DOE EERE Research Reports

Geothermal heat pumps can employ deep well vertical-tube heat exchangers to extract and reject heat to and from the surrounding soil. These can be comprised of U-tubes, the currently favored approach, or concentric tubes sealed at both ends with water, or brine, flowing down the smaller inner tube at high velocity and then rising slowly through the annular region between the tubes.

1. Lincoln, Nebraska Public Schools
• Benchmark for Performance: Geothermal Applications in Lincoln Public Schools
• Geothermal Heat Pumps in K-12 Schools: A Case Study of the Lincoln, Nebraska Schools
• Comparing Maintenance Costs of Geothermal Heat Pump Systems with Other HVAC Systems in Lincoln Public Schools: Repair, Service, and Corrective Actions
• Comparing Maintenance Costs of Geothermal Heat Pump Systems with Other HVAC Systems: Preventive Maintenance Actions and Total Maintenence Costs
2. Comparison of Practical Vertical Ground Heat Exchanger Sizing Methods to a Fort Polk Data/Model Benchmark
3. A Comparison of Vertical Ground Heat Exchanger Design Software for Commercial Applications
4. Determining Effective Soil Formation Thermal Properties from Field Data Using a Parameter Estimation Technique
5. Experimental Study of Direct-Expansion Ground Coil Heat Exchangers
6. Field Test of a New Method for Determining Soil Formation Thermal Conductivity and Borehole Resistance
7. A New Comparison of Vertical Ground Heat Exchanger Design Methods for Residential Applications
8. Performance of a Ground Coupled Heat Pump with Multiple Dissimular U-Tube Coiles in Series
9. Residential Vertical Geothermal Heat Pump System Models: Calibration to Data
10. Selecting the Design Entering Water Temperature for Vertical Geothermal Heat Pumps in Cooling-Dominated Applications
11. Technical and Economic Feasibility of Horizontal, Multiple Shallow-Well, and Deep-Well Ground Coupling for Residential Heat Pump Applications
12. A Theoretical and Experimental Analysis of Vertical, Concentric-Tube Ground-Coupled Heat Exchangers
13. Theoretical Heat Pump Ground Coil Analysis with Variable Ground Farfield Boundary Conditions
14. Vertical Concentric-Tube Ground-Coupled Heat Exchangers