This paper reports on the development of a new type of heat exchanger with bimetal fins for controlling the calorific value of water through phase change material (PCM) heat storage. It presents detailed numerical and experimental data on the velocity and temperature of water flow in a channel equipped with bimetal fins on the wall. Computational fluid dynamics and particle image velocimetry are used to analyze the flow behavior around the bimetal fins. The bimetal fins increase the insulation performance at the wall, such that the heat loss rate is decreases by a maximum of 56%. Furthermore, the flow rate and calorific value can be controlled at 10 L/min and 50 kJ, respectively. Consequently, the discharging-time during which hot water can be generated increases by a maximum of 70 min.