Study and implementation of home automation system with energy monitoring

Abstract

Home automation is about “bringing life” into various devices installed in a building or apartment, giving home owners the access to control these devices using central hubs or smartphones. Home automations systems are quite common in both residential, commercial and industrial applications. The management and control of residential or commercial devices is relatively established but still lacks in the proper management of energy flows. Recently, home owners have become more aware of energy consumption and had started investing in energy monitoring systems to observe energy consumption and reduce energy waste. A real time power meter is an electronic device that is used to record the electric power being consumed by devices. The main objectives covered in this project is the design and construction of a single-phase electrical energy monitoring system compatible with the KNX system. Furthermore, the project also developed a graphical user interface (GUI) for energy monitoring and to provide a platform-based control of electrical equipment. This document describes the design, development and implementation of a low budget single-phase real time KNX power meter. In this project, an accurate power meter is built using the instantaneous power calculation method; 𝑝(𝑡) = 𝑉𝑚𝐼𝑚 cos(𝜔𝑡 + 𝜃𝑣)cos(𝜔𝑡 + 𝜃𝑖) A voltage and current sensing circuit was designed and constructed to sample the voltage and current of a connected load. These are then sampled using the KAIstack development board which carries out the power calculation and communication with the KNX system. The rms voltage, rms current, power, power factor and phase angle are transmitted in real-time to the KNX system and are displayed on a graphical user interface (GUI) over a HTTP connection. Thanks to the HTTP connection, users can easily control and monitor data from a tablet, computer, smartphone or any device which have access to Wi-Fi. The developed meter was targeted to be used on single phase electrical appliances. It can accurately measure true power regardless of the type of connected load being resistive, inductive, capacitive or a mixture of all. The designed KNX power meter, is aimed to set the basis for a system whereby energy management algorithms can be applied to increase energy efficiency inside a domestic application.