Paper proposes reduction in the consumption of active electrical energy (kWH) by 67%, while maintaining the same mechanical work speed (RPM)at variable torque loads of water and similar fluids using the fan affinity law'' in an innovative way in PMSM-type synchronous motors.The work is carried out comparatively between brushed asynchronous motors with with starting loop (motors with a short-circuited loop) versus brushed asynchronous motors and PMSM-type synchronous motors without the need to use variable frequency drives (VFD), simplifying the technology (electronic) and saving costs in an innovative way (R+D+i). The case study was developed on a design applied to a centrifugal air extractor/blower with PMSM/IPM type synchronous motor. the study focused on a specific bibliographical review of ecodesign and energy efficiency in refrigeration and ventilation systems, taking into account a cople of personal works and other general ones by various authors.