HEAT TRANSFER PERFORMANCE OF A PULSATED TWO-PHASE LOOP THERMOSYPHON

Thermoloop is a pulsated two-phase thermosyphon (PTPT) comprising of evaporator, condenser and a liquid reservoir with associated tubing and fittings with a view to cooling electronic devices. This study presents an experimental investigation on the thermoloop to address some issues on design and heat transfer performance. The evaporator employed in this study was of 72.5 mm x 60 mm x 20 mm in dimension with inside volume of 75 cm(3). The reservoir had a liquid storing capacity of 80 cm(3). A copper tubular condenser was used as the heat sink having two different convection conditions. For various heat input, evaporator wall temperatures, condenser inlet and outlet temperatures and reservoir liquid Column height were recorded at a regular interval. For the variation of heat input from 100 W to 250 W, the maximum temperature of the evaporator wall increased from 106 degrees C to 112 degrees C and the minimum temperature of evaporator wall increased from 73 degrees C to 95 degrees C at an evaporator fill ratio of 30%. The values of other functional parameter such as cycle time, height of liquid column in the reservoir and condenser temperature also increased with an increase in thermal load. The inclusion of a fan to cool the condenser increased the operational limit of the device from 125 W to 275 W. T)is thermoloop device transported heat in cyclic and pulsated manner; the amount of heat transported was as high its 250 W with a thermal resistance of 0.116 m(2) K/W. Furthermore, various functional parameters of the thermoloop attained a steady value after 5 to 6 heat transport cycles.