rotary type heat and mass exchanger is used in ventilation system. it is very difficult to estimate the inner physical phenomenon of enthalpy exchanger because the heat and mass transfer occur at the same time. so, the design model to make the enthalpy exchanger is insufficiency. the analysis model is come from the Kurzweg model adding the mass transfer. to simplify of the theoretical analysis , it is necessary to linearization assumption of atmospheric air. the dimensionless parameters that play dominant role in performance of enthalpy exchanger is induced.