVT-based S-CCHP system demonstrates strong economic and environmental potential in urban environments, while the DAR integration offers a compelling pathway for electricity-free cooling, revealing significant opportunities for optimisation and future development.