chilled water

[martinw58]

can water flow be calculated from t/d of flow and return water temp can you recomend book or manual for flow rates

[The Viking]

Yes,
But only if the cooling duty is (accurately) known

[Pooh]

Not accurately as other things can effect the readings but some people use this method as a guide, it is better to use an orifice plate and pressure gauges.

Ian

[Magoo]

where are you people trained? Water has a specific heat value of 4.192 Kj/kg/s. Go back to basics. Mass x flow x TD. Interpolate with variables and you can extract: for example flow rate
magoo

[wambat]

For chilled and condenser water, the expected temperature drop or rise is normally 8° to 10°. Just like air, water has a temperature drop or rise as it is cooled or heated. As a chiller cools water, the number of gallons per minute (gpm) circulated determines the number of degrees of drop.
The same is true for a water-cooled condenser. An 8° temperature change is proportional to about 3.8 gpm circulated per ton. A 10° change is proportional to about 3 gpm circulated per ton.

For example, if a 25-ton system has a chilled water temperature differential of 8°, then 25 tons times 3.8gpm/ton gives a total estimate of the chilled water flow of 95 gpm.


Normal chilled water supply temperature is in the range of 45° to 55°. This is the correct range of chilled-water supply temperatures for comfort cooling. So if you have the compresor fully loaded and your pressures are within the normal range and you are getting the proper delta T then you are getting the right amount of GPM flow

[nike123]

For chilled and condenser water, the expected temperature drop or rise is normally 8° to 10°. Just like air, water has a temperature drop or rise as it is cooled or heated. As a chiller cools water, the number of gallons per minute (gpm) circulated determines the number of degrees of drop.
The same is true for a water-cooled condenser. An 8° temperature change is proportional to about 3.8 gpm circulated per ton. A 10° change is proportional to about 3 gpm circulated per ton.

For example, if a 25-ton system has a chilled water temperature differential of 8°, then 25 tons times 3.8gpm/ton gives a total estimate of the chilled water flow of 95 gpm.


Normal chilled water supply temperature is in the range of 45° to 55°. This is the correct range of chilled-water supply temperatures for comfort cooling. So if you have the compresor fully loaded and your pressures are within the normal range and you are getting the proper delta T then you are getting the right amount of GPM flow

Please put some units here. You are giving temperature degrees without indicating of what scale.

That way, all of us from around the world, will be able to understand you.

You know, we are engineers here and such freedom of interpretation is to much for ours non-poetic brains.

[frank]

Please put some units here. You are giving temperature degrees without indicating of what scale.

That way, all of us from around the world, will be able to understand you.

You know, we are engineers here and such freedom of interpretation is to much for ours non-poetic brains.

Hi Nike123

Wambat is from California so it would be my guess that he is talking of the Fahrenheit scale

[nike123]

Hi Nike123

Wambat is from California so it would be my guess that he is talking of the Fahrenheit scale

I agree, and I was aware of that fact when I was wrote that post. But as we all know, physics is not mathematic, and we need some units to be precise .
It is just my pettiness on action here.

P.S. Is that Gordon Bennett any good?

[TRASH101]

Water has a specific heat value of 4.192 Kj/kg/s. Go back to basics. Mass x flow x TD. Interpolate with variables and you can extract: for example flow rate
magoo

Please excuse me if I appear ignorant but wouldn`t you need the volume of the cooling medium to make that calculation?

I would personally go with POOH on this or most chillers I have seen have binder points and a pressure drop versus flow rate for the heat exchanger.

[frank]

where are you people trained? Water has a specific heat value of 4.192 Kj/kg/s. Go back to basics. Mass x flow x TD. Interpolate with variables and you can extract: for example flow rate
magoo

Assuming T1 to be 12C and T2 to be 6C can you give us a flow rate then Magoo?

The original question states that he wants to determine the flow rate (mass flow).

As the Viking said - it is possible to determine mass flow but you would need to know the duty capacity of the chiller first (Q). Without it you only have 2 parts of a 4 part equation - Q = m c dt