Xcel Energy works with NREL on study of heat pump performance in Colorado
A study by the U.S. Department of Energy’s (DOE) National Renewable Energy Laboratory (NREL) and Xcel Energy examined the performance of heat pumps in Colorado’s high altitudes and cold weather.
The study measured the performance of two heat pump configurations across a range of conditions at NREL’s Thermal Test Facility in Golden, Colo., which sits at 5,600 feet of elevation.
It found that the benefits of air source heat pumps are reduced as temperatures decrease. At mild temperatures, however, air source heat pumps are much more efficient than electric resistance heaters, such as a simple space heater.
At -20˚F, the performance for the tested unit was slightly better than an electric resistance heater. For below zero temperatures, a heat pump system may need supplemental electric resistance heating depending on various factors. Further, it found that lower performance is observed at the coldest temperatures. But, there is a 5.5% to 7.4% decline in performance observed for elevations similar to Golden, Colorado.
“The laboratory experiments generated comprehensive performance maps, empowering Xcel Energy to develop helpful guidelines for optimal heat pump installations that ultimately improve customer outcomes. This work also enhances the accuracy of estimates for monthly bill impacts, which may vary depending on multiple factors” Jon Winkler, senior buildings researcher at NREL, said. “We are also optimistic about the future of heat pump technologies, a major focus right now for industry, which promises greatly enhanced performance at temperatures as low as -20°F.”
Xcel Energy, which serves customers in eight states, including Colorado, commissioned the study and partnered with NREL to better understand how evolving technology can advance climate initiatives.
“Air source heat pumps are a key part of our strategy to reduce emissions in buildings,” Jeff Lyng, vice president external affairs and policy at Xcel Energy, said. “As grid planners, it is important to understand how technology performs during the coldest days of the year and how all-electric heating may impact customer costs and peak demand on the grid. We look forward to our continued partnership with NREL in the next phase of real-world field testing following these laboratory results.”
For the next phase of its heat pump studies, Xcel Energy, with guidance from NREL, is collecting field data from installed heat pumps in Leadville, Colo., the state’s highest elevated town. The data will provide greater insights into heat pump capabilities at higher altitudes and colder winter temperatures as well as cost impacts on energy bills.
