Each climate zone in the Priva Compass has two separate controls for curtains and each curtain control can have two motors. In this article, we will define what each of them means to you.
The curtain controls are designed for curtains that can be used as shading curtains (to protect the crop from intense sunlight during the day) and/or thermal energy curtains (to reduce the amount of energy that the greenhouse needs to maintain temperature during the night). If you have separate shading and thermal curtains, you would use one of the controls for the shading curtain and the other control for the thermal curtain.
The curtain can cover for shading if the sunlight levels are too high or if the temperature in the greenhouse zone climbs too high. There are five different positions available when the curtain is in shading mode.
The curtain can cover at night for energy conservation purposes. When the curtain is covered, the climat is maintained only in the area below the curtain. The area above the curtain does not get heated and acts as an insulating buffer for the greenhouse.
The curtain will cover at night when the outside drops below a predetermined set point. It is allowed to uncover slightly if venting or dehumidification is needed in the greenhouse.
When the curtain uncovers in the morning it will uncover in a number of small steps to allow the warm air below the curtain to mix with the cold air above the curtain in order to prevent a sudden temperature change on the crop as the curtains are uncovering.
Each of the curtain controls can operate two separate motors. These motor controls are typically used if both curtains are in use to achieve the same strategy. For instance, if one of the curtains is at the ceiling of the greenhouse and one of the curtains is along the wall, you will want them to work together, with the only difference being that the two curtains have different run times and you may only want the ceiling curtain to uncover for venting and dehumidification.
Another application for two motors would be if you have two shading curtains that are designed to work together. If only a little shading is needed, the lighter curtain is used to cover the crop. If more shading is needed, the lighter curtain is pulled back and the heavier curtain is used to cover the crop. If even more shading is needed, the lighter curtain is again pulled over the crop so that both curtains are used at the same time, providing maximum amount of shading.
For example, if you want to have five shading levels, you can set up your shading curtains to look like this.
- Level 1 shading – light weight curtain 50% covered – heavy weight curtain 0% covered
- Level 2 shading – light weight curtain 100% covered – heavy weight curtain 0% covered
- Level 3 shading – light weight curtain 0% covered – heavy weight curtain 100% covered
- Level 4 shading – light weight curtain 50% covered – heavy weight curtain 100 % covered
- Level 5 shading – light weight curtain 100% covered – heavy weight curtain 100 % covered
A more detailed example of the dual motor control can be found here.