Combining heat exchangers and metal foam and phase change materials for increased energy storage and heat generation using an exhaust heater: An experimental investigation

The increase in performance of home heaters, accompanied by energy and environmental crises, becomes noticeable in the construction industry. Hence, this paper has investigated a solution to enhance the system's efficiency. For this purpose, a novel experimental set-up is provided to simulate the heater, exhaust heater, and indoor environment. This setup includes two boxes, a heat source controlled by a Proportional Integral Derivative (PID) controller and an aluminum box with copper tubes. The heat is transferred from the first box as a heater to the aluminum box as a heat exhaust by the air force of the fan to warm the second box. Also, Lauric acid as a phase change material (PCM) and metal foam are used to increase heat absorption and heat transfer inside the heater exhaust regarding the thermal and physical properties of these two materials. Seven temperature sensors are located in different places to evaluate and control the system. Moreover, 6 modes are designed to find the best arrangement of materials for improving the system. The results show that a new arrangement of materials defined as filling the aluminum box with PCM and covering this box with metal foam, acquires remarkable efficiency. According to the achieved data, the mentioned design can decrease the outlet temperature of exhaust up to 2.3±0.1°C as well as increase the second box temperature in a home environment to 1.6±0.1°C. Finally, this mode can improve the efficiencies of the system both in outlet temperature and indoor temperature of the second box as much as 4.73±0.1% in the former and 3.72±0.1% in the latter.