Noise Reduction and Rapid Heat Storage for Vacuumed Electric Water Heater Using Main and Sub Heaters (Optimum Tune-Up Condition and Efficiency Assessment of Heat Storage Operation)

Abstract

Vacuumed electric water heater is useful for heat storage. However, it is still required to reduce its noise at boiling and to add the function of rapid heat storage. Therefore, a new heating method is proposed where both the main heater installed at the bottom and the sub one installed at the top are used. We investigated the process of bubble generation and its collapse in relation to the noise reduction mechanism with main and sub heaters used. From experimental results, we propose the optimal tune-up condition how these heaters should be controlled. It is also found the heat storage layer is robust to thermal disturbance and the necessary time for supplemental heat storage can be reduced nearly to 1/4 compared to the conventional one. We confirm that the proposed system is useful for industrial application.