Experimental investigation of a vapor compression refrigeration system integrated with thermoelectric generators for enhanced energy recovery.

Energy efficiency and waste heat recovery have become crucial challenges in refrigeration technology, especially with the increasing demand for sustainable and environmentally friendly cooling systems. In this paper, a hybrid thermoelectric generator system and vapor compression refrigeration, operated with R600a refrigerant, are analyzed with respect to utilizing waste heat sources as a means of generating electric power and enhancing the system’s efficacy. The experimental setup consists of a conventional vapor compression refrigeration cycle combined with thermoelectric generator modules between an aluminum cooling block. The experimental setup includes varying cooling water rates, ranging from 0.5 to 3.0 L/min, and condenser temperatures of 35 ◦C, 40 ◦C, and 45 ◦C to examine the influence of operating conditions on both thermal and electrical performance. The findings reveal that increasing water flow dramatically enhances cold-side heat transfer, resulting in a 40 ◦C temperature difference across the TEG, measured at a 45 ◦C condenser temperature, compared to 22.5 ◦C. Therefore, the electrical power output fluctuates from 0.05 W to 1.05 W, and the TEG efficiency reaches up to 2.2%, which is comparable to the best commercially available bismuth-telluride modules. The compressor pressure ratio and discharge temperature are reduced by 10% and 5 ◦C, respectively, which increases the system’s COP improvement to 7.9% and approximately 8% of total energy recovery. These findings confirm the thermodynamic benefit of TEG integration functioning as a desuperheating system for simultaneous cooling, power generation, and energy recovery.