Field Study of a Moisture and Heat Transfer Furnace Retrofit Device
Josh Quinnell, Ph.D., Dave Bohac, P.E., Dexin Wang — Jan 2015
The project team installed the TMH at four sites, all of which are ready to run on full TMH mode for the upcoming heating season. Each site represents a unique combination of occupant density and air tightness, providing a good variety of situations to better understand how the TMH works. Full project update
Why this research is needed
Few residential gas furnaces are replaced before failure; consequently the average furnace age in Minnesota single family homes is over 15 years. Most of these older systems are operating at 15 percent lower efficiency than today’s best available technology, offering a tremendous opportunity for energy efficiency. New transport membrane humidifier (TMH) technology can retrofit the standard older furnaces to make them as or more efficient than new furnaces. Transport membrane humidifiers transfer waste heat and water vapor from flue gases into the building air supply. This improves efficiency and also improves occupant comfort by adding humidity to dry winter air.
Project process and expected outcomes
This study will evaluate the actual savings, establish implementation protocols, and demonstrate non-energy benefits of transport membrane humidifier technology. Units will be installed in five single family homes currently equipped with standard efficiency (78 to 83%) furnaces that are representative of Minnesota installations. The project will extensively monitor and evaluate the units over the course of two heating seasons (2015 and 2016). Data will be used to model expected annualized and lifetime energy savings for the five sites, and extrapolated to the Minnesota market.
These data, combined with detailed observations on design, sizing, and installation of the retrofit units, will be analyzed to generate realistic estimates for payback and market adoption rates as well as potential contributions to Minnesota’s Conservation Improvement Program (CIP) goals.
Innovation Exchange research staff will also conduct periodic owner interviews to assess their perception of comfort and system operation. The outcome of this monitoring will be performance expectations for the new units in the Minnesota market.
*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.
Photos courtesy of Journal of Solar Energy Engineering