Heat exchanger outdoor conditions

The correct and efficient operation of any plant requires full flow at all times through the heat exchangers. Air and water filters need to be kept clean. Finned coils, especially outdoor condenser coils, must be cleaned frequently. The water side of heat exchanger coils should be cleaned of any accumulations of scale or algae as soon as a change in working conditions shows that they are getting dirty. 

Unless there is a specific reason, the supply temperature should be higher in order to increase the exergy efficiency of the heat pumps and hence the overall system, as shown in Figure 82. Other points to be considered in the design include the effect of outdoor conditions on the return temperature of the heat distribution network, the type of users connected to the system, and the characteristics of the heating apparatus. Also, in the heat exchanger... 

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