AN ENERGY SAVING SYSTEM IN AN EVAPORATIVE AIR- CONDITIONER

Abstract

This article presents the design, development and implementation of an energy saving system for an evaporative air-conditioning equipment. The proposed system is designed to decreased the amount of electric energy drawn by the air-conditioner. A single-phase induction motor that is commonly employed in this type of air conditioner is substituted by a three-phase induction motor that is driven with a three-phase inverter and a controlled voltage ac/dc rectifier. The system is controlled with a digital signal controller and a real time operating system, which manages the different subsystems within the energy saving system of the air-conditioning equipment. The use of a three-phase motor along with its voltage inverter allows the operation over a continuous speed range as a function of the ambient temperature, in contrast with the conventional air conditioners that have two fixed speeds. Furthermore, the real time operating system gives to the system the capacity to execute simultaneously different tasks with reliability. Among the tasks are the motor speed controller, inverter and rectifier control and the data logging of system variables. The experimental results demonstrate the feasibility of the proposed energy-saving system because it presents a 45% reduction in the electrical energy consumption when compared to a traditional system. Keywords: Induction motor, voltage source inverter, energy saving, controlled rectifier, real time operating system, evaporative air-conditioner.