Development of a Greenhouse Side-ventilation Controller driven by Photovoltaic Energy

This study developed a greenhouse side-ventilation controller driven by photovoltaic energy. Controller operation was tested in a greenhouse from 16 March 2004 to 28 May 2004. Side-vent opening and shutting temperatures were set at 25 and 20 °C. The side-ventilation system controlled side-vent openings in multiple steps according to the temperature in the greenhouse. The side-ventilation controller was operated using a stand-alone power system comprising an amorphous-silicon photovoltaic module of 0·078 m2 with a rated maximum power of 3·2 W and a battery with 28 A h capacity in a 5 h rate (12 V). Throughout the experimental period, the greenhouse side vents were well operated, without outage, according to the greenhouse temperature. Daytime interior temperatures of the greenhouse were concentrated between the side-vent opening and shutting temperatures. These results indicate that photovoltaic power systems are applicable for a greenhouse environment control system.