Facilities Saves Water, Steam, and Time

Water Conservation

MIT has had in place a water conservation program since 1990. Through this program we have retired or replaced most of the equipment that has used water for once-through-cooling, such as: refrigerating units, air conditioning equipment, air compressors, vacuum pumps, etc. We have also adhere to the prohibition of using domestic water for cooling of research equipment by requiring that chilled water be use as a heat sink in the laboratories. We have installed, where possible, low flow toilets and urinals, kitchen and bathroom sink aerators and low flow shower heads in existing buildings. We reuse reverse osmosis systems reject water as non-potable water for laboratories or re-circulate it to optimize R.O. product production and water discharge. We are continuously looking for ways to save and reuse water and have contracted with water conservation companies to provide us with surveys and creative solutions from time to time. Following is a list of water conservation measurements implemented over the last few years. Water and sewer rates have risen to such a degree that most of these projects have had about a 2 year payback. Between 1997 and 2005 campus water consumption was reduced by 60%.

Recent water conservation measurements:

Implemented in 2006

Building 46 (Brain and Cognitive Science): Brought to service a rainwater harvesting and re-use system for irrigation.
Water savings: 550,000 gal/year

Implemented in 2004

Building 32 (Stata): Brought to service a rainwater harvesting and re-use system for toilet flushing and irrigation.
Water savings: 550,000 gal/year

Implemented in 2002/2003

Buildings 68, E18, E23 and E25: Installed water tempering limiters in 12 autoclaves
Water savings: 3,360,0000 gal/year

Buildings 12, 13 and 26: Re-piped once-through-cooled equipment using domestic water to chilled water.
Water savings: 1,640,000 gal/year.

Building 39: Upgrade RO system.
Water savings: 1,985,695 gal/year

Campus wide: Installed an automatic central irrigation system with weather station and leak detection.

Implemented in 2000/2001

Building 39: Reuse reverse osmosis reject water as non-potable water to laboratories.
Water savings: 642,000 gal/year

Building 39: Tie-in vacuum pumps and air compressors to chilled water.
Water savings: 5,550,000 gal/year

Building 6: Replace water booster pumps with air-cooled pumps.
Water savings: 3,720,000 gal/year

Building 13: Tie-in refrigerated unit for electron microscopes to chilled water.
Water savings: 817,700 gal/year

Building 42: Redirected gas turbine inlet air cooling condensed water for cooling
tower makeup.

Energy Conservation

Implemented in 2006

In 2006, a lighting retrofit project was completed in Albany and West Garages, and the large athletic spaces of Johnson Track, Johnson Rink, Rockwell Cage and DuPont. The new technology employed doubles the lighting levels and halves energy consumption. By completing on an accelerated schedule, 50% extra rebate was awarded by NStar, so a $300,000 project cost MIT $150,000 and will save $120,000 in electricity annually, and lighting quality is substantially enhanced. We also implemented an outdoor lighting control system for the artificial turf soccer field and tennis courts that allow Athletics to schedule the lights on via the web just as they book the space itself (~1.5 year payback).

In 2006, we initiated another multi-year steam trap renewal program that should save us about $700,000 per year in energy cost.

Implemented in 2000/2001

“Vending Misers” have been installed on over 70 cold beverage machines across campus. Controlled by occupancy sensors, the machines are powered down when no one is near for a period of time (i.e. over night), automatically re-powering when traffic returns. This translates to an annual savings of up to $140 per machine.

In 2001, we implemented oxygen trim controls for boilers 3, 4 and 5 at the central utility plant which reduces excess air admitted to the boilers, a source of combustion inefficiency.

Renewal of over 2700 steam traps and thermostatic valves was performed in 2000/1 on main group radiators and heat exchangers in mechanical rooms (there are 6000 traps on campus). The estimated annual savings was 18 million pounds of steam worth $233,000 at that time.

Steam Trap Replacement Program

The Department of Facilities, as part of an ongoing program to save energy, conducted a steam trap repair and replacement program throughout the campus in 2006-2007. These traps are a major source of energy loss when not operating properly.

Radiator steam traps, which capture steam in the radiator until it has given up all latent heat, can cycle open and close 150,000–200,000 times during one heating season. The failure rate after five years could be 10–20 percent. If the trap is closed when it fails, the results are a cold radiator. When the trap fails in the open position, more often the case, steam still can enter the radiator. The result is a constant flow of steam to the radiator, which usually leads to overheating and potential damage to the radiator.

Benefits

The project’s energy savings amount to 17,925,000 steam pounds per year with a value of $233,000 at current prices. This figure is based on a conservative estimate that five per cent of the steam traps have failed in the open position and one percent is leaking. An additional $20,000 has been saved from avoided maintenance.

Repairs benefited room occupants by including the installation of thermostatic valves, as needed, to allow occupants to set comfortable room temperatures.