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Thread: 30°C to 20°C in one hour?
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18-11-2014, 04:31 AM #1
30°C to 20°C in one hour?
Hi all, greetings from Indonesia again...
I need to calculate how much compressor power needed for this:
I need to cool 10.000 liter (roughly 2,641 gallon) of water from 30°C (86°F) down to 20°C (68°F) within one hour.
I found this formula:
BTU = gallons x temperature change x 8.33
The result for my numbers would be... 395,991 BTU or 155 HP.
Is that number seems realistic? It seems so high, or is there a mistake?
Thank you for all your input, really appreciate it.
Regards,
Yahya.
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18-11-2014, 06:15 AM #2
Re: 30°C to 20°C in one hour?
10000l/hour = 2.8l/sec
30deg - 20deg = 10deg
specific heat capacity of water = 4.2
2.8 x 10 x 4.2 = 117.6kW of refrigerating capacity.
I don't really know what BTU's and Gallons are?
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18-11-2014, 07:01 AM #3
Re: 30°C to 20°C in one hour?
For getting 120 kW cooling considering 10 C evaporating and 40 condensing temperature refrigeration compressor will need around 20 to 25 kW power input depending upon which refrigerant is used.
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18-11-2014, 11:27 AM #4
Re: 30°C to 20°C in one hour?
Thank you so much for all the replies, really helps.
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18-11-2014, 12:16 PM #5
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18-11-2014, 07:11 PM #6
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Re: 30°C to 20°C in one hour?
also
Q= MC (t2-t1)
M=10000 Kg/ h
C=1 for water
Q= 10000 * 1(30-20)
Q= 100000 cal/h
1 Kw = 860 cal
to get that you need to add %10 for safety and then you have to choose your Comp.
your evaporator temp. about 10 c ( out let temp. - delta T )
your condenser temp. about (ambient temp. + 10)
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19-11-2014, 09:18 AM #7
Re: 30°C to 20°C in one hour?
As mbc has explained I tried to select compressor 120 kW capacity with 10 deg C evaporation temp and 40 deg C condensing temperature and I got the power consumed by compressor.