Air Conditioning Explained
The principle of air conditioning always comes down to the same:
- absorb energy in one place and release it in another place
The process requires an indoor unit, an outdoor unit and copper piping to connect both. Through the piping the refrigerant flows from one unit to another. It is the refrigerant that absorbs the energy in one unit and releases it in the other.
 Cooling Mode
1 Indoor unit. A fan blows the hot indoor air over a heat exchanging coil through which cold refrigerant flows. The cold refrigerant absorbs the heat from the air and cooled air is blown into the room.
2 Copper piping. The refrigerant circulates through the units and the piping and takes the heat from the indoor unit to the outdoor unit.
3 Outdoor Unit. Through compression, the refrigerant gas is heated and it's boiling point increases. In the outdoor unit the obtained heat throughout compression is released to the outdoor air by means of a fan which blows the outdoor air over a heat exchanging coil.
4 Refrigerant. The liquid refrigerant flows back to the indoor unit.
5 Indoor unit. Back in the indoor unit, the refrigerant is decompressed and thus enabled to extract heat form the indoor air.
The Refrigerant Cycle
An air conditioner works similar to a refrigerator. The refrigerant flows through the system, and changes in state or condition. There are four processes in the 'refrigeration cycle' .
 1. The compressor which pumps the refrigerant around the system, is the heart of the air conditioner. Before the compressor, the refrigerant is a gas at low pressure. Because of the compressor, the gas becomes high pressure, gets heated and flows towards the condenser.
2. At the condenser, the high temperature, high pressure gas releases its heat to the outdoor air and becomes subcooled high pressure liquid.
3. The high pressure liquid goes through the expansion valve, which reduces the pressure, and thus temperature goes below the temperature of the refrigerated space. This results in cold, low pressure refrigerant liquid.
4. The low pressure refrigerant flows to the evaporator where it absorbs heat from the indoor air through! evaporation and becomes low pressure gas. The gas flows back to the compressor where the cycle starts all over again.
In case of a heat pump the cycle can be reversed.
How Do Heat Pumps Work?
Heat pumps are air conditioners which can be used both for cooling and heating. The principle is that it is able to reverse the process of transporting heat from one place to another.
Energy efficiency?
Moreover heat pumps are much more energy efficient than other heaters. The reason for this is simple: rather than burning a fuel, what it does is 'moving heat'. Because of this heat pumps are up to five times more energy efficient than other heaters.
Heat pumps additionally allow the refrigerant cycle to be reversed. A heat pump extracts energy from the outdoor and transfers the heat indoors. This principle even continues to function on very cold days with temperatures down to _5°C, -10°C or -15°C, depending on the type of air conditioning system used.
Therefore, heat pumps eliminate the need for a heating system and allow you to cool and heat with the same unit, with savings in costs and energy throughout the year.
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