Can a Solar Chimney Compensate for Heat Loss?

Steven, Most people don't think about their chimney, and since this is winter you raise some interesting issues. According to the U.S. Department of Energy, we waste about 10 percent of our energy through our chimney, whether we have a furnace or a fireplace. One way to prevent your warm inside air from venting out your chimney shaft is using lock-top dampers, energy-top dampers, top-mounted dampers, lymance dampers, top-sealing dampers, flues, chimney dampers, or termination dampers. These chimney energy-top fireplace dampers save you from $100-$250 annually on heating and air conditioning energy costs. These chimney dampers also deter cold draft entry, wind down-draft elimination and outside odor entry. A solar chimney -- often referred to as a 'thermal chimney' -- has been a way of improving the natural ventilation of buildings by using convection of air heated by passive solar energy. A simple description of a solar chimney is that of a vertical shaft utilizing solar energy to enhance the natural stack ventilation through a building. The solar chimney has been in use for centuries, particularly in the Middle East, as well as by the Romans. In its simplest form, the solar chimney consists of a black-painted chimney. During the day, solar energy heats the chimney and the air within it, creating an updraft of air in the chimney. The suction created at the chimney's base can be used to ventilate and cool the building below. This was used in early American architecture routinely. However, I have not personally seen any in the modern context, and my contacts with several solar architects didn't turn up anything -- most use more modern air-to-air heat exchangers. So I am putting the call out to the Renewable Energy Access readership to see what else we unearth about your idea. -- Scott Sklar Scott Sklar is President of The Stella Group in Washington, D.C., a distributed energy marketing and policy firm. Scott, co-author of "A Consumer Guide to Solar Energy", uses solar technologies for heating and power at his home in Virginia. Have a question? Please contact Scott regarding new products, technologies or experiences for future Q&A columns.