Features of the 5 kW System

Inside front view of a 5 kW fuel cell system using a liquid-cooled stack. Courtesy of Wuhan Intepower Fuel Cells. 

Part of the coolant loop has two separate paths one path does not go through the heat exchanger and is used from the startup of the fuel cell system until the coolant temperature increases to a preset value (e.g., 60°C) to accelerate the rise of the coolant temperature the other path goes through the heat exchanger and is used when the coolant temperature reaches the preset value. Based on the stack needs, the coolant flow rate is adjusted by the coolant pump, and the heat that is dissipated out of the system enclosure is controlled by the fan mounted on the heat exchanger. 

Incoming air is humidified by a tubular humidifier made of many PEM tubules. It transfers some heat and moisture from the outgoing air from the cathode exhaust to the incoming air to make it hotter and humidified to a certain extent (e.g., 75%). 

Each of the two battery banks has a charger. The battery banks are charged by the grid AC power. The parasitic power needs of the fuel cell system when it is in the idling state come from the battery banks. When the grid power is disrupted, the battery banks first provide power for the load and then start the fuel cell system after a few seconds of preset delay time. 

---