In a Cappricia crop in the 2SaveEnergy Greenhouse, we are seeing how far we can go with limited ventilation. Among other things, an average 24-hour temperature of 21.4ºC was achieved in April.
The crop tolerated this for quite a while, but in early May we had to start providing more ventilation. But venting more during the day means that less CO2 and moisture are retained in the greenhouse. In the 2SaveEnergy greenhouse, we have also been trying to save as much energy as possible without affecting the strength of the crop. That has worked well so far. Up to April, we were using 5 m3/m2 (planting date: 5 January) plus 10 kWh electricity for the heat pump.
This greenhouse has a double glass roof with an F-clean film and is also equipped with a double aluminium screen and a transparent (Luxous) screen. To limit outgoing radiation, the screen is closed quite early at the end of the day, at around sunset. In winter and spring we don’t generally vent off heat towards the evening. During dehumidification, we recover both the sensible and latent heat from the air and we also use the heat from the heat pump for heating the greenhouse air.