A Municipal Waste Heat Dissipation Modular Approach for Open Field Heated Agriculture

Waste heat from low temperature geothermal resources, industrial, municipal district heating services, and combined heat and power (CHP) systems is a valuable resource that can be dissipated in open field heated agricultural systems. Since 2008 the authors have been developing and field testing an energy intensive year-round shallow soil warming technology. Heated green roof test beds in New York City and heated gardens in Iceland are analogous to heated sidewalks. Heat dissipation rates for the test beds varied from 0.086–0.336 kW/m2, depending upon working fluid temperatures, weather conditions, soil types, soil depths and moisture content. Plant growth increases of 20% and growing season prolongation are documented when a soil temperature of 25–30°C is maintained continually at a depth of 8 cm. This enables the survival of cultivars that normally thrive in more than two United States Department of Agriculture climate zones to the south. This coincidentally mirrors some global climate changes predictive models. The authors have developed a basic 5 × 10 square meter module based on their 10 years of experience, which can be used alone or combined for larger installations. Construction guidelines, thermal projections, and expected plant growth results are provided for both urban and municipal installations.