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.
Results from Gas-Fired Heat Pump Demonstrations and Research Across Multiple Sectors
2021 ETCC Webinar Series - June 24, 2021
Improving the Performance of Wall Furnaces in California
Wall furnaces are prevalent in California’s single-family homes and low-rise multifamily residential buildings as primary or auxiliary sources of heating, but many have low thermal efficiencies. A recently completed California Energy Commission shows high potential for cost-effective energy savings by replacing older existing wall furnaces with more efficient advanced retrofit models that can reduce emissions and improve indoor air quality.
Quantifying potential energy, emissions, and cost savings for heating equipment in a variety of settings with GTI’s Virtual Test Home (VTH) method
To assess the energy savings potential of a suite of efficiency measures targeting low-load homes, GTI developed a novel Virtual Test Home (VTH) method to determine as-installed performance of residential appliances such as emerging low-capacity space and water heating systems and furnaces.
The method integrates multiple test rigs and associated algorithms to simulate real-world conditions in a controlled laboratory environment. It can be used to evaluate gas and electric equipment across a wide range of as-installed conditions. This holistic approach—characterizing performance in the laboratory with the VTH, quantifying savings through modeling, and validating the savings in the field—provides a comprehensive understanding of performance that can be used to assess energy impacts for low-income, single-family, and multifamily housing applications.
Showcasing gas-fired heat pump (GHP) technology for water heating and air-conditioning in restaurants
Gas-fired heat pumps can bring notable savings to commercial businesses. There are several projects underway and one recently completed collaborative effort led by GTI with the California Energy Commission and several key industry partners demonstrated an integrated Ultra-Low NOx GHP system for water heating and space cooling at two full-service restaurants in the greater Los Angeles basin. Installed in new-construction or as a retrofit to an existing commercial water heating system, the integrated GHP system shows high potential for cost-effective energy savings and greenhouse gas emissions reductions.
California Energy Commission Project: Demonstration and Assessment of Natural Gas Heat Pumps for Integrated Water Heating and Air-Conditioning in Restaurants
Bringing low-cost gas-fired heat pump (GHP) technology to high-efficiency homes
Natural gas is the preferred fuel for thermal comfort in North America, and gas heat pumps offer simple efficiencies of more than 100%.
GTI along with various strategic partners like Trane, Rinnai, Stone Mountain Technologies, and others, 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.
California Energy Commission Project: Demonstration and Assessment of Residential Gas-fired Heat Pump Water Heaters in the Los Angeles Basin
Advancing thermally-driven heat pump technology towards commercialization for residential heating
Thermally-driven heat pumps (THPs) are gaining traction in residential and commercial sectors, with an uptick in various pre-commercial installations. GTI is supporting the development of a family of thermally-driven heat pump technologies to lower energy consumption, reduce energy costs, and minimize environmental footprint, with a focus on heating in residential buildings.
Numerous RD&D activities to verify equipment durability and performance and provide consumers with knowledge and confidence to buy have been undertaken.
GTI has performed a number of whole-house combined space and water heating (combi) system demonstrations, replacing a home’s furnace and water heater with a combi system to save energy. Demonstrations took place in Wisconsin, Illinois, and Ontario for the 2019-2020 heating season, and prior THP combi system field tests took place at residences in Tennessee.
The GTI team built upon early prototypes to develop the latest generation THP—a low-cost gas-fired heat pump that provides space and water heating in a “combi” application. Researchers created a proof-of-concept and evaluated it through laboratory and field testing for pre-production design of system components. This demonstration evaluated many aspects, including THP performance and reliability, efficacy of system controls, end user comfort, ease/complexity of installation, and servicing/maintenance.
The THP combi requires less energy for operation—offering therm savings between 33%-46% across demo efforts over baseline furnace and water heaters—with commensurate greenhouse gas reductions. Host sites gave positive feedback about heating/hot water comfort across a range of weather conditions. Delivered air temperatures above 105⁰F at or below 5⁰F outside air conditions.
With an outdoor location, a smaller form factor, and lower emission, the THP combi creates a significant opportunity for residential and commercial retrofits, and potentially Zero Net Energy (ZNE) home markets.
In addition for multifamily buildings, a hybrid heat pump/boiler system was tested in a Chicago multifamily building, and innovative heat pump prototypes from Europe were experimentally evaluated for potential adaptation for North American markets.
Several significant efforts are underway to bring residential combined space and water heating systems and residential heat pump water heaters to market, in partnership with major manufacturing and innovative technology partners. Pre-commercial pilots, design for manufacturing, and market transformation efforts are driving towards anticipated commercial availability by 2022.
The GTI team is also active in modernizing industry codes and standards, improving the accuracy of building energy modeling tools, and reducing installation barriers through innovative controls and infrastructure solutions.
The CEESM Residential Heating and Cooling Systems Initiative harmonizes binational program approaches by supporting the production and adoption of high efficiency and connected equipment in the market, implementation of installation and maintenance guidance, and facilitation of program opportunities aimed at selection of the appropriate heating and cooling system solutions for each unique customer.
GTI assisted with the development of the most recent Natural Gas Equipment Specifications released in January 2021 by CEE. It covers residential central air conditioners, air source heat pumps, gas furnaces, gas-fired boilers, gas heat pumps, and connected thermostats.
- Summary of Recent Demonstrations: Thermally-Driven Heat Pump Combis—December 2021
- Thermal Heat Pumps – The Time is Now! – ACEEE Summer Study on Energy Efficiency in Buildings — August 2020
- Pathways to Decarbonization of Residential Heating — International High Performance Buildings Conference 2021
- Results from the Demonstration of GHP “Combi” Systems in the Upper Midwest — 2019 ACEEE Hot Water Forum Presentation March 13, 2019
- Pre-Commercial Scale-Up of a Gas-Fired Absorption Heat Pump — DOE EERE, Building Technologies Office June 17, 2020
Bringing next-level energy efficiency with heat pump technology
To support next-level energy efficiency, the natural gas industry sponsored development of a gas heat pump roadmap. The comprehensive techno-economic and market study resulted in two new initiatives:
- A Joint Industry Program (JIP) was created, focusing on delivering high-efficiency, low-cost technology for space conditioning and water heating systems. This Gas Heat Pump Collaborative is initiating market transformation efforts targeting several new gas product categories, including residential and commercial heat pump water heaters, heat pump boilers, and combined space and water heating heat pump systems.
- In 2020, GTI launched a partnership with several U.S. and Canadian utilities to conduct a large-scale residential gas heat pump water heater (GHPWH) demonstration project while preparing utilities to support the commercialized product through energy efficiency programs. As a collaborative, sponsors will commit varying levels of financial resources to be involved at one of two membership levels: champion sponsor or supporting sponsor. Champion sponsors will host GHPWHs within their service territory as part of the field component of the project. All sponsors will have access to the full results and deliverables of the project. The project will include a range of field, laboratory, and market activities to meet sponsor-prioritized objectives.
Demonstrating hybrid gas/electric space conditioning system in high-performance homes
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 with multiple sites at the Rockford Housing Authority in Rockford, IL with funding support from local electric and gas utilities, and at multiple sites in Syracuse, New York, with funding support from NYSERDA. These demonstration projects of the hybrid space conditioning system are in retrofit applications in both market-rate and income-eligible homes. These projects have resulted in validated energy savings over the heating and cooling seasons.
Tackling Residential Space Heating Opportunities and Challenges
In a 2022 report, GTI Energy examined the current state of space heating energy use and assessed the impacts should space heating across the U.S. be electrified. The results are now available in an interactive data viewer that explores the state-by-state impacts on GHG emissions and annual heating costs for an average single-family home, and on peak electricity demand across the state.
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