Thermodynamic Performance Analysis of Hydrofluoroolefins (HFO) Refrigerants in Commercial Air-Conditioning Systems for Sustainable Environment

Muhammad Farooq,Rida Nadeem,Ahmet Turan,Muhammad Imran,Muhammad Naqvi,Allah Razi,Ahsan Hamayoun,John M Andresen,Muhammad Usman,Salman Raza Naqvi,Alberto Pettinau,Saad Nawaz

doi:10.3390/pr8020187

Abstract

Global warming is one of most severe environmental concerns that our planet is facing today. One of its causes is the previous generation of refrigerants that, upon release, remain in the atmosphere for longer periods and contribute towards global warming. This issue could potentially be solved by replacing the previous generation’s high global warming potential (GWP) refrigerants with environmentally friendly refrigerants. This scenario requires an analysis of new refrigerants for a comparison of the thermodynamic properties of the previously used refrigerants. In the present research, a numerical study was conducted to analyze the thermodynamic performance of specifically low GWP hydrofluoroolefens (HFO) refrigerants for an actual vapor compression refrigeration cycle (VCRC) with a constant degree of 3 K superheat. The output parameters included the refrigeration effect, compressor work input, the coefficient of performance (COP), and the volumetric refrigeration capacity (VRC), all of which were calculated by varying the condenser pressure from 6 to 12 bars and vapor pressure from 0.7 to 1.9 bars. Results showed that R1234ze(Z) clearly possessed the desired thermodynamic performance. The drop in refrigeration effect for R1234ze(Z) was merely 14.6% less than that of R134a at a 12 bar condenser pressure; this was minimum drop among candidate refrigerants. The drop in the COP was the minimum for R1234ze(Z)—5.1% less than that of R134a at a 9 bar condenser pressure and 4.7% less than that of R134a at a 1.9 bar evaporator pressure, whereas the COP values of the other refrigerants dropped more drastically at higher condenser pressures. R1234ze(Z) possessed favorable thermodynamic characteristics, with a GWP of 7, and it can serve as an alternative refrigerant for refrigeration systems for a sustainable environment.

Highlights

Global warming is one of most severe environmental concerns that our planet is facing today.One of its causes is the previous generation of refrigerant gases and carbon dioxide emissions [1,2,3].Upon release, these gases remain in the atmosphere for longer periods and contribute towards global warming [4]
The member countries of the Montreal Protocol during October, 2016, agreed to phase down hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs) to reduce net earth warming by 0.5 ◦ C by the year 2100 and to protect the ozone layer [9]
The results showed that cooling capacity obtained with the R1234yf and R1234ze was decreased to 9% and 30% on average, the coefficient of performance (COP) for R1234yf and R1234ze(Z) was 7% and 6% less than R134a, respectively, and the use of an internal heat exchanger (IHX) resulted in reduced differences between the two refrigerants [35]

Summary

Introduction

One of its causes is the previous generation of refrigerant gases and carbon dioxide emissions [1,2,3] Upon release, these gases remain in the atmosphere for longer periods and contribute towards global warming [4]. These gases remain in the atmosphere for longer periods and contribute towards global warming [4] The severity of these gases’ environment impacts is determined by their life cycle analysis (LCA) [5] and the conversion efficiency of refrigeration systems [6]. Earth’s temperature is expected rise 2.5–10 degrees Fahrenheit over the period of the 100 years [7]. Chlorofluorocarbons (CFCs) and HCFCs were already depleting the ozone layer [10], so these were wiped out after the Montreal Protocol and the Kyoto Protocol, respectively [11]

Methods

Results

Conclusion