Program for borehole heat exchanger design. Its easy of use, short learning curve, quick calculation times and inherent databases make EED a useful tool in everyday engineering work for design of ground source heat pump system (GSHP) and borehole thermal storage. In very large and complex tasks EED allows for retrieving the approximate required size and layout before initiating more detailed analyses. Even for very small plants EED values the effort to do a calculation instead of using rules of thumb is worthwhile.
In ground source heat pump system, heat is extracted from the fluid in the ground connection by a geothermal heat pump and distributed to the building. The fluid is then re-warmed as it flows through the ground. In cooling mode, the process is reversed. This is a renewable, environmentally friendly energy source. This sustainable technique can be used for cooling and heating of houses, cooling of telecommunication switchboards, etc.
Algorithms have been derived from modeling and parameter studies with a numerical simulation model (SBM) resulting in analytical solutions of the heat flow with several combinations for the borehole pattern and geometry (g-functions). Those g-functions depend on the spacing between the boreholes at the ground surface and the borehole depth. In case of graded boreholes there is also a dependency on the tilt angle. The g-function values obtained from the numerical simulations have been stored in a data file, which is accessed for rapid retrieval of data by EED.
Calculation of brine temperatures is done for monthly heat/cool loads. The borehole thermal resistance is calculated in the program, using the borehole geometry, grouting material, pipe material and geometry.