APPLICATION AND REFINEMENT OF ICE BOX CALORIMETRY FOR HEAT FLUX MEASUREMENTS IN DIVERSE THERMALLY ACTIVE AREAS

Surface heat flux, an important tool in characterizing geothermal areas, is often difficult, if not impossible, to measure. In this study, we present the refinement of a calorimetry method developed by Terada et al in 2008 known as an icebox calorimeter (IBC). This method was previously used for measuring heat flux in geothermal areas with steaming ground. We have expanded the application to various types of geothermal areas.

The method was initially tested at the Alvord Basin, OR. The basin has several hot springs of varying temperature but no steaming ground. After this preliminary field test, we determined that when natural convection is the dominant mode of heat transfer, it prevents the calorimeter from measuring the heat flux accurately. The IBC was tested in the lab with various arrangements to limit the convective forces. During this process, we also determined that the stored heat in the surficial material needs to be accounted for when calculating the heat flux. After adjustments were completed, field experiments were carried out at Vulcan Hot Springs, ID, a heavily sintered area with multiple high temperature hot springs and no steaming ground. Final experiments were completed in Yellowstone National Park, WY in areas with springs of varying temperature, varying amounts of sinter deposition, and no steaming ground. The modified IBC was successful in both locations.