Experimental Analysis of a R-744 Refrigeration Unit for Light Commercial Vehicles

This manuscript presents the design and development of a transcritical R-744 refrigeration unit for light and medium-sized refrigerated transport applications, along with an experimental campaign carried out on a laboratory prototype. The steady-state performance of the system is evaluated for both a conventional baseline back-pressure cycle and an ejector-enhanced configuration, under different refrigerated space temperatures (−5°C, 0°C, and 5°C) and ambient conditions ranging from 20°C to 40°C. The results show that the ejector configuration leads to significant performance improvement compared to the baseline back-pressure operation, particularly at higher ambient temperatures, where the coefficient of performance (COP) increases up to approximately 25%. At lower ambient temperatures however, back-pressure cycle provide a higher COP. In addition, when compared to systems based on synthetic refrigerant reported in the literature, the proposed R-744 unit demonstrates competitive energy performance. Specifically, a COP improvement of about 15% is observed at an ambient temperature of 20°C in back-pressure configuration, while improvements of approximately 17% are achieved at 30°C and 40°C in ejector configuration.