In connection with imposing a ban on high GWP refrigerants use the interest is growing to the use of natural refrigerants, in particular carbon dioxide, in refrigerating plants. There are several circuits of CO2 refrigerating plants. The paper examines a cascade refrigerating plant with CO2 in the lowstage part and with R134а in the upperstage part. A basic circuit and refrigerating cycle are cited. A cascade cycle was analyzed for adopted initial conditions that provide the supply of needed cold to consumers of lowand average temperatures using the entropy and statistical method of analysis (ESMA). A sequencing of calculation is given as well as the formulae and results of calculation of all necessary values to specify energy losses through components of the cascade system. The data are compared with the losses through components of other СО2 and R404А systems. The power efficiency of all systems was compared as well, and the comparison proved the advantage of the R744/R134а cascade system.

HFC refrigerant mixtures are widely used now in cold supply and air conditioning systems. R404А, R410A, R407С are the most popular of them. But the list of HFC refrigerant mixtures is not limited by these refrigerants. The paper envisages the properties, fields of application, environmental characteristics of HFC refrigerant mixtures that are not well known. The statutes of EU regulations ЕС 517/2014 on phasing out of fluorinecontaining gases by 2030 are cited. A diagram presentation of the values of refrigerant mixtures GWP in comparison with R134a is given. It is recommended to replace refrigerant mixtures at high GWP with R134a during an interim period until HFO refrigerants are tested, studied on safety and price reducing.

An improved method of calculation of a cryogenic freezer to freeze smallfruited products of vegetable origin and smalllump products of animal origin is examined. This method is intended for designing a cryogenic freezer that uses liquid nitrogen as a refrigerant, and the method may be used at the enterprises applying the technology of cryofreezing of smallfruited products of vegetable origin as well as smalllump products of animal origin. An example of calculation of the cryogenic freezer of given capacity is presented. Pineapple guava fruits were chosen as a basis object for cryofreezing. The calculation of the apparatus begins with determination of initial data (characteristics required), then the selection of the apparatus construction materials, the calculation of a drum and a conveyor belt, the calculation of drive, insulation, shaft fit on the drum etc. are performed.

The role of heat insulation in food quality preservation along the cold chain is emphasized. It is offered to apply the stateoftheart heat insulation of domestic foamed synthetic rubber (FSR) in heatinsulating constructions used in different facilities of the cold chain to maintain given temperature conditions and to preserve foodstuffs quality. The properties of the FSR are described as well as the spheres of its application and factors influencing the expansion of FSR domestic production segment. Heat insulation produced using domestic raw materials (synthetic rubber with addition of fillers, plasticizers, foaming agents etc.) is presented. The types and marks of this insulation are examined, the characteristics of heat insulation different marks are cited; the spheres of application of each of them are given as well. The advantages of these heatinsulating materials are described.