Air Conditioning :- For human comfort we need air conditioning system. Air conditioning means not only to mainatain room's temperature but to condition the air as well. Means in air conditioning we maintain comfortable temperature, air purification, control humidity, control odours and maintain level of oxygen by ventilation. Air conditioners are designed to maintain a temprature not below than 16 degree celcius. But human comfort level according to ASHRAE is from 20-24 degree celcius. An air conditioner should not run at temperature below this limit to protect human body's health.
Air conditioning and refrigeration has same cycle and four components and same cycle to produce cooling effect. But main difference between them is, air conditioning is done for human comfort and refrigeration is done to increase the life of eatable products.
Let's understand how cooling effect is produced ?
There are four main components of refrigeration or air conditioner.
1. Compressor
2. Condenser
3. Expansion valve or capillary tube
4. Evaporator
Compressor is called heart of refrigeration cycle. Compressor has two ports one is for suction and other is for discharge. Compressor discharge the refrigerant to condenser (outdoor unit ) at a high pressure and high temperature. At this stage the refrigerant gas is in vapor form and when it starts to pass through the condenser it looses its temperature and comes in liquid form but pressure remains the same. After passing through the condenser refrigerant starts to pass through the expansion valve or capillary tube. Here is the hidden truth. This is the basic principle of gases that if gases are expanded in vaccum they loos temperature, same principle applies in air conditioning and Refrigeration. The expansion valve has very small dia through which refrigerant with high pressure tries to pass but because of tiny space it tends to loose its velocity and suction pressure of compressor start expanding this refrigerant due to which refrigerant's temperature goes down and cooling effect is produced. When this referigerant with low pressure and low temperature passes through the evaporator (indoor unit like split ac) it again gain the heat and space gets cool due to blower which is circulating room's air on its coils. If humidity level (moisture) is high in air, cooling and dehumidification process is performed by air conditioner. When room's air is circulated over the cooling coil of evaporator (indoor unit) humidity content starts to condense over the coils and start to flow through drain pipe in the form of water. This process in called cooling and dehumidification, so there is no separate humidifier installed in air conditioner.
Before filling the refrigerant with refrigerant vaccum inside the copper tube circuit is created so that expansion of refrigerant could take place.
This is how an air conditioner works.