Fogger
Climate control in a greenhouse is based on the principle of the exchange of energy between the air and the fog moisture supplied by the Balson Fogger.
One calorie is the amount of heat necessary to raise the temperature of 1 cm³ of water by 1° C.
The conversion of water from liquid to vapor absorbs heat from the surrounding air, at a rate of 590 calories/1 gram of evaporated water. This process lowers the air temperature.
Efficient installation and operation can reduce the temperature in the greenhouse by 4 to 6° C, depending on the environmental conditions. The efficiency of the cooling system depends on two environmental factors:
– External temperature
– External humidity
Essential conditions for efficient cooling with the Balson Fogger are:
-An efficient ventilation system that continuously introduces external dry air into the greenhouse to replace the humid air.
-Pulse operation of the fogging system, to minimize the amount of water that may settle on the foliage.
How much water is needed to cool a greenhouse?
In our experience, fog precipitation of 2.5 to 3 mm/h is suitable in the majority of cases (3 mm/h = 30 m³/h per ha.)
How to choose the fogging duration and the interval between fogging pulses?
The interval between fogging pulses is set at 10 seconds. The duration of fogging depends on the air velocity created by the ventilation system.
Cooling
Determining the fogging duration
| Air velocity | Interval | Duration |
|---|---|---|
| 0.10 m/s | 10 seconds | 1 – 2 seconds |
| 0.50 m/s | 10 seconds | 3 – 5 seconds |
| 1.0 m/s | 10 seconds | 10 seconds |
A controller will be installed to manage these pulsations. The controller will be connected to temperature and humidity sensors. Due to the short intervals between fogging pulses, the Balson Fogger should be installed with an anti-drainage device. This will ensure that all Foggers will start up and shut down quickly and simultaneously.
What is the importance of the droplet size created by the Balson Fogger?
What a 7 l/h nozzle at 4 bars, the average fog droplet is 90 microns. These droplets evaporate without wetting the leaves or the greenhouse floor.
Installation design of 7 l/h Balson Fogger (T-shape)
– Distance between lines: 3 m
– Distance between Foggers: 1.5 – 2 m
– The Foggers should be installed as high as possible above ground
– The Foggers should be mounted on a T, with two Foggers installed perpendicularly to the mainline (anti-twist PVC).
Cooling and humidifying cannot be conducted simultaneously.
Humidification
If we need to increase the humidity, ventilation must be shut down. The duration of fogging should be as short as possible (1 second). The intervals between fogging vary according to the minimum relative humidity required. In the morning, when temperatures rise and humidity decreases, the humidity sensor will start the fogging system.
Determining the interval between fogging
| Air velocity | Interval | Duration |
|---|---|---|
| 30 – 40% | 60 seconds | 1 second |
| 40 – 50% | 90 seconds | 1 second |
| 50 – 60% | 120 seconds | 1 second |
Spraying
Spraying pesticides through the Balson Fogger system has been tested successfully in various countries.
Water quality
In order to avoid clogging by carbonates or the accumulation of salt deposits on the leaves, it is recommended to avoid irrigation with hard or saline water. Rainwater, soft water, or osmosis-treated water is the most suitable.
Optional nozzles
| Colour | Blue | Orange | Red | Black |
|---|---|---|---|---|
| Flow rate 1/H at 0.4 bar | 7.0 | 14.0 | 21.0 | 28.0 |