Some Basic Concepts and Definitions a Heat flux transferred heat quantity per unit time and per unit area perpendicular to the direction of the heat flow Heat source equipment or region to produce or provide heat flow for system a Heat transfer elements thermal resistance thermal capacity thermal inductance a Change in phase substance state is changed Continuity Supposition the macroscopic continuity but the microscopic discontinuity1 Some Basic Concepts and Definitions „ Heat flux transferred heat quantity per unit time and per unit area perpendicular to the direction of the heat flow „ Heat source equipment or region to produce or provide heat flow for system „ Heat transfer elements thermal resistance, thermal capacity, thermal inductance „ Change in phase substance state is changed „ Continuity Supposition the macroscopic continuity but the microscopic discontinuity