R22 Pressure Temperature Chart
R22 Pressure temperature chart will help us in identifying the problem areas inside the air conditioner.So R22 PT chart will show the condition of refrigerant at any point of system .
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- If we have presence of liquid and vapor mixture (as in evaorator and condenser).We have saturated refrigerant that will correspond to PT chart .
- we have superheated vapor if measured temperature is greater than saturation temperature (in pt chart).Superheat will be calculated by taking the difference between measured and saturated temperature.Superheated vapor will be present in suction and discharge lines.
- Refrigerant is Subcooled liquid if measured temperature is less than the saturation temperature (pt chart).Amount of subcool is the difference of measured temperature and saturated temperature(pt chart).Subcooled liquid will be present in liquid line connecting the condenser and evaporator.
You can easily find the problem areas inside the system using pt chart.For example,if measured values at compressor inlet shows saturated condition then its a problem because in suction line refrigerant must exist only as vapor.
Calculate subcooling at condenser coil
Take the reading at Outlet of condenser coil and let us say that the Measured pressure 155 psig.The pressure inside the condenser coil will also be 155 psig assuming the minimal pressure drop.155 psig corresponds to 114 degree farenhite in R22 PT Chart.
Liquid and vapor must be present in condenser coil and so We must have refrigerant at 114 f.If the temperature reading at condenser coil outlet is 114f then we know refrigerant inside condenser is saturated and a mixture of liquid and vapor enters the liquid line.
But suppose that the actual measured temperature is 105 degree farenhite.We know that it is lower than saturated temperature,So refrigerant is subcooled liquid.The Amount of subcooling is difference between measured and saturated (114f-105f) and it equals to 9 degree farenhite.
Points to Remember
- When refrigerant exist as liquid and vapor.It is saturated and its temperature will correpond to pt chart.
- If there is difference between measured temperature and pt chart then we have super heated vapor.Amount of superheat is difference between measured temperature and saturated temerature.
- If measured temp is below the saturated temp (pt chart) then We have subcooled refrigerant.Amount of subcooling is difference between measured temperature and saturated temerature.