Wireless temperature and illuminance sensor nodes with energy harvesting from insulating cover of power cords for building energy management system

A new energy harvesting with low installation cost is proposed to enable stable power supply to battery-less wireless sensor nodes for energy management systems. Two electrodes (copper tapes) are attached on the insulating cover of two-wire power cords and the leakage electric-field energy is harvested by the capacitive coupling between the electrodes and the core wires. The proposed energy harvesting does not require an additional ground connection and the current in the power cords. 3-4V, 1.4μW is harvested with 20-cm electrodes from 100-V AC power supply. Temperature and illuminance sensor nodes with the proposed energy harvesting and ZigBee modules for the building energy management system are demonstrated. Both the temperature and illuminance are measured and transmitted to a wireless receiver within a 100-m radius every 250s.