By Healthcare Facilities Today

Advances in chiller systems such as heat recovery and oil-free chillers with magnetic bearings allow healthcare occupancies to reap significant energy efficiency gains, according to a Health Facilities Management article.

There are numerous technological advances in chillers that facilities can consider during new construction or significant retrofits. Modular chillers, variable-speed drives, oil-free magnetic bearing compressors and greater tube efficiency are all gaining in popularity.

Chiller efficiency at part load has risen to the point where the article suggests some chiller types should be designed for peak load but run at part load as much as possible. In some climates, it might be more efficient still to use air-cooled chillers because of their part-load efficiencies.

Depending on a hospital's cooling load, heat-pump chillers might be a good fit. "A heat-pump chiller removes heat from the building's cooling loop and transfers it to the building's heating loop at temperatures up to 170 degrees F," the article says.  "At these temperatures, heat-pump chillers often can handle the entire cooling and heating load of a hospital without having to turn on additional boilers."

Because hospitals have significant base loads, with specialized cooling requirements, most often high-efficiency, variable-speed, water-cooled centrifugal chillers are selected for their efficiency and price points.  A growing trend is quick-start systems that can recover from a dead state to full cooling capacity in a matter of seconds instead of the typical 15 minutes, or more.

Using variable speed drives can be another way to increase a chiller's energy efficiency. By installing variable-speed drives with low harmonic content — some are available that produce less than 5 percent total harmonic distortion — facility managers can protect other sensitive electrical devices in the facility.

Improvements in chiller efficiencies are also helping to compensate for the removal from the market of older refrigerants, which were more efficient in the vapor-compression cycle. However, facility managers should be sure to select a new chiller that will have an adequate supply of refrigerant for its expected life and be aware that some reclaimed and recovered refrigerants have been subject to price volatility.

Read the article.