Low-Temperature Soil Heating Using Renewable Energy
Publication: Journal of Environmental Engineering
Volume 132, Issue 5
Abstract
Data from a pilot study, in which renewable energy was used for low-temperature subsurface heating in a northern climate, suggests that such an approach may be useful for remediating low permeable soils. Low-temperature soil heating is expected to enhance remediation effectiveness by increasing contaminant volatility, diffusion, desorption, and microbiological activity. Direct and indirect solar energy was harvested with a hybrid photovoltaic/wind electric system. The electrical energy generated by the hybrid renewable energy system was distributed to the subsurface using a control system and wire, then converted to heat energy using a resistive element emplaced in an unsaturated silty layer below grade. Renewable energy system performance, soil temperature, and environmental data were collected. Ambient soil temperatures fluctuated seasonally within the silt layer from . The small renewable energy system performed as predicted and injected of energy into the soil over the eight-month study. This energy input translated to increased soil temperatures ranging from and from above ambient at distances 0.3 and from the heating well, respectively. The system supplied sufficient heat to maintain soil temperatures above ambient even in winter in Vermont, where low direct solar energy was available and sustained low ambient temperatures prevail.
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Acknowledgments
The writers would like to acknowledge Vermont EPSCoR for Phase 0 SBIR funding to construct and monitor the field site, and the National Science Foundation BES Program for some additional funding. This report has not been subjected to Foundation review and therefore does not necessarily reflect the views of the Agency, and no official endorsement should be inferred. In addition, the writers thank Joe Rossabi, formerly at the Savannah River National Laboratory, for data acquisition equipment, field cost estimates, and advice; and Kathy Rossman, Sue Altman, Nik Ponzio, Martin McGowan, Chris McKay, Dave Whitney, and John Worthen for help with setting up the field site.
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© 2006 ASCE.
History
Received: Jul 2, 2004
Accepted: Sep 8, 2005
Published online: May 1, 2006
Published in print: May 2006
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