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"I wanted to install the most energy efficient heating and plumbing equipment available."
Ken Relyea, Director of
Facilities and Operations |
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Maple Avenue Middle School
Saratoga Springs, New York
 The Maple Avenue Middle School, built in early 1992, is one of nine schools in the Saratoga Springs district. A two-story building of approximately 180,000 square feet, the school includes offices, 66 classrooms, one kitchen serving two cafeterias, and two gyms. It was designed for an enrollment of 1,200 students with an anticipated expansion to 1,800. At the time of construction, the school district was involved in an energy management program to reduce annual energy consumption. The goal: to reduce energy usage as much as possible. A 10 percent reduction in fuel used would save hundreds of thousands of dollars.
Problem: In the initial design phase of the new middle school, it was suggested to make it "all electric" with lower first cost. The district already had two all-electric schools - the Junior High and Geyser Road Elementary - which had proven to be costly and not very energy efficient. Ken Relyea, director of facilities and operations who was actively recruited by the school district, wanted to look into other options.
Solution: After researching many products, Relyea, with help from his consulting engineer, Henry Shouse of W-P-S Consulting Engineers, P.C., selected Aerco's Multiple Hydronic Boiler System consisting of eight boilers with Aerco's sophisticated Boiler Management System (BMS), and two Aerco Domestic Water Heaters.
 "I wanted to install the most energy efficient heating and plumbing equipment available," said Relyea. "Although the other boilers I looked at had a lower initial cost, I knew Aerco's specially designed units would provide lower energy consumption over the lifecycle of the building and, thus, save a substantial amount of money year after year."
In order to meet the alternate fuel heating requirements of the New York State Education Department, a cast-iron boiler was also installed as backup. But, by selecting Aerco as the primary heat source, the school was able to put in less expensive back-up equipment to keep installation costs down. To date, the cast-iron boiler remains dormant, waiting for backup use.
Application: Within 10 working days, 10 Aerco units were up and running. The Aerco Hydronic Boiler System includes air-handling units and unit ventilators for forced hot air in classrooms with 40°F temperature change design loop (160°F maximum to 120°F). The two domestic hot water heaters service the entire load requirements of the 1,000-2,000 student school including the gymnasium's showers with three-gallon-per-minute shower heads. The two Aerco water heaters maintain precise temperature control of +/- 4°F regardless of peak demand.
 Aerco was the only manufacturer that met, and exceeded, the minimum requirements of the district's energy management program," said Relyea. Unlike other brands, Aerco's thermal efficiency actually increases with decreasing loads resulting in the lowest possible energy consumption. The effect is an inverse efficiency curve. Aerco's boilers and heaters are designed to precisely modulate energy input and match the energy input to the load continuously, reducing energy losses and maximizing overall system efficiency.
"I like the Aerco Multiple Boiler System approach because of its cost efficiency, serviceability and ease due to Aerco's high-tech Boiler Management System," said Relyea. "Aerco's BMS interfaces directly with the district's previous energy management system."
The Aerco boiler's condensing design allowed W-P-S to specify the heating system with a 160°F supply design temperature and a 40°F differential between design and return water temperatures. This differs significantly from a conventional system incorporating a 180°F design temperature with a 20°F differential temperature. These lower system temperatures ensure that the Aerco boilers will always be condensing, and thus running at peak efficiency. Water flows are cut in half, reducing the size and cost of pumps and piping system components. Higher system efficiencies are achieved through decreased radiant heat loss and pump electrical draw. The Aerco BMS Control Panel maximizes efficiency by operating the total number of available boilers at the lowest possible firing rate that will satisfy the load. Hence, the BMS maximizes the effect of each unit's inverse efficiency curve.
 In addition, the Aerco units' compact size was an advantageous feature. They fit through standard doorways and take significantly less floor space. Construction costs are cut because there is no need for reinforced floors or special supports.
Maintenance: The Aerco units have a lower maintenance cost when compared to other brands. Other boilers must be thoroughly cleaned every six months. Required maintenance on the Aerco units is limited to a periodic replacement of the flame rod and spark ignitor that takes less than 15 minutes.
Savings: By installing the Aerco boilers and water heaters, Maple Avenue Middle School realized immediate savings on energy cost when compared to "averaged" fuel/utility bills of the electric schools. The school district reduced energy usage by more than 10 percent, saving over $300,000 annually resulting in a two-year payback. There was also an overall reduced installation cost because Aerco's engineered designed equipment do not require ancillary parts such as extra blending valves, pumps, piping, etc. The school is planning to install more Aerco units when an addition to the school is complete.
In addition, Aerco's boilers have been bought by the contractors for major retrofitting in two other schools in the Saratoga Springs school district. The district wants to retrofit the remaining six older schools with the same equipment. Currently, the schools use steam-to-water converters via main steam boiler plant for heating and electric water heaters for domestic hot water. Cost estimates show that the district could save approximately $375,000 annually in fuel costs by employing high-efficiency equipment.
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