To meet the requirements on computation speed

accuracy

application range for modelling non-adiabatic capillary tube for refrigeration system simulation

a fast calculation method for a non-adiabatic capillary tube is proposed. The approximation correlations for thermodynamic properties of refrigerant are proposed for subcooled zone

two-phase zone and superheated zone

respectively

and then the explicit approximate analytic solutions for the three zones are obtained using integral method. In the solution for two-phase zone

approximation correlation for thermodynamic properties is obtained by curve-fitting method

and the length is obtained using Green’s theorem. Case studies on R134a

R600a

R12

R410A and R407C show that the deviation between the predicted results of the proposed method and those of the existing distributed parameter model is less than 2% while the computation speed of the proposed method is 1000 times faster. The proposed method can meet the requirements for refrigeration system simulation.