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I have a simulation model of a cylindrical hot water storage tank. The heat loss is determined by the surface area and the heat transfer coefficient.

A configuration of the storage tank with 900 liters was validated with a real scenario.

Now I would like to test how the scenario changes when the storage tank gets bigger. Thereby my surface becomes bigger, but I don't know if the heat transfer coefficient changes as well.

Does a larger storage tank usually improve the insulation so that the heat transfer coefficient changes?

MerklT
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In a tank with no fluid movement and no heat source with steady ambient temperature, the temperature of fluid are layered strata roughly in onion layers but favoring the top of the tank, meaning the heat is gradually decreasing from the top in ellipsoid layers roughly following the geometry of the cylinder in you question, imagine inverte flames getting colder as they get near the tank walls and gently sliding up till they reach the top and flare open turn back down in a perpetuous circulation.

So if you increase the volume of your tank, it means you are providing new insulation for the hot core. So in the larger tank the surface temperature will be less than the smaller tank while keeping similar distribution topography.

So the ratio of heat loss will be smaller than jast smaller ratio of surface to volume of fluid.

kamran
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In solid-fluid interfaces the heat transfer coefficient (HTC) is dominated by the properties of the fluid and flow, geometry has no effect on the HTC other than promoting zones where flow changes velocity/pressure/turbulence.

In your case, for a simple geometry like a cylinder, the HTC will not change with the change in dimensions (if you keep the magnitude of the scaling within a reasonable range).

So yes, if you increase the surface area you will dissipate energy quicker.

corcholatacolormarengo
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