Case Study: Elementary School Saves 25 Percent on Energy Costs Within Two Years of Installation
Screven Elementary School, Sylvania, GA, serves 1,400 pre-K to fifth-graders. The 143,000-square-foot facility was built in 1989. A renovation of the school in 2002 took care of many issues, but left a dated and inefficient HVAC system sorely needing replacement. A CITY MULTI® Variable Refrigerant Flow (VRF) zoning system from Mitsubishi Electric US, Inc. Cooling & Heating Division (Mitsubishi Electric) provided an efficient, cost-saving solution.
The pipes of the building’s original water-source heat pump system eventually deteriorated. William Bland, superintendent, Screven County School System, said, “There was no question about the need for a renovation of the HVAC system at the elementary school.” The original plan was to repair the old system but the cost of that work was going to be substantial and was not going to increase energy efficiency.
The direction changed when Bland and other school representatives attended an educational session on Mitsubishi Electric CITY MULTI units. Bland said, “We were very impressed and left that meeting with much more knowledge and an interest in learning more. The more we studied and researched and questioned other users, the more we liked the product.”
Mike Dixon, maintenance director, Screven Elementary School, said, “It was the energy efficiency that grabbed our attention. We were also interested in the ability of the units to maintain the temperature within one or two degrees and the quiet operation. It almost
sounded too good to be true.” Choosing Mitsubishi Electric over other brands involved comparing attributes and offerings. “We talked with Daikin and a couple more companies and the features, capabilities, controls and warranty of Mitsubishi [Electric] made it the right system to go with,” said Dixon.
Pruett, Ford & Associates, Inc., Augusta, Georgia, was called in to specify the system. Bob Pruett, partner, supported the choice of a Mitsubishi Electric system because “we felt it would be less maintenance.” If one part of the previous system needed to be serviced, the whole system had to be shut down. “The Mitsubishi Electric system is compartmentalized, though, so if you lose a compressor you might lose part of a system, but never the whole system,” said Pruett. Using a Mitsubishi Electric system meant easier maintenance with less of an impact on ongoing operations.
The installation, completed in less than 12 weeks, took place over the summer when school was not in session. Dixon said, “It went unbelievably. If there was a problem we made a phone call and someone was there – more times than not – within the same day. It was remarkable.”
The VRF system allows Preston Dees, director of school safety and energy manager, Screven County School System, to monitor and control the cooling and heating in each classroom. Dees said, “Now we’re on a control system and we can manage our energy usage.” Controlling energy usage throughout the school from a centralized controller offers ease and cost savings. The savings in the first two years post-renovation have been substantial:
|Average Monthly Cost||Energy Use|
Average Yearly Savings: $16,226
Average Energy Savings: 25%
“We were able to cut out another big part of our energy costs when we installed the new system because we were able to remove the old boiler and cooling tower,” Dees said. The boiler had provided heat, which was no longer necessary with the Mitsubishi Electric system. “We saved about two-thirds on our gas costs, so we’ve saved on energy and gas.”
Bland said, “We have had an aggressive energy management system in place for five years, and we are documenting substantial savings with the CITY MULTI system from previous years of records.”
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