WATER COOLED CONDENSERS BASIC INFORMATION AND TUTORIALS


In a water-cooled condenser, latent heat of condensation released from the refrigerant during condensation is extracted by water. This cooling water, often called condenser water, is taken directly from river, lake, sea, underground well water or a cooling tower.


Two types of water-cooled condensers are widely used for air-conditioning and refrigeration: double tube condensers and horizontal shell-and-tube condensers.

A double-tube condenser consists of two tubes, one inside the other. Condenser water is pumped through the inner tube and refrigerant flows within the space between the inner and outer tubes in a counter flow arrangement. Because of its limited condensing area, the double-tube condenser is used only in small refrigeration systems.

A horizontal shell-and-tube water-cooled condenser using halocarbon refrigerant usually has an outer shell in which copper tubes typically 5/8 to 3/4 in. in diameter are fixed in position by tube sheets. Integral external fins of 19 to 35 fins/in. and a height of 0.006 in. and spiral internal grooves are used for copper tubes to increase both the external and the inner surface area and their heat transfer coefficients.

Hot gas from the compressor enters the top inlet and is distributed along the baffle to fill the shell. Hot gas is then desuperheated, condensed, subcooled into liquid, and discharged into the liquid line at the bottom outlet.

Usually one sixth of the volume is filled with subcooled liquid refrigerant. Subcooling depends on the entering temperature of condenser water Tce, in °F, and usually varies between 2 and 8°F.

Condenser water enters the condenser from the bottom for effective subcooling. After extracting heat from the gaseous refrigerant, condenser water is discharged at a higher level. Two-pass or three-pass water flow arrangements are usually used in shell-and-tube water-cooled condensers.

The two-pass arrangement means that water flows from one end to the opposite end and returns to the original end. Two-pass is the standard setup. In a shell-and-tube water-cooled condenser, the condensing temperature Tcon depends mainly on the entering temperature of condenser water Tce, the condenser area, the fouling factor, and the configuration of the copper tube.

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