SAN DIEGO - Usually when the words government and green appear in the same sentence, our thoughts may turn to higher taxes. But, that’s not the case in California, where the federal government’s campaign to “go green” means converting more than 30 post offices to more efficient, environmentally friendly R-410A cooling systems.

Heading up the project is commercial contractor A.O. Reed & Co. of San Diego. A.O. Reed, with the support of Johnson Controls-Unitary Products, has installed York light-commercial air conditioning units in 17 post office locations across the San Diego and Los Angeles areas. The jobs represent $1.8 million in York equipment, which is part of an overall $5 million United States Postal Service (USPS) project.

With the San Diego skyline as a backdrop, A.O. Reed workers help position a 20-ton York Sunline Magnum high-efficiency, light-commercial unit onto the rooftop of a U.S. Post Office building. (Click on the image for an enlarged view.)


Those in the HVAC industry know R-22 refrigerant is on its way out, but chemical manufacturers can produce R-22 for use in new a/c equipment until 2010 and can continue producing it until 2020 for service purposes. So, why is the USPS in such a rush to change out R-22 cooling units for R-410A units?

The government is responding to increasing pressure to recognize global warming as a real and serious threat to the environment and is looking for ways to proactively address these conditions within its own government facilities. One way to start is by eliminating CFC-containing refrigerants in its facilities well before the clock runs out. It was this post office push for CFC-free refrigerants that ultimately opened the door for Johnson Controls-Unitary Products to team up with A.O. Reed.

“York launched the R-410A units sooner than some other manufacturers,” said Chris Cosgrove, the A.O. Reed project manager responsible for the USPS projects. “The big rush for the project was to make the buildings green, and the fact that the York brand offered more choices using R-410A certainly worked to their advantage.”

According to Cosgrove, a bid was packaged for each post office location and with consideration given to minimal downtime. The bid included equipment replacements and retrofit built-up systems that packaged the equipment to simplify changeovers. Equipment replacements included split-system heat pump and gas/electric units, York® Affinity™ Series package units, Predator™ package units, and Magnum™ and Millennium™ package units. Each package was customized to upgrade the selected locations’ existing systems with high-efficiency, reliable equipment that also eliminated CFC refrigerants.

Diego Stefani, Western regional sales manager for Johnson Controls-Unitary Products in Riverside, Calif., noted that each post office had a different cooling system configuration.

“There wasn’t one cookie cutter solution we could apply to all the buildings,” said Stefani. “Every building was different, but we were able to accommodate the unique requirements of each because we had a variety of products to choose from.”

Stefani particularly enjoyed incorporating York’s Simplicity control on larger units like the 40-ton Millennium. “The Simplicity control responded to whatever was needed, like cooling at specific times of the day, and the building’s automation was built directly into the Simplicity control board, which allowed control of the units even when a post office was closed.”

Round-the-clock temperature control is particularly critical in mail-handling environments, as humidity levels can adversely affect processes and equipment. “The mail requires what the USPS calls ‘process cooling,’ and that’s where the Simplicity control comes into play in this type of installation,” said Stefani.

A Simplicity Elite control, for example, was installed on a 40-ton Millennium unit at one USPS site. The Simplicity Elite provides a 365-day real-time clock, an occupancy schedule that allows two different occupied schedules per day, 20 holiday schedules, and an energy-saving economizer operation with the option of using a dry bulb, outside enthalpy, and differential enthalpy. The economizer enthalpy control has setpoints for outside air temperature, supply air temperature, small space cooling demand, and large space cooling demand. There is also a CO2 sensor, indoor air quality function with a programmable, maximum outside air damper position, and a temperature humidity algorithm that offsets the operating setpoint based on high humidity in the space and programmable limits to control humidity.

Another challenge, said Stefani, was working in a fully operational facility without affecting the mail-processing operation. This required a fast-track replacement process, as these facilities were spread out over a large area between San Diego and Los Angeles.

“All parts of the project were unique because we had to form custom adaptor crews for almost all the units,” added Stefani, who was directly involved in reviewing the plans, equipment, and pricing with A.O. Reed.

“A.O. Reed chose York because it provided the largest selection of equipment using R-410A refrigerant, and it offered a longer warranty period of five years,” said Cosgrove, who is hoping A.O. Reed will win a second round of bids for 34 additional post office locations.

Cosgrove also noted that York equipment availability met the completion requirement of the projects. Purchase orders were issued in December 2006, and projects began in February 2007. Work was completed on the first portion of post offices in late May.

Several York Affinity 13 SEER units are ready for operation at a U.S. Post Office facility in San Diego. A wide variety of York units - from 40-ton Millennium models to 5-ton Affinity Series units - were installed at 17 USPS facilities throughout Southern California. (Click on the image for an enlarged view.)


Some of the cooling units being replaced date back to the 1960s, while others are as recent as 1998. Brand names on the old units also run the gamut, covering five different major manufacturers. As this variety of units suggests, no two cooling systems were the same, and no two systems that replaced them are the same either. The York units that can now be found at these 17 facilities include a range of sizes and models - from the 40-ton Millennium, 15- and 20-ton Magnum, and 6.5- and 7.5-ton Predator to a set of 5-ton Affinity Series units. And they all use R-410A refrigerant.

One project in Fullerton, Calif., for example, previously comprised one 25-ton gas/electric multi-zone unit and two 5-ton gas/electric package units. In this case, the multi-zone unit zones were disconnected and the unit was being used as a single-zone unit. To update this facility, A.O. Reed installed one 25-ton Magnum R-410A Economizer gas/electric package unit and two 5-ton 13 SEER units, adapting the new units to the existing curb configuration. The contractor also installed all of the necessary electrical connections to hook up the new units to the existing power service and all of the new gas piping to the new units from existing gas service.

New condensate piping, designed to connect the new units to the existing drain line, was also added, as were new setback thermostats and smoke detectors in the supply air of each unit over 5 tons. To complete the installation, A.O. Reed started and tested each unit and provided crane service to replace the units.

“We believe that the completed projects will provide these U.S. Post Offices with many years of energy cost savings and efficient operation,” said Cosgrove. “Our success is thus far a clear advantage to A.O. Reed and York as we enter this second phase of projects.”

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Publication date:01/07/2008