The Fourth Street Heritage Corridor could have a snowmelt system using water-source heat pumps, a city of Ketchum-sponsored study says.
"The most viable geothermal option, and the focus of this feasibility study, is water-source heat pumps, with the source being groundwater pumped from a well(s) and injected into a receiving well(s)," the report from the Oregon-based Geo-Heat Center and the Idaho Energy Division of the Idaho Department of Water Resources said. The report was completed after an on-site investigation by the Geo-Heat Center.
The heat pumps could be placed in underground vaults, which is where boilers would also be located.
According to the study, several options for sources of geothermal energy were considered following an on-site inspection of Guyer Hot Springs in the Warm Springs area on Aug. 21. The options were narrowed to just the water-source heat pumps after the inspection, but it was determined the availability of Guyer water was questionable and piping it into the city was not cost effective.
Other conclusions from the study include:
- Water-source heat pumps with 12-inch snow-melting tube spacing could be used. Based on Boise weather studies, some snow would pile up during big storms, but all the snow would be melted when the system catches up.
· Annual heating energy savings with a geothermal heat pump system versus a natural gas boiler system is estimated to be $10,360.
- Before a heat pump design can proceed, test wells would need to be drilled in alleys near the proposed pump vaults to insure sufficient groundwater flow rates are available.
- Water well logs for the downtown Ketchum area from the Department of Water Resources show possible well flows of up to 300 gallons per minute.
The type of system considered for sidewalk snow melt in the study is designed by Forsgren Associates, Inc. of Boise.
