CONDENSERS

CONDENSER

FUNCTION• The function of the condenser is to transfer heat that has been

absorbed by the system to the air or water.

CONDENSER

PURPOSE• Thus the purpose of the condenser in the refrigeration system is to

remove heat from the refrigerant vapor leaving the compressor (or generator in case of absorption system) so that the refrigerant will condense to its liquid state.• This liquid refrigerant will then be able to achieve the refrigerating

effect in the evaporator.

CONDENSER

PURPOSE• The condenser is one of the important part of the refrigeration

system.• The rate of heat transfer in condenser depends upon:

a. Temperature differenceb. Material of constructionc. Types and quality of cooling mediumd. Surface condition

CONDENSER

OPERATION• Refrigerant always leaves the compressor at a temperature well

above its saturation (condensing) temperature.• The refrigerant is thus in a superheated state.• In the first part of the condenser, sensible heat is removed.• The vapor is cooled to its saturation temperature.

CONDENSER

OPERATION• After this, latent heat is removed when the vapor is cooled.• The size of the condenser is such that, the refrigerant leaving the

condenser is a saturated liquid at the condensing temperature.• In number of cases, the condenser heat transfer surface area is great

enough so that the liquid refrigerant is subcooled before it leaves the condenser.• The heat removed in the condenser is called the Heat of Rejection.

Types of condenser

AIR COOLED CONDENSER

a. Natural convection air cooled condenser

b. Forced convection air cooled condenser

WATER COOLED CONDENSER

a. Tube in tube condenserb. Shell and coil condenserc. Shell and tube condenser

CONDENSER

Fig 1: NATURAL DRAFT CONDENSER Fig 2: PLATE TYPE CONDENSER

CONDENSER

FORCED CONVECTION AIR COOLED CONDENSER

AIR COOLED CONDENSER

OPERATION

•This is the condenser in which the removal of heat is done by air.•These condensers are the most popular type used on small commercial and domestic refrigeration and air conditioning units.• They consist of steel or copper tubing through which the refrigerant flows.•Tubes are usually provided with plate type fins to increase the surface area for heat transfer.

AIR COOLED CONDENSER

OPERATION

•There are two types of natural draft air-cooled condensers.•The TUBE and FIN type shown in figure 1 and the plate type as shown in figure 2.•The FIN spacing is quite wide to reduce dust clogging.

AIR COOLED CONDENSER

DISADVANTAGESi. It operates at a higher condensing temperature

than a water cooled condenser. The higher condensing temperature causes the compressor to work more.

ii. Large condensing surface is required for air cooled condenser as the air quantity circulated over the condenser is low.

FORCED CONVECTION AIR COOLED CONDENSER• In this condenser, fan is used to force the air over condenser coils to increase the heat transfer capacity.•The propeller type fan or the centrifugal type fan may be used to move the air.•The type of fan used depends on design factors such as air resistance, noise level, space requirements etc.

SHELL AND COIL CONDENSERS•Coil of tubing enclosed in a welded shell•Water flows through the coil•Refrigerant from the compressor is discharged into the

shell•The shell also acts as the receiver•When refrigerant comes in contact with the cool coil, it

condenses and falls to the bottom•This condenser must be cleaned chemically

Shell and Coil Condenser

Shell Hot discharge gas from compressor

Subcooled liquid from condenser

Cool water inWarm water out

Water coil Droplets of condensed refrigerant

Bottom of shell acts as a receiver

SHEL AND TUBE CONDENSERS•Can be cleaned mechanically

•Compressor discharge gas is piped into the shell•Water flows through the tubes in the condenser•The ends of the shell are removed for cleaning•The shell acts as a receiver•Refrigerant circuit is not disturbed when the ends of the

shell (water boxes) are opened•Most expensive type of condenser

Hot discharge gas from compressor

Subcooled liquid from condenser

Cool water in

Warm water out

Water Tubes

Bottom of the condenser acts as the receiver

Shell

Thank you….