Selection of refrigerant for use in chillers

Abstract

BACKGROUND: Chillers (chillers) are essential components in various industrial processes. They are primarily used when direct cooling through direct heat exchange between the boiling coolant and the cooled medium is not feasible. This could be attributed to the cost of the refrigerant, especially when a large amount of expensive substances for long refrigerant lines is needed, or the risks associated with using toxic and flammable refrigerants, which could be hazardous in case of leaks. Chillers are typically classified into three types based on their temperature applications: high-temperature chillers for uses like plastic manufacturing and data centers, medium-temperature chillers for air conditioning systems, etc.) and low-temperature chillers for applications like ice fields and food storage. Given their widespread use and high production volume, designing efficient chillers is an important task. AIMS: Substantiating refrigerant use in terms of efficiency and service life of refrigeration equipment. MATERIALS AND METHODS: Chillers are designed for various industrial applications, with specific inlet and outlet temperatures for the evaporator: +26°С / + 20°С (ВТ); +12°С / +7°С (ST); −10°С / −13°С (НТ)). These chillers operate using refrigerants R134a, R410A, R404A, and R1270, evaluated through an entropy-statistical method of thermodynamic analysis [1]. R1270 is highlighted as a promising refrigerant for monoblock chillers, since there are no filling restrictions for these chillers when installed in open space [2]. RESULTS: Among the refrigerant reviewed, R1270 demonstrates the highest thermodynamic efficiency in BT mode, outperforming R404A by 11.97%, R134a by 2.15%, and R410A by 5.48%. In CT mode, R1270 also leads,–with a 14.13% advantage over R404A, 3.04% over R134a, and 3.41% over R410A. Similarly, in HT mode, R1270 shows superior thermodynamic performance, being 21.95% more efficient than R404A, 29.73% more than R134a, and 11.44% more than R410A. The use of R410A and R134a in NT mode is limited owing to high discharge temperatures during compression, namely 116.94°C for R410A and 114.63°C for R134a, potentially reducing equipment lifespan. The lowest discharge temperature during actual compression, 84.63°C, is achieved using R404A coolant. However, despite its efficiency, this refrigerant results in a relatively high discharge temperature of 96.84°C. CONCLUSIONS: The analysis highlights specific applications for various refrigerants in chillers and underscores the potential of natural refrigerant R1270, which is produced in the Russian Federation.