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Determining effective soil formation thermal properties from field data using a parameter estimation technique

Description: A one-dimensional thermal model is derived to describe the temperature field around a vertical borehole heat exchanger (BHEx) for a geothermal heat pump. The inlet and outlet pipe flows are modeled as one, and an effective heat capacity is added to model the heat storage in the fluid and pipes. Parameter estimation techniques are then used to estimate various parameters associated with the model, including the thermal conductivity of the soil and of the grout which fills the borehole and surrounds the u-tube. The model is validated using test data from an experimental rig containing sand with known thermal conductivity. The estimates of the sand thermal conductivity derived from the model are found to be in good agreement with independent measurements.
Date: November 1, 1998
Creator: Shonder, J.A. & Beck, J.V.
Partner: UNT Libraries Government Documents Department

Advanced geothermal primary heat exchanger (APEX). Quarterly progress report Q-5, 1 January 1977-31 March 1977

Description: The current program status relative to the schedule and key mileposts is described. The technical progress meetings held between ALRC and LBL are summarized. A technical discussion is presented covering the experiment design, assembly, and laboratory testing. The work effort planned is described. (MHR)
Date: January 1, 1977
Creator: Addoms, J.F.
Partner: UNT Libraries Government Documents Department

Stability analysis of direct contact heat exchangers subject to system perturbations. Final report, Task 2

Description: This report includes a project summary, copies of two papers resulting from the work and the Ph.D. Dissertation of Dr. Mehdi Golafshani entitled, ''Stability of a Direct Contact Heat Exchanger''. Specifically, the work deals with the operational stability of a spray column type heat exchanger subject to disturbances typical of those which can occur for geothermal applications. A computer program was developed to solve the one-dimensional transient two-phase flow problem and it was applied to the design of a spray column. The operation and design of the East Mesa 500kW/sub e/ direct contactor was assessed. It is shown that the heat transfer is governed by the internal resistance of the dispersed phase. In fact, the performance is well-represented by diffusion of heat within the drops. 5 refs.
Date: January 1, 1985
Creator: Jacobs, H.R.
Partner: UNT Libraries Government Documents Department

Manual for the thermal and hydraulic design of direct contact spray columns for use in extracting heat from geothermal brines

Description: This report outlines the current methods being used in the thermal and hydraulic design of spray column type, direct contact heat exchangers. It provides appropriate referenced equations for both preliminary design and detailed performance. The design methods are primarily empirical and are applicable for us in the design of such units for geothermal application and for application with solar ponds. Methods for design, for both preheater and boiler sections of the primary heat exchangers, for direct contact binary powers plants are included. 23 refs., 8 figs.
Date: June 1, 1985
Creator: Jacobs, H.R.
Partner: UNT Libraries Government Documents Department

Direct contact condensation of immiscible fluids in packed beds

Description: An experimental study of a film type direct contact heat exchanger using immiscible fluids is made. Laboratory experiments were conducted on a R-113-water system using both 2.5 cm Berl saddles and 3.2 cm spheres as packing, in a 14.6 cm diameter column. The configuration was counter flow, with the vapor phase entering at the base of the column, and condensing on the laminar water film that coated the packing surface. Packing height, water temperature and both water and vapor flow rates were varied in obtaining heat transfer data. These and other packed bed heat transfer data published in the literature were reduced and correlated to yield a relationship between the Stanton number and the important vessel operating parameters.
Date: November 1, 1978
Creator: Thomas, K.D.; Jacobs, H.R. & Boehm, R.F.
Partner: UNT Libraries Government Documents Department