Behavior of R410A Low GWP Alternative Refrigerants DR-55, DR-5A, and R32 in the Components of a 4-RT RTU

Concerns about the impact on the environment of the refrigerants used in HVAC&R equipment are driving the development of alternative refrigerants with lower global warming potentials (GWPs). This paper reports the performance of DR-55 (now designated as R452B), DR-5A (now designated as R454B), and R32 in comparison to R410A at the component level from tests run on a 4 RT (14 kW) commercial unitary rooftop heat pump. Overall unit performance was previously reported (Schultz and Kujak, 2016), showing DR-55 and DR-5A to be design-compatible replacement candidates for R410A. This paper further confirms this by comparing performance at the compressor, evaporator, and condenser component level.