As technology has developed, the fight against Legionella and its lurkings in water based air cooling systems has moved on too.
Previously manufacturers got away with all sorts of over complicated cooling setups – paying no heed to health and safety risks or the potential for outbreaks of respiratory illnesses like Legionnaire’s disease – but now it’s a different story. Local authorities and risk assessors stipulate stringent controls.
What’s different about our adiabatic products?
Our adiabatic coolers introduce a fine mist of water into an oncoming airstream to increase its relative humidity thereby reducing its temperature. They’re especially good for when required water temperatures can’t be achieved with dry air cooling alone.
Designed in conjunction with leading Legionella risk assessors from the Biological Agents Unit at the British Health and Safety Executive, our adiabatic coolers have so many safety measures and failsafe mechanisms, that – compared to a lot of our competitors – they don’t need to be registered with local authorities and don’t require regular ongoing chemical treatment.
This is confirmed in the latest HSE endorsed ‘The Control of Legionella in Dry/Wet Cooling Systems’.
This document also lays to rest any uncertainty surrounding certain ‘Hybrid Cooling Systems’. It essentially outlines that any alternative type of cooler that directly trickles water over heat exchange material or one which has a water collection basin or tank in order to recirculate the evaporative water, must be registered with a local authority and may need regular ongoing chemical treatment due to their higher risk nature.
Also making Transtherm products the better option, we have safety measures easily visible to the end user via a BMS (building management system) so that any faults can be detected and resolved swiftly and to the satisfaction of risk assessors.
The basics of how we ensure Legionella is eliminated:
1. Mains water is taken into our adiabatic systems and UV sterilised as standard, by a UV system that’s 99.999+% effective at killing all know strains of Legionella bacteria
2. The UV system is monitored by an integral control system and should any fault be picked up, the adiabatic system is shut down pending repair
3. An alarm signal is sent to the site BMS via a simple volt free contact or by using a Modbus signal from our PLC (programmable logic controller) allowing the customer to act quickly in order to keep their system running at optimum temperatures
4. If it is a particularly critical system (e.g. data centre cooling application) then we can also supply a standby UV system so the adiabatic system can keep running
Getting down to the adiabatic detail:
1. Mains water is pushed through spray nozzles into the oncoming air stream
2. The fine mist of water is easily evaporated into the airstream. To correctly control droplet size, we include an integral booster pump to achieve the correct pressure at the nozzles
3. Water droplets are typically circa 100µ to avoid smaller aerosol droplets of between 1-5µ as ASHRAE (American Society of Heating, Refrigeration and Air-Conditioning Engineers) warns that water droplets of between 1-5µ can be carried far enough into the human system for diseases to be contracted
4. Controls are in place to monitor the usage and health of these pumps as it’s vital that any issue is visible to the end user so optimum system performance and efficiency can be maintained
And for extra protection?
Our control systems incorporate PLCs (programmable logic controllers) that gather information for end user system operators showing outlet water temperature, unit input power and any fan inverter faults giving you complete peace of mind and Legionella risk cut to an absolute minimum.
