Heat transfer to refrigerate or heat uses a thermoelectric semiconductor structure including a P-type composite of dices of semiconductor material alloyed with P-type material forming spaced collector regions at junctions with a P-type conductive material for flux of electrical current and a N-type composite of dices of semiconductor material alloyed with N-type material forming spaced collector regions at junctions with a N-type conductive material for flux of electrical current. The thickness of each the dices is sufficient to form a PN junction. Electrically conductive buss bars form an electrical circuit between the dices of N-type conductivity and the dices of P-type conductivity. An electrically conductive buss bar forms an electrical circuit connection between the dices of N-type conductivity and the dices of P-type conductivity. An electrical potential is applied by terminals between the P-type composite and the N-type composite to induce a flux of heat concurrent with the flux of electrical current.