What Are the Different Types of Condenser and What Type of Condenser Is the Most Efficient?

The condenser is a device used in the high-pressure side of a refrigeration system. The function of the condenser is to remove the heat of the hot vapor refrigerant discharged from the compressor. The heat from the hot vapor refrigerant in a condenser is removed first by transferring it to the walls of the condenser tubes and then from the tubes to the condensing or cooling medium.

The types of condenser:-

• Air-cooled condensers
• Water-cooled condensers
• Evaporative condensers

• Air-cooled condenser:- In these condensers, the heat is removed by air and it consists of steel of copper tubing through which the refrigerant flows. The size of the tube usually ranges from 6 mm to 18 mm outside diameter.

     Air-cooled condensers are two types:

           1:-Natural convection air-cooled condenser
           2:-Forced convection air-cooled condenser

• Natural Convection Air-cooled Condenser: In these condensers, the heat transfer from the condenser coils to the air is by nature a condenser. As the air comes in contact with the warm condenser tubes, it absorbs heat from the refrigerant, and thus the temperature of air increases. The warm air being lighter rises up and the cold air from below rises to take away the heat from the condenser. This cycle continues in natural convection air-cooled condensers.

• Forced Convection Air-Cooled Condenser:-In this type of air-cooled condenser, a fan or blower is employed to move air over the condenser coil at a certain velocity. The condenser coil is of the finned type and fines are closely spaced (ranging between 5-7 fins/cm). the space the fins gets choked with dirt. Therefore to obtain optimum capacity, the fins should be kept clean.

• Water-Cooled Condenser:-In these condensers, the heat is removed by water and they are always preferred where an adequate supply of clear inexpensive water and means of water disposal are available.

     Types of water-cooled condenser:- The types of water-cooled condensers are given below:-

• Tube-in-tube or double tube condensers,
• Shell and coil condensers, and
• Shell and tube condensers.

1. Tube-in-tube or double tube condenser:- This type of condenser consists of a water tube inside a large refrigerant tube and the hot vapor refrigerant enters at the top of the condenser. The water absorbs the heat from the refrigerant and the condensed liquid refrigerant flows at the bottom. Since the refrigerant tubes are exposed to ambient air, therefore some of the heat is also absorbed by ambient air by natural convection.
   
2. Shell and coil condensers:- In a shell and coil condenser vapor refrigerant enters the shell whereas the cooling water flowing through the coil causes condensation.
3. Shell and tube condenser:- This type of condenser consists of a cylindrical steel shell containing several straight water tubes. The tube is expanded into grooves in the tube sheet holes to form a vapor-tight fit. The tube sheet is welded to the shell at both ends and the removable water boxes are bolted to the tube sheet at each end to facilitate the cleaning of the condenser.

• Evaporative condensers:- In an evaporative condenser, both air and water are employed as condensing mediums. Water is pumped from the sump of the evaporative condenser to a spray header and sprayed over the condenser coil. At the same time, a fan draws air from the bottom side of the condenser and discharged it out at the top of the condenser. The spray water coming in contact with the condenser-tube surface, evaporates into the air stream, the amount of heat for vaporizing the water being taken from the refrigerant, thereby condensing the gas. The cold water that drops down into a sump is recirculated. To make up for the deficiency caused by the evaporated water, additional water is supplied to the sump. A float valve in the sump controls the make-up supply and the eliminator is provided above the spray header to stop particles of water from escaping along with the discharge air.