Concentric solar collector

A concentric solar collector comprising a round disk, an insulating substrate, a refective plate, a coiled absorber pipe, plurality of vertical heat-transfer plates and a transparent top envelope said round disk serving as a base and being formed as a round recess to insert and bond said insulating substrate, said insulating substrate being moulded to form plurality of concentric parabolic troughs facing upwards, said reflective plate being moulded with plurality of concentric parabolic troughs each corresponding to and engaged with each trough of said insulating substrate which is bonded under said reflective plate by adhesive, said coiled absorber pipe being led from an outside piping system to pass through said round disk, said substrate and the center of said reflective plate and then wound at a bending angle to extend along the focal circle line on the reflective trough and subsequently wound outwards to form a continuous coiled absorber pipe passing from inner trough to outer adjacent troughs and mounting along every focal circle line of each trough and finally being packed or coated with insulating material after leaving the collector for end-use connection, each of said plurality of vertical heat-transfer plates respectively connecting said coiled absorber pipe on each focal circle line and the parabolic trough positioned perpendicularly under said coiled pipe and said transparent top envelope being covered on said collector.