Forced Circulation Evaporator
Forced circulation evaporators compact arrangement of the refrigerant is cooled tubes and fins. Fan with electric motor, blows air over them. Evaporator and fan usually enclosed in a metal housing. Evaporator takes up little space, and does not need additional unclear.
These evaporators, tend to lead to rapid dehydration (drying) of food. Special care must be taken to avoid this. Drying will be minimized, if the evaporator is large. It should work with a small difference of temperatures of 10F 12CF or 6C to 7C). The air must be circulated slowly.
In some cases, drying is not harmful and air can flow through the evaporator quickly. In such installations, small evaporators practical. They are operated on a large temperature differences, 20F 30F (11 C to 17 C). Thermostatic expansion valve the refrigerant controls are used, as a rule, with a forced convection of evaporators.
The fan motor can be any size and can be operated continuously. It can also be controlled using the evaporator or temperature device.
The refrigerant temperature is usually kept fairly low. Fast air circulation will help the evaporator from freezing. However, a significant sweating occurs drainage must be provided in the installation.
Blower evaporators operating at low temperature refrigerant need special defrosting assistance. Fin pitch a small surface of the evaporator small. Therefore, frost or ice can interfere sharply heat transfer. Forced circulation evaporator, used in medium and low temperature walk in coolers. They are built in different positions, depending on the load on the evaporator is required. Larger systems can contain up to six evaporator fairs. Fig. 13-55 illustrates the internal components of the same evaporator. A microprocessor controls the operation of the expansion valve, defrost system and fan.
In condensate pump can be used to give a positive way to remove condensate. The pump is mounted on the plums and self-priming. It uses about 10 watts and operates continuously. It is also used for pumping slightly acidic condensate produced by high-efficiency gas furnaces. Thus, there are two reception. One for air conditioning condensate drain line, one of which is for the furnace.
Many evaporators use the hot-gas bypass system. This system provides above-zero temperatures the cooling load is decreased. It provides hot gas, necessary to prevent the evaporator hosting during low load conditions.
 ..
|
Industrial 
..