skip to main content


Title: Exergy Analysis of a Two-Stage Ground Source Heat Pump with a Vertical Bore for Residential Space Conditioning under Simulated Occupancy

This twelve-month field study analyzes the performance of a 7.56W (2.16- ton) water-to-air-ground source heat pump (WA-GSHP) to satisfy domestic space conditioning loads in a 253 m 2 house in a mixed-humid climate in the United States. The practical feasibility of using the ground as a source of renewable energy is clearly demonstrated. Better than 75% of the energy needed for space heating was extracted from the ground. The average monthly electricity consumption for space conditioning was only 40 kWh at summer and winter thermostat set points of 24.4°C and 21.7°C, respectively. The WA-GSHP shared the same 94.5 m vertical bore ground loop with a separate water-to-water ground-source heat pump (WW-GSHP) for meeting domestic hot water needs in the same house. Sources of systemic irreversibility, the main cause of lost work are identified using Exergy and energy analysis. Quantifying the sources of Exergy and energy losses is essential for further systemic improvements. The research findings suggest that the WA-GSHPs are a practical and viable technology to reduce primary energy consumption and greenhouse gas emissions under the IECC 2012 Standard, as well as the European Union (EU) 2020 targets of using renewable energy resources.
 [1] ;  [1] ;  [1] ;  [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Applied Energy
Additional Journal Information:
Journal Volume: 155; Journal ID: ISSN 0306-2619
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Building Technologies Research and Integration Center (BTRIC)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Building Technologies Office (EE-5B)
Country of Publication:
United States
15 GEOTHERMAL ENERGY; Renewable Energy; Second Law; Thermodynamics; Availability; Geothermal; Ground-source
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1247579