Abstract: For uniformly heating a snow collecting surface on an outdoor structure, e.g., a roadway, a heat exchanging pipe system is embedded in the structure near the surface. The pipe system comprises two sets of parallel, and preferably, interdigitated sets of pipes, and means for pumping heated water in one direction through one of the sets of pipes and for pumping water in the opposite direction through the other set of pipes. Preferably, underground water is used; one well being used from which the underground water is pumped, and another well being into which the water discharged from the heat exchanger is pumped for eventual reheating of the discharged water.

Abstract: Snow lying on a road or building structure is melted and removed without sprinkling water on the snow by pumping up from a well and circulating underground water, which is contained in an underground aquifer and warmed by geothermy of the aquifer utilizing the heat retaining function thereof, through pipe arrangement laid under the surface of the road or building structure. The used and cooled underground water is returned into another artesian well without being wasted and exposed to the atmosphere. Underground water warmed by the solar heat and stored in the aquifer in a hot season may be preferably used in a cold snow season. An antifreezing liquid may be filled and circulate in the pipe arrangement to perform effective heat transfer through a heat exchanger between the antifreezing liquid and the underground water which circulates from one well to the other well. A pipe having excellent crystal structure of the welded joint portion can be used for the pipe arrangement.

Abstract: An underground water warmed by the geothermy in an aquifer is pumped up by a pumping means disposed in a pump-up well and the pumped up underground water is introduced into a heat exchanger located in the pump-up well near the opening thereof. The heat exchanger is connected to a heat radiating pipe laid under a road or a building structure on the ground through feed and return conduits. An antifreezing fluid is filled in the heat radiating pipe and circulates through the heat radiating pipe and the heat exchanger through the conduits. The antifreezing fluid warmed in the heat exchanger by the heat exchanging operation stores the heat in the road and transfers the heat to the snow on the ground during the passing through the heat radiating pipe by the heat radiating operation, whereby snow lying on the road is melted without sprinkling water.