Session: 20-01 Radial Turbocompressors Analysis

Paper Number: 79574

79574 - Economizer Location Optimization for a Centrifugal Compressor With Refrigerant as Working Fluid 

In a typical HVAC chiller, centrifugal compressors are used to compress the refrigerant. These compressors are of single or multi-stage cycles that can be configured for a reinjection between cycles. This reinjection introduces cascade cycle options while improving the Coefficient of Performance (COP). One cascade cycle option that has become industry standard is an economizer cycle. During this process, the goal becomes to reinject flow back into the compressor between stages while the remaining flow continues through the cycle. The exact location of the economizer where its benefit would be at a maximum has yet to be determined. Testing for such a location typically involves a cycle of manufacturing of parts, demanding large amounts of testing and further resulting in long development cycle time. Therefore, a numerical approach where multiple economizer locations can be investigated is ideal. This paper develops a high-fidelity full compressor model where an economizer may be simply added into any location. However, this numerical approach requires a method for reducing the number of locations investigated, as testing the economizer position throughout the interstage in search of an optimal location would lead to a computationally expensive methodology. The proposed solution is a thermodynamic cycle analysis comparing compressor economizer benefit to an interstage pressure split. The compressor model is first investigated under 100% the design speed without the added economizer where a baseline is achieved. Three different models are investigated with increased model complexity for model validation. The most complex agreed with experimental results with high-accuracy and was used for further economizer testing. The thermodynamic cycle analysis is then implemented to identify the optimal economizer location based on the interstage pressure. Four locations are determined to fit the criteria. Two economizer locations were found to exhibit improved performance when compared to the remaining locations, increasing the aerodynamic efficiency of the base model by 10%.

Presenting Author: Jin Yan Danfoss Turbocor Inc

Presenting Author Biography: Dr. Jin Yan is the Director of Aero-thermal Engineering in Danfoss. He manages the new compressors aero design and new compressor technology development activities in Danfoss. Before he joined Danfoss, Dr. Yan was the manager of combustion aero in GE. His team developed aircraft engine/Gas turbine designs and prototypes with GE aviation, GE power, and GE Oil & Gas. He worked as the worldwide turbomachinery expert for Ansys before GE. He got his PhD in turbomachinery from Durham University.

Authors:

Jin Yan Danfoss Turbocor Inc
Jose Urcia Danfoss Turbocor Inc
Tadeu Fagundes Danfoss Turbocor Inc