DC-2770 -- Total Energy Center Wellington Hospital Design of Systems and Services PDF

The Total Energy Center (TEC) provides power, high-temperature hot water, chilled water, domestic hot water, and other services to the various blocks of Wellington (New Zealand) Hospital. The basic plant consists of four 2.5 MW, 11 kV dual fuel engine alternators, two 7.3 MW (25 x 10⁶ Btu/hr) high-temperature hot water boilers, three 3.5 MW (12 x 10⁶ Btu/hr) steam generators, two 3.5 MW (1000 ton) absorption chillers, two 2.1 MW (600 ton) chillers, high-voltage switchgear, cooling towers, and plumping systems.

The center is located about 0.3 km (0.19 mi.) from the hospital blocks to which services are moved through a tunnel. Variable-speed pumps controlled by pressure transducers maintain a predetermined pressure at an indexing point for high-temperature hot water and chilled-water systems. No secondary pumping is used, and all heat exchange surfaces have two-way control valves. Low-grade heat from engine jackets is utilized for domestic hot water heating, and high-grade heat from the engine exhaust is used by the absorption chillers and reticulated to remote heat exchangers.

The TEC and hospital complex are designed to remain operational after a major earthquake . Despite the varying load pattern of the hospital, the overall efficiency of the system over primary fuel input is 600. The system permits utilizing indigenous natural gas for normal operation and diesel for emergencies.