how to calculate actual air cooled condenser TD.

[beeran]

Hi,
I have a doubt, as we know the TD of air cooled condenser is the difference between the saturated condensing temperatures minus air entering temperature. But my question is what we consider the as saturated pressure is compressor discharge pressure or liquid line pressure. My chiller display is showing the saturated pressure is the compressor discharge head pressure.:confused:

[saintmichael36]

It's the head pressure and an air cooled condenser TD is the difference in between the entering and leaving temperature of the air through the condenser.

[marc5180]

condenser TD is the difference in between the entering and leaving temperature of the air through the condenser.

No that's Delta T (ΔT)
TD is is condensing temperature - air in

[Rob White]

Hi,
I have a doubt, as we know the TD of air cooled condenser is the difference between the saturated condensing temperatures minus air entering temperature. But my question is what we consider the as saturated pressure is compressor discharge pressure or liquid line pressure. My chiller display is showing the saturated pressure is the compressor discharge head pressure.:confused:

How far is your condenser away from your compressor?

Your gauge is NOT reading the compressor discharge pressure,
it is reading the condenser saturation pressure, the pressure
you read at the compressor will be the pressure inside the condenser,
unless it is many meters away, at another part of the build.

So you can use the compressor discharge pressure for the saturation
temperature of the condenser.

Rob

.

[beeran]

How far is your condenser away from your compressor?

Your gauge is NOT reading the compressor discharge pressure,
it is reading the condenser saturation pressure, the pressure
you read at the compressor will be the pressure inside the condenser,
unless it is many meters away, at another part of the build.

So you can use the compressor discharge pressure for the saturation
temperature of the condenser.

Rob

.
Thanks your replay, this is single package air cooled chiller, carrier 30gh.discharhe and liquid line pressure difference is 30 psig. My question is to calculate the condenser TD, subtract the air temperature from discharge head pressure or liquid line pressure?

[marc5180]

Thanks your replay, this is single package air cooled chiller, carrier 30gh.discharhe and liquid line pressure difference is 30 psig. My question is to calculate the condenser TD, subtract the air temperature from discharge head pressure or liquid line pressure?

From discharge head pressure, before the heat exchange takes place.

[moideen]

From discharge head pressure, before the heat exchange takes place.
In microprocessor based control chiller system, the discharge saturation sensor fixed on the centre of condenser or transducer fixed on discharge service valve, it is not consider the liquid line pressure. As beeran said, if there is 30 psig high side pressure drops, raising a question, which pressure will be considered as saturation temp and measuring TD.

[D.D.KORANNE]

Use discharge head pressure.............since due to pressure losses in condenser / piping , liquid pressure could be shade lower