Vergelijking tomatenteelten met een Ventilation Jet systeem: als onderdeel van het monitoringsproject

The tomato companies Greenco and Gardener’s Pride grow a small tomato and are equipped with a: Ventilation Jet (VJ) system, SON-T lighting system, blackout screen and an energy screen. The energy consumption that was brought into the greenhouse by the heating pipes at Gardener’s Pride was 37.8 m3/m2/year between 1 December 2016 and 1 December 2017 and 25.4 m3/m2/year at Greenco. The higher energy consumption at Gardener’s Pride could be explained by: (1) Sunstream is a variety that is grown very generative; (2) Gardener’s Pride did not dare to hold high relative humidity levels due to the lack of a working VJ system and (3) Gardener’s Pride had fewer screening hours. Thanks to the Ventilation Jets, the growers were able to keep the blackout screen (almost) 100% closed at times when the lighting system was on. During certain periods both growers have decided to use the Ventilation Jet system less. The growers suspect that the air movement caused by the recirculation fan ensures sometimes undesired extra generativity. At Gardener’s Pride, it turned out that less than 3% of the air blown in by the VJ leaves the greenhouse through the gap at the central path. It can therefore be concluded that under these circumstances this gap is not necessary