Analysis of a bowtie compressor with novel capacity modulation
Abstract
A novel refrigeration compressors with an integrated method of capacity modulation for use in domestic refrigerators/freezers is proposed and analyzed here. The compressor is called bowtie compressor due to its two sector-shaped, opposing compression chambers forming a bowtie. The bowtie compressor modulates the cooling capacity by changing the piston stroke without changes of the clearance volume for better thermodynamic efficiency. The new compressor includes a unique off-center-line mechanism so that the piston stroke can be varied without changes in motor rotation. To investigate the feasibility of the proposed compressor, a simulation model has been developed. The simulation model predicts the cooling capacity, COP, mechnical friction loss, volumetric efficiency, leakage flow rate, mass flow rate, overall isentropic compressor efficiency, and the compressor power input. After validating the simulation methodology by employing direct and indirect comparisons to a compressor map and compressor data in the open literature, parametric studies have been carried out to see how the proposed compressor performance can be improved. At the operating conditions of ANSI-ASHRAE Standard 23-1993 of Tcond =54.4°C [130°F], Tevap=-23.3°C [-10°F], and Tamb=Tsuct=32.2°C [90°F], the current simulation results show that the proposed compressor design is able to modulate the cooling capacity from 50 to 100% with a 20% change in overall isentropic compressor efficiency.
Degree
Ph.D.
Advisors
Groll, Purdue University.
Subject Area
Mechanical engineering
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