Geothermal power cycle analysis for commercial applicability using sequestered supercritical CO2 as a heat transfer or working fluid

Brian Janke, Thomas Kuehn

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

Thermodynamic analysis has been conducted for geothermal power cycles using a portion of deep ground sequestered CO2 as the working fluid. This allows energy production from much shallower depths and in geologic areas with much lower temperature gradients than those of current geothermal systems. Two different system designs were analyzed for power production with varying reservoir parameters, including reservoir depth, temperature, and CO2 mass flow rate. The first design is a direct single-loop system with the CO2 run directly through the turbine. This system was found to provide higher system efficiency and power production, however design complications such as the need for high pressure turbines, two-phase flow through the turbine and the potential for water-CO2 brine mixtures, could require the use of numerous custom components, driving up the cost. The second design is a binary system using CO2 as the heat transfer fluid to supply thermal energy to an Organic Rankine Cycle (ORC). While this system was found to have slightly less power production and efficiency than the direct system, it significantly reduces the impact of design complications associated with the direct system. This in turn reduces the necessity for certain custom components, thereby reducing system cost. While performance of these two systems is largely dependent on location and operating conditions, the binary system is likely applicable to a larger number of sites and will be more cost effective when used in combination with current off-the-shelf ORC power plants.

Original languageEnglish (US)
Title of host publicationASME 2011 5th International Conference on Energy Sustainability, ES 2011
Pages1237-1244
Number of pages8
EditionPARTS A, B, AND C
DOIs
StatePublished - Dec 1 2011
EventASME 2011 5th International Conference on Energy Sustainability, ES 2011 - Washington, DC, United States
Duration: Aug 7 2011Aug 10 2011

Publication series

NameASME 2011 5th International Conference on Energy Sustainability, ES 2011
NumberPARTS A, B, AND C

Other

OtherASME 2011 5th International Conference on Energy Sustainability, ES 2011
CountryUnited States
CityWashington, DC
Period8/7/118/10/11

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  • Cite this

    Janke, B., & Kuehn, T. (2011). Geothermal power cycle analysis for commercial applicability using sequestered supercritical CO2 as a heat transfer or working fluid. In ASME 2011 5th International Conference on Energy Sustainability, ES 2011 (PARTS A, B, AND C ed., pp. 1237-1244). (ASME 2011 5th International Conference on Energy Sustainability, ES 2011; No. PARTS A, B, AND C). https://doi.org/10.1115/ES2011-54397