Building Management

A BEMS Benefit: HVAC and Electrical Cooperation

In my last post, I talked about how software and BEMS can make a building more comfortable and its occupants more productive. Here I’m going to discuss how a building energy management system, aka a BEMS, can improve cooperation between your electrical service and heating, ventilation and air conditioning (HVAC).

Getting those two systems to play better together is important. HVAC systems run on electricity and so it is critical. Indeed, as much as 40% of all unscheduled HVAC downtime is due to power quality issues such as transients, swells, under/over voltage and harmonic distortions.

Power problems can do more than just temporarily knock HVAC equipment offline. Quality issues can damage control circuits and other electrical components, leading to repair bills that range from a few hundred dollars for a motor to almost $10,000 for an entire rooftop unit. Even if power fluctuations don’t cause immediate downtime, they could shorten the 15-year typical lifespan of such units. So, power fluctuations should be accounted for and their effects minimized as much as possible.

OK, you may be saying, I get that electrical quality is important. But, what can I do about it?

Quite a lot. While some of these problems are from the incoming supply, many electrical quality issues are caused by what’s inside a building. Specifically, problems can arise from equipment switching on or off. The inrush of current as a motor, transformer or power converter starts up can be many times the steady-state load. The power draw of a server can be much higher under full load than it is at other, less busy times. Satisfying these temporary demand surges can impact electrical quality.

Even office equipment can contribute significantly to fluctuations in the overall load and thereby impact power. That’s not surprising since such plug loads can represent up to half of the electrical demand in buildings. If a building’s occupants all show up and switch on everything from printers to monitors to computers and more at about the same time, the spike in power can be significant.

Given this situation, a properly designed and deployed BEMS can mitigate electrical quality shortcomings. As noted in the Navigant Research Leaderboard Report: Building Energy Management Systems, a BEMS directs “automated and/or manual improvements to system operations.” One of those operational units is the HVAC system. If the BEMS is state-of-the-art, with such capabilities as full IP connectivity, then a building energy management system can lead to more efficient operation – and an improved response to power fluctuations.

What’s needed to accomplish the last item is a way to handle electrical quality issues, which is best done via software that monitors power distribution. With that, you can identify problems early and as they occur, thereby minimizing any damage and resulting downtime. Linking HVAC and power together through the right software also allows for the generation of a series of analytics. These can be used to manage resources and assets, as well as electrical demand and supply.

To see how this works, look at SmartStruxure. Our BEMS for large buildings, it can be teamed up with our software for power distribution, called Power Manager.

The result is more cooperation between HVAC and electrical systems, resulting in less downtime and lower expenses. You also get greater workplace efficiency and a more optimized structure. You can, for example, get the most out of the fact that people never use all the space in a building, which means you can put what would otherwise be a wasted 5-10% to some use or, at the very least, not have it consume resources.

The hardware, software and services outlined in this series can be extended to the developing world, enabling greater efficiency, increased comfort and higher productivity.

 

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