A centrifugal chiller from Johnson Controls, Milwaukee, has a capacity range of 8,800 to 11,200 kW, which the company says is well-suited for large chilled-water plants.

The York model YK-EP Energy Plus unit can reduce the total cost of ownership while improving plant sustainability, says the manufacturer. Its mechanical-compression economizer cycle provides increased capacity and improved efficiency.

The chiller delivers energy savings at off-design conditions, where 99 percent of chiller operating hours are spent. The savings is due to the equipment’s ability to use entering condenser-water temperatures as low as 55°F (12.8°C). The lower ECWT reduces energy consumption by as much as 50 percent compared to chillers limited to a minimum ECWT of 75°F (23.9°C). According to the company, off-design performance can be improved by adding a York OptiSpeed variable-speed drive. And, in central utility plants and district-cooling facilities that use multiple chillers, piping the chillers in a series-counterflow arrangement improves energy efficiency further by reducing the compressor work on each chiller. For more details, go to www.johnsoncontrols.com.