Thermodynamic assessment of an integrated solar power tower and coal gasification system for multi-generation purposes

Multi-generation energy production systems allow higher efficiency by integration of different systems for recovering the highest possible exergy of the energy input. This paper concerns the thermodynamic assessment of a solar-based multi-generation system with coal gasification, involving power, heating, cooling, hydrogen, oxygen and hot water production. The coal gasification system is integrated with a solar power tower to utilize the concentrating solar energy. The clean syngas produced from the system is stored for the continuous power production. This multi-generation system has divided to the six subsystems. Energy and exergy efficiencies of each system are studied to show the system performance under the chosen conditions and also how to approach the ideal case. From the results, energy and exergy efficiencies of the sub-systems change between 19.43-46.05% and 14.41-46.14%, respectively, and the multi-generation system has the maximum energy and exergy efficiencies as 54.04% and 57.72%, respectively. Additionally, parametric studies, including the thermodynamic performance of the multi-generation system components, are conducted by the change in some major design parameters, as variation of the environment temperature, compressor pressure ratio, nitrogen supply ratio for the combustion chamber and gas turbine entry temperature. (C) 2013 Elsevier Ltd. All rights reserved.