Why switch from Pneumatics to DDC? - Case Study
by the ABC Advantage Team - Tuesday, July 10, 2012
PROJECT SUMMARY - Washington County, Pennsylvania
"Washington County will conduct an Energy Audit on the County buildings before completing any retrofits, to assess where savings can be achieved. The County had a preliminary study done on retrofitting of lights within the Courthouse Square Office Building and the efficiency of air handling units around the beginning of May 2009, and here are some of the findings:
• This study shows that it would cost $180,000 to install new lamps with the LFB electronic ballasts into 1323 existing fixtures. Our current cost of electricity is $42,865.20/year for the existing lighting fixtures and the anticipated cost after the retrofit is $26,989.20/year.
• The Courthouse Square office building has two AHUs with a 60HP supply fan motor and an estimated 15HP return fan motor. At an estimated cost of $.09/Kwh, running these fans 24/7 at full speed is costing the county an estimated $96,200 each year. Heating and cooling the building during unoccupied times is also costing the county energy dollars in natural gas and chiller electricity. It is recommended that the county replace the pneumatics with web-based DDC controls and in the office space replace the existing pneumatic thermostats and actuators with electric actuators, small DDC controllers, and electronic sensors with set point adjustment and over ride capabilities. The estimated conversion cost is $125,000, and the estimated yearly savings is $80,700.
Anticipated energy savings will be achieved through various energy efficiency improvements, including those activities mentioned above, with all changes dependent on the completed energy audit. All retrofits will be made based on findings in the completed energy audit that show the most energy savings.
• The retrofitting of the lights gives us an estimated savings of $15,876.70/year. The simple payback is 126 months and the energy savings is 37%.
• By replacing the pneumatics on the AHUs the estimated yearly savings is $80,700. The simple payback is 1.54 years and estimated energy savings is 66%.
• Other retrofits will be utilized based on energy audit findings (based on the budgetary amount)"
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