Heat is a formidable enemy in MR and CT chiller design

by John W. Mitchell, Senior Correspondent | September 09, 2015
From the September 2015 issue of HealthCare Business News magazine

“Regardless of the market or the application, the main objective is to ensure as close to 100 percent uptime as possible. The only downtime should be scheduled,” said John Carmody, vice president of sales and marketing for KKT Chillers, Inc. “Obviously any unplanned downtime is not favorable from a health care or revenue perspective.” Carmody said KKT designs a couple of features in their chillers to ensure performance longevity and redundancy. These include variable speed in such components as the compressor, pumps, and fans, which keep the chiller unit running at all times in response to the heat load. This prevents sudden on-and-off starts to reduce wear and tear, which in turn extends the life of the components.

In addition, according to Carmody, pump failure tops the list of components that fail in a chiller, so KKT is introducing a new chiller model — the cBoxX line — which uses two pumps. Hansel, with Filtrine, said a common cooling design known as storage method is prominent in their chillers. “We build our units with a 55- to 550-gallon tank, filled with a combination of glycol and water to cool both the cryo compressor and the gradient coils. Each component has different cooling needs,” he explained. Hansel said additional backup could be provided either from city water (if below 75 degrees) or building chill water.

According to Donald Decker, national account manager for health care with Daikin, many of their hospital clients are operating in buildings constructed earlier than the 1970s. Daikin generates $18 billion in space cooling revenue a year. “Adding new technology tends to change the design of these buildings from how the space use was originally intended,” said Decker. “They need more cooling tonnage, but only have the same amount of space available to put a new unit in.” He said new design and technology advances, such as magnetic bearings, variant refrigerant flow, and centrifugal design, produce very little heat, save energy and are much quieter, all of which helps fit more powerful units with higher capacity into existing spaces.

“This is a very common problem and solution,” said Decker. “We understand the pain points that administrators have with behind-thewall costs that don’t directly touch the patient, so we work to make a case for upgrades as an investment.”

To this end, Mark Kearschner, vertical market manager for health care, also at Daikin, cited the advantages in considering the entire cooling needs of a hospital, not just spot solutions. He said the payback on a facility redesign with the new available designs and technology can actually produce much-improved cooling and pay for a project through energy savings in as little as three years or less. Daikin client Methodist Dallas Medical Center, for example, achieved payback with a new HVAC system design in 18 months.

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