Development of an air flow sensor for heating, ventilating, and air conditioning systems based on printed circuit board technology

This work presents a novel air flow sensor for measuring flow velocities in heating, ventilating, and air conditioning systems. The transducer relies on printed circuit board technology allowing the fabrication of robust, design flexible, and cost-effective devices. Due to the interaction with the streaming fluid, the transducer generates an electrically measurable signal for determination of the total flow of the fluid. The measurement principle is based on a modified calorimetric principle where the heater is excited through a DC current and the sensing resistors are excited through a sine. Guided by extensive numerical simulations, a series of electrically transducer designs were investigated, optimized, and fabricated. Afterwards, these samples were characterized and compared to simulation results.