Resilient Buildings: Keeping the lights and heat on when the grid fails

by / Monday, 26 October 2015 / Published in CHP, COGEN

Disaster Proof your heat and power with CHP

As New York City and surrounding communities were left partially flooded and prolonged power outages after Hurricane Sandy, the lights and heat stayed on a select number of facilities including in the New York University and Co-Op City high rise housing complex. [ref: The New York Times]

These facilities remained lit and warm through the use of Combined Heat and Power (CHP) plants. CHP units are miniaturized power plants consisting of a high efficiency natural gas turbine or internal combustion engine connected to an electric generator and exhaust gas heat exchanger. Hot Water obtained from this heat exchanger supplies energy for building heat, domestic hot water, and may be used drive an absorption chiller.

The electricity generated is used to supply the buildings’ base-loads to help offset the increased natural gas use. At current energy prices, it is less expensive for a facility to generate their own power with a CHP generator. Carbon footprint reductions are also realized with natural gas CHP systems. Facilities that have high energy use and are heated year round can particularly benefit from CHP. Princeton University in New Jersey has successfully operated a CHP plant since 1996 to generate 50% of their electricity and all of their daily steam needs [ref: Daily Princetonian], and was virtually unaffected by Hurricane Sandy that resulted in more than 75% of Princeton

In events of a power failure, the CHP plants island the facility and provide power for lighting and essential systems until grid power is restored. Unlike facilities with emergency generators only, the useful heat generated helps in lowering reliance on boilers exclusively and permit them to operate at full capacity during a blackout. [ref: thestar.com]

Facilities with ageing emergency backup generators, or boilers and domestic water heaters requiring replacement can also benefit from CHP as power is at the ready. [more information]

It is very important that CHP systems be designed to closely match the buildings heating load, incorporate thermal storage and heat rejection for the summer when heating load is reduced [ref: Toronto Atmospheric Fund Case Study]. Each installation business case is unique and may require evaluation of multiple options

In a world of increasing dangerous and unpredictable weather events, fan ageing power distribution grid susceptible to prolonged power outages, facilities with CHP can provide operational savings, high reliability, increased occupant comfort and value for owners as businesses and critical infrastructure may remain operational.

Sheldon Petrie, BACc.

Sheldon is a Mechanical Designer at Efficiency Engineering with a degree in Mechanical Engineering from the University of Waterloo. He been designing HVAC systems for more than 8 years. His experience includes, equipment selection and sizing, design heating and hot water plant retrofits and Combined Heat and Power (COGEN) retrofits.

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