Page 383 - Sustainable On-Site CHP Systems Design, Construction, and Operations

356 Ca s e S t u d y 4

• Domestic cold water
• Domestic hot water
• Compressed air
Over time, typical university campuses expand and many facilities are in need of reno-
vation and/or retrofit. In addition, many institutions have embraced sustainability as the
foundation of their facility operations, and adopted sustainable development policies.
Given the mix of required utilities, which almost always includes electricity, heat-
ing, and cooling energy, the combined generation of heat and power becomes a very
attractive option for universities that are faced with requirements to meet increased
campus loads or retrofit/replace older equipment.
This case study analyzed the operation of a diversified central utilities plant and
offers a methodology to help facilitate the decision-making process for the plant opera-
tors faced with open energy market conditions.

Central Utilities Plant Description
The university campus considered for this analysis includes buildings with a total area
of approximately 7.5 million square feet. These facilities are served by a central utilities
plant (CUP) and a distribution system with

• Steam—generated by
• Two cogeneration units
• Four steam boilers
• Chilled water—produced by
• Six electric chillers
• One absorption chiller
• Electricity—generated by
• Two cogeneration units
• Compressed air—generated by
• Three air compressors
• Domestic water supplied by the municipality
For the purpose of this central plant optimization analysis, compressed air and
domestic water were not included. Table 22-1 presents the CUP utility inputs and out-
puts considered in this case study.

Utility In Utility Out to Campus
Natural gas Steam (cogen or boilers)
Raw utility used: natural gas
Electricity Chilled water (electric chillers or absorber)
Raw utility used: electricity and/or steam
Electricity Electricity (grid transfer or cogen)
Raw utility used: electricity and/or gas
TABLE 22-1 Conversions or Transfers within CUP