Retrofit assessment of automobile air conditioners using hydrocarbon refrigerants

Abstract

• R600a and HR12 were selected as alternative refrigerants for the R134a MAC. • Optimal charging amount of HR12 was 45% of that for R134a. • R600a was not suitable to directly replace R134a in the MAC. • Q c and DH were better than those of R134a at T oa of 30 to 40 °C. • T oa of 40 °C could cause a substantial decrease in the EER of HR12. In this study, hydrocarbons (R600a and HR12) were selected as alternative refrigerants to evaluate their performance and feasibility as direct replacements for the R134a used in automobile air conditioners (MACs). The MAC performance tests were performed under fixed indoor conditions (27 °C, 50% RH) and outdoor ambient temperatures ( T oa , 35 °C) to determine the optimum charging amount and availability of hydrocarbons. The results showed that the optimal charging amount of HR12 (247.5 g) was 45% of that for R134a, and its cooling capacity ( Q c ), dehumidification capacity ( DH ), and energy efficiency ratio (EER) were significantly better than those of R134a and R600a. Therefore, HR12 was more suitable for replacing R134a than R600a. In terms of the influence of T oa changes on MAC performance, the Q c , DH , and EER of HR12 used in MACs at a T oa of 30 °C were 5.96%, 6.62%, and 81.02% higher than those of R134a, respectively. The differences of the Q c , DH , and EER between the HR12 and R134a used in the MAC at a T oa of 40 °C were 1.02%, 7.59%, and −9.79%, respectively. The results showed that a T oa of 40 °C could cause a substantial decrease in the EER of HR12, mainly due to the increase in power consumption of MACs. However, in the T oa range (30–40 °C) of this study, the Q c and DH of HR12 were still higher than those of R134a, indicating that HR12 was suitable as a direct replacement for R134a in MACs.