CAMBRIDGE, Mass.--Peter Cooper, the manager of sustainable engineering and utility planning at the Massachusetts Institute of Technology, stands in front of a typical air handling unit. Giant fans pull in outside air, heat it or cool it, and pump it through campus buildings.
Using a combination of variable-speed drive motors and air quality sensors, which can test for room occupancy and humidity, MIT plans to significantly reduce its heating and cooling load. Rather than have the system pump at full force at all times, the building management system will modify the air circulation flow to fit weather conditions and occupancy. It's part of a $13 million, three-year investment to cut electricity by 15 percent, or enough to power 4,500 Massachusetts homes in a year.
At first blush, there's nothing wrong with this picture of one of the libraries at MIT. But if you're looking to improve energy efficiency, there are few things that can be done.
For starters, the room's artificial lights are on, even though the building benefits from south-facing windows that let a lot of light in. MIT will be installing daylight sensors that can control how much light the overhead lights give off as a way to save energy. Also, the occupancy of the room is only about 10 percent, but the heating and cooling system is programmed to run as if the room were full. By reducing the amount of circulated air, it can cut electricity and heating costs, while reducing noise.
About half of MIT's projected electricity savings will come from lighting upgrades, which don't need to be very high tech. This fixture uses typical florescent bulbs, but it is equipped with a more reflective encasing. MIT will be testing these fixture in the stacks to see if the combination of less powerful bulbs with reflective fixtures can replace the existing lighting.
This is one of the fans that operate the air-handling system at this MIT building, which was built in 1949. For the most part, the systems have had only minor upgrades since then. Through this efficiency program, MIT will install variable-speed drive motors, which means that the fans can run at different speeds, rather than at full bore at all times. The speed of the fans that take in outside air will be determined by a set of sensors that will gather data on the humidity of indoor air and carbon dioxide level, which indicates how many people are in a room.
This motor was originally used for elevators, but was replaced for a more efficient one. It's a reminder of how energy efficiency investments can be coordinated with equipment upgrades. Because this is so heavy, it may be staying a while as a relic.