A method for operating a heat exchanger comprising a top side, a bottom side, and a thermoelectric device including thermoelectrically active elements which are electrically energizable for generating a heat flow between the top side and the bottom side, the method may comprise electrically energizing the thermoelectric device with an electric alternating current.

A thermocouple (TC) protection gauge may guard TCs from flying debris and fragments in an explosive environment or demanding commercial environments. The gauge may contain multiple co-located TCs. By using the protection gauge, the survivability of the TCs is significantly increased and allows for a longer time frame of data collection. Temperature data is acquired from multiple TCs that are experiencing approximately the same gas temperature and gas velocity. The temperature data may be used to reconstruct the real gas temperature of a dynamic event. Each of the TCs has a different diameter and therefore has a different time resolved temperature trace. The individual temperature traces may be used to extrapolate the real gas temperature using, for example, a reconstruction algorithm.

A temperature difference power generation apparatus according to one aspect of the present invention includes a thermoelectric conversion element configured to convert thermal energy into electric energy based on a temperature difference, radiation fins which are thermally connected to a low-temperature side of the thermoelectric conversion element and contactable to outside air, and a pipe which is thermally connected to a high-temperature side of the thermoelectric conversion element and through which a high-temperature fluid at a higher temperature than the outside air is flowable.

A temperature difference power generation apparatus according to one aspect of the present invention includes a thermoelectric conversion element configured to convert thermal energy into electric energy based on a temperature difference, radiation fins which are thermally connected to a low-temperature side of the thermoelectric conversion element and contactable to outside air, and a pipe which is thermally connected to a high-temperature side of the thermoelectric conversion element and through which a high-temperature fluid at a higher temperature than the outside air is flowable.

A cooling device for integrated circuits. The device includes: a plurality TEC cooling cells arranged in an array, wherein each of the cells includes a controller coupled to at least one TEC device; and a single power connector that provides power to all the cells in the array. The controller of each cell in the array is operable to control the at least one TEC it is coupled to with power received from the single power connector.

A cooling device for integrated circuits. The device includes: a plurality TEC cooling cells arranged in an array, wherein each of the cells includes a controller coupled to at least one TEC device; and a single power connector that provides power to all the cells in the array. The controller of each cell in the array is operable to control the at least one TEC it is coupled to with power received from the single power connector.

An apparatus includes a thermoelectric generator and a lens. The thermoelectric generator includes a hot plate, and is configured to convert heat directly into electrical energy. The lens faces the sun on one side and faces the hot plate on the other side. The lens is configured to concentrate heat from the sun and onto the hot plate.

Systems and methods for wirelessly transmitting power across a room or space are disclosed herein. One such system is comprised of a power receiving element positioned to receive wireless power transfer, comprised of a power receiving cell and a retroreflector positioned proximate the power receiving cell, and a power transmission element configured to wirelessly transmit power towards the power receiving element. The power transmission element includes an optical power transmitter configured to emit a first laser beam with a first power density towards the receiving cell, a guard beam emitter positioned proximate the optical power transmitter and configured to emit a second laser beam with a second power density towards the retroreflectors, a light detector positioned proximate the guard beam emitter and configured to detect light reflected by the retroreflectors, and an interlock system configured to interrupt power transmission when a decrease in light incident from the retroreflectors is detected.

A power generation element includes a first crystal region including Al.sub.x1Ga.sub.1-x1N (0<x1≤1), and a second crystal region including a first element and Al.sub.x2Ga.sub.1-x2N (0≤x2<x1). The first element includes at least one selected from the group consisting of Si, Ge, Te, and Sn. The first crystal region includes a first surface and a second surface. The second surface is between the second crystal region and the first surface. The second crystal region includes a third surface and a fourth surface. The third surface is between the fourth surface and the first crystal region. An orientation from the fourth surface toward the third surface is along a <0001> direction of the second crystal region. An orientation from the second surface toward the first surface is along a <000-1> direction of the first crystal region.

A thermoelectric device is disclosed. The thermoelectric device comprises: a body part comprising a hollow in which a semiconductor device is disposed; a plurality of connecting parts protruding on the lateral sides of the body part and comprising connecting holes; and a plurality of electrode parts connected to the semiconductor device and extending to the connecting holes of the connecting parts.