Toward an Optimal Control Strategy for Sweet Pepper Cultivation - 2. Optimization of the Yield Pattern and Energy Efficiency

摘要

Sweet pepper production is characterized by large fluctuations in fruit yield in time. These fluctuations have a detrimental effect on the operational planning of labor at nursery level as well as on the efficiency of the supply chain. At the same time, the dependence of temperate zone greenhouse horticulture on fossil fuel needs to be reduced for long-term viability. Growers are aware of the fact that by modifying the indoor temperature, these fluctuations can be influenced, but the dynamics involved are complex and hard to master. Therefore, in practice the degree of control achieved is limited and sometimes obtained at the cost of a higher energy consumption. In this research, using the framework of optimal control theory and employing a sweet pepper production model, alternative temperature strategies were searched for with the aim of reducing production fluctuations and using a minimum amount of energy. The results obtained in this research indicate that fluctuations in sweet pepper productioncan be reduced using optimized temperature strategies, either by controlling production in one compartment or by controlling production in opposite phase in two compartments. By doing so, energy savings of 10% can be obtained. In contrast with standardhorticultural practice, a striking feature of the optimized temperature trajectories is their considerable variation in time.