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• A model for predicting the performance of rotor-only axial fans, given the tangential flow velocity distribution, was proposed. • Using this model, a screening of possible solutions was carried out to find a design that provides maximum efficiency, and another with maximum flow. • The results were compared with the free-swirl methodology. • The designed fans were prototyped through 3D printing and their results were compared with a commercially used model. • The fan for maximum efficiency obtained a gain of 11 % while the one for maximum flow obtained a gain of 10 %. The paper puts forward a computer methodology for designing low-pressure axial fan blades for small-capacity refrigeration applications. Based on the blade element theory (BET), the airfoil efficiency of the airfoil, the principles of mass and momentum conservation together with empirical correlations for the flow irreversibilities, a mathematical model was devised for screening the blade geometric parameters (e.g., radial chord and pitch variation, and hub radius) by varying the induction coefficient distribution for a given fan diameter, motor speed, and airflow system characteristic curve. The best blade configuration is selected by means of a tailor-made optimization algorithm and undergoes a series of linear transformations for translating the fan parametrization into a CAD drawing. Two new fan blades were designed, one for maximum blade efficiency (MBE) and another for maximum airflow rate (MAR). In comparison with the free-swirl design approach, a standard procedure adopted in the open literature, the proposed blades showed an efficiency and an airflow by 20 % (MBE) and 14 % (MAR) higher than the reference. The airflow characteristics of the new designs were also assessed by means of wind-tunnel testing, which confirmed an increase of 11 % in the case of MBE design, while an enhancement of 10 % was observed in the case of MAR design. [ABSTRACT FROM AUTHOR]