Study on Design modifications and feasibility in Conversion of scroll compressor into Scroll expander for using as battery charger.

Abstract

Scroll expanders are well suitable for low grade power production with an ORC. In this paper, scroll compressor design aspect in conversion to a compact scroll expander is taken. The major application of scroll expander is to generate power. The investigation of its application to charge batteries in automobiles is done to extend its application range. This analysis is done in two stages. In the first stage, a refrigeration scroll type compressor is taken to make it as a scroll type expander, as the availability of scroll type expanders are not wide in range. Its design modification has taken to make it compact and suitable for use as a battery charger with compressed air as working fluid. A mathematical simulation is done to find the design and thermodynamic properties like redesigning of the shaft to maintain eccentricity of rotating scroll and pressure ratio that influence the mechanical power developed in the scroll expander. A proto type of scroll expander is developed to conduct experiments for further analysis. In the second stage, the numerical feasibility analysis is done to verify the factors like speed and torque that influence the electrical power generated through mechanical work. In the trails carried, a voltage of 12.23 has been developed at inlet pressure of 15 bar and temperature of 303k.