F. Buwalda et al., An energy efficient heating strategy for cut rose production based on croptolerance to temperature fluctuations, ACTA HORT, (507), 1999, pp. 117-125
There is scope for improvement of the fuel efficiency of modern greenhouse
climate controllers. In order to maintain a desired temperature level in th
e 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 feas
ible. However, such strategies will only be acceptable to growers if there
are no adverse effects on crop production or quality. A simple model was fo
rmulated for rose, in which the conventional temperature set point was repl
aced by a band of permissible temperatures and a band of permitted deviatio
ns from the standard temperature integral. This model was tested for four r
ose 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 ventilatio
n by delaying heating actions.