This paper presents a new contact heat transfer model for estimation of wallto-bed heat transfer rates based exclusively on information on particle flow andmixing within a stirred granular bed. The effects of solids flow ability, bedheight, blade rotational speed, size of the annular wall-to-blade clearance, vesseldiameter and aeration of the bed on the overall solids mixing patterns, particlerenewal rates and contact heat transfer in vessels agitated with flat paddles arepresented and discussed. The model is shown to yield satisfactory agreementWith expenrnental data.