Sunday, January 29, 2017: 11:00 AM-12:30 PM
HVAC&R Systems and Equipment
Chair:
Rick Heiden, Trane, Inc.
Technical Committee: 8.2 Centrifugal Machines
Sponsor: 1.11, 8.1
CoSponsor: 1.11 Electric Motors and Motor Control
Variable speed drives are increasingly being applied to chillers with both positive displacement compressors and centrifugal compressors. In addition, advancements in variable speed drive technology are continually enabling enhancements in chiller component design and control. From enabling compressors to be designed for optimum speed to eliminating traditional capacity control mechanisms such as inlet guide vanes to hybrid systems with drives on some compression elements, variable speed drives are revolutionizing chiller designs.
1 Variable Speed Drive Basics
This presentation explains why Variable Speed Drives (VSDs) are used in many HVAC applications and how they operate. Explains variable torque vs constant torque loads. Describes the different Variable Speed Drive (VSD) terms commonly used in HVAC applications and defines the acronyms and names commonly used:
Variable Speed Drive (VSD), Variable Frequency Drive (VFD), Adjustable Frequency Drive (AFD), Adjustable Speed Drive (ASD), Freq Drive Inverter.
Variable Speed Drive (VSD), Variable Frequency Drive (VFD), Adjustable Frequency Drive (AFD), Adjustable Speed Drive (ASD), Freq Drive Inverter.
2 Variable Speed Screw Chiller Basics
Positive displacement chillers, more commonly known as Screw chillers, offer significant energy savings when applied as variable speed chillers. Screw chillers are offered around 550 nominal tons and can be easily incorporated into multiple chiller designs. This seminar segment describes the differences between how variable speed screw chillers and centrifugal chillers operate. An energy analysis demonstrates efficiencies reflecting true building and chiller operating conditions.
3 Variable Speed Centrifugal Chiller Basics
Centrifugal chillers are very dependent on operating speed in order to achieve maximum efficiency. Advances in Variable Speed Drive (VSD) technology are enabling optimized operating speeds that improve system efficiency over a broad range of centrifugal chiller applications and operating conditions. This presentation provides technical understanding of how VSD’s work within a chiller system as well as application examples of how that chiller system can be optimized within an HVAC system.