IMPROVING THE EFFICIENCY OF GREENHOUSE CLIMATE CONTROL - AN OPTIMAL-CONTROL APPROACH

In this paper a method to improve the efficiency of greenhouse climate control is described. This method is based on the framework of optima l control theory. By exploiting a dynamic model of the greenhouse crop production process, information of the auction price, the operating c osts of the climate conditioning equipment and the outdoor climate con ditions, the optimal greenhouse climate control scheme balances on a p urely objective basis costs against revenues of operating the climate conditioning equipment. Though optimal control of greenhouse climate h as received considerable attention in the literature, until now little evidence supported by experimental work has been reported as to the p ossible improvement in efficiency which can be realised using this app roach during a whole growing period. This paper reports a first explor ation of this matter for a lettuce crop. In a greenhouse experiment th e behaviour of conventional greenhouse climate control supervised by t he grower was measured. Then, in simulation experiments, optimal contr ol strategies were calculated for the same conditions (outdoor climate , auction price, energy price). The results obtained support the concl usion that a considerable improvement in the efficiency of greenhouse climate management is possible. This improvement may well exceed 15%.