Experimental investigation of wraparound loop heat pipe heat exchanger used in energy efficient air handling units

Numerical modelling of the temperature distribution in a two-phase closed thermosyphon

“…This is different from a wicked heat pipe, where the working fluid is returned from the condenser by capillary forces [1][2][3][4]. Heat pipes have been successfully used for waste heat energy recovery in a vast range of engineering applications, such as heating, ventilation, and air conditioning (HVAC) systems [5], ground source heat pumps [6], water heating systems [7] and electronics thermal management [8]. This is mainly because of their simple structure, special flexibility, high efficiency, good compactness, and excellent reversibility [9][10][11][12].…”

CFD modelling of a two-phase closed thermosyphon charged with R134a and R404a

“…Water has been proven to be a suitable working fluid for temperatures between 30°C and 300°C, with good compatibility with various metals including copper and stainless steel. Liquid metals and various organic fluids have been selected for thermosyphons when the working temperature is above 300°C [6,[10][11][12][13][14].…”

“…The condensed liquid is then returned to the evaporator due to gravitational or capillary forces, according to the type of heat pipe [1][2][3][4][5]. Heat pipes have been successfully used for waste heat energy recovery in a vast range of engineering applications, such as heating, ventilation, and air conditioning (HVAC) systems [2], ground source heat pumps [6], water heating systems [7] and electronics thermal management [8].…”

“…Water has been proven to be a suitable working fluid for temperatures between 30°C and 300°C, with good compatibility with various metals including copper and stainless steel. Liquid metals and various organic fluids have been selected for thermosyphons when the working temperature is above 300°C [6,[10][11][12][13][14].Two-phase closed thermosyphons have been extensively used in many applications For mass transfer during the evaporation process:For mass transfer during the condensation process:where T mix and T sat are the mixture and saturation temperatures, respectively, and and are the volume fraction of the liquid and vapour phases, respectively. …”

“…The condensed liquid is then returned to the evaporator due to gravitational or capillary forces, according to the type of heat pipe [1][2][3][4][5]. Heat pipes have been successfully used for waste heat energy recovery in a vast range of engineering applications, such as heating, ventilation, and air conditioning (HVAC) systems [2], ground source heat pumps [6], water heating systems [7] and electronics thermal management [8].The most important characteristics to consider in identifying suitable working fluids are compatibility and wettability with the heat pipe materials, good thermal stability and conductivity, high latent heat of evaporation, high surface tension and low viscosity for both liquid and vapour [9]. In typical thermosyphons, the selection of the working fluid and the shell materials is subject to the working environment and temperature under which the thermosyphon-based system will function.…”