Pressure drop in refrigerant lines
Pressure drop in refrigerant lines
(OP)
I have heard of a general rule of thumb for R134a refrigerant that 1ºF of cooling is lost for 2psig pressure drop on high side. If the pressure drops on the discharge side, the SCT decreases and thus the we would be closer to the SCT for the discharge pressure. Is this not an advantage to performance? The only reason I can think of for the loss of cooling is the pressure loss means more work for the compressor which then increases the THR for the condenser.
Am I out to lunch on this?
Am I out to lunch on this?





RE: Pressure drop in refrigerant lines
the temperature being a result of the differential between added heat and retracted heat.
what do you mean by the high side
what is SCT and THR?
RE: Pressure drop in refrigerant lines
RE: Pressure drop in refrigerant lines
liquid (condensor to TXV):if Pressure condensor < pressure drop pipe + pressure evaporator
vapour (compressor to condensor):if Pressure discharge < pressure drop pipe + pressure condensor
the biggest cooling loss comes from the pipe between evaporator and compressor, there you could have a rule of thumb: every degree of temperature increase is so much increase in suction pressure
RE: Pressure drop in refrigerant lines
Condenser performance is determined by the amount of heat that must be rejected and the condenser air temperature.
If there is pressure drop in the line between the compressor and the condenser the system compensates for this by increasing the discharge pressure. Increased discharge pressure = decreased performance.
If there is a pressure drop in the line between the condenser and the expansion valve the system again compensates by increasing the discharge pressure, but in this case the pressure in the condenser is also increased, increasing the SCT.
RE: Pressure drop in refrigerant lines
When the system compensates for the pressure loss in the discharge line, does that mean the compressor is working harder and so adds work heat to the system which is where the performance loss is derived?
RE: Pressure drop in refrigerant lines