Method and apparatus for construction of a solar collector

A solar collector having a liquid heat transfer fluid carrying means exposable to solar radiation and connectable to a heat transfer fluid circulating system, the collector comprising:

• at least one layer of transparent material positioned above an air space over the liquid heat transfer fluid carrying means, for insulating and sealing the heat transfer fluid carrying means from ambient conditions;
• a plurality of outer frame members for bearing the transparent material and for enclosing and sealing the heat transfer fluid carrying means from ambient conditions, about its perimeter, each outer frame member having means for attachment to a collector-bearing structure and comprising, in cross-section, at least one inner and at least one outer vertical wall section providing abutment surfaces against lateral movement and at least one upper and at least one lower horizontal section providing abutment surfaces against vertical movement, the at least four abutment surfaces defining an interconnection opening for positively aligning and joining the outer frame members;
• a plurality of interconnection members, each dimensioned to be fitted longitudinally into the interconnection openings of adjacent outer frame members, whereby all of the outer frame members may be positively and permanently aligned and interconnected by the interconnection members.