Columbia Square

Project Summary

Columbia Square worked with Trane to install new water chillers that improved chiller plant efficiency by 40 percent and reduced energy use by 527,000 kWh. The chiller plant upgrades also resulted in annual operating cost savings of $35,600 due to decreased maintenance and service requirements of the new Trane chillers. In addition, Columbia Square has earned the Green Building Initiative’s highest rating of Four Green Globes, and achieved U.S. EPA ENERGY STAR™ certification.


Melvin Mark Companies wanted to improve the comfort, efficiency and reliability of the mechanical systems at Columbia Square. The two existing 300-ton chillers in the basement were more than thirty years old and it made sense to replace them before they failed. Replacement allowed installation of modern, significantly more efficient chillers. The basement equipment room added to the challenge as the old chillers had to be disassembled for removal, as did the new chillers to get them into place and then reassembled. The chilled water and condenser water loops used a constant volume pumping system. Two large built-up air handling systems serve the building with one air handler in the basement serving lower floors. A second air handler in a rooftop penthouse serves the upper floors.


To cost-effectively maximize energy efficiency, a Trane Trace 700™ energy analysis was completed. This modeling software established a base line to compare previous energy bills with chiller and pumping system upgrades. After running several iterations of the TRACE 700 analysis, Trane recommended installing two new, high-efficiency model CVHF centrifugal chillers, one of which includes an AFD (Adaptive Frequency Drive) on the compressor. Trane also recommended installing AFDs on the chilled water and condenser water pumps. The air handler control valves were changed from three-way to two-way valves. A flow meter and bypass line with a control valve were installed to ensure proper minimum flow through the chillers. A new Trane Tracer Summit™ chiller plant control system was installed to coordinate and optimize chiller plant operation for most efficient operation.


The upgrades have cut the Columbia Square chiller plant annual electric energy use by 40 percent and 527,000 kWh. The chiller plant upgrades also generated annual operating cost savings of $35,600 due to the decreased maintenance and service needs of the new Trane chillers. Columbia Square is also saving 194,000 gallons of water per year. Thanks to Energy Trust of Oregon incentives and a State of Oregon tax credit, the HVAC upgrade costs were nearly cut in half to only $239,850. A Trane Service Agreement helps to ensure that the new Trane chillers continue operating efficiently. The Service Agreement includes a comprehensive annual inspection of each chiller with an oil analysis. 

Byron Courts, Director of Engineering Services for Melvin Mark Companies, said, “My relationship with Trane in the building industry started thirty-five years ago. The quality of their products is tops and their service is great. That’s very important when you consider that our business objective is to provide comfortable work environments for our tenants. Trane may not always have the lowest first cost, but life-cycle cost is a big value for us. It’s hard to look at anything but Trane. Most of our work is updating existing buildings and Trane is very responsive to our needs!”

About Columbia Square

Columbia Square is a flagship property in the Melvin Mark Companies real estate portfolio. Built in 1979, Columbia Square is a fifteen-story, 313,000 square-foot office building that is the first existing building in the U.S. to earn the highest rating of Four Green Globes from the Green Building Initiative. The building was rated under the Green Globes environmental design and assessment tool. The Four Globes designation is the highest possible rating, recognizing achievement in green design and sustainable operations.