Investigation of a Renewable Energy System Using HVAC Condenser Fans for Low-Power Surveillance Systems

Abstract

This study presents an innovative approach to sustainable energy generation by integrating energy harvesting mechanisms into outdoor air conditioning units. The proposed system employs miniature generators embedded within the fan assembly to capture mechanical energy produced during operation. A pulley-driven transmission system converts this mechanical energy into electrical power, which is stored in a rechargeable battery and subsequently used to power Closed-Circuit Television (CCTV) systems. To regulate and optimize the electrical output, the system incorporates a DC-DC buck converter to adjust voltage to a usable range, and a solar charge controller to monitor current and voltage during the charging process. The prototype was implemented on a 1-horsepower outdoor air conditioning unit, with operational testing conducted under typical usage conditions to evaluate system behaviour and ensure performance reliability with two types of testing conducted. The first involved evaluating different pulley ratios. Results show higher pulley ratios produced higher power output both before and after DC-DC conversion, indicating improved mechanical-to-electrical efficiency. The second test examined system performance under two ambient conditions, 24°C during nighttime and 30°C during daytime. Results indicate that the battery reaches a full state of charge more rapidly at 30°C compared to 24°C, primarily due to the longer duty cycle and extended operation of the condenser fan under higher thermal load. The system successfully powered the 5W CCTV unit without relying on grid electricity, demonstrating its feasibility as a renewable and environmentally friendly energy solution for residential and commercial infrastructure.