The summers in India can get very hot. The AC is the most important accessory in practically every home today. It is very easy to just switch on the AC and have a cool experience.
However, a lot of processes go inside the AC machine before you get the cool waft of air. Let us look at the basic principles of air conditioning before discussing about the AC compressors.
Basic principle of Air conditioning
Any AC unit has three main components, the compressor, condenser, and evaporator. The compressor is the heart of the machine.
The principal function of the compressor is to draw the cool, low-pressure refrigerant gas and compress it thereby converting increasing its temperature and pressure resulting in the release of a hot, high-pressure gas.
The fans take over as they blow cold air over the coil thereby extracting the heat and transferring it to the outside air. Once, the heat escapes from the gas, it condenses into a warm liquid.
This liquid is then made to pass under high pressure to an expansion valve whereby the temperature of the warm liquid decreases considerably.
The liquid then passes through the evaporator coils where the pressure is considerably low. Warm air from the room is blown over these coils by another set of fans thereby resulting in a heat transfer reaction. This cools the air that is supplied to the rooms.
The refrigerant thereby completes the cycle and becomes a low-pressure gas. The entire cycle is repeated to supply a continuous flow of cool air to the room.
Different types of compressors
We have just mentioned that the compressor is the heart of the AC machine. Let us look at the different types of compressors inside in an AC and understand the difference. We shall also look at the uses, advantages, and disadvantages of the individual type of compressors.
These compressors work on the cylinder and piston arrangement in a way very similar to that we see in automobile engines. The piston uses a back and forth movement for compressing and discharging the gas.
In this system, there is a pair of specially designed rotors having very little clearance between them. They rotate in opposite directions. Therefore the air comes out at high pressure when it emerges through the rotors.
You have a couple of other type of compressors like the screw compressors, scroll compressors, and centrifugal compressors. However, the reciprocating and rotary compressors are the most common in this industry.
Reciprocating vs Rotary Compressor
Which of the compressors is the better one? Which one should you opt for while purchasing your AC? As a lay person, distinguishing between the two is difficult. However, you can get a fair idea once we list out the merits and demerits of both these types of compressors.
Advantages of a reciprocating compressor
- The pistons and shafts require maintenance, but it is easy to maintain them. It is not an expensive procedure at all.
- The reciprocating compressor is capable of working at extremely high pressure.
Demerits of reciprocating compressor
- This process releases the air at a higher temperature.
- You experience vibration and high noise while the compressor functions.
Advantages of rotary compressor
- This type of compressor is well suited for large-scale cooling such as office, factories, and industries.
- You do not experience much noise as compared to the reciprocating compressor.
- The out-coming air is not as hot as you experience with the reciprocating compressors.
Disadvantages of rotary compressor
- These compressors are comparatively expensive.
- You need to use these compressors for a minimum period of time in a day / week. Hence, they are better suited for offices and other business establishments.
Why do you need to use the rotary compressors for a minimum amount of time?
The system is such that there can be formation of water condensate in case you do not use the compressor for the minimum period. This can lead to corrosion of the metals thereby causing damage to the motors.
Customers should therefore understand the functioning of the compressors. The choice of the customer depends on the usage.
The usage of the Air Conditioner is very important before deciding on the type of compressor. If you are buying one for your house where the use of the AC will be intermittent, it is always better to go for the reciprocating air compressor. However, if you run an office or a shop or industry requiring frequent use of the air conditioner, it makes sense to opt for an AC with rotary compressors.
You have now understood the difference between the two different types of compressors in use. Normally, you need not make the choice as such because the domestic air conditioners always come with the reciprocating compressors. However, a little bit of knowledge is always helpful.