Solar Combined Cooling, Heating and Power System based on Photovoltaic-Thermal (PVT) Technology

Tesis Energía y Ambiente (maestría) - Instituto Tecnológico de Buenos Aires, Buenos Aires - Karlsruher Institut für Technologie, Karlsruhe, 2023
"The energy transition in the residential sector has witnessed substantial growth in the use of solar energy in recent years, owing to its ability not only to curtail CO2 emissions but also to enhance energy independence. Photovoltaic-Thermal technology (PVT) plays a crucial role by enabling simultaneous heat and electricity generation, improving overall efficiency. Moreover, previous studies shown the presence of residual heat in summer months.

In this context, the study examines the potential of a Solar Combined Cooling, Heating, and Power (S-CCHP) system with PVT and thermally driven Diffusion-Absorption-Refrigeration (DAR) technologies in Spain, Germany, and Poland, employing a techno-economic analysis through MATLAB modeling. In the coldest months, 75 % of Space Heating (SH) and 95 % of Heating Water (HW) demand was covered in Spain, contrasting with Germany and Poland where only 15–25 % of HW demand was met; the covered electricity for appliances ranged from 46–48 % across all countries.

The organic refrigerant-absorbent combinations of n-butane/n-octane and n-pentane/iso-octane exhibited 2–3 times lower energy requirements than the traditional NH3-H2O combination, while economic viability indicated a promising Net Present Value (NPV) and Payback Time (PBT) of 7240 euros and 21.4 years for Germany, but unattractive results for Spain and Poland with negative NPV and PBT of at least 35 years. Emissions reductions of up to 2.26, 42.4, and 42.5 ton/CO2 were observed for Spain, Germany, and Poland, respectively.

Sensitivity analysis demonstrated that variations from 25 % to 75 % could significantly improve system economic and environmental performance. The findings stress the importance of evaluating system improvements based on regional demand profiles and climate conditions; possible future research could be directed towards enhancing the proposed system, comparing alternatives in high cooling demand regions, and improving SH and HW provision systems in colder areas."