Enhancing Efficiency in Space Conditioning and Water Heating

GTI is addressing key challenges in bringing new technologies related to high-efficiency space heating and water heating systems. This includes natural gas heat pumps and combined space and water heating systems – and the integration of these systems into homes and commercial buildings.

Project Highlight:

Bringing low-cost gas-fired heat pump (GHP) technology to high-efficiency homes

GTI and strategic partner Stone Mountain Technologies are developing advanced natural gas heat pump solutions that can be used for space heating, water heating, and combination space and water heating products. These represent next-generation solutions for efficiently using natural gas and achieving greenhouse gas emission reductions.

A latest genera­tion gas-fired heat pump water heater (GHPWH) is undergoing testing at different U.S. field test sites, including a major effort in California in collaboration with Southern California Gas and the California Energy Commission. This novel technology can meet Ultra-Low NOx requirements and has a projected Uniform Energy Factor (UEF) that is more than twice that of standard gas water heaters. It offers the lowest operating cost and cost of own­ership, with projected 50% energy savings.

The partners are also deploying a gas-fired heat pump combined space and water heating (GHP combi) system at residences in Tennes­see, Wisconsin, and California. The combi system replaces a home’s furnace and water heater, providing a projected 45% energy savings over the base­line equipment. The USDOE is also funding part of this technology development and evaluation effort.

Project Highlight:

GTI is conducting several field evaluation projects to assess the benefits of low-capacity natural gas furnaces and electric heat pumps in high-performance homes. This includes an effort at the Rockford Housing Authority in Rockford, IL and at multiple sites in the State of New York, with funding support from NYSERDA.  These demonstration projects of the hybrid space conditioning system will be in retrofit applications in both market-rate and income-eligible homes. Testing results will monitor energy savings over the heating and cooling seasons.

Project Highlight:

Under a grant from the Minnesota Conservation Applied Research and Development (CARD) program, GTI demonstrated emerging condensing rooftop units (RTUs) at two field sites in Minneapolis—a hotel commercial kitchen make-up air unit (MAU), and a conventional RTU installed in a restaurant dining area. Based on the study, condensing heating generated natural gas savings up to 17% compared to standard efficiency (80% thermal efficiency) systems, and both applications resulted in a positive net natural gas cost savings. The results confirm that 100% outside air (OA) applications, such as dedicated outside-air systems (DOAS) and MAUs, are the most promising initial market entry since they provide the long, predictable run times and larger heating loads required to generate net energy savings large enough to pay back the installed cost premium.

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