# Heat Exhchanger Selection (what is kw/C)

## Main Question or Discussion Point

Hello, everyone.

I have a problem in finding a suitable heat exchanger for cooling coils.
I would like to cool down 28 lier/min; from 70 Celsius to at least 25 Celsius.

I wonder how to fit "kw/C"(performance spec.) to my case so that i can find a suitable heat exchanger.

Thanks for your help.

## Answers and Replies

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mgb_phys
Science Advisor
Homework Helper
kw/C is a measure of how much power (kw) the heatsink can remove for each degree C temperature it rises.
Once the heat sink reaches the temperature of the incoming hot fluid it is obviously not going to remove any more heat.

You can work out the amount of energy to be extracted each second to cool 28/60 litres of water by 45 C and then from the kw/c work out how much this will heat the heatsink.

Note - this is just an approximation - the kw/c is only correct for a certain amount of power. At very high or very low energy inputs it might not be accurate..

kw/C is a measure of how much power (kw) the heatsink can remove for each degree C temperature it rises.
Once the heat sink reaches the temperature of the incoming hot fluid it is obviously not going to remove any more heat.

You can work out the amount of energy to be extracted each second to cool 28/60 litres of water by 45 C and then from the kw/c work out how much this will heat the heatsink.

Note - this is just an approximation - the kw/c is only correct for a certain amount of power. At very high or very low energy inputs it might not be accurate..
Thanks for your reply.

To confirm your meaning, is that mean suppose the water will reject heat 92kw/s (from 70->25;Q=M*Cp*(T1-T2) ) then the kw/C required is 92kw/45C=2.04kw/c.

That's mean I have to find a radiator that can achieve 2.04kw/c cooling effect at 28l/min?

Thanks for your help.

LEt see, you need 60 liters per minute of Water to drop from 70 down to 25 C?