The fuel cell and atmospheric water generator hybrid system for supplying grid-independent power and freshwater

Abstract

Despite the success of atmospheric water generators for providing drinking water to remote regions, this technology has a high specific energy consumption. This paper proposes to reuse the electrochemical water of the fuel cell for the vapor compression cycle based atmospheric water generator (VCC-AWG); After passing through an ambient heat exchanger to remove the electrochemical waste heat, the fuel cell flue gas that enters the VCC-AWG is at a higher relative humidity than natural atmospheric air, thus the freshwater yield per energy input can be significantly increased. Hence, the FC-VCC-AWG hybrid system is proposed to be a power and freshwater supply of a grid-independent home. The fuel cell model, the vapor compression cycle’s thermodynamic model, and humid air physics are coupled to analyze the overall system in terms of the fuel cell’s working condition, incoming airflow rate, compressor power consumption, and the ambient relative humidity. When RH = 0.75, adding a 2 kW fuel cell generated up to 3 kg/hr of freshwater, which is 50% higher than excluding the FC. The specific energy consumption can be 200 Wh/kg, so the VCC-AWG can be integrated with small sacrifices to the FC power output.