Multi-objective optimization of a solar-driven trigeneration system considering power-to-heat storage and carbon tax

Advanced solar driven tri-generation systems are highly relevant to reduce emissions and increase energy security. Here, solar collectors and photovoltaics are coupled to a tri-generation system to produce multiple final energy forms simultaneously for an office building. The excess solar electricity is employed for cooling/heating through a power-to-heat conversion employing thermal energy storage. Comprehensive optimization is performed to maximize the energy, environmental, and economic benefits, and the carbon tax is included to monetize the emissions. A coupled decision-making method is then used to choose the ideal scheme from the optimized sets of system configuration accompanied with a sensitivity analysis against key parameters. Compared to the conventional system, the proposed system improves the energy performance by 41.4% and the environmental benefits by 41.7% with the highest solar energy utilization rate. The economic performance improves in the best case by 14.4% only, but with the lowest utilization rate of solar energy. The ideal solution covers 30%, 54%, and 62% of the electricity, cooling, and heating loads, respectively, and the corresponded energy, environmental, and economic performance improves by 29.1%, 34.6%, and 7.7%, respectively. The sensitivity analysis shows that the economic performance is more sensitive to the electricity price than to the carbon tax.