Original scientific paper
IMPACT OF GEOTHERMAL GRADIENT ON GROUND SOURCE HEAT PUMP SYSTEM MODELING
Tomislav Kurevija
orcid.org/0000-0002-5469-3653
; Faculty of Mining, Geology and Petroleum Engineering
Domagoj Vulin
; Faculty of Mining, Geology and Petroleum Engineering
Marija Macenić
orcid.org/0000-0002-7632-033X
; Faculty of Mining, Geology and Petroleum Engineering
Abstract
Undisturbed ground temperature is one of the most crucial thermogeological parameters needed for shallow geothermal resources assessment. Energy considered to be geothermal is energy stored in the ground at depths where solar radiation has no effect. At depth where undisturbed ground temperature occurs there is no influence of seasonal variations in air temperature from surface. Exact temperature value, and depth where it occurs, is functionally dependent on surface climate parameters and thermogeologic properties of ground. After abovementioned depth, increase of ground temperature is solely dependent on geothermal gradient. Accurately determined value of undisturbed ground temperature is beneficial for proper sizing of borehole heat exchangers. On practical example of building which is being heated and cooled with shallow geothermal resource, influences of undisturbed ground temperature and geothermal gradient, on size of borehole heat exchanger are going to be presented. Sizing of borehole heat exchanger was calculated with commercial software Ground Loop Designer (GLD), which uses modified line source and cylinder source solutions of heat conduction in solids.
Keywords
borehole heat exchanger; shallow geothermal energy; geothermal gradient; undisturbed ground temperature
Hrčak ID:
129490
URI
Publication date:
4.7.2014.
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