U.S. Department of Energy - Energy Efficiency and Renewable Energy
Building Technologies Office
Multi-Function Fuel-Fired Heat Pump Research Project
The U.S. Department of Energy is currently conducting research into multi-function fuel-fired heat pumps. Multi-function fuel-fired heat pump technology has the potential for a significant impact on the electric industry compared to other building equipment technologies that use electricity, particularly during summer peak electric demand. The multi-function heat pump will be equipped with a power generation module that supplies all the power for ancillary loads and emergency power back-up, thus reducing peak electric demand. Peak-load conditions can lead to high electricity prices, power quality problems, grid system inefficiencies, and eventually brown outs.
This project seeks to develop a residential multi-function fuel fired heat pump. Achieving the proposed technology-cooling source coefficient of performance (COP) of 1.3, and heating source COP of 1.5, while maintaining the hot water capacity of 40 gallons, would result in a significant increase in energy efficiency compared to separate heating, ventilation, and air conditioning (HVAC) and water heating equipment.
If successfully developed, this unit will deliver an annual primary energy savings for space conditioning of 30% and 80% primary energy savings for water heating compared to separate HVAC and water heating equipment. A control strategy will be developed to optimize the waste energy use from the engine for space heating and water heating and for determining optimal use of the generator. Following the successful design and construction of the Beta unit, which is the first prototype with all the functions (heating, cooling, water heating, power generation), laboratory testing will be performed.
Research is being undertaken through a cooperative research and development agreement (CRADA) between the Department of Energy, Oak Ridge National Laboratory, and a CRADA partner.
The goal of this project is development of of a four-ton natural gas residential multifunction heat pump with a cooling COP of 1.3 and a heating COP of 1.5. The unit aims to achieve an 80% reduction in water heating energy consumption with a 1 to 2 kilowatt electricity generation capability for ancillary loads, and a 5 year payback.
Benefits and Impacts
Life cycle costs for a residential fuel-fired multi-function heat pump are lower than traditional HVAC systems and water heaters. This is the result of lower energy costs and the use of waste engine heat to supplement space heating and water heating. The highest savings will be realized in locations where space heating loads, water heating consumption, and electricity rates are high. In areas where demand and time-of-day or use charges exist, savings would be even greater since the unit is capable of operation without any electrical requirements from the grid.