question about chiller

[steven86]

how can i calculate a water tank size is 5' x 40' x 5'(H) and the temp. is from 31 celsius to 28 celsius need how many KW chiller ?

[frank]

Use the formula Q =mcdt

Where
Q = duty in kW
m = mass flow (kg/s)
c = specific heat capacity (water = 4.19)
dt = difference in temperature required

What you are lacking at the moment though is a time scale. How long do you want the chiller to take to reduce the water temperature?

From the tank size we can calculate the mass of water at 28.316 metric tonnes or 28316kg or 28316litres

[The Viking]

Another missing bit,

What heatload is there on the tank?

[steven86]

tat is an aquarium . now the chiller is want maintain the temp in 28 celsius from 32 celsius.

[frank]

I give up?

Steven - how long do you want the chiller to take to bring the temperature down?

How much external heat is the tank exposed to?

[steven86]

i want to reduce the temp in 3hrs o something . the ambient temp is 35 celsius .

[frank]

i want to reduce the temp in 3hrs o something . the ambient temp is 35 celsius .

Now we are getting somewhere.

If we divide the tank volume by 3 hours (10800 secs) we get 2.62 l/s

so, Q = 2.62 x 4.19 x 3 = 32.93kW

Assuming that you don't have excessive external heat gains to the tank, a 35kW chiller will do the job.

Oh, and make sure the fish don't end up in the heat exchanger circuit

[The Viking]

a 35kW chiller will do the job.

Hmmm,

I'm too lazy to do the maths but 35kW for an aquarium

[frank]

Hmmm,

I'm too lazy to do the maths but 35kW for an aquarium

Considering that the volume weighs over 28 tonnes, it's not surprising.

You can only work with the figures.

I would have thought that initial pull down over 24 hours would have been sufficient, but, hey ho - what do I know about aquariums

[steven86]

Now we are getting somewhere.

If we divide the tank volume by 3 hours (10800 secs) we get 2.62 l/s

so, Q = 2.62 x 4.19 x 3 = 32.93kW

Assuming that you don't have excessive external heat gains to the tank, a 35kW chiller will do the job.

Oh, and make sure the fish don't end up in the heat exchanger circuit

thanks ya !!!

[frank]

If you can live with a 24 hour pulldown then a 4.2kW chiller will do it

Saves a LOT of money both on purchase and running costs

[steven86]

ok ... thanks