Another koi pond refrigeration question

[ysh1317]

Hi all,
Can anyone help me with these?
1. I need to cool 120.000 liter of water in a pond down to 22°C (initial temperature is 30°C), the pond is in enclosed area. Will 2 x 5pk compressor enough?

2. Another one is water tank with 6.500 liter of water (3.250 liter in the tank and 3.250 liter inside the pipes), initial water temperature is 44°C and plan to keep it stable at 10°C.
Right now they are using six unit of 2pk chiller, but couldn't bring the temperature down to the desired level, only down to 34°C. The water flow is 300 liter/minute.

Thank you all.

[frank]

Your figures don't really make any sense. 120.000 litres = 120 litres. Do you mean 120000 litres?

Again, does 3.250 litres mean 3250 litres?

Can you explain what you mean by 2pk chiller and 5pk compressor?

[Peter_1]

Well, Frank if we say 3.250 in most EU countries, then we mean 3250 and 3,250 is 3 units and 250/1000.
I think the poster is referring to only the HP of the compressor. a 2 x 5 pk (strange he uses pk because this is the Dutch expression for hp)

So 10 hp (2 x 5) will give you +/- 40 kW of cooling at te=0°C
It all depends on the heat losses of the systems which are unknown and very hard to calculate. How much of the surrounding heat will warm up your water again. Is the pond covered, is the pond isolated (guess not), sun influence, wind influence, the DT between water and ambient which is never the same...

Only a trial and error test will give you exact numbers from where you can start your calculation.

A good reference point now is where iun the second case a DT of 10 K is apparently possible with 12 hp (6 x 2p) and you need a DT of 34K so you will need at least a total of 3.4 times 12 hp or +/- 40 hp.
40 hp is +/- 120 kW cooling capacity.
You have a waterflow of 300 l/minute or 18.000 l/h (18,000 for the US and UK guys :-) ), so rough calculated, your 120 kW can cool this massflow +/- 5,5°C.

[ysh1317]

Thanks a lot for the replies, it surely gives me something to start with.
Sorry for the little confusion regarding the numbers, and thank you Peter_1 for clearing that up :)

[mmack1993]

I am still a bit confused on this issue and would like someone to help me out.
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[Tesla]

Hi mack
If you search this forum with the word Koi Pond you will find a lot more threads which detail the calculations and of course Koi Ponds.