TECHNOLOGY FOCUS - POLYMERS - Preferred Tube/Collector: In the polymer tube or solar collector, the inner tube layer is the innermost tube layer, and the outer tube layer lies adjacent the inner tube layer. The inner tube layer has a hardness of 10 Shore A to 90 Shore D, and the outer tube layer has a hardness of 45 Shore A to 90 Shore D. The polymer tube is composed of a thermoplastic material or of a thermoset material. The polymer tube is composed of a thermoplastic material from either the olefin group or the polyvinylchloride (PVC) group. The polymer tube is composed of a thermoplastic elastomer, a thermoplastic rubber or a thermoplastic alloy. The thermoplastic elastomer, thermoplastic rubbers or thermoplastic alloys include olefin based polymers comprising an olefin block copolymer or cross linked or non-cross linked polyolefins. The polymer tube is composed of a material from the PVC group, the material comprises a PVC, a modified plasticized PVC or unmodified plasticized PVC. The polymer tube is composed of a thermoset material, the material comprises a thermoset elastomer. The polymer tubes are laterally connected via a co-extruded web. The web is made of a hard, rigid material or a soft, flexible material. The web is co-extruded using the same material as that of the inner tube layer, the outer tube layer or using another material, where the web is plasticized with elastic properties to give flexibility and allow for variable spacing between the polymer tubes. The tube, or tubes, has a strip co-extruded on it that covers less than 100% of an outer surface of the tube. The polymer tube comprises an outermost tube layer co-extruded with the inner and outer tube layers. The outermost tube layer covers less than 100% of the outer tube layer. The strip covers approximately 25-75% of the outer tube layer. Moreover, the polymer tube comprises an inner tube layer co-extruded inside of the at least one tube layer, and where the strip covers approximately 25-75% of the at least one tube layer. The inner tube layer is made of a cross-linked polymer. The inner tube layer is comprised of a moisture curable, silane grafted cross-linked high density polyethylene or a moisture curable, silane grafted cross-linked polyolefin elastomer. The outer layer is comprised of one of the following: a polypropylene, a polyethylene (low density (LD)PE or high density (HD)PE), an olefin block copolymer, a thermoplastic elastomer or a thermoplastic rubber. The polymer tube has a strip co-extruded on it that covers less than 100% of an outer surface of the tube. Alternatively, the solar collector for heating and transferring fluids comprises an inlet manifold and an outlet manifold through which fluid is respectively transferred into and out of the solar collector; and a set of polymer tubes, each polymer tube being weldable to either the inlet manifold or outlet manifold, or to both.