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ysh1317
18-11-2014, 03:31 AM
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 30C (86F) down to 20C (68F) 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.

piewie
18-11-2014, 05:15 AM
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?:D

sandybapat
18-11-2014, 06:01 AM
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.

ysh1317
18-11-2014, 10:27 AM
Thank you so much for all the replies, really helps.

ysh1317
18-11-2014, 11:16 AM
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.

May I know how did you came up with the number 20 to 25 kW power input? Thanks.

mbc
18-11-2014, 06:11 PM
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)

sandybapat
19-11-2014, 08:18 AM
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.