In three growing seasons it has been proven that we can grow a crop with less than half of the energy use of growers in practice without compromising production en product quality. These results were achieved in the ultra -efficient Venlow energy greenhouse. But the search for further energy savings continues. Where is the energy consumption of 16 m3/m2 including electricity use, yet?
Analysis revealed that further insulation only will gather small extra savings. But nearly half of the today’s energy use is related to the evaporation during periods of heat demand. On an annual basis in this greenhouse we transpire less than 80 l/m2 during heating. In this way the evaporation has become the largest user of energy. If we can halve the liters of evaporation and compensate this loss at times when the sun shines, we expected to be save 4 to 5 m³ of natural gas per m²/year.
Can we reduce this evaporation without affecting crop production and quality? That is one of the questions we try to answer this year. We will achieve this in two ways: If there is heat demand we reduce the vapour deficit to reduce evaporation. In addition, we try to achieve this evaporation reduction with an EC control without increasing average EC in longer term. In short, towards a highly energy -efficient crop production, we must first look for evaporation " to find the balance between necessity and excess."