Optimization of energy output in multimodal and multi-load CCHP systems with integrated electric energy storage

In energy supply networks, fluctuations in external energy inputs and internal equipment power consumption critically impact system output stability, necessitating advanced optimization strategies for multi-energy systems. To address this, a novel Combined Cooling, Heating, and Power (CCHP) system is proposed, integrating grid, internal combustion engine, gas boiler, lithium bromide absorption chiller, waste heat recovery system, electric chiller, and electric energy storage (EES). Targeting multi-energy load demand, four operation strategies are defined based on load prioritization while considering equipment power self-sufficiency and time-of-use tariffs: FPL-H (prioritize heating load after meeting electrical demand), FPL-C (prioritize cooling load after meeting electrical demand), FHL-P (prioritize cooling and electrical loads after meeting heating demand), FCL-P (prioritize heating and electrical loads after meeting cooling demand). To optimize equipment capacity and dispatch strategies, a bi-layer framework based on the P (Particle Swarm Optimization)-G (Gaussian mutation) algorithm is developed. The result shows that FPL-C strategy achieves minimal comprehensive economic cost (3471.16 ¥/day) at an optimal EES capacity of 119.26 kW, and reduction of 4.25 % in the amount of electricity purchased from the grid outside the minimum tariff period. Moreover, the study reveals the impact of the EES’s maximum discharge power and storage capacity on system performance and comprehensive economic cost. Excessive EES capacity and insufficient discharge power can lead to higher total economic costs. A study of CCHP system in different states and at different loads reveals the economic advantages of incorporating electric energy storage into the system structure with improved operation strategies • Establishment of CCHP system with electrical energy storage. • Proposed four new operation strategies based on load self-consistency. • Analyzed the impact of the parameters of the electrical energy storage on the comprehensive cost.