Lecture+20.++Refrigeration

Lecture+20.++Refrigeration - UNIVERSITY OF CALIFORNIA...

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UNIVERSITY OF CALIFORNIA Department of Viticulture and Enology VEN 135 WINE TECHNOLOGY AND WINERY SYSTEMS 20. REFRIGERATION SYSTEMS Refrigeration is used in several applications throughout the sequence of winemaking operations. These range from the cooling of must, juice, wine or air (in cellars and barrel rooms) to maintaining temperature by heat removal during fermentation and storage. In certain locations, ambient conditions can be used to contribute to cooling applications either as evaporative water in films or cooling towers and as air cooling for cellars at night during the summer. The more common cooling situation will be the use of one or more mechanical refrigeration systems. THE REFRIGERATION CYCLE The principle of the refrigeration is to allow a liquid to evaporate at a reduced pressure, drawing the latent heat for the phase change from the surroundings and thereby cooling them. The vapor is then compressed to a higher pressure in a "compressor" and then condensed to form a liquid at this pressure. The liquid is then allowed to flow to a lower pressure and to evaporate again. The fluid involved is called the refrigerant and the compressor, condenser, expansion valve and evaporator are the major components in the refrigeration system. The expansion may take place in a heat exchanger and provide the desired cooling directly, such systems are referred to as a "direct" or "direct expansion" refrigeration system. Alternatively, it may cool an intermediate fluid (such as water or a glycol solution) which then provides the cooling as desired in what is referred to as an "indirect" refrigeration system. REFRIGERANTS
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Lecture+20.++Refrigeration - UNIVERSITY OF CALIFORNIA...

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