Patent ID: 8550786
Filing Date: 2013-10-08
Classification: F03D,F05B,Y02E

Abstract:
1. A vertical axis wind turbine comprising: a rotary body operable to rotate about a rotary axis; and a plurality of blades coupled to the rotary body to rotate the rotary body, wherein each blade of the plurality of blades comprises an airfoil-shaped body having a substantially symmetrical portion, and an asymmetrical portion having a outer camber bordering a cut-away portion, and wherein a cross-section through each blade of the plurality of blades transverse to the rotary axis comprises a first endpoint located at a first longitudinal extremity of the cross-section, a second endpoint located at a second longitudinal extremity of the cross-section, a chord line extending from the first longitudinal extremity to the second longitudinal extremity, a widthwise direction substantially perpendicular to the chord line, an inner camber line, an outer camber line, a cut-away length, and a cut-away depth, wherein i) throughout the substantially symmetrical portion of the cross-section of each blade, an average magnitude of a widthwise distance between the outer camber line and the chord line is between 90 percent and 110 percent of an average magnitude of a widthwise distance between the inner camber line and the chord line; ii) a length of the substantially symmetrical portion comprises more than one tenth of the length of the chord line, the length of the substantially symmetrical portion being measured parallel to the chord line; iii) the outer camber surface of each blade of the plurality of blades faces away from the rotary body; iv) throughout the asymmetrical portion of the cross-section of each blade, an average of a first displacement from the chord line to the inner camber line is more than three times an average of a second displacement from the chord line to the outer camber line, the first displacement being positive toward the rotary axis, and the second displacement being positive away from the rotary axis; v) at any point along the chord line, there is one and only one corresponding point along the inner camber line in the widthwise direction, and one and only one corresponding point along the outer camber line in the widthwise direction; vi) the cut-away length comprises more than seventy percent of the overall length of the cross section; and vii) the cut-away depth comprises more than sixty percent of the maximum thickness of the airfoil-shaped body and less than eighty percent of the maximum thickness of the airfoil-shaped body.