Abstract: Magnetocaloric refrigerator or heat pump comprising an externally activatable thermal switch for transferring heat from a heat source to a heat sink, comprising: an insulator cage with thermally conductive windows for the source and sink; a magnetic nanofluid, comprised within said cage, wherein said magnetic nanofluid is able to flow under a magnetic field inside the insulator cage between a contact of the thermally conductive window of the heat source and a contact of the thermally conductive window of the heat sink; and a activatable magnet placed at either one of the thermally conductive windows, such that the produced magnetic field is aligned substantially parallel to the temperature gradient from heat source to heat sink.

Abstract: The present disclosure relates to a rotary triboelectric generator, device comprising different triboelectric materials for generating electricity, said generator comprising: a rotor shaft; a first triboelectric material plate fixed on said shaft; a bracket framework for receiving at least a second triboelectric material plate; a second triboelectric material plate fixed in said framework; arranged such that the first triboelectric plate comes into successive contacting and sliding against the second triboelectric plate, when said rotor shaft rotates, wherein both the first triboelectric material plate and the second triboelectric material plate are flexible plates. In particular, the first triboelectric material plate and the second triboelectric material plate are flexible plates having a different stiffness. In particular, the plate or plates fixed on the shaft are flexible and the plate or plates fixed on the brackets are stiff or flexible but less flexible than the plate or plates fixed on the shaft.