The mechanical systems and their energy demands are reported in. Mechanical components drawing electricity were a water pump, an air blower, four in-tank electrical water heaters, a 4-ft wall-mounted greenhouse fan, an inflation blower to maintain a pillow of insulation between the layers of greenhouse film, several box fans to distribute air throughout the greenhouse, and fluorescent lights. In cold weather, thermostat-controlled, propane-fired space heaters maintained the air temperature at no less than 4–7 °C. If the water temperature dropped below 22 °C, the thermostat-controlled electric heaters operated.