Thermo-economic modeling and optimization of a solar network using flat plate collectors

Abstract

A solar network heater using flat plate collectors is modelled and optimized in this work. To have a reasonable comparison between the optimum network and traditional system (boiler), cost ratio (CR) (defined as a ratio between annual cost of the collector network and boiler) is used. In addition, both CR and exergy efficiency are considered as two objective functions. Bottom isolation, edge isolation, length of collector, width of collector, number of tubes, and tube diameter as well as the number of collectors and arrangement of collectors in the network are considered as design parameters. Fast and elitist non-dominated genetic algorithm (NSGA-II) is applied to find the values of optimum design parameters. The results reveal that it is not cost-effective in the case of high collector efficiency. Finally, the optimization is also performed for the different fuel cost, mass flow rate, equipment lifetime and required temperature. It should be noted that for final optimum point, by an increase of 10% in the fuel cost, cost ratio decreases by 4.75% and by an increase of 10% in the total solar energy incident on the collectors, cost ratio decreases by 9.69% and efficiency increases by 0.0178%.