The unique feature of a Daylight Greenhouse is its ability to convert incoming sunlight into energy that can be used to heat the entire greenhouse complex. This principle, devised ten years ago by Technokas and Wageningen University, is starting to bear fruit for Ter Laak. Not only is the company making energy savings of up to 50%, but plant quality is even better than before.“For this complex project, we found the right partners in Stolze and Priva to share ideas about how best to control the climate in the Daylight Greenhouse.”
The principle of the Daylight Greenhouse, devised ten years ago by Technokas and Wageningen University, is that not a single beam of sunlight is lost. The roof on the south side of the Daylight Greenhouse consists of special Fresnel lenses that focus incoming sunlight on two black-painted collector pipes mounted under the greenhouse roof. These collectors track the position of the sun, which heats up the water inside them. The resulting hot water is then transferred to an overground buffer or stored in the soil, for use in heating the greenhouse at a later time. This system enables Ter Laak to use all the sunlight entering the greenhouse.
A complex project calls for close cooperation
Phalaenopsis prefers to be out of direct sunlight, which is why this crop is exceptionally well suited to this type of greenhouse. The system ensures that the sunlight not required by the plants is used efficiently and does not go to waste.
“In the summer months, most of the sunlight – about 70% – falls on the collectors and only the remaining 30% reaches the crop,” explains Ewald de Koning, Manager Operations at Ter Laak. However, the system is not entirely without risk: the amount of light reaching the plants should not be too high. Light levels are measured continuously using Priva PAR sensors and the Priva Connext process computer. “When a PAR sensor detects that the limits of the light settings have been exceeded, it automatically sends a signal to the computer, which triggers the preset measures such as closing the screens. We also receive a direct notification on our phone via the Priva Alarms App,” says Ewald. “For this complex project, we found the right partners in Stolze and Priva to share ideas about how best to control the climate in the Daylight Greenhouse.”