An experimental study was conducted to determine the performances of silicon microheat pipes (MHPs) filled with different fluids. The MHP arrays are made of 27 triangular microchannels chemically etched in a silicon wafer. This wafer is closed by molecular bonding of a bulk oxidized silicon wafer. The results show that the use of MHPs with low liquid charges can increase the effective thermal conductivity of the array. The best improvement of the effective thermal conductivity of the MHP array is equal to 41% for methanol and pentane, 12% for ethanol and nil for water and FC72.