The most effective and versatile climate control tool in greenhouses are screen systems. They directly address the largest variable all greenhouse growers come up against, the amount of solar radiation hitting the greenhouse at any given moment. The more variability expected in the solar radiation load, the more impactful the systems can be at managing those climate extremes.
While screen systems can have a high upfront cost, in the long term they are economically and environmentally advantageous. They consume exceptionally low amounts of energy to operate, and have incredible operational returns with the possibility of energy savings, environment optimization, and limited operational costs. They are also highly versatile systems that provide growers many ways to manage the climate in their greenhouse in all seasons. Other tools like boiler systems, mechanical cooling systems, evaporative systems, and misting systems are usually deployed on a seasonal basis – depending on a greenhouse’s location.
Increasingly, growers are implementing dual screen systems. While this can be a more complex system to control, environmental control programs are equipped with programs to optimize these installations. Importantly, dual systems allow growers to gain many benefits.
For example, deploying a light pollution curtain with a shade curtain allows the grower to have many choices about how to manage their climate. Generally, these systems are optimized when they operate in the opposite direction of each other. This means growers can utilize the light pollution curtains in times of low outside light to 1) prevent light pollution 2) optimize the use of supplemental light by reflecting light back to the crop and 3) take advantage of the higher energy retention value of the light pollution curtain. Then, in the summer, a diffuse light shade curtain can be used alongside the light pollution screen to control light levels from 20-100%. Airflow can also be maintained through the roof vent as there is an air gap between the curtains to allow air to passively ventilate.
Overall, dual curtain systems are a highly versatile tool that growers can use to balance the climate in their greenhouse year round. They allow growers to optimize their climate while also reducing the required energy inputs for heating and cooling.
