Performance evaluation of ecofriendly R1234ze(E) refrigerant in an automotive air conditioning system

Abstract

A mathematical model for an air conditioning system used in five‐seater cars is developed with R1234ze(E) and R134a refrigerants, consisting of real system geometry like an evaporator, compressor, condenser, and thermostatic expansion valve. The mathematical model includes refrigerant properties, heat transfer, and pressure loss correlations for two‐phase and single‐phase regions. The performance parameters of a system like evaporator cooling duty, condenser heat loss, compressor power, refrigerant flow rate, and compressor volumetric efficiency obtained from a mathematical model are validated with the results of an experimental facility developed with R134a. The uncertainty analysis performed for the testing facility showed below 11% deviation. The simulation and experimental results showed an overall 10%–15% difference. It is found that the experimental cooling capacity with R134a and numerical cooling capacity with R134a show a 4%–12% variation, experimental cooling capacity with R134a and numerical cooling capacity with R1234ze(E) show a 7%–20% variation, and numerical cooling capacity with R134a and numerical cooling capacity with R1234ze(E) show a 5%–15% variation for the given range of compressor speed (500–1500 rpm), and condensing temperature (26–45°C). The study concluded that R1234ze(E) could potentially replace R134a because it has similar thermophysical properties and an average performance difference of up to 10% with R134a. Due to the limitations of the electric motor used to drive the compressor, tests in the current study were conducted at modest compressor speeds (500–1500 rpm). Future research will focus on experiments with high compressor speed (in the range of 1500–4000 rpm) and R1234yf and R1234ze(E) refrigerants for performance evaluation of automobile air conditioning systems.

Performance evaluation of VCR system with pure and various blends of R134a, R1234yf, and R1234ze (E) refrigerants

“…In the recent years, it has been observed that the various pure refrigerants, such as R436a, R515a, R456a, and R445a, as well as mixtures of R290 and R600a, and combinations like R1234yf with R134a and R1234ze (E), have been considered as potential replacements for R134a in various applications. In our previous work, 33,34 the experiments and simulation work were performed to investigate the performance of automotive AC systems with low GWP refrigerants R1234yf and R1234ze (E). In this research work, the investigation is focused on assessing the impact of several critical factors, including compressor speed, condensing air velocity and temperature, the humidity of cooling space on the cooling capacity, the work of the compressor, and the COP of the VCR system of a small 5 seaters passenger car is discussed.…”