As a result of the master planning study, the University committed to a campus-wide steam-to-hot-water conversion project to modernize our campus district heating system and significantly improve its efficiency. The hot water conversion is part of an overall effort that includes more thermal storage, geo-exchange, building system conversions, and solar photovoltaic power generation in the context of Princeton's Sustainability Action Plan. 

Two new energy facilities (T.I.G.E.R. and CUB) have been constructed to provide new and converted campus buildings with hot water for heating and chilled water for cooling. Other campus utility upgrade projects will provide the infrastructure to connect campus buildings to the new T.I.G.E.R. and CUB facilities. Using heat pumps and geo-exchange technology, these plants are at the forefront of district energy technology. The existing, upgraded cogeneration plant (and new solar arrays) will continue to act as part of the Princeton Microgrid, providing a clean and highly reliable electricity supply to keep the campus (and the new hot water system) running regardless of weather conditions or power outages. 

• The T.I.G.E.R. building along FitzRandolph Road is a single-story structure combining both geo-exchange utility facilities and operations spaces to expand the University’s capacity to deliver thermal energy, as well as storage and operations space for Princeton Athletics. The geo-exchange utility space will house required equipment and electrical rooms at ground level along with limited mezzanine space. In addition to the main TIGER building, two Thermal Energy Storage (TES) Tanks, two electrical transformers, and a natural gas generator are located on the project site. The TES Tanks are used to store water that will be utilized to heat and cool campus. These tanks are designed and sized to allow utilities to be produced and stored during times of the day that are both economically and environmentally advantageous. 

• The CUB (central utility building) in the new Meadows Neighborhood is a single-story structure with geo-exchange facilities to deliver thermal energy for buildings. In addition to the main CUB building, there will be two TES Tanks, electrical transformers, and a natural-gas powered back-up generator. The TES tanks are used to store water that will be used to heat and cool the Meadows Neighborhood. They are designed and sized to store energy for use during times that are both economically and environmentally advantageous. 
   

• Thermal Energy Storage (TES) Tanks are big tanks of water that can store hot or cold water when electricity is inexpensive or when ample solar energy is being produced. One tank holds hot water and the other cold. Then, when electricity is very expensive – like on a hot August afternoon when everyone wants a lot of energy – the water from the TES tanks can be used instead of the heat pumps to deliver heating and cooling to the campus. TES tanks help minimize cost of energy and add reliability and resilience to the Princeton systems. The TES tanks enable short term storage while geo-exchange provides a means of storing energy on a seasonal basis. 

Path to Net-Zero

Check out the other projects that will enable us to begin converting from steam to hot water, conserve energy, increase our efficiencies, and decrease our carbon footprint and reliance on fossil fuels:

1. New Energy Facilities based on heat pumps (TIGER & CUB)
2. Geo-Exchange bore fields
3. Thermal distribution piping campus-wide
4. Building heating & cooling system conversions
5. Solar Expansion 
6. Energy Conservation Initiatives