Coal, Gas

On-Site Power Cures Energy Ills

Issue 11 and Volume 110.

State-of-the-art energy systems are becoming increasingly common in medical facilities across the U.S. Hospitals’ requirements for power, thermal energy and emergency stand-by power, coupled with their load profiles, provide significant opportunities to benefit from high-tech distributed generation/CHP technologies and products.

Dell Children’s Medical Center in Austin, Texas, now has its own 4.3 MW integrated hybrid energy plant that provides the 35,000-square-foot facility with power, chilled water and steam. The system is connected to the local grid, giving it flexibility during normal operations, while remaining open to island-mode operation during grid outages

Burns & McDonnell provided architectural, construction and environmental engineering for the $11 million project, which makes Dell Children’s Medical one of the state’s first hospitals to meet all its own energy requirements with an on-site energy system It will achieve fuel efficiency greater than 70 percent by combining a high efficiency, low-emission Solar Turbines Mercury 50 combustion turbine, a nominal 1,000-ton steam absorption chiller and an 8,000-ton/hr thermal energy storage tank. Standard on-site power generation facilities typically achieve fuel efficiencies averaging 30 percent.


Dell Children’s Medical Center’s CHP package achieves 70 percent fuel efficiency. Courtesy of Burns & McDonnell
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CHP systems can be more than twice as efficient as standard central generating plants. In addition, the systems reduce NOX and CO2 emissions. The system uses exhaust heat from the natural-gas-fired combustion turbine as the primary heat source for a heat recovery steam generator (HRSG). Steam from the HRSG serves 100 percent of the hospital’s process heating needs and is also used to produce chilled water, with the heat recovery absorption chiller. Electricity and natural gas costs are further reduced by a thermal energy storage tank with a chilled water capacity of 880,000 gallons, or 8,000 ton/hours of chilled water capacity.

The energy system is an integral part of Dell’s application to become the first hospital in the nation to earn Leadership in Energy and Environmental Design (LEED) EA1 efficiency credit. The advanced turbine technology will reduce NOx emissions to less than 5 ppm, allowing the system to meet state emission standards without additional exhaust treatment equipment.

The integrated energy system is the result of a public-private partnership between the U.S. Department of Energy, Oak Ridge National Laboratory, Austin Energy, Burns & McDonnell and Dell.

Orders for Pentadyne’s second-generation VSS+DC flywheel-based energy storage system, introduced this summer, have surpassed 100 units. The new model delivers 50 percent greater power than the original VSSDC model. Photo courtesy of Pentadyne Power Corporation.