Abstract
Due to the implementation of the Kigali Amendment to the Montreal Protocol, the paper explores the prospects for replacing HFC refrigerants R404a and R507 in refrigeration machines for fruit and vegetable storages. For the optimal choice of environmentally friendly synthetic and natural refrigerants, calculating the coefficient of performance for single-stage refrigeration machines with direct supply of refrigerant to air coolers was carried out. The calculations were made for the conditions of a sharply continental climate at an atmospheric air temperature of +20°C. It was found, that in the near future such refrigerants as R407a, R407c, and R407f can be used as a replacement for R404a and R507 refrigerants in the new energy efficient systems with reciprocating and scroll compressors in developing countries. In the long term, refrigerants such as R290 (propane), R450a, R455a, and R513a can be used after 2036. The use of refrigerants R450a, R455a, R513a will lead to an increase in capital costs for the creation of refrigeration machines due to the need to increase the volumetric performance of compressors. In addition, R450a and R513a refrigerants have a relatively high global warming potential GWP > 150, which may lead to restrictions on their use in large refrigeration systems. As refrigerants R290 and R455a are flammable, their safe use requires a reduction in their charge weight. Therefore, R290 and R455a can be used either in refrigeration systems for individual cold chambers, or in systems with an intermediate heat transfer liquid.