Prior calculations of heat transfer coefficients for an experimental horizontal tube in a bubbling fluidized bed have assumed that heat conduction through the tube wall is a one-dimensional problem. However, a comparison between one-dimensional (1D) and two-dimensional (2D) analyses using experimental data shows that there exists a significant difference between 1D and 2D calculations, especially at the side of the tube. In addition, because of the periodic character of the bubbling fluidized beds, a theoretical analysis of a horizontal tube subjected to a periodic temperature boundary condition which varies in the circumferential direction is presented. The 2D analysis was accomplished by solving the unsteady two-dimensional heat conduction equation numerically, where the boundary conditions were taken from temperature data measured at five different locations of the tube simultaneously.