Cooling

 

Technically, three methods are used for cooling and reducing greenhouse temperatures:
 
Air exchange between the air inside the greenhouse and the outside atmosphere.
This exchange is accomplished either passively through roof and side vents, or actively by operating  ventilators that increase the rate of air exchange when natural  air exchange is insufficient for the plant’s requirements.

Adiabatic cooling, which increases the humidity while lowering the temperature inside the greenhouse. Coolnet foggers or wet pads are used for this process.

1. Coolnet
A super-fine mist sprayer is highly suitable for rooting. Does not wet crop leaves, Operates at accepted working pressures.
Delivers an ultra-small drop size of 80 microns at a pressure of 4 bars. Used in extremely short water bursts, it can reduce the ambient temperature by 5-10°C (depending on atmospheric conditions, relative humidity and/or temperature).
·         Acid resistant.
·         Fogs at any pressure.
·         Can be used for chemical applications.
Coolnet’s complete system includes;
         Coolnet emitters with micro-sized droplets of 80-90 micron at 4 bar
         AD (anti drainage) valve
         Fans
         Pipe system for water supply
2. Wet Pad
The wet pad system includes:
         Wet pad
         Fans
         Pipe for water dispersion over the wet pad
         Submerged pump
         Water tank
         Pipe system for water supply
 
Reducing radiation penetration uses stationary or movable shade screens. Radiation causes the greenhouse space to heat up (the greenhouse effect). By reducing the intensity of radiation penetration, the heat inside the greenhouse is decreased. Radiation reduction also cuts down light penetration, essential to the plant’s photosynthesis process. This conflict can be optimized by using moveable screens operated automatically or manually, and/or screens with relatively low shading percentages.
 
The shading rate can be adjusted to between 20% and 80% depending on climatic conditions and type of crop. House plants, for example, will have relatively high shading levels in comparison with vegetables.

The most common shade screens are black. However, it was recently found that by Colorshadenets, which change the light spectrum while retaining the same level of shading, can reduce radiation penetration and influence morphological changes in a large range of plant varieties.