View Full Version : Calculating compressor of a chiller

Alexandretta

17-09-2013, 02:04 PM

Hi all.İ have a flow rate which is 3.6 m3/h

İnlet water temperature:80 degrees of celcius

outlet water temperrature:17 degrees of celcius

Q = M x Cp X DT

Q = Capacity in kW

M = Liquid mass flow rate kg/s

Cp = Liquid specific heat kJ/kg.K

DT = Liquid temperature difference °C

İ calculated and result is 264 kilo Joules.

Can you verify this result?And can you help me find a compressor for this conditions?

Thanks a lot

chemi-cool

17-09-2013, 03:30 PM

Its 264 KW.

It is correct.

Alexandretta

17-09-2013, 03:49 PM

Thanks a lot chemi-cool

This is very much heat capacity,isn't it?

chemi-cool

17-09-2013, 06:15 PM

This is the heat you want to remove from the water to be cooled.

Alexandretta

17-09-2013, 07:10 PM

Yes it is,i know.i need a compressor to remove that heat.How many horsepower should be?or kW

Alexandretta

18-09-2013, 03:08 PM

Somebody help me please

hookster

18-09-2013, 04:32 PM

HP = 0.735KW

Is your calculation a realistic idea?? 80 - 17 DegC :mad:

Alexandretta

18-09-2013, 05:37 PM

İ know this HP = 0.735KW equation.

The water reaches 80 degrees of celcius after using it.as far as I know

So this is the important question:How big a compressor do i need for doing that?

hookster

18-09-2013, 06:22 PM

You need a big compressor and massive heat exchanger!!

So before wasting time answering this question lets think realistically!

Take your 80 degree leaving and put this through a dry cooler even in Turkey you can lower this 80 - 35 DegC with mechanical ventilation, add some evaporative cooling for better heat rejection!

Now do your sums again with a delta T of 30 - 17 :confused:

I would check your original calculation as Cp for water at 80 DegC is 4.198 KJ/KgK

Alexandretta

18-09-2013, 06:59 PM

i have 3.6 metriccube/h flow.

This means mdot=1 kg/s -- C=4.180 kJ/kg.K --- deltaT=13 K

Qdot(kJ/s)=mdot(kg/s)xC(kJ/kg.K)xdeltaT

Qdot=54.4 kJ/second.

So, is this the actual compressor size?or what?

As you say i will use mechanical ventilation but i can obtain only 80>70 dCelcius.

İ am mechanical engineering student.İ am new at this sector.As you can appreciate i need help.So i must say thanks for helping.

Alexandretta

18-09-2013, 07:02 PM

I would check your original calculation as Cp for water at 80 DegC is 4.198 KJ/KgK

Is this important?I took it as average.I guess

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