At the end of 2015, airmix fans were placed in four sections at Dutch grower Berg Roses. These are screen fans that can mix air from above the screen with greenhouse air, and then blow the mixed air horizontally into the greenhouse. By using air from above the screen, the greenhouse air becomes cooler and dryer. Therefore, less often a gap has to be opened up in the screen cloth.
Presently, it is recognized by many that the use of gaps should be avoided as much as possible. Firstly, in order to keep the light emission within the legal limit of 98% and, secondly, in order to maintain an even temperature distribution. Wageningen University & Research, Greenhouse Business Unit has employed twelve ventilated wireless sensors to measure temperature differences in the period between 20 October and late November. It was found that the difference between the highest and the lowest temperature during the night were typically between 1° and 3° C, whereas this difference could be more than 5° C in previous years. The difference between the second highest and the second lowest temperature always was less than 1° C.
Berg Roses has stated its satisfaction with the system. In four other departments, however, only fans were installed during the past month. This has to do with the age of the screen cloth in those sections. When these screens are replaced, the fans can still be converted into airmix fans.