Multi-objective optimal operation and energy coupling analysis of combined cooling and heating system

• A multi-objective optimization model for micro-CCHP system is proposed.
• The model maximizes energy-saving ratio and minimizes the energy costs.
• Optimal operation strategies with different operational parameters are identified.
• These objectives always conflict with each other under different conditions.
• Contradiction due to coupling of gas supply and interaction power with the grid.

The internal coupling relationships are essential issues that impeding the efficient operation of a complicated CCHP (combined cooling, heating and power) system. In this paper, a multi-objective optimization model is proposed, aiming to maximize the energy-saving ratio and minimize the energy costs of a micro-CCHP system consisting of an absorption and electric chiller. Based on a novel co-simulation optimization platform, the NSGA-II (Non-dominated Sorting Genetic Algorithm-II) is employed to identify a series of compromised optimal operation strategies with different operational parameters. Moreover, the characteristics analysis is further made to reveal the energy coupling between these conflicting objectives in the operation of CCHP system. The implementation of this method will be beneficial to understand the internal energy variation and improve the system performance, thus providing a guiding principle for CCHP system optimization.