Abstract: Systems and methods are described for the in situ recovery of hydrocarbonaceous products from nonrubilized oil shale and/or oil sands. The inventive system comprises a closed loop, in-ground radiator that is suspended from a support cable (or rod) along with support bracket(s) and perforated outer casing sections into a borehole, in order to target and heat kerogen and/or bitumen within oil shale and/or oil sand deposits, and to collect the resultant hydrocarbonaceous product gases from the borehole without the need for separating processing gases and/or liquids. The inventive system avoids the drawbacks associated with “open” systems including the mixing of processing and product gases, and the problems historically associated with control and management of prior art in situ recovery systems.