Real-time monitoring is enabling HVAC systems to operate more efficiently, reducing energy wastage, chemical use and maintenance costs, says Toby Hunt from Guardian Water Treatment.
Closed-circuit water systems provide cooling through the circulation of fluid within a sealed unit. The fluid never meets the air or external contaminants – at least in theory.
In practice, oxygen ingress is common within closed circuit systems. The subsequent corrosion issues can cost hundreds of thousands of pounds in increased running costs, replacement and repair of valuable plant equipment, and downtime – a concern for facilities managers and maintenance teams.
So, what can FMs do to combat corrosion?
Real-time corrosion monitoring technology offers a superior approach to FMs that want to regain control of their HVAC costs. The technology provides a one-off health check to give incoming FMs peace of mind or as a long-term solution to closed-circuit water system maintenance.
Far more effective than traditional sampling and corrosion coupons, it gives FMs access to the data and insights required to identify the root cause of a problem, allowing a swift response and resolution before further damage occurs.
1. Target dissolved oxygen (DO)
Monitoring oxygen is the most important action FMs can take to keep their HVAC systems healthy and operational. Oxygen is the precursor to all corrosion, either directly damaging pipework and components or by creating the perfect conditions for bacteria to thrive. Common problems include:
- Build-up of debris in pipes and components restricts the flow of water through the system, causing poor energy performance and increased running costs;
- Corrosion debris affecting the performance of heat exchangers and emitters;
- Erosion to valve seats causing changes in flow characteristics; and
- Leaks and general degradation to pipework and components.
These problems can only be prevented by continuously monitoring for DO – something that is not picked up by sampling and corrosion coupons. Early intervention is crucial to preventing major issues further down the line.
2. Monitor system pressure
Changes in pressure could indicate a leak in the system, risking oxygenation and water loss. Rather than waiting for a physical sign of system distress, real-time monitoring technology continuously monitors pressure to ensure the system is air-tight – particularly important following planned maintenance activities such as flushing.
3. No need to panic
With access to live data and insights, FMs can plan informed maintenance and avoid knee-jerk reactions. Using real-time data points, changes in condition can be attributed to planned events, such as routine maintenance, with the results monitored to prevent unnecessary interventions and costs.
If a problem escalates, corrosion monitoring technology can be used to identify the root cause and bring about a swift and necessary resolution.
4. Check the data
To truly combat corrosion, a combination of sophisticated data acquisition and intelligent analysis is required, leading to preventative maintenance regimes and fit-for-purpose water treatment.
Alongside DO levels and pressure checks, corrosion monitoring systems track a wide range of parameters that indicate a risk of corrosion, including:
- pH – a change in pH could be the first sign of problems with the water chemistry;
- Temperature – to ensure a system is operating effectively;
- Steel corrosion rate – measuring galvanic currents in proportion to DO and temperature indicates whether inhibitors are working correctly;
- Inhibitor/glycol concentration – chemical treatments are an essential part of closed-circuit system maintenance but to achieve optimum performance and sustainability a balance is required. Real-time access to inhibitor concentration levels gives FMs more control over water treatment products, reducing chemical waste and costs; and
- Crevice corrosion – early indication of this subtle but highly damaging form of corrosion means swift action can be taken on problem areas.
Live data is displayed on a user-friendly dashboard, accessed from a laptop or mobile device. Any event, whether planned or unplanned, is flagged on in-built charts, ensuring electronic records are easily accessible and all in one place.
Readings are colour-coded to indicate acceptable conditions, and proprietary algorithms provide intelligent insight and analysis. If any parameters fall below accepted levels, FMs are notified via SMS or email to ensure quick reaction to changes in condition.
Transparency and control
With real-time corrosion monitoring systems in place, FMs can be sure their system is working efficiently and that any problems will be swiftly identified and rectified in the most cost-effective way.