Edgar Experimental Mine as a Geothermal Resources Laboratory

Abstract

The authors propose a system that can cool buildings in the summer time and melt snow on the pedestrian sidewalks during the winter using an underground mine and a hot spring in Idaho Springs, Colorado. In the proposed system, the mine would be used as cold thermal energy storage, and the heat of geothermal fluid transported from the hot spring would be re-used to melt snow in the historic downtown of Idaho Springs. To assess the feasibility of the proposed system, a series of temperature measurements in the Edgar Mine (Colorado School of Mines’ Experimental Mine) and heat transfer analyses of geothermal fluid were conducted. The results of the temperature measurements proved that the temperature of the underground mine was low to be used to store cold groundwater for the summer. Furthermore, the temperature profiles of two different tunnels in the Edgar Mine were discussed to determine the most appropriate place to store cold groundwater. In the heat transfer analyses, the heat loss of the geothermal hot fluid during its transportation was modeled and calculated, and then heat requirement for snow melting was compared with the heat supply from the geothermal hot fluid. It was concluded that the heat supply was not sufficient enough to melt snow on the entire sidewalk area of the downtown. The result, however, indicated the proposed snow melting system could be realized if the required snow melting area were smaller or additional geothermal wells were drilled. This case study should serve as a good example of a sustainable energy system that promotes “local consumption of locally available energy”.