Data Loggers Investigate Energy Waste in Indiana School District
With a degree in Industrial Technology, Rob Lovett, a teacher for nine years with the Penn-Harris-Madison (PHM) School Corporation in Mishawaka, Indiana, was the natural choice when, in 2007, the corporation decided to create a position for a full-time Energy Educator/Manager. At that time the scope of Lovett’s responsibility expanded from the fifth-grade classroom to the entire PHM school district, which includes 20 buildings, ranging in size from 1,600 square feet to 581,000 square feet, for a total of 1.9 million square feet of buildings.
As an energy manager, Lovett’s main focus is to identify opportunities to reduce energy use and costs for the corporation, whose utility bills add up to about $2 million a year. He finds these opportunities by monitoring the buildings – both by walking around to see “what’s on and whether it should be on” and by analyzing data recorded by HOBO® data loggers from Massachusetts-based Onset Computer Corporation. Lovett deploys the loggers for two-week time periods at various locations throughout the schools, either in known or suspected problem areas, or just to conduct random checks to verify equipment operation.
As an energy educator, Lovett visits classrooms from time to time throughout the school year to talk to the students about energy conservation, but says that the education aspect of the job pertains more to ensuring that the staff understands what they need to do to save energy, as well as the importance of their actions. While HOBO data loggers provide the temperature and humidity data that Lovett needs to do his job as an energy manager, they also provide the benefit of “increasing the awareness of energy conservation for the corporation.” Their very presence in a classroom or other school space heightens staff attentiveness with respect to appropriate thermostat and lights control, opening/closing windows and doors, and raising/lowering blinds. Fortunately, the energy-conscious behavior that’s displayed while a data logger is situated in a particular location tends to become habit – perhaps in part because staff members know that that “energy pincher” Lovett is like a detective on the lookout, who could be back at any time to conduct another two-week data logger study of their classrooms.
Energy Education, the consulting firm that helped the PHM school system start up its energy management program, supplied two HOBO data loggers as part of an initial “tool kit.” The PHM soon purchased additional loggers and now owns one per building, as well as a data “shuttle” that Lovett uses to offload the recorded information from the logger, and HOBOware Pro software to graph the data.
The loggers' portability is a great advantage for Lovett, who moves them from room to room every two weeks. He says that the HOBOs are “…a great way to just keep an eye out, to be in places that I can’t be, because as an energy manager you want to be able to see it all.” Lovett notes too that the shuttle is extremely valuable because he no longer has to bring his laptop with him to each monitoring location to retrieve data. Instead, the shuttle device offloads the data and re-launches the logger automatically before it’s moved to a new location. Lovett can then take the graphed information from about ten loggers at once and transfer it to the computer in his office for analysis.
When deploying a data logger in a classroom, Lovett leaves a note informing the teacher of the logger’s location – generally in a visible spot, but preferably beyond the reach of most students. He also offers to share data from the logger with the teacher and students and provides contact information to answer any questions they might have. The HOBOs are set to record temperature, relative humidity, and light intensity at ten-minute intervals for a two-week period, allowing Lovett to collect information pertaining to occupied/non-occupied and weekday/weekend conditions.
Lovett also uses the HOBOs for routine verification of equipment operation, such as confirming that an Energy Management System (EMS) is starting up or shutting down a heating system on schedule and maintaining a comfortable temperature range of 68ºF to 72ºF when a building is occupied. His use of a date logger helped him to discover that the EMS in one of the schools was running until 5:00 p.m., about an hour later than necessary. In another instance, Lovett was able to make a correction after using a data logger to detect that the EMS’s calculated optimal start in two of the corporation’s largest buildings was overshooting the schedule and heating the space unnecessarily for five hours before the school day begins. In spring, summer, and fall, he uses the loggers to look at humidity, with the goal of running the air-conditioning the minimal amount of time necessary to achieve a comfortable 40% relative humidity and avoid conditions that could lead to mold problems.
Currently, at the recommendation of the head custodian of the one of the middle schools, Lovett has a data logger deployed in a gymnasium which was previously heated using just one of two available air handler units, but now seems too cool even with both air handler units operating. Lovett suspects some kind of maintenance problem, but notes that the first step is to “get that logger in there and see what’s going on.”
Another case involves two identical elementary school buildings in the PHM School Corporation. The schools are located only a few miles apart, were built around the same time, and contain the same equipment, except one has a central vacuum system, which has been shut off. Although both schools use about the same amount of electricity, the one with the central vacuum system has been using 200% more natural gas than the other to achieve similar temperatures. Lovett noticed that a significantly greater number of icicles form along the roof line of the school that uses more natural gas, which led him to suspect that it might not be as well insulated as the other school. Because it’s not practical to visually inspect the roof of an industrial building for insulation, Lovett deployed a HOBO data logger in the space above the ceiling tiles in identical locations of each building. The answer to this mystery is yet to be solved, but if it turns out that the temperature is warmer in the building that uses more natural gas, Lovett can conclude that it’s not as well insulated as its twin and work toward correcting the problem.
Between Lovett walking the beat at various hours of the day and night to directly observe conditions at the school buildings and the dedicated HOBOs steadfastly logging data for his analysis, from January 2007 to December 2010 the PHM School Corporation realized a savings of $2,110,212 in energy costs.