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Abstract
Greenhouse operations are labor, capital and energy intensive. The energy cost for its operation vary in between 15 and 20 percent of the total production cost. A passively heated and cooled solar greenhouse design was analyzed to study its energy savings.
An Alpine type passively heated and cooled greenhouse system was studied through a dynamic simulation model and measured greenhouse environmental data. The Alpine greenhouse had a built-in Trombe wall system to store thermal energy during the day, which is recovered during the cool night. The Trombe wall was responsible for the maintenance of inside greenhouse air temperature above the outside air temperature during cool winter nights. It offers an energy savings of 44.5 GJ/year.
The greenhouse natural ventilation was also analyzed. The summer operation of the greenhouse required an additional ventilation of 500 m$\sp3$/min to keep the inside air temperature from rising 2 to 3 degrees C above the outside ambient air temperature.
The dynamic simulation model accurately predicted the greenhouse environment, and is a reliable tool to design, analyze or select a passively heated and cooled greenhouse system.
