Energy is one of the largest operational expenditures for all greenhouse operations. To improve the energy efficiency of a greenhouse, horizontal screens have been installed in greenhouses for decades now. The horizontal screening system forms an insulating layer suspended over the crop. Depending on the type of screening fabric installed, the screening system can have energy saving-, diffusing-, shading- and also black-out properties. Due to the impact on the climate the screens have, they are also referred to as climate screens.
The horizontal screens are installed between two truss spans, and run over each bay. The screens are supported on a wire bed. A few wires on top of the screens are installed to prevent the climate screens from blowing up. The screens are pulled from one side to the other, while fixed to the trellis on one side. The screens move along with an aluminum screening profile to the other. A fixed rubber in this aluminum profile provides for a tight closing against the truss.
The mechanism of choice by DutchGreenhouses® is the pull wire system, this has minimal light interception and requires minimal maintenance during the years of operation. The screening system is partially integrated into the greenhouse steel frame. Proper fixation points are provided in the greenhouse design to ensure trouble free installation.
The drive motors of the screens are connected to the climate computer. When properly commissioned, the computer registers the time a motor is operated and knows by time the opening or closing position of each screen in each department.
The screen material has evolved over the years from a linen material to a complex technical fabric. Combinations with aluminium bars, plastics and special yarns allow for a highly accurate and consistent screening property. With moist control and diffusion, the screening has become a very important tool in the search for the perfect climate.
Double Screening System
The improved characteristics of the screens make for an accurate climate regulation. A double screening system has become more and more applied, as it has proven to provide growers with the flexibility they need. Double screens are installed above each other and are always fitted with different type of climate screens. The layers can be opened and closed to complement the functionality of both.