CAMBRIDGE, Mass.--The Massachusetts Institute of Technology is out to prove that green buildings don't have to be all that high tech.
MIT and utility Nstar on Wednesday announced an energy efficiency initiative to cut its electricity usage by 15 percent over the next three years. If met, the reduction will be 34 million kilowatt-hours, or about the same as 4,500 homes in Massachusetts in a year.
The efficiency push, which MIT hopes will be a model for other institutions, is an offshoot of the MIT Energy Initiative launched five years ago, which has helped make MIT a vibrant source of clean-energy technology research and development. The university wanted to create a "living lab" for clean energy and efficiency, students and school administrators said during a press conference here.
The measures that MIT facility managers plan to take at its campus here, for the most part, won't include cutting-edge technologies. Instead, the reductions will come by modernizing existing equipment, with a focus on lighting and on heating, ventilation, and air conditioning (HVAC).
The total investment will be about $13 million over three years. The payback period will vary depending on the project, from less than one year to about eight years, according to MIT. The school plans on reinvesting the savings into more efficiency programs.
About half of the electricity reductions will come in the form of more efficient lighting systems. The university will put in new lighting products, such as more efficient LEDs, and use lighting controls, such as sensors to detect daylight or when a person comes into a room, explained Peter Cooper, the manager of sustainable engineering and utility planning at MIT.
"LEDs are really advancing every year and you can buy more reliable, proven products," Cooper said, although MIT plans to put in florescent bulbs as well, which are also getting more efficient.
A significant amount of the electricity reduction will come from modernizing the HVAC systems. MIT will put in variable-speed drives in the motors that run the air handling systems and will install a sensor system from Aircuity to monitor air humidity and carbon dioxide level, which indicates how many people are in a room.
That data, which will be fed to the Carrier building energy management system, will help determine how much conditioned air needs to be moved around. Typically, HVAC systems are designed for maximum room occupancy and run at the same rate all day and night. With the air data, the building management system can be programmed to slow down at night or to reduce the amount of air that gets pulled in if, for example, it's very humid outside.
MIT has done HVAC improvements in the past and found that about two-thirds of the energy savings come from less heating and about one-third from less electricity use by fans and motors, Cooper said.
NStar provides an incentive, in the form of a payment to MIT, for the investments in efficiency, which is funded by a small surcharge on ratepayers, said Andrew Coffin, a program manager for NStar. The utility is interested in reducing its peak-time demand, which means it can defer investments in new power generation. State regulators have also set "aggressive" targets for energy efficiency at utilities, which is also driving the utility to run efficiency programs, Coffin said.
Although many of the efficiency savings are expected to come from upgrading to new equipment, MIT is also working on changes in behavior to cut usage. For example, the university's labs consume two to three times as much as average buildings. By closing the sash on fume hoods after experiments, students can save the equivalent of two homes' energy use, while improving safety, Cooper said.