Solar heater with bondless honeycomb heat trap

In a solar air heater comprising in combination:

• a housing having a light-transmitting front wall for passing incident solar radiation and including an inlet and an outlet for establishing a flow path for a gaseous medium to be heated,
• a gas permeable radiation absorbent collector element positioned across the flow paths in said housing and arranged to accept incident solar radiation passing through said front wall and to transfer the absorbed heat to said gaseous medium passing along said flow path through said collector element, and
• a heat trap disposed in said housing adjacent to the surface of said front wall facing said collector element, said heat trap comprising a cellular honeycomb structure containing a multiplicity of open cells in communication with said flow path and having cell walls that are substantially perpendicular to said front wall and which serve as baffle elements to inhibit the flow of said gaseous medium through said heat trap in a direction substantially parallel to the plane of said front wall, said cellular structure being maintained in at least firm mechanical contact with said front wall and being composed of a light-transmitting material which is opaque to infrared radiation emitted from said collector element in a direction toward said front wall, such that said heat trap is integrally formed as a unitary member thereby eliminating interfacial surfaces, joints or adhesive bonds therebetween which can act as scattering sites for incidental light.