CHALLENGE - Stirling engine driven by solar energy for thermal to electricity conversion is one of the most promising solution of renewable technologies to reduce the dependency from fossil fuels. Unfortunately, the lack of data about the performance and some operational parameters of this technology limited its detailed characterization and sizing. A mathematical model was developed to determine geometrical and optical parameters of concentrator-cavity system. These parameters were a support for calculating thermal balance and electrical power generated by the Dish-Stirling system.
SOLUTION - Multi-objective optimization based on NSGA-II algorithm has been employed to optimize the power and the efficiency of the system, by means of integration of Dish Stirling mathematical model in modeFRONTIER. Numerical results show that for low wind speed the radiation heat losses have more influence over system performance, representing 96.06% of total heat losses; when wind speed is greater than 8 m/s convection heat loss (45.27% of the total heat losses) becomes larger than emitted and reflected
radiation. Pareto optimal front has been obtained for dual objective, and a final optimal solution has
been selected using a decision-making approach by Simple Additive Weighting of decision variables
(output electrical power and heat losses).
BENEFITS - Multi-objective optimization perfomed by modeFRONTIER shows a way to obtain an
output power of 11.1 kW, with an overall efficiency of 21%, with a significant decrease in heat loss, for
the weather conditions of Itajubá-MG.