Enhanced photovoltaic (PV/T) –heat pump performance through a novel direct-contact finned evaporator design
International Journal of Refrigeration, cilt.189, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 189
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.ijrefrig.2026.107012
- Dergi Adı: International Journal of Refrigeration
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, INSPEC, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Anahtar Kelimeler: Heat and mass transfer, Heat exchanger, Heat pump, Phase change, Photovoltaic, Renewable energy, Waste heat recovery
- Atatürk Üniversitesi Adresli: Evet
Özet
This study aims to reduce the electrical efficiency losses caused by the increase in cell temperature in photovoltaic (PV) modules exposed to continuous solar irradiation. In addition, it seeks to enhance building energy efficiency by recovering waste heat from the PV system. In this context, a PV/T–heat pump (HP) system was developed and comprehensively investigated using both experimental and numerical methods. In conventional PV–HP systems, heat transfer is predominantly achieved through indirect fluid loops, resulting in high thermal resistance between the PV module and the evaporator, which limits the utilization of the high heat transfer potential generated during phase change. This limitation leads to electrical efficiency losses and restricted waste heat recovery, particularly in building-integrated applications. To overcome this drawback, a novel direct-contact evaporator with expanding–contracting rectangular fins was designed. The energy efficiency potential of the proposed design for building applications was evaluated under laboratory conditions through experimental measurements and CFD analyses. The structure enhances turbulence during the two-phase boiling process, thereby accelerating heat transfer and maximizing heat extraction from the PV module. Experimental results revealed that the system automatically switches to active cooling mode when the cell temperature exceeds 45 °C and deactivates when it drops to 25 °C, thus maintaining optimal operating conditions. As a result, the PV electrical efficiency increased from 7.8% at 74 °C to approximately 14% within the controlled temperature range, corresponding to an improvement of nearly 80% under 1100 W/m² irradiance. Using R134a as the working fluid, the tests yielded a coefficient of performance (COP) of 2.49 and an exergetic efficiency of 30.8%. The findings demonstrate that the developed direct-contact evaporator significantly reduces thermal interface losses in PV–HP systems and enables the recovery of waste heat as high-quality hot water. By effectively controlling the PV surface temperature, both the electrical efficiency and the building’s cooling performance are improved, contributing indirectly to sustainable thermal comfort and indoor air quality enhancement.