Chiller Plant Renovation

The client’s research facility is a campus formed by an aggregation of several buildings. It is roughly divided into North and South halves for the delivery of building and process services. One chiller plant is located in each half of the campus.

Five Trane gas fired absorption chillers were operated in each chiller plant. A Trane Tracer System controlled the chillers and associated cooling towers. These chillers also provided hot water in addition to the chilled water for their respective campuses. The absorption chillers were approaching the end of their useful lives, had lost efficiency and had reliability issues.

The decision was made to replace the absorption units with seven York Electric Centrifugal Chillers using R-134a refrigerant distributed between the two plants. Additionally, seven 2M BTU high-efficiency Aerco boilers were added in the North Chiller Plant to make-up for the loss of hot water production by the abortion chillers. With the removal of the old equipment and installation of new, the building automation system controls was also transitioned to the client’s standard.

The challenge was to maintain sufficient chilled water capability during the replacements and through the peak summer period for long term testing in progress and people comfort. This was accomplished by phasing the work between the two plants. Equipment replacement was done in phases within each plant. Additionally, temporary (portable) chilled water capability was added to each plant to address reasonable temperature extremes during the project duration.

The project cover the design, construction, start-up and commissioning of the phased installation of the new chillers, boilers and transition to the building automation system. The project team was comprised of the client representatives, design engineering firm, construction manager, subcontractors, and commissioning agent.

O’Brien & Gere, was selected as the third-party commissioning agent for the project, which included:

• Review of preliminary and final designs
• Attendance at weekly project meetings
• Development of equipment/instrument listing for client maintenance systems
• Preparation an update of project schedule
• Training of contractors and client on focus of commissioning and execution of commissioning documentation
• Preparation of and execution of major Equipment Receipt inspections
• Monitored and reviewed construction progress
• Preparation and execution of Pre-functional Checklist for the various project phases
• Preparation and execution of Functional Tests for the various project phases
• Prepared preventive maintenance procedures for the new equipment
• Prepared and executed Performance Verification on the chillers
• Prepared project turn over documents

Commissioning
O’Brien & Gere acted as a Commissioning Authority during installation of 5,250 tons of electric-centrifugal 134a chillers, which replaced the failing absorption chillers. High efficiency gas boilers were installed to make-up hot water capability lost with removal of the absorption units. Third Party commissioning services for the renovations included design reviews of initial and final designs, preparation and witnessing execution of pre-functional and functional checks and performance verification.

The firm facilitated project commissioning and the turnover process from detailed design through installation, startup, and turnover phases of the project.

The following commissioning tasks were required:

• Design/equipment review
• Commissioning plan
• Commissioning meetings
• Commissioning protocols
• Monitoring protocol execution
• Training support
• Turnover package
• Commissioning protocols execution