Built in 1938, Waterloo High School in Waterloo, Ill., part of Waterloo Community Unit School District No. 5, had become seriously overcrowded. In 2006, voters approved a referendum to build a new high school. Three years later, in August, the new Waterloo High School was dedicated and opened to the community.

Designed by Design Architects Inc., a subsidiary of Hillsboro, Ill.-based Hurst-Rosche Engineers Inc., the new school comprises 227,000 sq ft of classroom, laboratory, activities, and administration space. It contains a single-pipe-loop, heat-pump-based system featuring Taco's LoadMatch system and a complete building-automation system (BAS)/energy-management system (EMS) from Johnson Controls. In addition to compliance with a new state energy-conservation code, the mechanical systems were designed with redundancy and flexibility in mind, with a possible geothermal option.

“We were looking for energy efficiency in accordance with (ANSI/) ASHRAE (/IESNA Standard) 90.1 (Energy Standard for Buildings Except Low-Rise Residential Buildings),” Superintendent James W. Helton said.

According to Tom Baker, PE, president of Hurst-Rosche Engineers, the school's HVAC system is a “hybrid system” consisting of 120 Trane constant-speed heat pumps, some direct expansion with fluid coolers, boilers, and a 100-percent dedicated-outside-air makeup unit with distributed ventilation. The LoadMatch option for fluid circulation adds redundancy to, and simplifies control of, the heat pumps while lowering first costs because of a reduction in piping and control valves.

Introduced to the LoadMatch concept by St. Louis-based manufacturer's representative Behrmann Co., Hurst-Rosche Engineers utilized Taco Hydronic Solutions Software (HSS) to design and equip the heating and cooling system.

“HSS proved to be a great time-saver for us,” Baker said. “It helped minimize errors, allowed us to check and then guarantee our design with Taco, and to link in associated disciplines, such as electrical, plumbing, condensate piping, and controls, into the system design.”

Because this was the first project on which Hurst-Rosche Engineers employed the LoadMatch system, there were initial challenges to overcome.

“A temperature cascade will occur with LoadMatch because the system doesn't incorporate a dedicated return pipe, and, therefore, as you go down the piping system, temperatures will rise or decrease depending on whether you're in the heating or cooling mode, and it is more efficient to maintain the same entering water temperature at the last terminal unit on the primary loop as you do on the first,” Baker said.