Abstract: A precast concrete solar collector panel of moldable hardenable material is developed with a serpentine-like passageway disposed in proximity to at least one planar surface of the panel. The passageway serves as a conduit for conveying a fluid to effect a heat transfer intermediate the proximate planar surface of the panel and the fluid rendering the panel useable as a heat collector or as a source of radiant heat, depending upon the relative temperatures between the conveyed fluid and the proximate planar surface. By constructing the panel as a structural member, a plurality of panels can be employed as a roof, exterior building wall, walkway, driveway or fence to receive radiant energy from the sun and transfer the collected heat to the fluid flowing within each of the panels; further panels can be employed as interior walls, ceilings or floors in buildings as sources of radiant heat by passing a heated fluid through the passageways.