Refrigerating System Condenser Functions
Condensers are the mirror image of the evaporator. Whereas the function of the evaporator is to absorb heat from the refrigerated space, the condenser must reject that heat outside the refrigerated space.
In addition to evaporator heat and suction line superheat, the condenser must also reject the heat of compression and motor heat picked up by the suction vapor on its way through the compressor. This additional heat can be as much as one-third more than that absorbed by the evaporator. For example, a 36,000 Btuh per hour system must reject about 48,000 Btuh of heat. To accomplish this, there must be more effective condensing coil surface than evaporator surface. Airfl ow through condensers is also an important factor. AC air handlers move about 400 cubic feet per minute per ton (cfm/ton), whereas condenser fans move about 1,000 cfm/ton. Most condenser coils are designed to have airfl ow across them of about 1,000 cfm/ton of refrigeration. This is two and a half times the air flow of most AC evaporators, which is 400 cfm/ton.
Source : Commercial Refrigeration: For Air Conditioning Technicians
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