To cool liquid a refrigerating machine - chiller is used. The chiller compressor is the main consumer of electric power. To reduce energy consumption the schemes with natural cooling - free cooling are used. Energy consumption reducing is caused by partial or full dead time of the compressor when the equipment is operating at natural cooling. Reducing operating costs allows saving means, but when capital costs are increased, the payback period is one of the criteria to take a decision. The paper presents the method of calculation of the payback period of natural cooling application in order to reduce the chiller power consumption. Using a method offered the customer may analyze investment profit of free cooling, and a contractor may reason the application of one or another circuitry of free cooling.

The systems of liquid vacuumevaporative cooling have a variety of advantages such as power efficiency, environment safety and high hygienic quality in comparison with conventional vaporcompression installations. Thanks to these advantages vacuumevaporative cooling became one of the most perspective trends in refrigeration engineering development. The paper analyzes the process of vacuumevaporative cooling of a liquid supplied into a vacuumizing space in the form of drops. An analytical dependence that allows defining the drops core and surface temperatures was obtained as well as the heat transfer parameter during vacuum impact on drops of supplied liquid was estimated. The test bench and the method of the experiment execution were described. The experimental data on dynamics of vacuumevaporative cooling of dropping liquid supplied under conditions of spray irrigation for a wide range of initial temperatures were obtained. The experimental data were compared with the results of a theoretical calculation using the model presented. The comparison allowed concluding the adequacy of theoretical research results. The results presented in the paper may be used when designing vacuumevaporative systems of dropping liquid cooling.

As is known, heat processing (blanching), preliminary cold storage and quick freezing are the means widely used to prevent oxidation and microbiological processes in food produce. Lately the impact using high frequency electromagnetic fields is widespread for heat processing. This method is applied in the technology of different products preserving. Sometimes the ultraviolet irradiation (UV) and ozone are used as additional factors of impact. A complex impact of SHFUVО3 on vegetable raw materials (cut carrot, potato, beet) before freezing was investigated. The processing of vegetables was carried out using a special bactericide SHFUVО3 plant with electrodeless gasdischarge lamps (source of UVradiation). After treatment the raw material was quickly frozen and stored at -18 оС. The samples of the same vegetables, blanched in hot water, then quickly frozen and stored at -18 оС were used as control samples. It was defined that SHFUVО3 processing gave the possibility to reduce mass losses in comparison with hot water blanching; the raw material kept more soluble dry substances, when defrosting moisture recovery reduced. The evaluation of organoleptic properties during storage was higher in comparison with the control samples. At complex processing of vegetables before freezing the quantity of viable microflora was reduced (from 1,2·105 to 1,0·104 CFU/g), while hot water blanching reduced the quantity of vial microflora only to 2,1·103 CFU. The SHFUVО3 complex processing as a part of a quick freezing technology prolonged the shelf life of frozen vegetables up to 24-26 months, at the same time it provided a high quality of produce.