Development of 1kW DMFC system with waste heat recovery for improving energy efficiency

Direct methanol fuel cells (DMFCs) are electrochemical devices that convert chemical energy of liquid methanol directly to electricity. DMFC can provide electricity and heat continuously as long as methanol and oxygen are provided. Therefore, DMFC is expected as power source for emergency, mobile and so on. The system maintains the fuel cell stack working at constant temperature and optimized methanol concentration. Moisture from the cathode is captured at the condenser, and the condensed water is sent to the liquid/gas separator for compensating the water loss. The dilute methanol solution is circulated through the stack and radiator. A novel concept of recovery waste heat is verified in real DMFC system working conditions. This DMFC system is completely self-maintained with the capability of providing 1 kW electricity and 3 kW heat. The total energy efficiency of the system is greater than 80%. This paper shows the fundamental research approaches for evaluating the performance of 1 kW DMFC system and optimizing the system working conditions. It shows that the higher system energy efficiency could be achieved based on the optimization of the system thermal management.