Efficiency of Refrigeration Equipment on Natural Refrigerants

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EFFICIENCY OF REFRIGERATION EQUIPMENT ON NATURAL REFRIGERANTS V. V. Shishov and M. S. Talyzin

UDC 536.75:621.565

A comparative investigation of losses in refrigeration plants applied in the food industry was carried out using the natural refrigerants CO2 and refrigerant grade propane (R290) at two working temperature levels (evaporation temperature minus 35 °С and minus 10 °С) using entropic and statistical analysis methods. A comparison of energy losses and efficiency for a transcritical refrigeration plant having an aircooled gas cooler and CO2 as refrigerant, a cascade refrigeration plant with R134a in high cascade stage and CO2 in low cascade stage and a refrigeration plant working on one stager cycle and water cooled condenser with R290 was performed. The principles of losses by refrigeration plants elements, COP and the degree of thermodynamic efficiency of plants are illustrated in diagrams. On the basis of the analysis results prospects for the application of refrigeration plants with R290 as refrigerant are outlined to permit improvements to the efficiency refrigeration plants applied in food industry using natural refrigerants. Keywords: entropic and statistical method of analysis, efficiency, natural refrigerants, CO2, propane.

Due to the need to improve the efficiency of refrigeration technology and reduce its negative impact on the environment [1], work is underway to upgrade equipment [2–4] and control systems, as well as to search for alternative environmentally-friendly refrigerants [5]. In this connection, a promising direction involves the use of so-called natural refrigerants (ammonia, propane, and CO2 ) in refrigeration equipment. For the purposes of refrigeration system design, it is necessary to consider the disadvantages of these refrigerants, as well as their obvious advantages [6, 7]. Operation of Refrigeration Units at the Premises of Food Industry Companies Using Natural Refrigerants Refrigeration units used in the food industry operate at low (LT) and medium temperature (MT) levels. Initial data for the analysis of the refrigeration unit efficiency used at a typical food industry company are as follows: Boiling point of the LT refrigerant, °C (K) .............................................. −35 (238)

Boiling point of the MD refrigerant, °C (K) ............................................. −10 (263) Ambient temperature, °С (K) ................................................................... +32 (305)

Air temperature in LT consumers, °С (К) ................................................ −20 (253)

Air temperature in MT consumers, °С (К) ..............................................

Cooling capacity of the LT circuit QLT, kW ..........................................

0 (273)

70

Cooling capacity of the MT circuit Qmt, kW .......................................... 360

Bauman Moscow State Technical University, Russian Federation; e-mail: [email protected], [email protected]. Translated from Khimicheskoe i Neftegazovoe Mashinostroenie, Vol. 56, No. 5, pp. 31–34, May, 2020. 0009-23