Energy Monitoring at PECI—Why Do We Care?

Here at PECI we take energy use seriously.  In fact, we monitor exactly how much energy we use in our office space.  This isn’t unusual, as many newer buildings have this capability, and even some older buildings have been upgraded to be able to do this.  But we are unique with respect to the level of detail we have with our ability to monitor how much energy we use. 

Unless a building was built with energy monitoring capability in mind from the start, adding this capability can be difficult and expensive.  Buildings that add this capability will typically install a smart meter provided by their local utility company which provides overall or “whole building” energy use data which can be used to compare building energy use to other buildings.  Capability may also be added to monitor specific end use energy within a building by adding similar sub-meters.   This is a photo of a smart meter installed by a utility company.

Source: Flickr: miheco

With one of these meters installed, it’s possible to monitor how much electricity the building is using at any time as well as trend the data over time.  But this information is usually maintained by the utility company.

If a building has energy monitoring capability beyond just a smart meter, it may only have monitoring on the primary panels in the building.  As certain panels are dedicated to lighting, HVAC, and plug loads, for example, the best they can do is monitor the energy use by these categories.  Although this is excellent information to have, it doesn’t provide energy use information in much detail.  For example, it couldn’t tell you how much energy was being used by one electrical circuit or even a combination of circuits within a panel.

PECI's First & Main offices is somewhat unique in our energy monitoring capability.  We have the capability to monitor energy use at almost every circuit in our office.  Whereas most buildings that monitor energy use monitor only whole building energy or, at best, energy use by category such as HVAC or lighting (depending on how their electrical panels are laid out), we monitor over 500 points.  Each of these ‘points’ is a single circuit in our office space.  Here's a photo showing one of the electrical panels in our office with individual circuit monitors.

To be honest, this level of detail is almost too much.  We don’t necessarily care to monitor each circuit’s energy use.  But what we can do is combine points into groups that are useful.  For example combining all of the HVAC, lighting, and plug load circuits on one floor can allow us to compare energy use in these three areas by floor.  We can also divide up a floor into multiple zones, and look at the HVAC, lighting, and plug load energy use by zone.  This could be useful if, for example, we want to see how the office cooling load may shift from the East side of the building to the West side throughout the day.

PECI has also installed its own software to monitor and analyze the energy use data we collect.  Our system, called the Pulse Energy Monitoring System, collects all of our energy use data and presents this information in a very user-friendly format.  We can log into the system and view real time energy use data, and also trend energy use data over time.  It can even predict our energy use based on historical data it has collected and outside air conditions.

Here's a screenshot of the Pulse Energy Monitoring System software showing HVAC energy use by floor over several days.  You can see energy use peaks during the weekdays and drops off to zero at night and on weekends. 

This begs the question: why are we collecting all this information and how are we using it? Well, we are collecting it because, as I mentioned in my first blog post, we consider our office space at PECI to be a living laboratory.  We talk about energy efficiency programs and measures, and it’s useful to be able to monitor energy use to determine how these measures are working.  Reviewing this information can be a useful tool to determine if our HVAC, lighting, and plug load controls are working properly.  If we notice an unusually high amount of energy use at night for example, when systems should be turned off, this would be an indication that something in the building controls system may not be working properly.  Therefore, it’s an effective way to make qualitative observations about how our systems are performing and correct operational issues more quickly. In addition, it has allowed us to determine that our lighting energy use is around 0.5 Watts per square foot, approximately 40% better than code. Similarly, it has allowed us to determine that we have a reduction in plug load energy use of about 54% when our office is unoccupied.

I know I just skimmed the surface of our energy monitoring system and capability at PECI, but I hope it helped you understand a little more about what an energy monitoring system is and how we can use the information it provides.