Kingston General Hospital is the major tertiary care referral facility complementing community hospitals and other health care providers serving southeastern Ontario. Integrally linked with Queen's University in Kingston, the 452-bed hospital supports a comprehensive array of acute and ambulatory clinical services in a vibrant and dynamic academic and medical environment. The hospital has a long history, reaching back to the 1830s, and today is one of Ontario's most important healthcare resources.
According to Carr-Braint and maintenance supervisor Chris Rousseau, numerous developments came together in 2002 which made action necessary. Three of the four chillers serving the hospital were over 30 years old, and used R-11 refrigerant. These three machines had operating efficiencies in the area of 1.0 kW per ton, and under the best circumstances were unable to carry the peak cooling load of the hospital.
At this point, the hospital brought in an Ottawa consulting firm, Goodkey, Weedmark and Associates, to evaluate the situation and make recommendations for system improvements. George Carscallen, a senior engineer with Goodkey, Weedmark, headed up this review process and developed recommendations for extensive improvements by the hospital. Working with the Department of Physical Plant and the Joint Planning Office, the firm made recommendations for improvements which could be made in stages, allowing the hospital to prioritize work. Its review indicated that numerous improvements in the chilled water plant and air distribution system would be required.
The first priority, according to Carscallen, was to upgrade the chiller plant. The existing plant had been designed for chilled water âˆ†Ts of approximately 10 degrees F, but because of an unbalanced primary/secondary pumping arrangement, on the hottest days the âˆ†Ts were as low as 7 degrees F, and the system simply couldn't keep up with cooling demand. Rousseau noted that the temperature and humidity levels in July and August would frequently creep up well above levels appropriate for the surgical suites and patient care areas.
The firm also made recommendations to modify the primary/secondary pumping arrangement, to extend the secondary loop, to upgrade airside equipment, and to replace the remote chillers. Goodkey, Weedmark also recommended improving system controls and making changes in the distribution of conditioned air to spaces within the hospital. The recommendations were made in late 2002, and the hospital forwarded them for review and approval by the provincial board that must approve capital expenditures for healthcare facilities. An approval was received for the first stages of the project, and the hospital and engineering firm immediately began planning for work to solve the most urgent problems before the coming summer of 2003.
The proposals by vendors were received by January 22, 2003, and the hospital selected Ottawa Trane for the project. According to Carr-Braint, one factor in the decision was the hospital's previous successful experience with Trane, as well as the fact that Trane had a preventive maintenance package to go along with the new chillers. A second factor was the fact that the existing mechanical plant had some significant constraints based on the space footprint available and weight limitations. Further, there were restrictions in the size of the available electric service. The electric utility had service amperage limitations on the site, so the machines selected had to fit within this electric constraint. The Trane proposal would squeeze the greatest available tonnage into those physical and electrical constraints.
Ottawa Trane worked with the manufacturing group in La Crosse, Wis., to secure the best possible delivery schedule for the machines, and to assure that the new machines would fit the site constraints. Another major part of the project handled by Ottawa Trane was the installation of two new Evapco cooling towers on the building rooftop, replacing the old, failing towers. The new towers not only have more capacity, but would have variable speed fan drives, which allows tower operation to be optimized for cooling load and weather conditions.
A third improvement was the installation of a Trane Tracer Summitâ„¢ chiller plant management system. This system optimizes operation of the chillers, pumps, and cooling towers, and communicates with the hospital's existing Siemens building automation system. All of these improvements were done in the spring, before the peak cooling season. The first chiller, the 515 ton machine, was delivered in April and was installed and on-line by the first week of July. The second (777 ton) machine was received in May and was on-line by early August.
Carr-Braint pointed out that another important effect is reduced system operating costs. "We've seen a 40 percent reduction in energy use by our comfort system during cooling operations. That's very impressive." Also important is the fact that it was no longer necessary to cancel surgeries because of inadequate temperature control in the surgical suites.
Kingston General Hospital is already well on the way to having a modern comfort system. As the funding dollars are released, an old and respected name in Canadian healthcare is also leading the way in comfort system efficiency and control.
Publication date: 09/27/2004