Manufacturers’ tips and tricks for commissioning, balancing buildings
CSE: What’s the one factor most commonly overlooked when commissioning electrical system projects?
Onset: Commissioning projects that focus on electrical systems often focus at a high level and never probe down to focus on which specific pieces of equipment or areas of a building are using a disproportionate amount of energy. We’ve found there is tremendous value in the right amount of sub-metering for this purpose. It is easy to look at whole building energy use and even to meter the energy use on some of the known high consuming engines within a building, but a lot can be learned from monitoring the kilowatt-hours consumed by various sub-metered circuits within your facility. Sub-metering for temporary commissioning doesn’t have to be complex or overly expensive. Just using a combination of an energy sensor, like the Wattnode in conjunction with our HOBO UX90 Pulse data logger can get you a lot of insight about how much a specific piece of equipment is using and help you formulate whether or not its energy consumed is proportionally relevant to the whole building energy use.
Fluke: The best way to assess an electrical system is to do so while it is in operation. This is where the value of non-contact temperature measurement can shine. Using an IR thermometer or a thermal imager to scan a circuit breaker can reveal overloaded devices, faulty connections, or weak connections. Similarly, scanning electrical insulation material could show movement of heat, revealing either faulty insulation or thermal bridging.
CSE: What unique requirements do HVAC systems have, and what commissioning questions/issues have you helped resolve?
Fluke: HVAC is tricky for many reasons. First, as mentioned earlier, when an HVAC system is active it changes the thermal patterns. So it must be characterized while it is operating, and under various conditions. Second, the weather outside affects the HVAC system more than might be believed. For example, wind will cool (or heat) surfaces. For these and other reasons, a professional thermographer could help characterize a building both during construction and following construction.
Onset: HVAC systems are unique for a couple of reasons; the first being that they come in a wide range of capabilities, sizes, and locations. For example, the modern-day HVAC unit is highly automated and programmed to respond differently based on the climate outdoors, while many buildings are still operating using a 15 or 20 year old HVAC unit that requires manual intervention when the weather pattern changes to accommodate a new damper position, or may not have a variable damper at all. You may also have entire equipment rooms dedicated for an HVAC unit, or you may find you have to climb on top of the roof to get a look at your HVAC. The second thing that is unique about HVAC systems is that to get a full picture of the way they are functioning means combining a variety of measurements together (temperature, relative humidity, kWh, and air quality parameters). While you certainly don’t have to measure all of those things with each commissioning project, it is entirely possible that you’ll want to measure multiple temperature points (inlets, outlets, evaporator performance, etc.). To satisfy both of these unique characteristics, means you want to be prepared with an adequate tool kit of options to complete your commissioning project successfully. You have to be prepared to measure energy as well as relative humidity and be prepared to do that for everything from a modern, programmable indoor unit or an archaic roof-top unit.
CSE: The public comment period has closed, but what’s your opinion about the International Accreditation Service's (IAS) Commissioning Accreditation Criteria, AC476, Proposed Accreditation Criteria For Organizations Providing Training And/Or Certification Of Commissioning Personnel?
Onset: Building commissioning is an investment that building owners, facility managers, and consulting firms alike need to consider as an ongoing process that should be measured to accurately track results. It is clear that to make this process a financially viable investment, the implementers need to be trained to do the job correctly. With so many different parameters to consider in a commissioning project (from lighting to comfort to HVAC), it is challenging for industry professionals to always be aware of local requirements, let alone broader industry standards. For this reason, the IAS recommendation for accreditation criteria is valuable to assuring that building owners and operators are provided with a high-value-add procedure when they choose to invest in a commissioning project. The challenge for this accreditation will be how it can seamlessly integrate with other standards that exist without causing undue burden on the relatively small commissioning agencies that require these projects to maintain a thriving business. Many commissioning projects with the highest return are run by relatively small, independent consulting firms that need to minimize their everyday expenses to be successful. Time away from the office for further accreditations might drive hardship to these businesses that could threaten their livelihood. On the flipside, we’ve all heard of failed commissioning projects that no doubt would have been significantly more successful had there not been such a lack of education available to the commissioning market. Driving an accreditation process can help avoid those commissioning pitfalls and also protect consumers from investing with firms that have neglected to stay on top of their field.