Heat Transfer 2

[ECD40]

Hello All,
I have a heat transfer problem of water flowing into and out of a large tank. This is an application on a mining project in northern Canada and how the issue impacts on the building HVAC design. We have a pipeline transporting 2,300 USgpm of mining waste in water from some distance. It discharges into a thickening tank where the solids are deposited. The clarified water then overflows the tank and is transported out of the building to another location. With such a throughput of fluid and a retention time of 200 minutes in the tank, the question has become what impact the passage of the water has on the heat load in the building. The attached sketch depicts the issue. In the winter, the incoming water is at 35 degrees F. I need to know the temperature of the outgoing water, so that the HVAC can be designed accordingly.
Can anyone help?
Thanks,
ECD40

 

[IRstuff]

Assuming a natural convection coefficient of 7W/m^2-K results in 65 kW heat exchange with a 33-F temperature difference.

Assuming infinite thermal conductivity and a full tank, that heat exchange on the water will raise its temperature by 0.185 C in 200 min

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[LittleInch]

You've basically got a very large ice block in the middle of your building. Insulation of the ice block sounds like a good idea to me if you're not going to freeze in that building.

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[Artisi]

Any similar plants / installations in the area or like environment, if yes, a few words to the appropriate people could give you some useful data.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[ECD40]

Thanks to everyone that helped me with this problem.
ECD40

 

[curtis2004]

I think, Ice Cube model seems close approximation for calculations. It is kind of chilled water line passing through a room.
Water temperature rise will be negligible due to relatively large water flow.

 

[LittleInch]

Never forget the heat capacity of water.

1m3 of water takes 4.2 MJ to change 1C.
1m3 of air takes 1.25 kJ

So more than 3000 times less heat energy in air.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.