Well, that's exactly what Refrigeration Design Technologies (RDT; Waxahachie, TX, U.S.; www.rdtonline.com) has done with its new refrigeration rack system. Introduced at the NAFEM show in February, the Eco-Cool system has done away with several energy-guzzling compressors—allowing foodservice applications that typically require eight compressors to only use two.

However, this disappearing act was not an easy task. "The main hurdle we faced prior to the introduction of the Eco-Cool system was how to harness the compressors’ capacity and not allow a disproportional supply to a minimal demand," says Randall Dyess, president of RDT. "For instance, if more than one fixture was grouped on a compressor and all but one fixture was satisfied—the compressor provided too much capacity for the remaining fixture. This approach would have resulted in an inefficient system prone to service problems."

The answer was Copeland Scroll Digital compressor technology from Emerson Climate Technologies (St. Louis, MO, U.S.; www.emersonclimate.com). Dyess says the technology allowed RDT engineers to group multiple fixtures on a single compressor without fear of disproportional loads or excess electrical consumption. "The compressors found in the Eco-Cool system allow for modulation and precise control of individual fixtures," he explains. "The compressor can operate at 100% capacity or unload down to 10% capacity. The digital scroll technology allows us to use only one medium temperature (MT) compressor and one low temperature (LT) compressor in a foodservice application that would have typically required a total of eight compressors in a conventional refrigeration system."

The reduction in compressors, of course, means more than reduced electrical consumption. According to RDT, it translates into a smaller system footprint, lower refrigerant volume, and reduced installation costs.

The system also uses Emerson's E2 controller, which allows the rack system to addresses the increasing demand for closer temperature tolerances and has the ability to monitor, control, and record these vital temperatures. The E2 controller, a standard feature on the Eco-Cool system, allows for remote monitoring, alarm, and control of the refrigeration rack via an internet connection. The controller can also interface with building monitoring systems (BMS), maintain a backlog record of temperature readouts, and alarm end-users upon high temperature or low refrigerant.

Although RDT's application didn't require any changes to the compressor solution, the OEM did ask Emerson to design a back-up operation option for system redundancy. "The request was accomplished by adding an optional fixed-capacity Copeland Scroll compressor for back-up," says Bob Chaney, district sales manager, Emerson Climate Technologies, Flow Controls Division. "The fixed-capacity scroll compressor would be sized the same as the digital scroll compressors, and capable of handling or taking over all of either the MT or LT systems’ loads as needed. This switch-over can be done manually or automatically through sensor inputs and diagnostic control communications."

Emerson and RDT worked together on the rack system from concept to completion, starting in mid-2007 and ending in January 2009. Dyess says RDT has now implemented engineering for the Eco-Cool on dozens of projects across the United States and is about to install a system in Texas for energy testing. "The objective is not to prove its viability or dependability, but rather to have hard numbers to compare against energy savings of conventional systems," he says.

"The feedback at NAFEM and resulting interest in implementing this system into new designs is incredible," Dyess continues. "We plan to blend some of the Eco-Cool features into our parallel designs and replace many of our multiple compressor racks with this concept."