As a result of studies of heat transfer between horizontal in-line and staggered tubes and a gas-liquid flow, heat transfer of higher intensity was obtained as compared with a single-phase liquid flow. The presence of solid particles in a gas-liquid flow, i.e., formation of a three-phase fluidized bed, results in a greater intensity of pulses (liquid-phase velocity and pressure fluctuations) near the heat-transfer surface. These fluctuations cause an increase in the heat-transfer coefficient for smaller Reynolds numbers.