What is the thermal conductivity of a heat pipe ?
HP ’ s do not have a set thermal conductivity like solid materials due to the two-phase heat transfer . Instead , the effective thermal conductivity improves with length . For example , a 4-inch long heat pipe carrying 100 watts will have close to the same thermal gradient as a 12-inch long pipe carrying the same power . Thus the 12-inch pipe would have a higher effective thermal conductivity . Unlike solid materials , a heat pipe ’ s effective thermal conductivity will also change with the amount of power being transferred and with the evaporator and condenser sizes . For a well designed heat pipe , effective thermal conductivity can range from 10 to 10,000 times the effectively of copper depending on the length of the heat pipe .
Are heat pipes reliable ?
Since HP ’ s have no moving parts , they are extremely reliable . This is the reason they are used extensively in space applications where maintenance is not available .
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