SAN FRANCISCO — Carrier Corporation has recognized an energy-efficient HVAC investment in a 14-story, two-tower, Sacramento, Calif., office building complex, by presenting the owners with a Carrier Regional Environmental Leadership Award.

The award was presented to Plaza Towers, Sacramento, during the Building Owners and Managers Association (BOMA) International’s Annual Conference and The Office Building Show, held at the San Francisco Marriott and Moscone Center. Representatives from Downtown Plaza Towers Associates, the owners of the Plaza Towers building, received a plaque recognizing their leadership in green building design.

“Periodically, Carrier Corporation presents Regional Environmental Leadership Awards to companies that have invested in energy-efficient projects which provide innovative, environmentally-sound design solutions for their commercial buildings,” stated Don Carlson, Carrier’s Northwest region commercial service area manager. “Plaza Towers is a great example of green building design.”

Originally built in 1969, Plaza Towers consists of two 14-story office towers. It houses a variety of commercial tenants in the heart of downtown Sacramento.

In 2002, management reviewed the Plaza Towers’ HVAC system, which consisted of two 30-year-old chillers and integrated boilers. While the old chillers still ran reliably, according to Patricia Sillix, RPA, Downtown Plaza Towers Associate’s vice president of asset management and past-president of BOMA’s Sacramento chapter, they realized that newer technology would undoubtedly provide better energy efficiency.

“We knew that if we could keep our HVAC system’s operating costs down, we’d have an advantage in our competitive commercial real estate market,” Sillix explained. “To be able to offer our tenants office space with high-quality, modern building features, at a reasonable price, is very important.”

In the end, Downtown Plaza Towers Associates decided to replace the building’s two aging chillers with two new 740-ton 19XRV Evergreen centrifugal chillers with unit-mounted variable frequency drives (VFDs). According to Carrier service sales representative Chris Countryman, the VFDs maximize the chillers’ efficiency by allowing cooling to be matched to the building load. The VFDs significantly reduce power consumption by slowing the speed of the compressor motor when less cooling is needed and when lower inlet condenser water temperature is available, he noted.

“Carrier’s 19XRV Evergreen chiller meets the key requirements of today’s customers who demand high-efficiency equipment to contain their operating costs, and deliver quick investment payback. In many cases, with the 19XRV’s price and performance, building energy analysis results in a two-year payback or less,” Countryman said. “This is an especially attractive option in climates like Sacramento, with wide outdoor temperature variations, where part-load conditions occur frequently.”

According to Plaza Towers’ chief engineer Tony Troglia, the performance of the chillers has been outstanding. “With our old chillers the best we could run was 0.9 kw/ton. With our new chillers, we’re reaching 0.38 kw/ton,” Troglia said.

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Publication date: 06/30/2003