In this study, a feasible trigeneration system coupled with biomass gasification and solar thermal process is proposed. Transforming mid-and-low solar thermal energy into chemical energy of bio-gas by heating the steam indirectly, and providing fuel for internal combustion engine and exhaust heat recovery subsystem. Simulation and performance analysis of the trigeneration system are performed to investigate the effects of key operating parameters on its performance. The main research and conclusion are as follows:
(1)
Air equivalence ratio, steam/biomass ratio and air preheating temperature have a significant effect on biomass gasification reaction, and consequently affect the overall energy efficiency of the trigeneration system.
(2)
The introduction of mid-and-low solar thermal energy in trigeneration system decreases the extra consumption of biomass, and the solar thermal energy input fraction can be reached up to 48.1% when steam/biomass varies from 0 to 4.0 at solar collector temperature of 350 °C. Similarly, the higher solar collector temperature improves the overall energy efficiency of the trigeneration system.
(3)
The analysis of primary energy saving ratio (PESR) achieves an advantage compared with the separated generation system, and the proposed system provides various products to meet the demand of different customers.
(4)
In a case study (ER = 0.4, SBR = 0.4), the cold gas efficiency can reach at 59.3%, the solar thermal energy input fraction and primary energy saving ratio are 8.6%, 16.7%, respectively. The overall energy efficiency and the total exergy efficiency of the trigeneration system are 77.4% and 19.2%, respectively.
(5)
From the perspective of economic analysis, the annual total cost saving ratio (ATCSR) compared with separated generation system is about 25.9%. The equipment initial capital cost of proposed system accounts for 51.5% of the annual total cost, and the operation cost is about 33.9% of the annual total cost in the proposed system.
(6)
The efficient utilization of renewable energy has a unique advantage compared with fossil fuels. And the novel trigeneration system will provide a new idea for the integration with solar energy and biomass energy.