Princeton Energy Plant Upgrades
About These Projects
Please note that the CO2 avoidance figures mentioned in these project profiles are Princeton Facilities engineers' estimates made prior to undertaking the projects. The estimates are conservative and the actual figures may vary. The figures are generally presented in metric tons per year. Princeton's carbon emissions reduction goal, as stated in the Sustainability Plan , is to reduce emissions to 1990 levels by 2020.
Reverse Osmosis Heat System
The water that circulates through boilers is constantly being replenished with water from an outside source. The reverse osmosis conditioning system removes minerals and ions from the incoming water. It's one of the key systems that keeps up efficiency and keeps down maintenance costs. As the water passes through the reverse osmosis cleaning system, it's warmed with heat recovered from elsewhere in the plant. This reduces the energy needed to heat it back to steam. It is estimated that this project could help Princeton avoid approximately 70 metric tons of CO2 emissions per year.
Exhaust Heat Recovery System
The Sofame heat recovery system uses a condensing heat exchanger to extract heat from the cogeneration turbine exhaust. The energy, which would have been wasted, is used to heat the incoming boiler water and condensate returning from campus. It is estimated that this project could help Princeton avoid approximately 4500 metric tons of CO2 emissions per year. (Pictured is one of the three condensing heat exchangers that were installed in the plant.)
Micro-steam Generating Facility in Dillon
Essentially a pair of small steam turbines driving electrical generators. These self-contained power systems can take the place of pressure reducing valves at key points. (see feature article)
Comprehensive Insulation Program for all Steam and Chilled Water Lines
Princeton has a network of miles of steam and chilled water lines that move heat around campus. Every inch of those miles represents a potential loss of energy. Princeton has undertaken a comprehensive insulation program to mitigate this problem. Every bit of heat that can be captured or preserved reduces the amount of fuel needed to heat or cool the campus -- that in turn reduces Princeton's carbon footprint.
Extensive Upgrades of Steam Traps
A steam trap is a device used to discharge condensate and non condensable gases with a negligible consumption or loss of live steam. Most steam traps are nothing more than automatic valves. Every steam trap, while necessary to safe and efficient operation of the system, represents a potential loss of energy. Princeton has undertaken a comprehensive upgrade program to evaluate and upgrade all steam traps in the Campus distribution system. So far, about 24% of Princeton's steam traps have been upgraded. It is estimated that this project could help Princeton avoid approximately 1200 metric tons of CO2 emissions per year.
Lighting in the Plant Replaced with More Efficient Technology
Princeton University has had a campus-wide lighting technology upgrade program for several years. The Energy Plant runs 24/7/365 and it must be lit at all times for safety reasons, therefore any savings gained with more efficient lighting is compounded by continuous use. Princeton Facilities engineers analyzed the existing high-pressure sodium lighting system and replaced it with conventional florescent lighting which turned out to be more efficient and provides a much better quality of working light. While all mechanical areas of the plant must remain lighted at all times, it was found that the lighting level could be lowered to a minimum safe level using occupancy sensors to detect when operators were not present. This more efficient setup is anticipated to result in 220,000 kWh in electricity savings per year. This in turn helps Princeton avoid 85 metric tons per year in greenhouse gas emissions. (Click here for a short article on Princeton's LED lighting evaluation program.)