From the start until now the two aluminium and the Luxous screen have been closed (partially) every night in the 2SaveEnergy trial greenhouse in Holland. Including during warm weather. This greatly limits the amount of light entering the greenhouse and saves energy during cold weather. In the months of June and July a total of only 0.2 m3/m2 of gas was used, totalling the usage at 5.6 m3/m2 now.
OCAP-CO2
The low gas usage in this greenhouse is due to other energy saving measures as well as the screens. There is a double deck of glass and F-clean on the greenhouse, no minimum tube is used and dehydration is done by winning back the tangible and latent heat. Of course some electricity is needed for the heat pump: until the end of July almost 15 kWh/m2 was used. Due to the use available residual OCAP-CO2 no energy is needed for the CO2 in the summer, which many other companies do need.
The Next Generation Growing
Cultivation is done as much as possible in the greenhouse according to the principle of The Next Generation Growing. This includes strongly light dependent cultivation at quite a high temperature level, in which the free solar heat is used as much as possible. This lowers the load on the plant and quickly releases the tomatoes. In recent weeks there have only been seven vines on the plants of the variety Cappricia, whilst the plant load in June and July was around 140 fruits per square metre.
If we now compare the realised temperature with research in the same greenhouse two years ago, we can see that the daily temperatures were around the same, but that the realised temperature at night was slightly higher this year. A warm night prevents having to heat in the morning and so saves energy.
Quality and production
This certainly doesn't seem to negatively affect the plants. At the start of August the BCO judged the head of the plants to be positive: good thickness and colour. Likely as a result of a few warm days, the plant were down a little a few weeks ago. This also happened in practice. The average fruit weight of the harvested tomatoes has been increasing again in recent weeks. The production and the quality of the tomatoes is good.
This project is financed by the programme Kas als Energiebron (Greenhouse as an Energy source), the innovation and action programme by LTO Glaskracht Nederland and the Ministry of Economic Affairs (EZ).
Source: Kas als Energiebron