Heat storage for room and tap water heating

Abstract

Heat storage for house warming over half a year can be constructed from the following principles: A large water volume typically around 10 000 m 3 is necessary to keep the ratio of the heat loss through the surface compared to the heat content in the volume low. To assist the heat loss prevention the storage is isolated on the sides and on the top. From the non-isolated bottom and upwards a cooler zone is developed over half a year because of heat conduction to the ground. The approximate thickness of the temperature transition zone can be estimated to 2.5 m

1 . The storage is ideally being shaped as a basin with a plane horizontal bottom and vertical sides filled with water 
   
   
       2 . The top and sides are isolated with Polystyrene or any other material until a heat loss below 0.05 W/m 2 K is obtained on the isolated parts. The bottom is not isolated. 
   
   
       3 . The ratio of the water volume to the area of the isolated part of the surface of the water is at least 4 m.
 All geometrical quantities in the above are assumed to be within common craftsman-like accuracy.