Clearance Control of Scroll Compressor for CO2 Refrigerant

This study presents a higher compression efficiency scroll compressor for CO₂ heat pump water heaters, focusing on reduction of leakage loss. Gas leakage through radial and axial clearances is caused by two predominant factors; “uneven thermal expansion on scroll members due to temperature difference between suction and discharge” and “difference of thermal expansion coefficient between fixed and orbiting scroll.” First, we measured temperature distributions on fixed and orbiting scrolls in operation, second, designed several new scroll profiles to reduce leakage loss in consideration of the uneven thermal expansion, and achieved a higher efficiency CO₂ scroll compressor.