The invention relates to a heat exchanger block 2 and to a heat recovery ventilation unit 1 comprising such a heat exchanger block. In the heat exchanger block 2, the individual flow cross-section (Q1) of flow passages of said plurality of first air flow passages (AFP1) in said parallel flow region (PF) and the individual flow cross-section (Q2) of flow passages of said plurality of second air flow passages (AFP2) in said parallel flow region (PF) gradually, preferably linearly, decrease along a straight line (x-perpendicular to the parallel air flow passages (AFP1 and AFP2) and from said first wall (W1) to said second wall (W2) of the block.

A constant density heat exchanger and system for energy conversion is provided. The constant density heat exchanger includes a housing extending between a first end and a second end and defining a chamber having an inlet and an outlet. A first flow control device is positioned at the inlet of the chamber and movable between an open position in which a working fluid is permitted into the chamber and a closed position in which the working fluid is prevented from entering the chamber. A second flow control device is positioned at the outlet of the chamber and movable between an open position in which the working fluid is permitted to exit the chamber and a closed position in which the working fluid is prevented from exiting the chamber. A heat exchange fluid imparts thermal energy to the volume of working fluid as the first flow control device and the second flow control device hold the volume of working fluid at constant density within the chamber.

A constant density heat exchanger and system for energy conversion is provided. The constant density heat exchanger includes a housing extending between a first end and a second end and defining a chamber having an inlet and an outlet. A first flow control device is positioned at the inlet of the chamber and movable between an open position in which a working fluid is permitted into the chamber and a closed position in which the working fluid is prevented from entering the chamber. A second flow control device is positioned at the outlet of the chamber and movable between an open position in which the working fluid is permitted to exit the chamber and a closed position in which the working fluid is prevented from exiting the chamber. A heat exchange fluid imparts thermal energy to the volume of working fluid as the first flow control device and the second flow control device hold the volume of working fluid at constant density within the chamber.

A temperature control body housing includes a monolithic housing middle portion penetrated by one or more than one fluid canal, each fluid canal being completely bounded on four sides by respective walls monolithically connected to outer walls of the housing middle portion; a first housing end cap and a second housing end cap between which the housing middle portion is disposed; wherein the first housing end cap has a first fluid port and either the first housing end cap or the second housing end cap has a second fluid port, and wherein the first fluid port and the second fluid port are fluidly connected to each other by means of the one or more fluid channels.

A temperature control body housing includes a monolithic housing middle portion penetrated by one or more than one fluid canal, each fluid canal being completely bounded on four sides by respective walls monolithically connected to outer walls of the housing middle portion; a first housing end cap and a second housing end cap between which the housing middle portion is disposed; wherein the first housing end cap has a first fluid port and either the first housing end cap or the second housing end cap has a second fluid port, and wherein the first fluid port and the second fluid port are fluidly connected to each other by means of the one or more fluid channels.

A tube for a steam cracking furnace comprising: at least one downstream tubular segment of circular section having a main diameter; at least one twisted tubular segment having a length less than a quarter of the length of the tube, and comprising: a central part with an elliptical or lobed section, having a helical pitch between one times and ten times the main diameter, and an aspect ratio of the elliptical or lobed section between 0.5 and 0.8; an upstream transition part establishing a geometric transition between the central part and a tubular segment of circular section; a downstream transition part establishing a geometric transition between the central part and the downstream tubular segment, with a fluid being intended to flow from the upstream transition part to the downstream transition part.

Solid-state thermoclines with internal baffle structures are in used in place of heat exchangers in a closed thermodynamic cycle power generation or energy storage system, such as a closed Brayton cycle system. The baffles limit the conductive and/or radiative transfer of heat between a solid thermal medium within different zones defined by the baffle structures.

Solid-state thermoclines with internal baffle structures are in used in place of heat exchangers in a closed thermodynamic cycle power generation or energy storage system, such as a closed Brayton cycle system. The baffles limit the conductive and/or radiative transfer of heat between a solid thermal medium within different zones defined by the baffle structures.

A heat pipe is provided having a hollow body defining an interior vapor space, evaporator and condenser regions, a wick structure lining an inner wall of the hollow body, and a working fluid disposed in the hollow body, wherein a path for the working fluid in liquid state extends from the condenser region toward the evaporator region or wherein the wick structure extends along a direction from a first end of the hollow body toward the second end, and wherein the wick structure includes first and second regions that extend along the path or direction and that each have wick particles defining respective pore sizes that are different from one another.

A constant density heat exchanger is provided. The constant density heat exchanger includes a housing extending between a first end and a second end and defining a chamber having an inlet and an outlet. A first flow control device is positioned at the inlet of the chamber and movable between an open position in which a working fluid is permitted into the chamber and a closed position in which the working fluid is prevented from entering the chamber. A second flow control device is positioned at the outlet of the chamber and movable between an open position in which the working fluid is permitted to exit the chamber and a closed position in which the working fluid is prevented from exiting the chamber. A heat exchange fluid imparts thermal energy to the volume of working fluid held at constant density within the chamber by the first and second control devices.