Wednesday 8 July 2015

Types of Water Liquid Chillers

Types of Water Liquid Chillers Points : types of water liquid chillers, floodedtype, direct expansion liquid coolers Water Liquid Chillers There are two types of liquid chillers.
1. FLOODED TYPE
2. Direct Expansion Liquid Coolers
1. FLOODED TYPE Most medium size and large liquid coolers are shell and tube flooded liquid coolers. In a flooded liquid coolers, several straight tubes are aligned iii a parallel staggered arrangement, usually held in place at both ends by the sheets as shown in figure given below chilled water circulates inside the tubes, which are submerged in a refrigerant filled shell.

Liquid refrigerant in an air conditioning application is fed into the bottom to the shell. It is evenly distributed over the entire length of the tubes. As the refrigerant boils and bubbles rise, the upper part becomes increasingly bubbly vapor refrigerant is discharged from the opening at the top of the cooler. Eliminator is sometimes installed to separate the liquid refrigerant from the vapor. A low pressure side floats valve, or a multiple orifice-throttling device controls the amount of refrigerant fed to the flooded liquid cooler.

When halocarbons are used as the refrigerant copper tubes are always used because they provide higher thermal conductivity and do not react with halocarbons, integral, tins are extruded on the outer surface of the tubes to increase the outer surface area. Spiral grooves or other enhancements may be added to the inner surface of the tube to increase the inner surface heat transfer coefficient by increasing the turbulence, dirt and suspended solids are prevented from settling on the inner surface during operation.
2. Direct Expansion Liquid Coolers In direct expansion liquid coolers as shown in the diagram liquid refrigerant evaporates in side the cooper tube while chilled water fills in the shell. An expansion valve and sometimes a distributor are used for each group of refrigerant circuit connected to the same suction headers and compressors. In direct expansion liquid coolers various inner surface configuration arid enhancements are used to heat transfer on the Water side, or the liquid coolers baffle plates are used to guide the water flowing the shell in multipass arrangements. Direct expansion coolers are usually used for refrigerant systems equipped with multiple compressors. Indirect expansion liquid cooler, refrigerant circuits may be connected to a single header and compressor.

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