Reversible thermal rectifiers for selectively controlling the direction of heat flow include a plurality of asymmetrically shaped objects disposed in a fluid medium, wherein each of the plurality of asymmetrically shaped objects include a refractive side and a reflective side such that heat flows past the plurality of asymmetrically shaped objects when approaching from the refractive side, and heat is reflected from the plurality of asymmetrically shaped objects when approaching from the reflective side, and a bidirectional field actuator system that selectively orients the plurality of asymmetrically shaped objects between a first orientation, wherein the reflective sides of the plurality of asymmetrically shaped objects face a first direction, and a second orientation, wherein the reflective sides of the plurality of asymmetrically shaped objects face a second direction, substantially opposite the first direction.