CCHP optimization for a building through optimal size of the prime mover considering energy, exergy, economics, and environmental aspects

Abstract

A CCHP is proposed for the central building in the gas supply company in Kerman city of Iran. This building has been using a separated generation system before, where it obtained its electrical demand from the main grid and thermal and cooling demand from a boiler with a fixed capacity established next to it. To optimally design the CCHP system, the optimum capacity of the prime mover must be determined. Many criteria can be considered in the optimization, however, this paper includes the environmental impacts, economics, energy, and exergy aspects which can be considered the most comprehensive approach. This optimization on the other hand requires a sophisticated optimization algorithm. The modified slime mold algorithm is proposed in this paper and to show its superiority, it is compared to some of the newest optimization algorithms using four standard benchmark functions namely Sphere, Rosenbrock, Rastrigin, and Ackley. The comparisons show more accuracy and consistency in the optimization by the proposed algorithm. The proposed algorithm is also compared to other methods in terms of optimization of the prime mover's size and the results are shown in terms of convergence rate. The proposed algorithm has resulted in 11.73% better performance on average. The optimum capacity of the prime mover is found to be 78.146 kW. Moreover, sensitivity analyses of the four assessment criteria and their sub-criteria are conducted and presented. Using the study and analysis given here, any system designer can have adequate tools to optimally design a CCHP system and fully benefit from the advantages provided by this technology.

Keywords

• CCHP
• 4E analysis
• Modified slime mold algorithm
• Sensitivity analysis
• Optimum capacity