Chiller Economizer Integration

Integrated Chiller Economizer Technology is ideal for the process chiller replacement and design build markets.  Legacy currently offers Integrated Economizer Technology on forty air-cooled and water-cooled condenser chiller models. These Integrated Economizer Systems can reduce process cooling energy costs a much as 60%.

Target Markets: Integrated Chiller Economizer Technology can be used in many climate regions throughout North America and Europe. In early 2009, Legacy Chillers continues Case Studies in several major U.S. and Canada markets.  Using data collected from these case studies, Legacy Chillers had developed an MS XL based Chiller Energy Audit Tool to help customers quickly determine savings potential.

How Our Integrated Chiller Economizer Works:  When chiller cooling is needed, the onboard Economizer Controller begins to check outdoor air temperature on approximately ten second intervals. If the outdoor air temperature is approximately five degrees (F) cooler than process fluid temperature, the Economizer Controller will be automatically switching between four economizer states:

  • Mechanical Cooling State: Outdoor air temperature has risen above the Economizer deployment threshold temperature. While in this operating condition, the Economizer Controller will stop process fluid flow to the fluid (or dry) cooler and turn off it outside air circulation fan(s).

  • Combination State: Outdoor air temperature remains below the Economizer deployment threshold.  While in this operating condition, the Economizer Controller will direct process fluid to a remote mounted fluid (or dry) cooler. At the same time, fluid (or dry) cooler fan(s) will be turned on. During the call cycle, the Economizer Controller will attempt to maintain desired process cooling setpoint using the economizer as much as possible saving additional KWH.

  • Economizer Cooling State: Outdoor air temperature remains below the Economizer deployment threshold. Process load and outdoor temperature conditions exists making it possible for the Economizer to maintain the process cooling setpoint. While in this operational state the Economizer Controller will lockout mechanical cooling creating significant KWH reductions.

  • Chiller De-ice State: When outdoor air temperature remains below the Economizer deployment threshold for prolong periods of time, by design the mechanical cooling system will be deployed less.  This can create opportunities for ice and snow to build up within condenser fans causing damage to air-cooled condenser fans. To address this potential problem, the Economizer Controller allow mechanical cooling to run on specially programmed intervals preventing damaging ice buildup.

  • Alarm State: In the event of a mechanical cooling system failure, the process fluid temp will begin to rinse. Once the process fluid increases to a point where Economizer cooling can be used, the Economizer controller will automatically start taking over full cooling until mechanical cooling can be repaired.

For more information or an on-line presentation on how Legacy Economizer system works, please contact or engineering office at 877-988-5464 x 101