Wetted Surface – Adiabatic Coolers
Wetted surface – Adiabatic Cooling enables water to be cooled to within 6 °C of ambient wet bulb, water is used to increase the cooling effect when the ambient dry bulb is 3°C above the design wet bulb – for most of the year the unit operates as a conventional Dry Air Cooler.
Therefore with a design ambient of 20 °C wet bulb it is possible to achieve fluid outlet temperatures of
The water is only needed when the load and ambient dry bulb temperature exceeds a predetermined set point, with very few hours of wetted surface operation over a year.
The question of causing possible conditions for legionella is no more than that of normal climate conditions of rain. The water used for wetting is quite small and is totally lost, not recycled or retained. Regional weather data analysis shows a typical 120 hours per year when ambient exceed 22 ° C.
The V configuration Dry Air Coolers can be adapted to take advantage of latent cooling effect in adverse conditions of high ambient dry bulb temperatures. Reversion back to dry air cooling takes place on lowering of temperature. All features of temperature control by fan off cycling with low or residential fan speeds are retained. The very large surface areas of the coils assure that evaporation takes place efficiently with the very minimum of wastage. The normal dry air cooler is regulated by fan off cycling by thermostat switches; a further thermostatic switch brings on the wetting cycle, only after all the fans are running.
The Wetted Surface option enables units to be economically sized for a lower ambient thus saving space and capital cost. Alternatively, units may be selected for cooling water solutions to a temperature below the ambient dry bulb approaching conditions near to evaporative towers.
The system comprises of sparge pipes with water distribution nozzles mounted on the air on face of the coils to effectively wet the coil surface, using mains pressure water @ 1 bar gauge, a water flow regulating valve, pressure gauge, mains water inlet solenoid valve, drain solenoid valve, purge timer and pressure gauge and manual drain points are fitted.
Connection to water mains requires a double check valve.
We would recommend that the coil fins are polyester coated to minimise any effect of corrosion.
Depending on the water quality it may also be necessary to fit a scale prevention device to the mains water supply.
- UV Ultra Violet Water Treatment
- Water Scale Prevention Device
- Mains Water Booster Pump