Evaluation of Ground Source Heat Pump Energy, Demand, and Greenhouse Potential in Colorado Residential Buildings

Abstract

This paper summarizes the results of a detailed energy analysis carried out for a typical Colorado residence using three different HVAC systems for 10 distinct locations in Colorado. The HVAC systems considered in the analysis include: • 78% efficient furnace with a 13 SEER air conditioner; • Vertical well ground source heat pump with a heating COP of 3.5 and a cooling EER of 17.1; • Slinky ground source heat pump with a heating COP of 3.5 and a cooling EER of 17.1. The results of the analysis indicate that relative to the conventional systems, ground source heat pumps (GSHPs) offer several benefits including lower annual energy costs, electrical peak demand, and carbon emissions. However, GSHPs use more electrical energy use. Specifically, it was found that relative to a 78 AFUE furnace / 13 SEER AC system, in all locations both GSHPs, vertical well and slinky, show on average a 41.2% increase in electricity use, a 10% decrease in energy cost, a 4.5% decrease in CO2 emissions, and a 16.8% average decrease in peak summer electric demand.