Study on the multitime scale rolling optimization operation of a near-zero energy building energy supply system

Abstract

The combined cooling, heating and power system of near-zero energy buildings can provide cold energy, heat energy and electricity to users at the same time, realizing combined cold, heat and power generation. However, the randomness of renewable energy output and the volatility of user loads lead to an imbalance between energy supply and demand. Therefore, a three-stage multitime scale optimization operation method is proposed. This method establishes a three-stage optimization model of ‘day-ahead, day-in rolling, real-time feedback’ to optimize the output of the unit step by step. In the day-ahead phase, the optimization goal is to take the lowest daily operating cost while considering the environmental cost. In the day-in rolling stage, the optimization goal is to control the minimum cost of energy purchase in the time domain and the minimum penalty cost of unit output change. The real-time feedback phase optimizes with the minimum total device power adjustment. The results show that the cost saving rates of multitime scale optimization strategies on typical winter days, typical transition season days and typical summer days are 0.90%, 2.32% and 2.12%, respectively. Compared with the ideal cost of different typical days, the cost deviation rates are 0.21%, 0.51% and 1.97%, respectively. Compared with the optimization of the previous day, the total power of the grid connection line on different typical days is −8.0%, −10.65% and −6.23%, respectively. Therefore, this novel optimization method has good economy, stability and accuracy and has a guiding effect on the formulation of each equipment operation plan.