A multiple vane roto-dynamic variable displacement kinetic system with a mechanism comprising: an Intermittent rotor element containing plurality of, an Individual Constituents along with a Counterpart, wherein said Individual Constituents and said Counterpart has a circular disc, placed coaxially with a central axis such that each of said Individual Constituents has an Inner surface that together with the Inner surface of said Counterpart forms a First Part of a torus chamber surface wherein said circular disc are fitted with plurality of overhanging, radial and concentric Vanes such that each of said circular disc have equal number of said Vanes; a Drive Element which is a continually rotating link of said mechanism when operating and either serves as the power input member or the power take off member; at least a Stator element that forms a part of a structural element to support said rotor element with its surface forming a Second Part of said torus chamber surface that along with said First Part forms a First Volume that encloses said Vanes, wherein said First Volume is partition into plurality of Second volumes equal to the total number of Vanes on said circular disc, characterized in that the mechanism further comprises: a Bi-purpose Coupling for engaging and disengaging said Individual Constituents alternatly with at least any one of said Drive Element and said structural element, through said Bi-purpose Coupling depending upon a signal provided by a Control Link actuated by a First Timing Device, such that there is at least one said First Timing Device for each said Individual Constituent wherein said First Timing Device of said Individual Constituent actuates said Bi-purpose Coupling of said Counterpart, wherein said First Timing Device reads the angular position of said Vanes and actuates said Bi-purpose Coupling at a desired angular position from said Counterpart for rendering said Counterpart either as fixed link or as rotating link, allowing said Circular Discs to perform a sequence wherein said Individual Constituents are rotating link of said mechanism for a first period, which is preceeded and succeeded by a second period wherein either of said Individual Constituent is alternatly a part of fixed link of said mechanism, while said Counterpart is rotating link of said mechanism, thus leading to alternate increase and decrease of said Second volumes entraped between said Vanes, and simultaneously decreasing and increasing on both sides of said Vanes respectively, keeping said Second volumes constant for said first period, wherein, the changes in said Second volumes are utilized for compression and expansion processes of thermodynamic cycles in fluid handling machines and the variation in time period of said first period and said second period by varying said desired angular position results in said multivane roto-dynamic variable displacement kinetic system. an Intermittent rotor element containing plurality of, an Individual Constituents along with a Counterpart, wherein said Individual Constituents and said Counterpart has a circular disc, placed coaxially with a central axis such that each of said Individual Constituents has an Inner surface that together with the Inner surface of said Counterpart forms a First Part of a torus chamber surface wherein said circular disc are fitted with plurality of overhanging, radial and concentric Vanes such that each of said circular disc have equal number of said Vanes; a Drive Element which is a continually rotating link of said mechanism when operating and either serves as the power input member or the power take off member; at least a Stator element that forms a part of a structural element to support said rotor element with its surface forming a Second Part of said torus chamber surface that along with said First Part forms a First Volume that encloses said Vanes, wherein said First Volume is partition into plurality of Second volumes equal to the total number of Vanes on said circular disc, a Bi-purpose Coupling for engaging and disengaging said Individual Constituents alternatly with at least any one of said Drive Element and said structural element, through said Bi-purpose Coupling depending upon a signal provided by a Control Link actuated by a First Timing Device, such that there is at least one said First Timing Device for each said Individual Constituent wherein said First Timing Device of said Individual Constituent actuates said Bi-purpose Coupling of said Counterpart, wherein said First Timing Device reads the angular position of said Vanes and actuates said Bi-purpose Coupling at a desired angular position from said Counterpart for rendering said Counterpart either as fixed link or as rotating link, allowing said Circular Discs to perform a sequence wherein said Individual Constituents are rotating link of said mechanism for a first period, which is preceeded and succeeded by a second period wherein either of said Individual Constituent is alternatly a part of fixed link of said mechanism, while said Counterpart is rotating link of said mechanism, thus leading to alternate increase and decrease of said Second volumes entraped between said Vanes, and simultaneously decreasing and increasing on both sides of said Vanes respectively, keeping said Second volumes constant for said first period, wherein, the changes in said Second volumes are utilized for compression and expansion processes of thermodynamic cycles in fluid handling machines and the variation in time period of said first period and said second period by varying said desired angular position results in said multivane roto-dynamic variable displacement kinetic system.