Feasibility study of geothermal heating, Modoc Lassen housing project

Abstract

This study evaluates the feasibility of using geothermal water for space and domestic water heating systems at the elderly housing project now ready for construction at the Modoc Lassen Indian Reservation. For the six units considered, the space heating load is four times the domestic water heating load. Since the geothermal water temperature is uncertain, two scenarios were evaluated. In the first, which assumes 160/sup 0/F supply temperature, the geothermal system is assumed to satisfy the entire space and domestic water heating loads. In the second, which assumes the supply temperature to be less than 120/sup 0/F at the wellhead only space heating is provided. The economics of the first scenario are quite favorable. The additional expenditure of $15,630 is projected to save $3522 annually at current energy costs, and the life cycle cost study projects a discounted rate of return on the investment of 44.4%. Surprisingly, the investment is even more favorable for the second scenario, due to the higher cost and lower resultant savings for the domestic water components. Forced air space heating from geothermal is recommended. Domestic water heating is recommended pending additional information on supply water temperature.