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Timer
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15-minute adjustable type, attached to remote control valve (solenoid). Aim to sprinkle cows for 1-3 minutes, which should be sufficient to wet the cow effectively, and then shut off for the remainder of each 15-minute cycle to allow the water to evaporate prior to the next cycle.
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Remote Control
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Set to shut off sprinklers and fans at below 26oC to minimise risk of chilling if is high air movement (Sprinklers are not suitable for young stock because of the danger of wetting animals and they should not be used if the risk of chilling is too great)
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Pipes
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Sizes to suit the length and area to be sprinkled, the number of sprinklers and their flow rates (assuming use of poly or PVC pipe and a good-quality water supply).
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Shed length
Up to 40 metres
40 – 60 metres
60 – 100 metres
Over 100 metres
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Diameter of main delivery line
20 mm
25 mm
32 mm
2 x 50m runs of 25mm
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A roof over the area where cows are to be spray cooled is ideal, so as to eliminate solar radiation, as is a concrete floor with facilities to collect and handle run-off.
PVC piping does not twist but polypiping is cheaper.
To maintain low temperatures, all exposed pipe should be painted white and header tanks should also be shrouded, insulated and painted white.
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Pressure Regulators
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Low pressure sprinklers work best (0.70 kg/cm2). Less velocity will give less mist and drift of spray. A main pressure regulator can be installed at the beginning of the pipeline. Operating pressures are usually in the range of 14 to 20m (140 – 200 kPa)
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Sprinkler Nozzles
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Should be spaced at twice the radius of their throw (for 1.2m radius, space nozzles every 2.4 m)
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Filter
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Sand or dirt may clog the nozzles, so a filter is required between the water supply and solenoid valves which control the water flow to the spray nozzles or drip outlets. A common filter type is a plastic filter with a grooved disc filter element. A 200 micron filter is used for spray cooling and an 80 micron filter for drip cooling. Filters should be capable of a flow rate of up to 1.4 litres per second for spray and 0.8 for drippers
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Water
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Water containing more than 1000 mg/l TDS should not be used in reticulation systems because of corrosion (dissolves concrete!)
An allowance of 0.5-1 litre per head per hour is common for spray cooling dairy cows.
Remember that excess water use will create issues with waste management.
For more complex or larger installations it is necessary to properly design the system taking into account friction losses, flow rates and component selection
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