Chiller Upgrade and Plant Interconnection at Kootenay Boundary Regional Hospital

Challenge

In early 2014, Prism conducted a detailed energy audit for Kootenay Boundary Regional Hospital in Trail, BC.  One of the recommendations of the audit was to replace the existing steam absorption chiller with an electric chiller to reduce Interior Health’s reliance on fossil fuels and to save on costs associated with the ageing equipment.

A major challenge of the project was the layout of the three chilled water plants, which each served separate sections of the facility – if one chiller were to fail, that section of the hospital would be without cooling.  Equipment redundancy is paramount in health care facilities, and so the Prism team was tasked to resolve this issue through an innovative design.

Solutions

Replacing Inefficient Equipment

To determine the most appropriate replacement chiller, Prism conducted a cost-benefit analysis for a number of different chiller types and configurations. Ultimately, a new high efficiency 300 ton centrifugal water cooled chiller was installed to replace the steam powered absorption chiller, in addition to a refurbishment of the existing cooling tower. 

Connecting the System

The three chiller plants (including the new centrifugal chiller) were then interconnected on the chilled water side using a combination of new and existing piping to ensure that cooling loads anywhere in the hospital could be supplied by all three chillers. Prism prepared a detailed sequence of operations for control that allowed the system to function not only effectively, but also efficiently, by selecting different chiller plants to act as the lead chiller depending on their energy performance as it relates to building loads and weather conditions.

Results

On an annual basis, the chiller retrofit alone is expected to save an estimated 194 tons eCO2, equivalent to $4,850 in BC carbon charges.  In terms of energy cost savings, the chiller upgrade will reduce overall energy costs by approximately $19,000 annually.

“Thanks to a structured design approach by the Prism consultant team, support and input of Interior Health staff, and competent contractors, the project was a technical success. The new system provides the equipment redundancy, energy performance, and greenhouse gas emission reductions required by the Interior Health Authority.”

– Sam Thomas, Prism Engineering