Tuesday, 28 June 2016: 8:00 AM-9:30 AM
HVAC Systems and Equipment
Chair:
Rick Heiden, Trane - Ingersoll Rand
Technical Committee: 08.02 Centrifugal Machines
Centrifugal chillers are broadly employed in building air conditioning systems. Recent advances in chiller component performance have substantially reduced chiller power consumption, improved machine responsiveness and reduced footprint. This presentation provides HVAC professionals more technical insight into the chiller components along with design practices used by heat transfer, controls and systems engineers in developing state of the art equipment. This seminar builds on Seminar 21 from the 2015 ASHRAE Conference in Atlanta, “Centrifugal Compressor Design: Back to Basics.”
1 Chiller Heat Exchanger Components
 |
Thomas Kelly, Carrier Corporation |
The vessel used as the Evaporator of a centrifugal chiller is described for different applications ranging from Brazed-Plate, DX Shell and Tube and the more normal Flooded Shell-and-Tube type. The market is water cooled centrifugal chillers, so the Condenser described will be a shell-and–tube vessel. Other condenser sources such as a once-thru system will be discussed and a comparison of pros and cons will be shown. The impact of oil and oil free systems and metering is compared along with existing ASHRAE Research Projects. A discussion on heat transfer and tubing is also included.
2 Chiller System Operation
 |
Seth Gladfelter, Johnson Controls, Inc. |
This presentation discusses the system components that make up a centrifugal chiller. Operational maps of centrifugal chillers will be detailed. The presenter discusses how operating conditions affect overall system efficiency of the equipment, and also describe how centrifugal chillers react to changes in operating conditions. Also, the differences between fixed speed and variable speed chiller’s reactions to these changes in load are shown.
3 Chiller Controls
 |
Scott Munns, Ingersoll Rand |
This session describes the core internal controls of a centrifugal chiller, illustrating the features and functions identified in the handbook chapters. While many chiller controls are related to efficiently providing cooling, others protect the chiller from “hurting” itself. New code requirements and trends in communication protocols will be discussed. The presenter identifies variations in the add and subtract sequences for pumping and piping configurations in multiple chiller plants.