More efficient motors. New control strategies that have improved part-load performance. Variable speed drives to control the chiller, improving part-load performance. One manufacturer uses a turbine to recover energy in the refrigerant cycle. Today, however, chillers using the alternative refrigerants can be more energy efficient than any chillers that used CFCs.
Reliability is another area in which chiller performance has improved.
Centrifugal chillers have always been reliable machines, but new designs and materials have improved on that track record. So have microprocessor controls. Now, the controls try to keep the machine on line for as long as possible without causing damage to the chiller. Furthermore, the controls record the reasons for problems so minor difficulties can be corrected before they become serious. Sophisticated algorithms also make it possible to tie chillers into sophisticated building-wide energy management strategies.