Condensers and water towers

The purpose of the condenser in a vapour compression cycle is to accept the hot, high-pressure gas from the compressor and cool it to remove first the superheat and then the latent heat, so that the refrigerant will condense hack to a liquid. In addition, the liquid is usually slightly suhcooled. In nearly all cases, the cooling medium will he air or water. 

This latter, again ignoring small heat gains and losses, will he the net shaft power into the compressor, giving 

Evaporator load + compressor power = condenser load 

Condenser rating is correctly stated as the rate of heat rejection. Some manufacturers give ratings in terms of the evaporator load, together with a de-rating factor, which depends on the evaporating and condensing temperatures. 

Example 6.1 The following figures from a compressor catalogue give the cooling capacity in British thermal units per hour X 10 and the shaft horsepower, for a range of condensing temperatures 

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