Condensing Boiler Optimization
Russ Landry, P.E., Neal Ray, Martha Hewett — Jan 2013
Field monitoring wrapped up in fall 2014 and the project team is now identifying measures to provide savings and analyzing potential savings. Full project update
Why This research is Needed
Condensing boilers are one of the most promising natural gas technologies for reducing Minnesota commercial energy use. However, many newly installed systems only achieve a fraction of their expected energy savings.
The efficiency of condensing boilers is extremely sensitive to operating conditions — in particular the temperature of the water entering the boiler. Often, an effective retrofit requires modifications of the boiler system controls and/or piping because the equipment and controls are based on standard boiler operating conditions, which are different than the low temperature and load conditions needed for condensing boilers to perform best.
Project Process and Expected Outcomes
This field research aimed to quantify how operating conditions impact the installed energy efficiency of commercial condensing boilers in Minnesota, and to determine the potential for optimization through enhancements to utility efficiency program.
The project team monitored systems at 12 representative buildings over several months to determine the achieved efficiencies and potential for optimization through low-cost upgrades. To do this the team analyzed the efficiencies at which the boilers were found to be operating, identified measures to provide energy savings, and calculated potential savings. The findings could help increase the installed energy savings of condensing boilers. The team also conducted industry interviews, which were used along with field results to recommend future program strategies in a draft final report.
This project supported in part by a grant from the Minnesota Department of Commerce, Division of Energy Resources through the Conservation Applied Research and Development (CARD) program. And with co-funding by CEE in support of its nonprofit mission to advance research, knowledge dissemination, and program design in the field of energy efficiency.
Photo courtesy of DOE/NREL. Diagram courtesy of allseasonshire.eu.