Modeling and Simulation of Evaporative Cooling System in Controlled Environment Greenhouse 71
Figure 6. Air flow rate of the fan.
Figure 7. Greenhouse relative humidity with PI controller.
settling time and good tracking performance.
An evaporative cooling system is presented, in this work,
to reduce the air temperature inside the greenhouse that
affects the greenhouse environment and consequently the
growing of cultivated plants. A control technique (PI
controller) is proposed to fix the greenhouse inside tem-
perature and relative humidity at the optimal values (i.e. ,
20˚C and 70% respectively) that are suitable for growing
of marjoram herb. The fine-tuned parameters of PI con-
troller are, Kp =10, KI = 0.0001, and Kp = 0.1, KI = 0.2
The proposed cooling system temperature controller is
designed to adjust the air volume flow rate of the fan by
adjusting the speed of the fan motor in pad-fan system; to
fix the greenhouse inside temperature at 20˚C. On the
other hand, the humidity controller operates between
dehumidify and humidify modes for removing unwanted
atmospheric moisture accumulating within the green-
house or to add the needed moisture to the air by means
of humidification, to fix the greenhouse inside relative
humidity at 70%. Also, a mathematical modeling and
MATLAB SIMULINK model for the different compo-
nents of the evaporative cooling system is presented in
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