Performance and Capacity Comparison of Two New Lgwp Refrigerants Alternative to R410a in Residential Air Conditioning Applications

Abstract

This thesis presents a ground breaking study on Low Global Warming Potential (LGWP) developmental refrigerants. An R410A 17.6 kW (5 ton) heat pump split unit commercially available off-the-shelf for US ducted HVAC applications, was retrofitted with two new developmental refrigerants, DR-4 and DR-5 that have GWP ranging from 300 to 500, which is significantly lower than that of R410A. The experiments were conducted at design and off-design conditions with outdoor temperature ranging from -8C (17F) to 46C (115F).Findings and Conclusions: The findings for this work showed that DR-5 had up to 3% higher capacity and up to 6% higher COP, while DR-4 showed up to 4% higher COP but 14% lower capacity in comparison with R410A. The experimental results showed that the thermal expansion valve could be further optimized for the new refrigerants to maximize the COP of the unit while preserving the cooling capacity and data showed that the COP of DR-4 could be augmented by an additional 6% with respect to drop-in tests. The experimental data discussed in this thesis are part of a broader campaign on LGWP refrigerants performance in heat pump systems. The analysis in thesis could inform the HVAC&R industry and regulatory agencies about characteristics and system level behavior of two new developmental LGWP refrigerants.