by on October 27, 2020
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A simple air conditioning circuit and cycle diagram that you might find  useful.

Air condition

 

When the humidity is high and the weather is hot , the body tries to cool itself by sweating but cannot dispose the moisture. The skin then feels continually damp and unpleasant .

The use of Air condition is very important in this situation to control humidity.

Air condition is used in control of humidity. If the humidity is low and the air is dry there is excessive evaporation from the body. This affected the throat and skin. This effect can also be overcome by Air condition.

The Working Principle of Air Condition

The component at 1 in the Air conditioning circuit and cycle
diagram is the compressor.

 

The compressor is the heart of the system; it keeps the refrigerant flowing through the system at specific rates of flow, and at specific pressures.

It takes refrigerant vapour in from the low pressure side of the circuit, and discharges it at a much higher pressure into the high side of the circuit.

 

The rate of flow through the system will depend on the size of the unit,

And the operating pressures will depend on the size of compressor, refrigerant being used and the desired evaporator temperature.

 

The component at 2 in the air conditioning circuit and cycle diagram is the condenser.

 

The red dots inside the piping represent discharge vapour.

The solid red colour represents high pressure liquid refrigerant.

When the hot refrigerant vapour discharged from the compressor travels through the condenser, the cool air flowing through the condenser coil absorbs enough heat from the vapour to cause it to condense.

 

If the outside air temperature is 80 degrees, the system is designed so that the temperature of the refrigerant, right at the point where it first condenses, will be about 42 to 46 degrees C.

 

The refrigerant is to condense at this relatively high temperature because

 

the air will be very cold relative to the temperature of the discharge vapour,

This will allow the latent heat energy in the vapour to transfer over to that relatively cold air,

And cause the refrigerant to condense.

 

This transfer of heat from the vapour to the flowing air is what makes hot air blow out of the air conditioner's condensing unit.

 

At this stage in the air conditioning circuit and cycle diagram, high pressure liquid refrigerant will flow down the liquid line, through a filter drier that is designed to prevent contaminants from flowing through the system, and on to the metering device.

 

The metering device, component #3 on this air conditioning circuit and cycle diagram, is the dividing point between the high pressure and low pressure sides of the system,

And is designed to maintain a specific rate of flow of refrigerant into the low side of the system.

 

If the wrong capacity of metering device is used, or if there is a problem with the metering device,

An incorrect quantity of refrigerant will flow into the evaporator.

 

When the refrigerant passes through the metering device, it drops from about 225 psi to about 70 psi,

It also drops in temperature from about 44 degrees C to about 4 degrees C,

It starts evaporating immediately,

It shoots out into the evaporator foaming, bubbling, and boiling,

at a low pressure, and at about 4 degrees C.

 

The evaporator component #4 in the air conditioning circuit and cycle diagram is

 

where relatively warm air flows over the evaporator coil, at about 25 degrees.

 

The air condition system is designed so that the refrigerant will evaporate in the evaporator at a temperature of about 5 degrees C, so that it will be cold compared to the warm air flowing over it.

 

The system is designed so that the heat in the warm air flowing over the evaporator will be absorbed by the cold evaporating refrigerant.

 

This cools the air flowing over the evaporator, and is the reason cold air blows out of the air condition.

 

Read more about PHYSICS for High Schools

 

 

 

Posted in: Education
Topics: air condition
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