Accomplishment summary at Duke University Medical Center Over 7 million gross square feet, ~ 100 bldgs Annual Steam and Electric cost approx $13M

Reduced ENERGY cost from Aug 1997 to Aug 2002 - five years

Air handling units
  • Cooling coil condensate recovery system reclaims over 2 million gallons of water for use in evaporative cooling towers. This has avoided over $6,000 of cooling tower make-up water expense at under a two-year simple payback.
  • Convert to high efficiency electric motors at motor failure in lieu of rewinds have resulted in an average two simple year payback.
  • Convert variable air volume AHU fans and tower fans to variable speed drives at inlet guide vane failure in lieu of unreliable inlet vane repairs.

  • Combine separate building chilled water piping systems to reduce the quantity of chillers running and electric consumption approximately 25%.
  • Revise control sequences and building automation programs to run less equipment while meeting bldg needs.
  • Research chilled water system - Lab Header, automate chiller starting and stopping by monitoring bridge flow real-time data directly in lieu of assumed calculations.
  • Prevent Duke Hospital North chilled water low delta temperature differential and overflowing with flow limiting control valves.
  • Modify a chiller to utilize its spare tube bundle by enlarging the condenser bundle size.
  • Relocate pump suction tap location to cold room condenser pump allowing the house chilled water pumps to be turned off during mild outside air conditions.
  • Add DDC cooling tower controls and utilize existing to rest condenser water temperature based on chiller tolerances, approach and wet bulb temperature.
  • Upgrade existing 7 to 8 seer DX cooling units to 12 seer.
  • Water balance and air balance critical and trouble areas.
  • Convert three way control valves chilled water systems to two way control valves, reducing the required pump energy and chilled water volume.

  • Purchased an ultrasonic meter and initiated steam trap survey program with state energy re-imbursement resulting in approximately 70 million pounds of steam consumption reductions the year after completion.
  • Addition of sterilizer time clocks and overrides to reduce unoccupied steam use.
  • Convert sterilizer electric steam generators to steam resulting in large reductions in steam usage.

  • Upgrade of durable T-12 and magnetic ballast with Lone Point Energy’s Duralux waveform controllers and high phosphor 4100 Kelvin or warmer color flourescent low mercury bulbs resulting in 2 to 4 year simple payback depending on local usage patterns.
  • Replace incandescent silver tip bulbs with compact flourescent bulbs resulting in simple paybacks well under a year.
  • Nominated the Sealy G. Mudd library for the Energy Star program Champion Award.

    Avoided cost:
  • Use energy surveys and BAS logs to Identify needs for repair or replacement of leaking steam control valves.
  • Modifying magnetic ballast with Lone Point Energy’s Duralux waveform controllers and high phosphor 4100 Kelvin or warmer color flourescent low mercury bulbs cools the fixture device temperature and extends component life reducing the lighting manpower maintenance needs.
  • Modify re-heat hot water system by adding end of loop bypass resulting in reduced steam consumption. Also resulting in less di-electric union pipe fitting heat and cooling cycle strain which reduced water leaks causing unsightly ceiling tile stains.
  • Initiated a summer winter steam shutdown list resulting in disabling additional steam equipment in the summer months reducing steam consumption.

  • Provide improved means of access and encourage more widespread and centralized utilization of building automation system information for the betterment of our customer service.
  • Explore causes of building automation network instabilities, devise and execute a correct action plan resulting in improved central alarm delivery and monitoring for our customers. Over five years these and other projects have resulting in approx two million dollars of reduced energy expense or avoided cost while overall facility square footage grew approx 15%.

    R. Michael Herran, P.E.