Improving the efficiency of greenhouse climate control: An optimal control approach

Abstract

In this paper a method to Improve the efficiency of greenhouse climate control is described. This method is based on the framework of optimal control theory. By exploiting a dynamic model of the greenhouse crop production process, information of the auction price, the operating costs of the climate conditioning equipment and the outdoor climate conditions, the optimal greenhouse climate control scheme balances on a purely objective basis costs against revenues of operating the climate conditioning equipment. Though optimal control of greenhouse climate has received considerable attention in the literature, until now little evidence supported by experimental work has been reported as to the possible improvement in efficiency which can be realised using this approach during a whole growing period. This paper reports a first exploration of this matter for a lettuce crop. In a greenhouse experiment the behaviour of conventional greenhouse climate control supervised by the grower was measured. Then, in simulation experiments, optimal control strategies were calculated for the same conditions (outdoor climate, auction price, energy price). The results obtained support the conclusion that a considerable improvement in the efficiency of greenhouse climate management is possible. This improvement may well exceed 15%.