Disclosed herein is a heat exchanger, comprising at least one electric resistance heating element, at least two conductors which are connected to the at least one electric resistance heating element in an electrically conductive manner in order to conduct electric current through the at least one electric resistance heating element and thereby heat the electric resistance heating element, at least one thermally conductive element for transferring heat from the at least one electric resistance heating element to a fluid to be heated, at least one electrically insulating element, which electrically insulates the at least two conductors, and at least one pipe, wherein the at least two conductors and the at least one electric resistance heating element are arranged within a cavity bounded by the pipe and the pipe lies on the at least one electrically insulating element under a compressive force at at least one contact surface.

The invention provides a heating device for thermal treatment of a hive structure adapted for pollinating insects comprising at least one a heating element, and a heat dispersion element comprised of a heat-conducting material at least partly surrounding the heating element or parts thereof, wherein the surface area of the heating dispersion element is larger than the surface of the area of the heating element.

A column-conditioning enclosure includes a column chamber adapted to hold one or more chromatography separation columns. A duct system provides an airflow path around the column chamber such that the one or more chromatography separation columns held within the column chamber are isolated from the airflow path. An air mover disposed in the airflow path generates a flow of air within the duct system. A heat exchanger system disposed in the airflow path near the air to exchange heat with the air as the air flows past the heat exchanger system. The air circulates through the duct system around the column chamber, convectively exchanging heat with the column chamber to produce a thermally conditioned environment for the one or more chromatography separation columns held within the column chamber.

A system includes a vortex tube. A first thermoelectric terminal is in thermal communication with the first outlet of the vortex tube. A second thermoelectric terminal is in thermal communication with the second outlet of the vortex tube. An electrical circuit is electrically connected to the first thermoelectric terminal and to the second thermoelectric terminal for electrical conduction of Peltier-effect thermoelectric current. The systems and methods described herein can be used to enhance temperature difference generated in a vortex tube, and/or to harvest energy from the temperature difference in a vortex tube.