Compressors are very important and expensive component of a refrigeration cycle. They are installed to produce a high pressure and high temperature refrigerant. If you look at a reciprocating compressor it will look like a car's engine. It is a combination of cylinder piston but an electric motor is connected to the shaft to move the piston. Lubrication is required same as an engine to minimize the friction of moving parts. If a compressor is out of oil, it will produce significant heat due to friction and parts will start to expand, finally it will seize the compressor. In compressors there is a crank case which is always filled with lubricant. To know how a refrigeration cycle works just go through the article https://myblog45214.blogspot.com/2018/12/how-ac-produces-cooling-or-heating.html
There two Type of Compressors according to their construction :-
1. External Drive compressors
2. Harmetic compressors
1.1. External drive compressor is bolted togather and can be overhauled easily by opening each part. Its crankshaft extends through the crankcase. This compressor is drived by an external motor by a V-belt. This compressor can be a double or four cylinder compressor. This type of compressor were used in the past decade, now a days these compressors have been replaced with harmetic compressors.
2.1. Harmetic compressor is totally sealed by proper welding. The motor is directly connected with compressor inside the body of compressor. Crankshaft is not needed in this type of compressor. The electrical connections to the motor pass through dome by means of an insulated leakproof seal.
In modern air conditioners compressors are integrated with VFDs to reduce the power consumption. A VFD (Variable Frequency Drive) controls the rotation of motor by increasing or reducing the voltage but system never cut offs or cut in like in old compressor units. That is the reason we can now purchase 3 or 4 star rating air conditioners. In old air conditioners, when temperature inside the room reached to desired range, a senor on the evaprotor (indoor unit) made the system to completely shut down and when temperature rises it again put on the system automatically. When a compressor is switched on it need high amperes or power and after some time of running it power consumption reduces to normal. This process increases the power consumption and electricity bills are usually high. But in modern compressors the rotation is controlled and system dont need to cut off or cut in, so the power consumption is very low. These modern compressors can be run on a home inverter too, only that is the reason these are called inverter air conditioners.
There are five basic types of compressors according to working principle. In all compressor original energy source is an electric motor.
1. Reciprocating ( piston-cylinder) compressor.
2. Rotary compressor.
3. Screw compressors.
4. Centrifugal compressors.
5. Scroll compressors.
1. Reciprocating compressors - In this type of compressor the rotary motion is changed to reciprocating motion. This change is made by using a crank and a rod connecting crank to the piston. The complete mechanism is housed in a sealed leakproof container called a crankcase. this compressor resembles to an automobile engine.
2. Rotary compressors :- There are two basic types of rotary compressors. One has the blades that rotate with the shaft and other has a stationary blade. The rotary blade compressor using two blades is typical of this type. The low pressure vapor from suction line is drawn into the opening and fills the space behind the blade as it revolves. As the blade resolves, trapped vapor in the space ahead of the blade is compressed until it can be pushed into the discharge line to the condenser.
3. Screw compressor :- A screw compressor uses a pair of special helical rotors. They trap and compress the refrigerant as they revolve in an accurately machined compressor cylinder. The two rotors are not the same shape. One is male, the other is female. The male rotor is driven by the motor and it has four lobes. The female rotor meshes with and is driven by the male rotor. It has six interlobe spaces. A cylinder encloses both rotors. This compressor is powered by an external motor.
4. Centrifugal compressors :- Centrifugal compressors are used in large refrigeration systems. In this type of compressor vapor as it is moved rapidly in a circular path, moves outward. This action is called centrifugal force. The vapor is fed into a housingnear the center of the compressor. A disc with radial (impeller) spins rapidly in this housing forcing vapor against the outer diameter. The pressure gained is small so that several of these compressor wheels or impellers are put in series to create a greater pressure difference and to pump a sufficient volume of vapor. This type of compressor looks like a steam turbine.
5. Scroll compressor :- Scroll compressor has male and female discs or scrolls and refrigerant vapors are discharged at a high pressure from the center of the discs. One disc is male and other is female. These compressors are used for high capacity air conditioning systems like package air conditioner, chillers etc. These type of compressers usually look like a cylinder and are in very compact size. In scroll compressors refrigerant enters form the outer most part of disc and gap and its compressed by the walls of the discs with the rotation of male disc. Refrigerant is discharged at high pressure and high temperature from the center of the disc plates. Scroll type compressors don't produce high level of sound and viberation. Installation and replacement of these compressors is easy as compared to other compressors.
In modern air conditioners compressors are integrated with VFDs to reduce the power consumption. A VFD (Variable Frequency Drive) controls the rotation of motor by increasing or reducing the voltage but system never cut offs or cut in like in old compressor units. That is the reason we can now purchase 3 or 4 star rating air conditioners. In old air conditioners, when temperature inside the room reached to desired range, a senor on the evaprotor (indoor unit) made the system to completely shut down and when temperature rises it again put on the system automatically. When a compressor is switched on it need high amperes or power and after some time of running it power consumption reduces to normal. This process increases the power consumption and electricity bills are usually high. But in modern compressors the rotation is controlled and system dont need to cut off or cut in, so the power consumption is very low.
There two Type of Compressors according to their construction :-
1. External Drive compressors
2. Harmetic compressors
1.1. External drive compressor is bolted togather and can be overhauled easily by opening each part. Its crankshaft extends through the crankcase. This compressor is drived by an external motor by a V-belt. This compressor can be a double or four cylinder compressor. This type of compressor were used in the past decade, now a days these compressors have been replaced with harmetic compressors.
2.1. Harmetic compressor is totally sealed by proper welding. The motor is directly connected with compressor inside the body of compressor. Crankshaft is not needed in this type of compressor. The electrical connections to the motor pass through dome by means of an insulated leakproof seal.
In modern air conditioners compressors are integrated with VFDs to reduce the power consumption. A VFD (Variable Frequency Drive) controls the rotation of motor by increasing or reducing the voltage but system never cut offs or cut in like in old compressor units. That is the reason we can now purchase 3 or 4 star rating air conditioners. In old air conditioners, when temperature inside the room reached to desired range, a senor on the evaprotor (indoor unit) made the system to completely shut down and when temperature rises it again put on the system automatically. When a compressor is switched on it need high amperes or power and after some time of running it power consumption reduces to normal. This process increases the power consumption and electricity bills are usually high. But in modern compressors the rotation is controlled and system dont need to cut off or cut in, so the power consumption is very low. These modern compressors can be run on a home inverter too, only that is the reason these are called inverter air conditioners.
There are five basic types of compressors according to working principle. In all compressor original energy source is an electric motor.
1. Reciprocating ( piston-cylinder) compressor.
2. Rotary compressor.
3. Screw compressors.
4. Centrifugal compressors.
5. Scroll compressors.
1. Reciprocating compressors - In this type of compressor the rotary motion is changed to reciprocating motion. This change is made by using a crank and a rod connecting crank to the piston. The complete mechanism is housed in a sealed leakproof container called a crankcase. this compressor resembles to an automobile engine.
2. Rotary compressors :- There are two basic types of rotary compressors. One has the blades that rotate with the shaft and other has a stationary blade. The rotary blade compressor using two blades is typical of this type. The low pressure vapor from suction line is drawn into the opening and fills the space behind the blade as it revolves. As the blade resolves, trapped vapor in the space ahead of the blade is compressed until it can be pushed into the discharge line to the condenser.
3. Screw compressor :- A screw compressor uses a pair of special helical rotors. They trap and compress the refrigerant as they revolve in an accurately machined compressor cylinder. The two rotors are not the same shape. One is male, the other is female. The male rotor is driven by the motor and it has four lobes. The female rotor meshes with and is driven by the male rotor. It has six interlobe spaces. A cylinder encloses both rotors. This compressor is powered by an external motor.
4. Centrifugal compressors :- Centrifugal compressors are used in large refrigeration systems. In this type of compressor vapor as it is moved rapidly in a circular path, moves outward. This action is called centrifugal force. The vapor is fed into a housingnear the center of the compressor. A disc with radial (impeller) spins rapidly in this housing forcing vapor against the outer diameter. The pressure gained is small so that several of these compressor wheels or impellers are put in series to create a greater pressure difference and to pump a sufficient volume of vapor. This type of compressor looks like a steam turbine.
In modern air conditioners compressors are integrated with VFDs to reduce the power consumption. A VFD (Variable Frequency Drive) controls the rotation of motor by increasing or reducing the voltage but system never cut offs or cut in like in old compressor units. That is the reason we can now purchase 3 or 4 star rating air conditioners. In old air conditioners, when temperature inside the room reached to desired range, a senor on the evaprotor (indoor unit) made the system to completely shut down and when temperature rises it again put on the system automatically. When a compressor is switched on it need high amperes or power and after some time of running it power consumption reduces to normal. This process increases the power consumption and electricity bills are usually high. But in modern compressors the rotation is controlled and system dont need to cut off or cut in, so the power consumption is very low.