Coolant fan control for fuel cell systems

A cooling system for a fuel cell power plant comprising:

• a radiator having a first radiator section in fluid communication with a first coolant loop and a second radiator section in fluid communication with a second coolant loop and a fan disposed adjacent said radiator and operable to pass air through said first and second radiator sections;
• and
• a fan control system including:
• a first sensor generating a first input signal as a function of a coolant heat energy in a first coolant loop;
• a second sensor generating a second input signal as a function of a coolant temperature in a second coolant loop;
• and
• a controller including a first control circuit receiving said first input signal and generating a first control signal having a high state and a low state, a second control circuit receiving said second input signal and generating a second control signal having a high state and a low state, and a fan control circuit receiving said first and second control signals and generating a fan enable signal to turn said fan on when at least one of said first and second control signals are in said high state, and generating a fan disable control signal to turn said fan off when both said first and second control signals are in said low state.

A method for controlling a fan in a cooling system of a fuel cell power plant, the method comprising:

• determining a heat energy of a coolant in a first coolant loop;
• determining a coolant temperature of a coolant in a second coolant loop;
• generating a first control signal having a high state when said heat energy is above a predetermined level and a low state when said heat energy is below said predetermined level;
• generating a second control signal having a high state when said coolant temperature is above a predetermined temperature and a low state when said coolant temperature is below said predetermined temperature;
• enabling a fan when at least one of said first and second control signals are in said high state;
• and
• disabling said fan when both said first and second control signals are in said low state.