VAPOR COMPRESSION CYCLE CHILLERS
As mentioned in Section 1.1, a secondary refrigerant is a substance that does not change phase, as it absorbs heat. The most common secondary refrigerant is water and chilled water is widely used in large commercial, institutional and industrial facilities to make cooling a large area without introducing a number of individual compressor systems. Chilled water has the advantage of being completely regulation can be applied and, thus, the closer the temperature tolerances can be saved at any load.
For very low temperatures, such as ice rinks, a component of antifreezes, most often ethylene glycol or propylene glycol mixed with water and the term brine (left over from a time when salt has been used as antifreeze) is used to describe a secondary refrigerant.
In the ventilation industry, refrigerating machine, which produces chilled water is generally referred to as the cooler and includes compressor(s), evaporator and condenser, all packaged as a single unit. Condensed medium can be water or air outside.
The evaporator is called cooler consisting of shell and tube heat exchanger with the refrigerant in the shell and the water in the pipes.
Coolers are designed for 3 to 11 frames per second speed of the water, when the cooling water flow rate is selected by 10-20F range.
For air coolers, condensers of air and refrigerant heat exchanger and fans to ensure adequate flow of outdoor air to transfer heat rejected by the refrigerant.
For water-cooled chillers, condenser is a second shell and tube heat exchanger with a refrigerant in a shell and condenser water in the pipes. Condenser water, as a rule, are supplied in 70-85F and flow rate selected 10 - 15F range. The tower is typically used to ensure condenser water cooling, but also other points of water sources such as wells, ponds, and so on, may be used...