This paper shares the results of an analysis of the energetic, emissions and economic balance of a simulated large-scale (multi-home) ground-source heat pump (GSHP) system in Austin, TX for heating and cooling. In contrast with traditional AC units and furnaces that use air outside of the house as a heat sink or source, GSHP systems use a ground loop heat exchanger to transfer heat to and from the soil where temperatures stay relatively constant throughout the year. GSHP systems operate more efficiently due to their use of the ground as a heat sink or source, whereas traditional AC units use the outside air. Consequently, GSHP systems typically use less energy than traditional HVAC units, but high capital costs have inhibited their widespread use. The monthly and annual energy costs for a home with a traditional AC unit-furnace are compared to a home with a GSHP system using hourly energy consumption data. The GSHP system modeled for the energy efficient home uses less energy (8.2 MMBtu) throughout the year compared to an efficient AC unit installed on the same home. Energy costs are lower using both the Austin Energy current rate schedule and for a proposed alternative schedule. Additionally, the GSHP system produces a net reduction in harmful emissions. Furthermore, GSHP systems reduce peak demand during the energy-intensive summer months, when air emissions are of greater concern. The installation costs for a large-scale residential GSHP system used in this research were based on interviews, current industry standards, and available pricing data. The analysis includes a sample case study of the cost of the GSHP system included with a home mortgage using a net monthly payment method and includes electricity price increases over time and federal tax incentives. If installed on a large scale, assuming best-case pricing with current federal tax incentives, the GSHP system case is $17 less per month than the traditional HVAC case. Federal tax incentives and high natural gas prices were found to make savings more significant for the GSHP system over time. Additionally, capital cost variability had a greater effect on savings than changes in electricity costs. Based on these analyses, large-scale GSHP systems are considered an economically feasible alternative to traditional HVAC units that will reduce energy consumption and air emissions.

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