Using Heat Pumps to Dry Wood Could Green Up Construction Industry, UMD Study Shows

A newly published paper led by the University of Maryland’s Center for Environmental Energy Engineering (CEEE) researchers makes the case for developing heat pump technologies to decarbonize the wood-drying industry, which prepares lumber for building construction, furniture and more.

The paper, published online for the Dec. 1 issue of the journal Energy, offers a comprehensive review of the literature on current wood-drying processes and heat pump technologies as well as another review examining the limited use of heat pumps in the wood-drying industry.

The vast majority of wood-drying relies on fuel combustion, a process that contributes 36 million metric tons of the greenhouse gas carbon dioxide to the atmosphere annually, a 2018 study showed.

The review paper bridges the gap between two fields. “A heat pump expert can learn a lot about the specific needs of the wood-drying industry,” said CEEE postdoctoral researcher Andrew Fix, who is the paper’s co-first author, along with former CEEE researcher Lei Gao Ph.D. ’22, now on the R&D staff at Oak Ridge National Laboratory. “Meanwhile, a wood-drying expert, who is comfortable using conventional techniques like combustion-fueled wood-drying kilns, can learn about heat pumps and how they could be applicable.”

The other co-authors are graduate research assistants Tamoy Seabourne and Yong Pei, Research Professor Yunho Hwang and mechanical engineering Professors Bao Yang and Reinhard Radermacher, who is also a Minta Martin Professor and CEEE director, as well as Patrick Adegbaye of the University of the District of Columbia.

Next, the research team is working to innovate more efficient heat pumps for the wood-drying sector. As part of a $2.7 million Department of Energy-funded project funded last year, researchers are developing a two-chamber wood-drying heat pump that captures the waste heat from the first chamber and uses it to heat a second chamber, nearly doubling the system’s efficiency. The eventual prototype will use refrigerants with low global warming potential, making the heat pump even more environmentally friendly.