water chiller-sizing
water chiller-sizing
(OP)
I am design a water chiller for 1320 gallon tank. The ambient will reach to 50c (122F) on summer. The Required water temperature 4c has to be reached within 70 minutes.1320 divided by 70=18 gpm. I assume if ambient is 122F then the water will be 104F.so I calculate the chiller capacity GPM*DELTA T/24(20*65/24=54 ton. Should I consider any other things? Thanks for the advice.
thnx
moideen-dubai
thnx
moideen-dubai





RE: water chiller-sizing
also consider what that tank does, does it buffer chilled water? Or what? You likely want to return the water from top of the tank and supply it to the bottom without mixing up all the water. but also depends on how you draw the water for your actual use.
You say ambient being 122°F makes the water start at 104°F. not sure how you come up with that, abut after some time the water in the tank will equal ambient.
RE: water chiller-sizing
RE: water chiller-sizing
Second, it is dangerous to estimate the temperatures, try to get a good engineering assumption. where does the water come from?
RE: water chiller-sizing
RE: water chiller-sizing
You seem to be working on the assumption that pumping the whole volume through the chiller will gradually lower the temperature. However the inlet condition to your chiller will keep changing, gradually lowering the inlet temperature. Therefore your chiller will gradually work less and less well. You can't lower the outlet temp below 4c and even that is quite difficult as there is only a very low temperature gradient without the water freezing.
I would look art the total gets loss you need to get to 4c and use Ann internal coil.
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RE: water chiller-sizing
RE: water chiller-sizing
Coming to think of it you need two insulated tanks. One holding your warm water and one holding your cold water. Then your system will work.
Even the best insulation will have some heat transfer...
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Also: If you get a response it's polite to respond to it.
RE: water chiller-sizing
RE: water chiller-sizing
Therefore whatever design you come up with needs to look at it properly.
I can't comment on your design as I don't know what your system is.
I'm curious as to why you want 132gallons of cold water presumably at a high flow, once every 70 minutes or so, adding on time to empty the main tank and time to fill the main tank.
Why don't you cool the water the water on the way into the main tank at say 20GPM or higher? Then your cooling load stays constant.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: water chiller-sizing
What you see the basic issues with re circulation system? Then how does typically cool the water tanks? Actually I don’t know the actual usage of this water. I was instructed by management to make a chiller that they want 4c water out only. I don’t know my understanding is correct from your advice for primary cooling the main tank and steady the inlet temperature. Then should I go with two stage system?
RE: water chiller-sizing
try to follow this
Q = M * Cp * Delta T
Where: Q = The amount of heat transferred to or from the fluid (BTU/hr)
M = Mass flow rate of the fluid (lb/hr)
Cp = Specific heat of the fluid (BTU/lb-°F)
Delta T = The change in temperature of the fluid (°F)
with this you will have the BTU/hr and you can convert it to TR
- After selecting the chiller from suppliers they will give you information for pump and min flow rate of water for this chiller .
- the insulation for tank is to save the that heat .
RE: water chiller-sizing
None of these things are very efficient or good.
It is therefore much better to have a constant flow with a constant temperature drop from inlet to outlet.
So either put the chiller on the water on the way into your insulated tank ( you'll also need some sort of internal cooling loop to maintain 4 C) or put the chiller on the piping on the way out.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: water chiller-sizing