It is well known that heat transfer characteristics can be improved by immersing the heat exchanger tubes into a fluidized bed. However, conventional fluidized beds are rather unstable and the comparatively large bed height causes a high pressure drop. To address this problem, one of the authors developed a very shallow fluidized bed heat exchanger which is composed of a horizontal array of tubes and a special designed multislit distributer that produces several two-phase jets. The solid particles carried in the jet impinge against the tubes and cause continuous defrosting by abrading ice formation. Here we shall present theoretical predictions for the flow properties within the jet, the impingement rate against the tube and calculations of the granular flow of particles on the inclined bottom chute that feeds the solids back into the jet. The theoretical models are based on experimental observations and data which we also present here.