EMAIL INTERVIEW – Dave Savage and Ken Sinclair

Dave Savage, Senior Director, Field Services Business Development, EcoBuilding Division, Schneider Electric

Dave Savage is a Senior Director of Field Services Business Development within the EcoBuilding division of Schneider Electric; he supports the deployment of advanced service solutions for energy efficient, comfortable and reliable facilities. Dave has over 38 years of experience with Schneider-Electric in the building controls industry, starting with the first generation of computer-based building energy management. He studied Building Services Design at Newcastle College of Arts and Technology in the United Kingdom and has experience spanning systems design, site project management, solution sales, product development and marketing.

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LinkedIn: https://uk.linkedin.com/in/dave-savage-6583579
Schneider Electric Blog: http://blog.schneider-electric.com/author/dsavage/

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Sinclair:  Given the rapid rate of progress in the buildings industry, why are reactive service models ineffective?

Savage:  While building management systems (BMS) can deliver innumerable benefits to the facilities staff that maintain them and to the businesses that they support, they are also inherently complex investments that require services expertise to maintain. Neglecting regular maintenance negatively impacts building performance and business operations through increased system failure and repair costs. 55 per cent of US building owners and operators rely on reactive maintenance, otherwise known as the ‘run around and put out fires’ approach. This approach all but guarantees downtime and maximum repair costs.

An effective BMS requires vigilance, since the BMS is only as healthy as the equipment and sensors that compose it. If these devices fail, so does your BMS. A perfect example of regular maintenance that is routinely ignored in reactive service models (and has potential for significant impact to the BMS) is hiding right in plain sight: HVAC system control valves and actuators.

Sinclair:  How is it that valves and actuators are often overlooked if their failure has the potential for significant impact to the BMS?

Savage:  Many facility managers figure that since their valves aren’t the big expensive chillers and pumps, they can rely solely on the naked-eye maintenance method.Most service contracts focus more on electrical components where it’s easier to see power usage and cost. But the simplicity of valves and actuators is deceiving: With potentially thousands of them spread throughout a building, the sheer number alone make proper maintenance a challenge.

Valves and actuators do an incredible amount of work in a building. The HVAC system, which on average eats 35 per cent of energy use, thermal energy runs through these devices. Energy use isn’t the only performance indicator tied to valves and actuators.Valves and actuators also form the foundation of an effective BMS; they’re the first line of defense when something goes wrong. In fact, these simple devices are often the root cause of serious problems such as poor equipment performance, unproductive maintenance calls, and unexplained rising energy use.

The bottom line: If HVAC control valves are not operating correctly, the building could be using much more energy than it should.

Sinclair:  What are the most common valve and actuator issues picked up by facility managers?

Savage:  The six most common problems that occur in both valves and actuators the building control systems that regulate them can cause energy waste, unnecessary equipment wear, poor occupant comfort or other costly headaches.

1. Damage to valve internals and seals: While a leaky seal may not sound like a big deal, it can create situations such as simultaneous heating and cooling. These issues are hard to detect because the system achieves desired temperature, but over time they can waste tens of thousands in energy costs.
2. Control loop hunting: Incorrectly set proportional-integral-derivative (PID) control loop parameters are hard to spot, but they can create a large amount of energy waste. Why? When heating and cooling valves overshoot set points, they can cycle from closed to 100 per cent open over and over again (hunting) to hit that set point, which is extremely inefficient.
3. Electrical noise in the control signal: A poor wiring job creates interference and impairs communication between valves and other systems. This issue can lead to premature equipment failure and energy waste.
4. Incorrect valve sizing and sensor-to-room pairing: During installation, sometimes the wrong size of valve can be selected or calibrate the sensor poorly. Over time these inconspicuous errors lead to major waste.
5. Too much pressure at valve inlets: When there is too much pressure at the valve inlet for example due to other valve positions affecting pressure, flow rates and pressure drops change from the initial design resulting in impaired valve operation and energy efficiency.
6. Seasonal temperature changes: As seasons change, the system set points and control parameters should be tuned to the new conditions, as part of this control loops PID settings and valve and actuators should be re-calibrated to maximize energy efficiency.
   

Sinclair:  How can technology and new approaches to service help address these problems?

Savage:  As BMS tools become more robust, many facility managers are using predictive maintenance to monitor individual valves, actuators, and other equipment in ways that humans alone simply can’t afford to do. This up-and-coming service trend has been fueled by energy-efficient building certification requirements and more stringent energy savings mandates. Predictive maintenance, sometimes referred to as continuous or monitoring-based commissioning (MBCx), is a strategy that leverages cloud-based data collection and analytics to enhance performance around the clock.

With these predictive analytics tools, BMS proactively alert facility managers to problems before they bring down the bottom line — or the HVAC system. These tools can spot leaky valves, control loop hunting, control signal noise and much more. Once they spot the problem, they also provide actionable data on how to fix it.

Download my white paper, “Valves and Actuators: Maintaining the Foundation of High Performance Buildings” to learn more.