The Department of Facilities, as part of its ongoing effort to conserve energy, will replace steam traps in radiators throughout campus beginning in September. These traps, located at the bottom of radiators (MIT's primary heating source), are a major source of energy loss when not operating properly.
As the name implies, steam traps hold steam inside the radiators until the steam condenses into water. The traps then open to release this water back into the system for recycling.
Thermostatic valves will also be installed in radiators that don't have them. Once these two steps are taken, occupants will be able to control a room's temperature much more easily.
Radiator steam traps can cycle open and closed 150,000 to 200,000 times during one heating season. In five years they may approach one million cycles, so the failure rate can be substantial--10 to 20 percent is not unusual. If the trap is closed when it fails, the results are obvious: the radiator receives no steam and stays cold. When the trap fails in the open position, which is usually the case, the result is a constant flow of steam to the radiator, which usually leads to overheating and wastes a lot of steam.
The resulting energy savings project to almost 18 million pounds of steam per year, with a value of $233,000 at today's steam prices. These savings are calculated by assuming that 5 per cent of the steam traps have failed in the open position and 1 percent of the traps are leaking. There is also a $20,000 savings from avoided maintenance.
The Department of Facilities has contracted with Aqualine Resources, Inc., to carry out this project. Aqualine, which has already completed the toilet retrofit program in the academic and housing buildings, is accustomed to working in occupied areas while being sensitive to the occupants' concerns.
Aqualine will post door tabs in every room to notify occupants several days before starting work there. A company employee will also visit the space the day before work is scheduled to talk to the occupants about the project and to verify that the radiators are uncluttered by cabinets, office equipment or personal effects. Aqualine estimates that repairing or replacing steam traps will take approximately an hour and a half per radiator, although many may take less time.
A version of this article appeared in MIT Tech Talk on September 12, 2001.