Analysis and assessment of a continuous-type hybrid photoelectrochemical system for hydrogen production

• A continuous-type hybrid photochemical cell – chloralkali system is developed.
• The hybrid system is analyzed based on steady state balance equations.
• The effects of flow rates, applied voltage, and operating temperature on production yields and efficiencies are investigated.
• The trade–off between production yields and efficiencies is discussed.

In this study, we conceptually develop and thermodynamically analyze a new continuous-type hybrid system for hydrogen production which photoelectrochemically splits water and performs chloralkali electrolysis. The system has a potential to produce hydrogen efficiently, at low cost, and in an environmentally benign way by maximizing the utilized solar spectrum and converting the byproducts into useful industrial commodities. Furthermore, by using electrodes as electron donors to drive photochemical hydrogen production, the hybrid system minimizes potential pollutant emissions. The products of the hybrid system are hydrogen, chlorine and sodium hydroxide, all of which are desired industrial commodities. The system production yield and efficiencies are investigated based on an operation temperature range of 20 °C–80 °C. A maximum energy efficiency of 42% is achieved between the temperatures of 40 °C and 50 °C.