A new power flow model for combined heat and electricity analysis in an integrated energy system

Abstract

As one of the important approaches to take complementary advantages of heat and electricity, an integrated energy system with combined heat and power (CHP) units enables the coupling of electricity and heating networks, which markedly increases energy utilization efficiency. However, the different characteristics between heat and electricity bring a great challenge to realizing synergy and complementarity. In this paper, a thermal–hydraulic model is developed based on the analogy between heating and electricity networks to analyze the district heating network. Thereafter, a new electricity-heat coupling model with matrix formulation, also known as the coupled power flow model, is proposed to realize the combined calculation of heat and electricity in an integrated energy system. The thermal–hydraulic model is validated by simulation results obtained from Advanced Process Simulation Software (APROS) with relatively small errors. The validated coupled power flow model is further applied to conduct an optimization study to evaluate the integrated energy system efficiency considering wind power and heat storage. Optimization results show that the simultaneous addition of an electric boiler and a heat storage unit can reduce the total operating cost by 17.36%. The present study indicates that coupling calculation of heat and electricity can be achieved with the proposed power flow model, which is beneficial to the design and optimization of practical integrated energy systems.