Data loggers investigate energy waste in Indiana school district
With a degree in industrial technology, Rob Lovett, a teacher with the Penn-Harris-Madison (PHM) School Corporation in Mishawaka, Indiana, for nine years, was the logical choice when the corporation decided to create a full-time position for an energy education manager in 2007. At that point, Lovett's responsibilities expanded from the fifth-grade classroom to the entire PHM school district, which includes 20 buildings ranging from 1,600 square feet to 581,000 square feet, totaling 1.9 million square feet of buildings.
As energy manager, Lovett's main focus is to identify opportunities to reduce energy consumption and costs for the corporation, whose utility bills total about $2 million a year. He finds these opportunities by monitoring the buildings - both by walking around to see "what's on and if it should be on" and by analyzing data recorded by HOBO® data loggers. Lovett deploys the loggers for two weeks at various locations in the schools, either in known or suspected problem areas or simply to perform spot checks to verify equipment operation.
As an energy educator, Lovett visits classrooms from time to time during the school year to talk to students about energy conservation. However, he says the education aspect of the job is more focused on making sure the staff understands what they need to do to conserve energy, as well as the importance of their actions. While HOBO data loggers provide the temperature and humidity data Lovett needs to do his job as energy manager, they also provide the benefit of "raising awareness of energy conservation for the community." Their mere presence in a classroom or other school space increases staff awareness regarding appropriate thermostat and lighting control, opening/closing windows and doors, and raising/lowering blinds. Fortunately, the energy-conscious behavior exhibited while a data logger is placed in a particular location becomes habitual - perhaps in part because staff know that this "energy saver" Lovett is like a detective who could return 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 launch its energy management program, supplied two HOBO data loggers as part of an initial "tool kit." PHM soon purchased additional loggers and now has one per building, as well as a data "shuttle" that Lovett uses to download the recorded information from the logger, and HOBOware Pro software to graph the data.
The mobility of the loggers is a big advantage for Lovett, who moves them from room to room every two weeks. He says the HOBOs are "...a great way to just be on my toes, to be in places I can't be, because as an energy manager you want to be able to see everything." Lovett also notes that the shuttle is extremely valuable because he no longer has to carry his laptop to every monitoring location to retrieve data. Instead, the shuttle device downloads the data and automatically restarts the logger before moving it to a new location. Lovett can then retrieve the graphical information from around ten loggers simultaneously and transfer it to the computer in his office for analysis.
When Lovett places a data logger in a classroom, he leaves a note informing the teacher of the logger's location - usually in a visible place, but preferably out of the reach of most students. It 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, which allows Lovett to gather information on occupied/unoccupied 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 or shutting down a heating system on schedule and maintaining a comfortable temperature range of 20ºC to 22ºC when a building is occupied. By using a data logger, he discovered that the EMS in one of the schools ran until 17:00, about an hour longer than necessary. In another instance, after using a data logger, Lovett was able to determine that the optimal start calculated by the EMS in two of the organization's largest buildings exceeded the schedule and unnecessarily heated the space five hours before school started. In the spring, summer and fall, he uses the loggers to monitor humidity levels, with the goal of running the air conditioning for as short a time as possible to achieve a comfortable relative humidity of 40% and avoid conditions that could lead to mold problems.
Currently, at the recommendation of the superintendent of one of the middle schools, Lovett has placed a data logger in a gymnasium that was previously heated by only one of two available ventilation systems, but now appears too cool even with both ventilation systems operating. Lovett suspects a maintenance issue, 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 district. The schools are only a few miles apart, were built around the same time and have the same equipment, with the exception of a central vacuum system that was turned off. Although both schools use about the same amount of electricity, the school with the central vacuum system used 200% more natural gas than the other to reach similar temperatures. Lovett noticed that there were significantly more icicles at the roofline of the school using more natural gas, which led him to suspect that it may not be as well insulated as the other school. Since it's not practical to visually inspect the roof of an industrial building for insulation, Lovett placed a HOBO data logger in the space above the ceiling tiles at identical locations on each building. The answer to this mystery has yet to be found, but if it turns out that the temperature is warmer in the building that uses more natural gas, Lovett can conclude that it is not as well insulated as its twin and work to correct the problem.
Between Lovett's walk-throughs at various times of the day and night to directly observe conditions in the school buildings and the dedicated HOBOs who tirelessly collect data for his analysis, the PHM School District has realized a savings of $2,110,212 in energy costs from January 2007 through December 2010.