An energy efficient heating strategy for cut rose production based on crop tolerance to temperature fluctuations

There is scope for improvement of the fuel efficiency of modern greenhouse climate controllers. In order to maintain a desired temperature level in the greenhouse, the heating system and ventilation windows are often actuated within a limited time span. When the greenhouse temperature is allowed to fluctuate to a larger extent, more efficient heating strategies become feasible. However, such strategies will only be acceptable to growers if there are no adverse effects on crop production or quality. A simple model was formulated for rose, in which the conventional temperature set point was replaced by a band of permissible temperatures and a band of permitted deviations from the standard temperature integral. This model was tested for four rose cultivars under realistic conditions, using a climate control algorithm based on temperature integration. The controller did not calculate optimal trajectories, but simply compensated for the effects of delayed ventilation by delaying heating actions.