[Bldg-sim] Underground Water Tank Heat Transfer

[Jeff Thornton]

<I’d like to estimate the rate of heat transfer between
an underground water storage tank and the surrounding earth.  Basically,
water would be pumped out of the tank through a coil and returned to the
tank. The system would function like a groundwater source heat pump with
two big differences:

 1.  the system will use a tank instead of vertical wells
so there will be much less transfer area/volume of water

2.  the tank is enclosed, water will not be drawn from
the water table

Does anyone know of a study or software that would estimate
the rate of heat transfer between the tank’s walls and the surrounding
earth?>

We've done a few studies similar to your project and have used TRNSYS
quite successfully.  There are models available in TRNSYS to study buried
storage tanks (rectangular and cylindrical) as well as models for coils,
heat pumps, buried pipes etc.  The buried tank models use a 3-D finite
difference conduction approach for the surrounding soil and allow for tank
stratification, varying levels of insulation, immersed heat exchangers and
a slew of other tank-specific features.  The buried tank model also comes
with a viewing package that let's the user see the temperature
distribution around the buried tank.

Jeff


Jeff Thornton
President - TESS, LLC

22 North Carroll Street - Suite 370
Madison WI 53703 USA

Phone: 608-274-2577
Fax: 608-278-1475
E-mail: thornton at tess-inc.com
Web: www.tess-inc.com