Indirect systems (including on the order of water chillers
The use of indirect systems increases, because some users switch from traditional Central systems of plants. Indirect systems primary secondary cooling system fluid, which cools show-Windows, refrigerating chambers and other Advantages of this system are:
- The main refrigerant is much less, that reduces the risk of diversion. The refrigerant is limited to plants in the area, so leak detection is a simplified and repair easier to implement.
- Refrigerant no longer has to go through very long pipe runs, so that the pressure falls considerably below.
- Room and case coolers are more effective, since 100% of the cooler tube in contact with the cooling medium. This increase in cooler efficiency negates the need to evaporate at low temperatures than conventional DX systems.
- More environmentally friendly refrigerants such as ammonia and hydrocarbons may be safely used as they are usually contained in plant on the roof and will circulate in public areas.
The disadvantage of this system is that there is an additional heat transfer needed which leads to some loss of heat.
This can cause high fever, Elevator compared to direct systems, although this disadvantage can be reduced to the reduced pressure drop.
Packaged water chillers can be used for secondary refrigerants, but they are becoming less appropriate as the temperature falls below 0C. usually, custom chillers are more appropriate for these duties. On Fig. 31 shows the typical indirect commercial system.
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Industrial 
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