HEAT EXCHANGER

Two fluids, of different starting temperatures, flow through the heat exchanger. One flows through the tubes (the tube side) and the other flows outside the tubes but inside the shell (the shell side). Heat is transferred from one fluid to the other through the tube walls, either from tube side to shell side or vice versa. The fluids can be either liquids or gases on either the shell or the tube side. In order to transfer heat efficiently, a large heat transfer area should be used, so there are many tubes. In this way, waste heat can be put to use. This is a great way to conserve energy.

SUBPARTS OF HEAT EXCHANGER

Ø      DX-CHILLERS:

For cooling the secondary refrigerants, chillers are used. In working the DX chiller is similar to the dry expansion coil. The liquid refrigerant feed is through an expansion valve which ensures superheated gas at the suction outlet of the chiller. Mainly it is shell and tube type. The water or liquid to be cooled in the shell, while the refrigerant is in the tubes. Baffles are provided in the water passage in the shell of the chiller, thereby maintaining good velocity of water/liquid over the tubes to get good heat transfer efficiency.

Ø      CONDENSOR: 

Condenser is the next most important component after the compressor in the refrigeration system. The condenser rejects unwanted heat to the atmosphere and converts refrigerant vapour in to liquid state, at high pressure. The condenser is selected on the basis of the Total Heat Rejection (THR) capacity. The Total Heat Rejection consists of two components namely heat picked up to the evaporator and the work of compression, both these parameters must be expressed in the same units, usually kcal/hr of Btuh.