Performance evaluation of multi pressure refrigeration system using R32 Aditya Bhamidipati a , Srinivas Pendyala a,⇑ , R. Prattipati a a Department of Mechanical Engineering, GITAM (Deemed to be University), Hyderabad, India article info Article history: Received 6 January 2020 Received in revised form 23 April 2020 Accepted 25 April 2020 Available online xxxx Keywords: Global warming Refrigerator R134a COP R32 R152a abstract One of the present worldwide trends in refrigeration sector is to substitute the refrigerant which con- tributes to the global warming such as R134a with a low global warming refrigerant. The aim of this paper is to investigate the use of R32 as a potential substitute for R134a and R152a in refrigeration sys- tem. The performance of R32 is compared with R134a and R152a at different condenser and evaporator temperatures. For this study, performance parameters such as coefficient of performance (COP), work done, refrigeration effect and compressor discharge temperature were considered. Thermo physical char- acteristics of the chosen refrigerants were compared under the operating range of temperatures. Results indicate that COP of R32 nearly matches with the R152a and is 5–7% higher than R134a. COP is more sen- sitive to the evaporator temperature than condenser temperature. The compressor exit temperature of the selected refrigerants is lower than their critical temperatures, therefore no condensation problems during heat rejection. R32 and R152a have a reduced global warming potential than R134a, which indi- cates that R32 can be used as substitute for R134a in refrigeration systems. Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 2nd International Con- ference on Advances in Mechanical Engineering and Nanotechnology. 1. Introduction In the heating ventilation and air conditioning (HVAC) sector, much study has been ongoing since last three decades to discover environmentally friendly refrigerant to meet Montreal and Kyoto protocols, including flammability problems. Earlier in 1990s R12 was used as the refrigerant for domestic refrigerator. It has excel- lent thermo-physical characteristics but it is contributing to the depletion of ozone. According to the Montreal protocol R12 was phased out by all the nations in 2010. R134a has been identified as an alternative fluid to R12. In the absence of chlorine molecule in its chemical structure ODP of the R134a is zero. Many authors reported that COP of R134a is comparable with R12. However, glo- bal warming potential (GWP) of R134a is considerably high (GWP = 1300). Therefore consumption of the R134a needs to be reduced according to Kyoto protocol [1]. In this regard, R152a attracts refrigeration industry due to its low global warming (GWP = 120) and zero ODP [2]. Saturation pressure of R152a is similar to that of R134a and also vapor density and refrigerant charge are more favorable for drop in replacement [3,4]. Cabelloa et al. [5] carried out experimental comparison between R152a and R134a. Their results observed that COP of R152a was increased by 13% compared to R134a. Same author extended his experiments to two stage cascade refrigeration sys- tem. The results show that performance of R152a is very much similar to that of the R134a. From the above discussion it was observed that R152a can be used as drop in substitute for R134a without compromising the performance. However, R152a is a flammable refrigerant. The lower and upper flammability limits are 3.7% and 16.9% by volume respectively [6]. Therefore it cannot be used for large capacity refrigeration system where more refrig- erant charge is needed. Hydrocarbons (HCs) came out as the promising refrigerants to replace R134a. HCs have zero ODP and negligible GWP. Srinivas et al. [7] carried out experiments to find substitute for R134a with a ternary mixtures of HFC/HC mixtures. Results show that the tern- ary mixture’s viscosity is lower than R134a, thus optimized the capillary length to achieve better efficiency. Yu et al. [8] experimented on a domestic refrigerator using HC mixture of R290/R600a with the mass fractions of 0/100, 50/50 and 65/35 to substitute R134a. It is found that the energy efficiency of R290/R600a (65/35) increases by 9.1%. Lot of work has been done to replace HFCs with HCs [9–11]. HCs are the natural refrigerants it can be considered as an environment friendly refrigerant but these are highly flammable (as per ASHRAE A3). While the charge https://doi.org/10.1016/j.matpr.2020.04.716 2214-7853/Ó 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 2nd International Conference on Advances in Mechanical Engineering and Nanotechnology. ⇑ Corresponding author. E-mail address: pendyala76@yahoo.com (S. Pendyala). Materials Today: Proceedings xxx (xxxx) xxx Contents lists available at ScienceDirect Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr Please cite this article as: A. Bhamidipati, S. Pendyala and R. Prattipati, Performance evaluation of multi pressure refrigeration system using R32, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2020.04.716