The essential technical problem facing the lumber industry is that in the evolution from air drying to kiln drying, driven by the need to offer a wider variation of lumber products in a more timely fashion, the energy cost component of the process increased significantly. So much so, that lumber drying efficiency has become a differentiating factor in the success of companies across the industry. And energy prices will continue to force more and more lumber companies to find alternative drying solutions, or get out of the business.
In the vein of this dilemma, a team of folks came together to adapt a neat, low-cost technology called the SolarWall to the field of lumber kiln drying. The problem was how to capture the "free" energy of the sun, the same energy that was used in centuries of air-drying lumber, and bring it back as a cost-effective substitute for kilns fired by traditional fuels. Instead of high-costing photo-voltaic solar panels, SolarWall allows solar energy to be captured with technology that is more in the price neighborhood that typical lumber kiln operators could consider in new kilns or in retrofits to existing kilns.
This article describes how it does that, and how the team made it all come together. The article describes how the SolarWall works:
Like all great solutions that adapt technologies to new applications, the concept of bringing the "solar" back into lumber drying will be an incremental succession of improvements and hybridizations that eventually result in a paradigm shift in the prevailing business model: one that is greener, less costly, and meets the needs of the customer. As far as lumber drying goes, that can't happen any too soon.According to the company, SolarWall systems produce up to 600 watts/m2 (60 watts/ ft2) of thermal energy.When the sun warms the surface of the SolarWall, heated air is drawn inside through thousands of tiny holes on its surface.The system essentially takes the heat out of the air, heat that is provided, of course, by the sun. In the case of the BC Hydro pilot project, the solar-heated air is then distributed and re-circulated throughout the kiln, to help dry the lumber. In effect, the SolarWall system displaces the need for most of the heating in the kiln, meaning absolutely no natural gas will be required."
To those who count out the solid wood industry in these increasingly difficult economic times, and maintain that substitute products are the wave of the future, I say:
Don't count us out yet. We've still got a few tricks up our sleeves.