Municipal
District heating and cooling (also known as district energy) is an especially viable energy-efficient option in a municipal setting, where a cluster of buildings in dense, downtown settings require continuous heating and cooling needs
A district energy system distributes heat and cooling from an on-site plant through underground, closed-loop pipes to buildings connected to the system. Individual buildings connected to the system do not need boilers, chillers or cooling towers. Customers in a municipal setting can use hot water and chilled water to meet their space heating, water heating, processing and air-conditioning needs. Once the energy (hot water, steam and chilled water) are "used" by the individual buildings, the water is returned to the central plant and is then either re-heated or re-chilled before being recirculated.
Favorable municipal sites include office buildings in dense areas and industrial parks.
Economic benefits include:
- Reduced upfront capital costs because the equipment necessary to tie into DES network costs less than stand-alone systems (boilers, chillers, water heaters
- Lower overall building operating, maintenance, and labor costs
- Economies of scale for fuel purchases
Environmental benefits include:
- A central plant is more efficient than many small plants, reducing energy consumption.
- Steam, hot water, and chilled water are 100 percent efficient "at the customer's door," compared with 80 percent or lower efficiencies when burning natural gas or fuel at individual buildings
- Central plants employ stringent emission controls - more so than individual buildings - providing air quality benefits
- Reduces peak electric power demand for air conditioning
Conveniences include:
- Removes combustion equipment from buildings, saving space and removing a real source of possible indoor air quality contamination.
- Eliminates need for boilers and chillers, resulting in less maintenance, monitoring and equipment permitting.
- Energy professionals at central plants operate around the clock and have backup systems available, with reliability rates near 99.9 percent.
- Building operators can manage and control their own indoor environments (like -the air conditioning can be turned on for an unseasonably warm January day).
Case studies
- Con Edison (New York) - The New York Steam Company began providing service in lower Manhattan in 1882. Today, Con Edison operates the largest district-energy steam system in the United States. The system contains approximately 105 miles of mains and service pipes and 3,000 steam manholes. Steam is provided to customers from five Con Edison steam-generating plants, three in Manhattan, one in Queens, and one in Brooklyn, along with receiving steam under contract from a steam plant at Brooklyn. Con Edison's steam system provides service to approximately 1,800 customers in Manhattan/ Commercial and residential customers use steam for heating, hot water, and air conditioning.
- Texas Electric Corporation (Houston, TX) -TECO is the largest campus district chilled water system in the country and provides district heating and cooling to 18 institutions in TMC, the world's largest medical center. TECO also received $10 million in federal stimulus funding for its 100 MW CHP project.
- Entergy (Houston, TX and New Orleans, LA)
- Austin Energy (Austin, TX)
- District Energy St. Paul (St. Paul, MN)
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