Temperature cross over in the air cooler calculation

[meyou]

Hi,
when I used the ACOL to checking one existing air cooler, I found the air side outlet temperature is higher than the fluid inlet side temperature.
I check the vendor datasheet , is also.
Is this possible the temperature in the aircool , for the shell tube the temperature is inpossible.

Thanks

meyou

 

[sailoday28]

You must supply much more information to get a resonable response to your question.

 

[MortenA]

If your air cooler is of the type where water is evaporated then yes since the water evaporation cools the air (so in reallity there is not a temperature cross. The actual lowering of the air temperature depends on inlet air humidity, and temperature

Best regards

Morten

 

[25362]

It may be a matter of thermometry: a stagnant temperature reading may show a higher temperature (than the "static" value) when the air stream is stopped dead by the temperature measuring instrument. However this usually happens at high air velocities, or under vacuum.

Anyway, to be sure, proceed as sayloday28 advises.

 

[quark]

I think the OP says that the air outlet temperature is more than cooling fluid inlet temperature. As you all are aware that, even in counterflow heat exchangers, it is not possible to get the hot fluid exit temperature equal to that of cold fluid inlet temperature, practically.

Or I am terribly missing something.

 

[jalvarez]

Something is wrong here
What does ACOL stand for?
What do you mean with: "I check the vendor datasheet , is also."?
etc.
J.Alvarez

 

[TD2K]

I believe he's saying he looked at the vendor's datasheet for the unit and it also shows the 'cross' temperature.

 

[25362]

Still no comments from meyou. A pity...

Where is the exit air temperature measured? One could expect a few degrees of exit air temperature rise when temperatures are measured downstream an induced draft fan.

Quark: what is your experience in this subject ?

 

[quark]

There will be a temperature rise across the fan depending upon the power drawn by the prime mover. This is always estimated and added to heat load calculations.

Regards,

 

[sshep]

I think this is all it can be- the fan effect of an induced draft configuration. ACOL is (was?) the HTFS aircooled exchanger rating and design program. ACOL should give zone analysis profile results across the bundle that meyou can use to check.