The Clean Aviation project TheMa4HERA “Thermal Management for Hybrid Electric Regional Aircraft” aims to develop and mature the key technology bricks to enable efficient thermal management on these new aircraft concepts, where the increasing exploitation of electrical power will come with increasing number and entity of heat sources even more widely distributed in the aircraft compartments. Collins Aerospace provides advanced Thermal Management systems and services for commercial, regional, business aviation, military, and government customers. In TheMa4HERA Collins Aerospace is leading the ventilation work package focused on cabin pressure control and ventilation in unpressurized areas. This paper presents the recent findings in the TheMa4HERA project related to the design and optimization of a novel e-fan using state-of-the-art Computational Fluid Dynamics (CFD) modelling techniques. The end goal is to replace conventional bleed-air-driven subsystems in terms of performance, efficiency, and volumetric flow while reducing their weight. This e-fan is expected to be used for the ventilation of unpressurized bay areas during ground operations of HERA.