Comparative study of different schemes of a novel solar tower receiver multigeneration system with SCO2 Brayton cycle and ORC

Solar energy is meaningful for energy structure transformation. This paper presents a comparison study of four different schemes of a novel solar tower receiver multigeneration system for providing electric power, hydrogen and oxygen. Super-critical CO2 Brayton cycle and organic Rankine cycle driven hydrogen production block are coupled in the proposed multigeneration system. Operation, exergy, economic and environmental analyses of four different multigeneration system schemes are conducted by using Ebsilon software, and the results show that Scheme 1, in which the evaporator of organic Rankine cycle is arranged downstream of the main heat exchanger of Brayton cycle, has the best exergy performance as it has the smallest overall exergy loss (273.99 MW) and highest exergy efficiency (26.7 %). By contrast, Scheme 4, in which the evaporator is used as the pre-cooler of the Brayton cycle, has the best operation, economic and environmental performances simultaneously. For Scheme 4, the output power, Brayton cycle efficiency, hydrogen and oxygen production rates are 64.32 MW, 50.53 %, 181.2 kg h−1 and 1449.6 kg h−1, levelized costs of electricity and hydrogen are 0.0687 $·kWh−1 and 4.44 $·kg−1, and the net present value and investment recovery period are 984.2 $M and 7.25 years. And annual emission reduction quantities of CO2, soot, SO2 and NOx of Scheme 4 are 88723.3 t, 1271.3 t, 2184.9 t and 2065.8 t.