| Title | SuperCOPs: Hybrid Geothermal Heat Pump Systems for Exceptional Economics, Environmental Performance, and Operational Control |
|---|---|
| Authors | Steve BEYERS, Olivier RACLE |
| Year | 2020 |
| Conference | World Geothermal Congress |
| Keywords | direct use, temperature optimization, district heating, heat pump, heat recovery chiller, coefficient of performance, operations, controls |
| Abstract | The use of heat pumps with exceptional Coefficients of Performance (COP), “SuperCOPâ€, systems can enhance geothermal operations. This paper describes design concepts that optimize SuperCOP effectiveness and examines a working system in the Dogger Basin. Systems that extract heat from the ground are typically categorized into two types. The first type uses heat pumps (or heat recovery chillers) connected to piping systems that extract (or exchange) heat from relatively shallow ground loops or wells. The second type uses deeper and hotter geothermal fluids directly without heat pumps. This paper reviews a third type of geothermal system with distinctly different design parameters and benefits compared to either of these primary types. This “hybrid†system relies on circulation of geothermally heated fluids as a primary energy source but also incorporates custom heat pump(s) deployed centrally or in various localized configurations, selected for high COP performance. Overall, a well-designed SuperCOP system can enrich system economics, enhance operational control, extend system life, and improve environmental performance compared to either of the typical primary systems. These advantages significantly reduce the financial risk posed by developing low temperature (below ~90oC) geothermal resources. Both modeling results and actual operating data demonstrate these advantages. Modeling results from a Cornell University study, funded by the U.S. Department of Energy, demonstrate potential benefits and quantify the energy implications of various system arrangements. Operating data using a recently commissioned system operating in the Dogger basin just outside Paris, France demonstrate one practical application where geothermal production is more than doubled through integration of heat pumps. Methods for further optimizing the performance of geothermal systems is discussed in the context of on-going and proposed research involving SuperCOP technology, expanding the range of economically feasible applications for heating using lower temperature geothermal resources. |