A receiver system for harnessing solar radiation. Embodiments of a receiver system include a receiver including one or more receiver elements, each receiver element including: a plurality of transparent tubes including a first tube and at least one second tube at least partially within the first tube; a first passage interposed between the first tube and the at least one second tube, the first passage having an inlet and an outlet; a second passage within the at least one second tube, the second passage having an inlet and an outlet; and an absorber in the at least one second tube, the absorber adapted to absorb the solar radiation. In some embodiments, a receiver further includes a housing having at least one transparent portion, the housing configured to enclose the plurality of receiver elements, whereby a third passage is formed between the first tube and the housing.