The Challenge
A large health care organization wanted to reduce energy use and operating expenses at one of its flagship facilities. Engineers provided a detailed analysis of the organization’s one million square foot medical center, focusing on its 24-hour HVAC system and chiller plant with an annual average load of one thousand tons and electrical demand in excess of 4.6 MW. Engineers found tremendous opportunities for savings.
The Solution
A bundled solution to deliver electric and natural gas savings as well as positive economic performance (return on investment). The strategic solution was centered on chiller plant optimization and the installation of a water-side economizer in the primary hospital central chiller plant.
Components included:
- A new, efficient 1,500-ton water-cooled chiller and a new 1,500-ton plate and frame heat exchanger
- A new high-efficiency cooling tower with variable frequency drives (VFDs)
- Six VFDs installed on three existing primary chilled water pumps, one condenser water pump, and two new pumps
- A complete redesign and overhaul of the cooling plant sequence of operation
- Eight VFDs to convert various air handlers from inlet guide vane or constant volume systems to VFD variable volume systems
- Chilled-water pump sequence optimization
- Daylight and occupancy sensor lighting controls
Results
- $450,000 annual energy expense savings (electricity & natural gas)
- 5.5M kWh annual savings
- 161,000 therms annual savings
- 5 Years simple payback
- 0.5 kW/ton annualized chiller performance
- 60% cooling plant performance improvement
- 12% EUI reduction, from 276 down to 244
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