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ISSN Druckformat: 2151-7975
ISSN Online: 2151-7991
TRANSIENT HEAT TRANSFER CHARACTERISTICS OF INCLINED LOOP-THERMOSYPHON-TYPE HEAT PIPE FOR SOLAR COLLECTOR WITH CHANGING INPUT SOLAR HEAT FLUX
ABSTRAKT
We experimentally study the steady-state and transient heat transfer characteristics of an inclined loop-thermosyphon-type heat pipe for a solar collector system when input solar heat flux changes according to the weather. The evaporator of the heat pipe is 1 m long, 6 mm in diameter and 30°-inclination. The input heating rate to the evaporator changes periodically 200 W for 240 s and 0 W for 240 s. The thermal conductance is defined as the effective heat transfer rate to the condenser divided by the temperature difference between the evaporator-wall and the condenser-wall. We found that the condenser temperature decreases just after the change of the input heating rate to steady-state heating condition 200 W by the effect of the low temperature vapor coming from the evaporator. The thermal conductance comes to be steady-state condition after 60 s from the change of the input heating rate to steady-state heating condition 200 W. Also we examine effects of liquid filling ratio and inclination angle on the thermal conductance.