The compressor is the very heart of an air conditioning system, for that matter any cooling system. Suffice to say without the compressor; there will be no cooling. But how well do you know this heart? In fact, were you aware that a compressor has at least 5 different types? If not, you need to read this article to learn something new. You never know when the information may come handy.
What Does The Compressor Do?
The compressor compresses the refrigerant in the gaseous state, thereby raising its temperature. This temperature increase changes the refrigerant to high-pressure gas. The subsequent high pressure pushes the refrigerant through a pipe, which leads to the outdoor coil. Here the refrigerant dissipates its heat and condenses into a liquid form. The liquid refrigerant continues to travel to the indoor unit, where it evaporates and attains the gaseous state once again. During this process, it absorbs the heat from within your home. The refrigerant then travels back to the compressor, and the cycle starts all over again.
What Forms The Basis Of Different Types Of Compressors?
The primary function of the compressor is to provide the cooling effect. If they all perform the same function, then how are they different? The answer to this question is straightforward. Though the compressor performs the same function, they work in varying ways, which forms the basis of their type.
Types Of Compressors In AC
As stated above, there are mainly 5 types of compressors used in HVAC installations.
1. Reciprocating AC Compressor – With a construction similar to that of an automobile engine, the reciprocating AC compressor is by far the most popular presently. A piston, fitted inside a cylinder, compresses or tightly packs the air by moving up and down. This rotating motion is accomplished by using an electric motor. When the piston travels down, it produces a vacuum effect which draws in the refrigerant. When it travels back up, the gas gets compressed and passes into the condenser. This type of air conditioning compressor is extremely efficient, as AC units can house multiple cylinders. Though 2, 4 and 8 cylinder compressors are most commonly used.
2. Scroll AC Compressor – Also known as a scroll vacuum pump or a scroll pump, this type of compressor has two scrolls. One of these is an immovable scroll and the other a revolving or circling scroll that rotates using the swing link. Due to this motion, the refrigerant pockets amidst the two scrolls are gradually pushed to the middle of the scrolls. When this occurs, there is a decrease in the gas volume. It then passes to the condenser through the center port. The prime benefit of a scroll compressor is that it has lesser moving parts and smaller torque variation as compared to the reciprocating AC compressor. This translates to a comparatively, smoother, and quieter operation. For this very reason as well as their reliability and efficiency, Scroll AC compressors are fast gaining popularity.
3. Screw AC Compressor – The screw air conditioner compressor is very dependable and efficient. It is mostly used in large structures where there is a significantly larger amount of air that needs incessant cooling. Using a pair of helical rotors (male and female), which move from one end to another in a revolving motion inside the cylinder, the refrigerant gas is compressed. Ideally, this kind of compressor is used in HVAC systems that have a capacity of 20 tonnes or more.
4. Rotary AC Compressor – Rotary compressors are of two types. One has slats or vanes which rotate along with the shaft. The other has fixed blades and is part of the unit which houses the compressor. In a single system, the blades can vary in number from anywhere between two to eight. In either type, the gas from the suction line is dragged inside the cylinder via the suction port. Rotary compressors are generally small and silent, so they are widely used in places where noise is a grave concern. The inside of a rotary AC compressor houses a shaft with some blades attached to it. The shaft with blades rotates inside a graduated cylinder. This motion pushes the refrigerant through the cylinder and compresses it at the same time.
5. Centrifugal AC Compressor – Centrifugal AC compressor uses centrifugal force to drag in the coolant or the refrigerant gas. Then it spins the gas rapidly with an impeller or a disk with radial blades to compress it. The pumping efficiency rises with speed. Higher the speed better the pumping efficiency. As such, these compressors are intended to function at high speed. The key benefit of a centrifugal compressor is that it has no valves, pistons or cylinders. The only wearing parts that demand care are the main bearings. These types of compressors are usually used in a large capacity cooling system and hence are earmarked for extra-large HVAC systems. In short, they are most suited to industrial installations.
Which Type Of Compressor Is The Best For Air Conditioners?
If the AC unit is of small capacity, say up to 10KW, a rotary compressor is the best. However, if the AC unit is of medium size capacity, from 10KW to 50KW, scroll compressors are more suited. Ultimately, its a toss between sacrificing a little silence for more reliability and efficiency, or vice-versa.
Innovation is the key to technological advancements. In the arena of AC compressors, great strides have already been made in trying to fulfil the varying demands of the consumers. The result is the different types of compressors in AC. This is nowhere near the end, but a niche has been carved so that people can choose what suits their needs the best. With its own set of pros and cons, each compressor offers something unique to the buyer.
Ultimately the decision regarding which compressor is best suited for your requirements will depend on how clear you are in what you want the most and where you are ready to compromise.