Netafim COOLNET PRO, Руководство пользователя

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34 UPSIDE-DOWN MICRO-EMITTERS HANDBOOK
MICRO-SPRINKLERS/EMITTERS ASSORTMENT
Definition of the different applications and Installation recommendations
Cooling
Cooling, specifically evaporative cooling, i.e. small droplets of water sprayed into the atmosphere and
are supposed to change state of matter (as explained on page 7 ) and thus consume energy from the
environment (cooling it).
Netafim™ recommends that the system be run on one-second fixed pulses at the frequency determined
based upon an environmental-condition sensor that measures humidity and temperature.
NOTE
Optionally, the amount of water required to cool a certain volume of air under a variety of
environmental conditions can be calculated using the psychometric chart or one of the many on-line
calculators based on the same data (for example:
http://www.uigi.com/WebPsycH.html ).
To run the system at fixed pulses of 1 second each, pay attention to the following conditions:
• Be sure that the valve in charge of the operation can open and close within a second (not all hydraulic
valves meet this criterion).
• Be sure that the command system and solenoid activating the valve can open and close within a second
(not all controllers and solenoid systems are adapted to do this).
• The transportation and distribution system is to be hydraulically planned according to the needs and not
over-designed. If this system is larger than required, working pressure will be "trapped" and cause the
misters to work beyond their designed capacity.
• It is recommended to divide the total area (that will function together) into a number of sub-areas to
enable planning and execution using relatively small valves and distribution pipes. This will facilitate the
execution of planned operations.
• In addition to the hydraulic design recommendations, it is highly recommended to place the misters at
the highest point possible in the greenhouse to create an air volume as thick as possible between the
misters and the crop. The thicker the air volume the more likely the droplets will evaporate and not reach
the crop.
ATTENTION
This condition has one very important limitation: All the misters should be at the same height. For
example, if the greenhouse has a triangular roof, do not place some of the misters close to the
top and some of them near the base of that triangle. All the misters will need to be at the base of
the triangle.
Installation recommendations for cooling with the cross mister with 4 nozzles of 5.5 l/h each, with a
pressure of 4.0 bar at the nozzles:
3.0 x 3.0 meters (Can be placed at other distances in the same order of magnitude,
e.g. 2.5 x 3.5 or 2.8 x 3.2 meters), at the maximum height possible above the surface.
Installation recommendations for cooling with the "T" mister with 2 nozzles of 5.5 l/h each, with a
pressure of 4.0 bar at the nozzles:
3.0 meters between the misters on the same distribution pipe and one distribution pipe above the gap
between every two rows of crop, at the maximum possible height above the surface.
It is also possible, depending on climatic conditions, to place one distribution pipe above the gap between
two adjacent rows of crop, alternately skipping a gap.