28-07-2012, 11:41 AM
Air Conditioner Condenser
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.Introduction
An Air Conditioning condenser works by exchanging the inside heat and building the outside air to a cool and pleasant air. All this is based on a simple refrigeration principle. Condenser coil plays a vital role in the entire refrigeration process. It is made of aluminum and surrounds the compressor of the AC unit.
What generally takes place inside the outside unit is the change of state of the refrigerant which happens inside the AC unit. The refrigerant which changes its state to a gas in the indoor coil flows outside where the high pressure compresses the gas inside the compressors. After this the hot gas moves from the compressor and travels through the tubing which is present in the condenser coil.
The Water Cooled Condensers
The water cooled condensers reject the heat absorbs by air conditioner system to the water. The water has to be clean, noncorrosive, and at certain temperature. This water has to be treating to prevent pitting corrosive, algae, scale, chalky, and mineral deposits.
Even though, water cooled condenser require regular maintenance, it is more efficient than air cooled condenser, and it operates at much lower condensing temperature.
COMPRESSOR
An air conditioning system has several parts that assist in the cooling of air. These parts are the compressor, the condenser, and the evaporator. An air conditioning compressor is the part of the air conditioning system that compresses cool, low pressure gas into a hot, high pressure gas. The compression of this gas is the first part in a multi-step process that helps keep the area cool. Though the compressor is an important part of the air conditioning system, if any one of these parts fail, the unit will fail.
A properly working air conditioner starts with low pressure gas traveling into the air conditioning compressor. The compressor compresses the gas into a high pressure gas with a higher temperature. This is why it is called an air conditioning compressor. At this point, the gas must be cooled down. This is when it travels to the condenser.
In the condenser, the gas is cooled into a liquid still under high pressure. After this, it travels to the evaporator. In the evaporator, the liquid is squeezed through a small hole and into tubing. In this tubing, the liquid uses the heat from the room to be cooled in order to turn back into a gas. The low-pressure, cool gas is then transported back to the air conditioning compressor to start the journey all over again.
How does an air conditioning compressor motor work?
The job of the compressor/condenser unit is to recompress warm refrigerant gas (pulled from the indoor air handler cooling coil) back to a liquid refrigerant that can be returned to the indoor cooling coil once again. When the room thermostat calls for cooling, both the indoor blower or air handler and the outdoor compressor/condenser begin to work. Control circuits and a contactor relay turn on the outside compressor/condenser motor and its outdoor cooling fan as well.
Refrigeration and Air Conditioning Theory:
In an air conditioning system, pressure is used to change (increase) the vaporization point (state change from liquid to gas) or condensation point (state change from gas to liquid) of the refrigerant. On the A/C system's high side (high refrigerant gas pressure side of the system), the condensation point must be some temperature above ambient outdoor air temperature (if air is being used to cool the condensing coil) or condensation of the refrigerant gas back to a liquid will not occur.
Creation of high side & low side in a refrigeration system:
The restriction in refrigerant flow created by the thermostatic expansion valve (TEV, discussed below) [or on many systems simpler CAPILLARY TUBES] located close to the evaporator coil (cooling coil) allows the compressor to raise the pressure and increase the temperature at which the refrigerant (coolant) will change state (from liquid to gas in the cooling coil, and from gas back to liquid in the condensing coil).This restriction in refrigerant flow at the TEV is what allows the compressor a pressure difference between the high side and low sides of the system. Evaporator coil is defined at A/C COMPONENTS and discussed further at AIR HANDLER / BLOWER UNITS. TEVs, AEVs, manual and adjustable expansion valves, and float valves are discussed at THERMOSTATIC EXPANSION VALVES. Capillary tubes for metering refrigerant are discussed separately at CAPILLARY TUBES.