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Home > Design Technical > Guidelines for Climate Control of Temperature and Humidity in Greenhouses

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 NaanDanJain 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 (1 cm3). 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.
Efficiency of the cooling system depends on two environmental factors:
- External temperature
- External humidity

An efficient ventilation system which 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.

With a 7 l/h nozzle at 4 kg/cm², the average fog droplet is 90 microns. These droplets evaporate without wetting the leaves or greenhouse floor.

Type	Fogger Configuration	Nozzle	Flow Rate	Spacing		Precipitation Rate
Type	Fogger Configuration	Nozzle	Flow Rate	Between Laterals	On the line	Precipitation Rate
Fogger	T	7.0 x 2	14	3.0	1.5	3.1
Fogger	Cross	7.0 x 4	28	3.0	3.0	3.1
Super Fogger	T	6.5 x 2	13	3.0	1.5	2.9
The foggers should be installed in as high as possible, with minimal height being 3.0 m. The nozzles should be situated perpendicularly to the main line. Operating pressure: 4.0 kg/cm² at the fogger.

In our experience, a fog precipitation of 3 to 3.5 mm/h is suitable in the majority of cases (3 mm/h = 30 m3/h per ha.)

(meter cube per hectare per 10 hour/day)

Nozzle l/hr	Model configuration	Net precipitation, (l/hr/m² for various spacing & pulses)
Nozzle l/hr	Model configuration	3.0 x 1.5 m			3.0 x 3.0
Fogger
		1:5*	1:10	1:15	1:5	1:10	1:15
Blue 7.0 x 2	T	0.62	0.31	0.21
Blue 7.0 x 4	cross				0.62	0.31	0.21
Water consumption m³/ha/day (10 hour)		62	31	21	62	31	21
Super Fogger
6.5 x 2	T	0.58	0.29	0.19	* On: Off pulse ratio Example: ratio 1:5 The system will operate only fifth of the time so the actual precipitation will be only 20%, or 10% for ratio 1:10
Water consumption m³/ha/day (10 hour)		58	29	19

The pulse duration should be as short as possible, between 1 to 3 sec. (Under certain conditions, longer durations can be considered).
The interval between fogging pulses should be based on the factors of humidity, temperature levels, greenhouse ventilation and height of the foggers.

In the event that the humidity level needs to be increased then the ventilation system must be shut down. The duration of the fogging process should be as short as possible (1.0 second).
The intervals between fogging pulses will vary according to the minimal relative humidity required.
During the morning, when temperatures rise and humidity decreases, the humidity sensor will cause the fogging system to operate.

In the event that the humidity level needs to be increased then the ventilation system must be shut down. The duration of the fogging process should be as short as possible (1.0 second).

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.