USING SHALLOW SOLAR PONDS AS A HEATING SOURCE FOR GREENHOUSES IN COLDCLIMATES

This paper presents a theoretical analysis of using shallow solar pond s in greenhouses in cold climatic conditions. A shallow solar pond, wh ich can be built as an integral part of a greenhouse, can be used for both collection and storage of solar energy. The heat given our by the shallow solar pond is used for heating the greenhouse during the day. In addition, the collected heat during the day can also be used effic iently for heating the greenhouse at night. The performance of the sha llow solar pond is investigated under different weather conditions for different solar pond areas. The results show, particularly, that usin g a shallow solar pond in a greenhouse can provide great saving of ene rgy needed to heat the greenhouses in the months between March and Oct ober. There is no need to use any auxiliary heat between May and Septe mber, as the solar heat alone is sufficient to provide all the necessa ry heating; the energy stored by the pond during the day is enough to provide the night time heating or the necessary heat under cloudy cond itions. The results suggest that there is a huge potential in using sh allow solar ponds in greenhouses to save energy. Another obvious attra ction is that it would be relatively cheap to implement the novel idea of such application. (C) 1998 Elsevier Science Ltd. All rights reserv ed.