Making Sense of Energy Information Energy monitoring system provides simple, easy to comprehend, visual tools to identify anomalies.

Abhay Ambati PMP, CEA, LEED GA Noveda Technologies

My office colleague has an energy monitoring system installed at his residence. While reviewing daily profiles of the electric loads he was monitoring at home, he noticed his son’s bedroom load ramp up at around 10 PM and subside by 6 AM. Perhaps his son’s electronic gadgets were to blame for this peculiar trend! Besides behavioral changes which can be brought about by using real-time energy information, there are several ways to monitor, trend and analyze energy information in a commercial setting which can catalyze effective decision making.

In many fields, monetizing big data still remains a challenging task to accomplish. For instance, in spite of petabytes of user data Facebook still struggles to come up with an effective model to monetize data amongst the advertising community. Compared to the length and breadth of user information at Facebook’s disposal, building energy information is relatively easier to tame and monetize.

I believe that the building operations team comprising of an energy manager, property manager, MEP technician, supervisor etc. is the best judge to determine the energy points to monitor, analyze data and take appropriate actions to reduce building’s energy footprint. A reduction in energy use boils down to lower OPEX, lower cap rates and higher asset values. On a portfolio level, energy information can also help develop better energy procurement strategies, re-evaluate utility tariffs, benchmark energy, address retrofit measures etc.  

While monitoring energy, some of the interesting observations made are listed below. Not only are the cases interesting, but addressing them led to immediate positive financial impact.  

1. One of the projects where we monitor heating BTUs generated from the building’s Solar Thermal system showed BTU generation during night time!  Further investigation revealed that the solar thermal circulation pump was not working. A work order was issued by the building operations team to fix it. Solar thermal system was designed to offset gas boiler usage for domestic hot water (DHW). A non-functional pump put the entire DHW load on the boilers thereby increasing gas usage as well as increasing the payback period of the solar thermal system. Early detection of this issue saved future losses.

2. Similar to previous example, water monitoring in a building revealed non-functional rainwater harvesting circulation pump.  Rainwater harvesting systems are expensive to install. A non-functional system only prolongs water savings and payback periods.
   

3. While validating data for a school, we observed a general trend of 20-30% reduction in energy usage during weekends as opposed to weekdays . However, this trend changed after some time. We started noticing a relatively flat energy profile with no considerable drop in energy consumption over weekends. Being a school which is operational on weekdays only, this new trend raised a red flag. Further investigation revealed that the thermostat setpoints and AHU schedules were changed a couple of days back because of a weekend event. However, the settings were never reverted to weekend schedule after the event. Hence, a flat energy profile. In the absence of real time energy monitoring, it would have taken a smart building technician a fair deal of time and effort to identify this issue using the utility bills.

4. One of our bigger clients has a highly sophisticated BMS system installed at one of its campuses comprising of five buildings. We used the BMS to acquire data from building mains and its sub-meters. After looking at the data collectively, the math simply didn’t add up! The electrical consumption being registered by the building mains meters was not even close to the number we get by adding the sub-meters. Closer examination by the building BMS team revealed that the DDC wasn’t performing as expected. The BMS had the ability to raise an alert if the metering points are defective. However, the BMS did not have the ability to raise a flag if the sensor detecting electrical consumption at the meter level is not calibrated right, which happened to be the issue in this case. Energy monitoring system provides simple, easy to comprehend, visual tools to identify anomalies. 

5. Using longitudinal benchmarking method² wherein we compare current year consumption data to baseline year, it came to our attention that during one of the peak summer months, the current monthly electrical consumption was about 30% lower than baseline year consumption. Interestingly, the Cooling Degree Days (CDD) for current and baseline year were comparable, but consumption was not. On examining the actual electric utility bills of baseline year, a discrepancy was noted! For some reason, the billing total kWh was much higher than actual metered readings which led to the jump in consumption and monthly expense. While we cannot comment on how and why the billing discrepancy crept in, but consumption trending and related analytics indirectly helped identify the discrepancy.
   

6. A common oversight by building operations team is to assume all building sensors and actuators are working as per design on an ongoing basis. On one of our highly sub-metered building, we could see a mild load on the site lighting panel during daytime. Though the panels were equipped with photo-sensors which would control site light on/off based on solar irradiance levels, a defective sensor remained undetected. The anomaly was easily detected while monitoring individual load profiles and fixed right away.

Information is power, only if we have access to critical information and know what to be looking for. The building operations team knows what to look for, but don’t have a cheap tool at hand to access that piece of information. Energy monitoring happens to close that missing link.
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¹ The nuts and bolts of Solar Thermal System are detailed out in Solar Thermal and Photovoltaic Systems 2007 by Pacific Northwest National Laboratory and Oak Ridge National Laboratory

² The method is detailed further in Energy Information Handbook 2011 – Application for Energy –Efficient Building Operations, by Berkeley Labs and United States Department of Energy

About the Author

Abhay Ambati, PMP, CEA, LEED GA - Noveda Technologies

Abhay is a project manager with Noveda Technologies. He works with clients worldwide to deploy and commission a comprehensive data acquisition system, custom design appropriate energy analytics and enable them to take effective decisions to forward their sustainability goals.

Noveda Technologies is an innovative leader in real-time, web-based energy and water monitoring. The company’s patented software solutions help reduce energy and water usage, optimize performance of renewable energy systems, and reduce the carbon footprint for customers across commercial, retail, government, education, and utility sectors. Noveda also offers sustainability communication tools that leverage social media to educate and empower stakeholder communities and make the smart grid a reality today.  The company has users in over 33 countries with offices in the US, UK, India and Israel.

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