Power Beat: A Low-cost and Energy Harvesting Wireless Electric Power Sensing for BEMS

This paper presents a wireless power sensing for existing electrical appliances in buildings and houses. A wireless transmitter operates with power harvested from the current flowing in the electrical appliances. Every time when the voltage is stored in a storage capacitor, the RF module transmits ID code to a receiver. The transmission forms Power Beat which includes information of the power of the appliance. The power of the electrical appliance is calculated by the cycle time of the transmission. The transmitter operates when the electrical appliance works, so that total energy of measurement system is low, even when the numbers of the transmitters in a building or houses become large. The transmitter doesn't need power sensing devices, achieving low cost of the system. In experiments, this system can measure appliances power down to 20W with +/- 10% accuracy.