free cooling heat exchanger
free cooling heat exchanger
(OP)
Hello there
I'd like to ask you an hint
I have to calculate a finned coil working in a free-cooling mode.
this means that
air inlet temperature
water inlet temperature
water outlet temperature
coil dimensions
are known.
I assume that since it is a free cooling coil, we have no air flow.
Is there a rule of thumb to calculate this kind of heat exchanger ?
Thanks !
I'd like to ask you an hint
I have to calculate a finned coil working in a free-cooling mode.
this means that
air inlet temperature
water inlet temperature
water outlet temperature
coil dimensions
are known.
I assume that since it is a free cooling coil, we have no air flow.
Is there a rule of thumb to calculate this kind of heat exchanger ?
Thanks !





RE: free cooling heat exchanger
what is your system setup, is it all-air conditioning? do you have dry coolers?
RE: free cooling heat exchanger
a free cooling system is a system like this one
http://searchdatacenter.techtarget.com/definition/...
http://www.youtube.com/watch?v=l8X6xhe0uFI
Thanks
RE: free cooling heat exchanger
that is not what this forum is for.
briefly saying, if we are talking about air side economizing, you don't have cooling coil in picture. air that is cooler than indoor design temperature is introduced, filtered and distributed to indoor space.
you should google a little more, i am pretty sure that you can find diagram of system that will give you clearer picture of the process.
RE: free cooling heat exchanger
Is there a reason you are considering finned-tube rather than plate-and-frame?
Best to you,
Goober Dave
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RE: free cooling heat exchanger
MR Drazen
as a matter of fact I am not preparing new school studies, but I am new to this work so that I would like to understand better how things work.
What I am looking for is knowing more and more and finding some advices.
I have googled a lot, but I could not find a satisfctory answer concerning this kind of systems.
This is the reason why I asked to the forum, where for sure I can find some advice from skilled people.
Mr DrWeig
Air is used since you find it everywhere and it costs nothing with respect of water
RE: free cooling heat exchanger
Why would you assume that?
If you have a fin-tube coil with no air flow, or no water flow then the coil does nothing.
The coil doesn't know if it is doing free cooling or paid cooling or volunteer cooling or it's working against its will. The performance calculations are the same.
RE: free cooling heat exchanger
Best to you,
Goober Dave
Haven't see the forum policies? Do so now: Forum Policies
RE: free cooling heat exchanger
RE: free cooling heat exchanger
Typically free cooling coil work best whne you don't want to introduce (and filter) outside air, like in IT or if you have high wetbulb temps outside.
typically airside economizer is better since you don't need extra fans (cooling tower) and don't have two temeprature differentials (on tower, and on coil).
And you add a second cooling coil with its permanent air pressure-drop. Yu may want to look into chillers with integrated economizer to avoid that added coil. that way the chiller makes up the temperature difference anyway and your cooling coil calculation is the same.
Remember to use glycol if you are in freezing climate.
If it is worrhtwhile depends on climate, load-profile, avaialble equipment for your size etc.