Developing operation of combined cooling, heat, and power system based on energy hub in a micro-energy grid: The application of energy storages

Abstract

This research presents optimum operation strategies for multi-energy systems as combined cooling, heat, and power systems with the approach of electricity supply priority regime. A grid with energy hub structure including electrical, thermal, and cooling hubs is explored. Accordingly, an energy hub structure integrated with storages and renewable resources is designed. The mathematical model of the operation system for the presented triple generation micro-grid is considered for energy flow to the energy grid. Considering the limitations of the storage system and the performance of the equipment as well as electricity and gas line, a dynamic optimum operation model is prepared on the basis of mixed integer linear programming and is solved in general algebraic modeling system optimization software so as to minimize energy supply costs. For the model verification, different scenarios are developed in a residential building for a typical summer day so that the renewable resources and storages are fed into the system gradually. According to the findings, as each element is included in the micro-energy grid, its operational parameters, viz. the cost of electricity, gas, and pollutant emissions, are improved remarkably. Scenario I includes a combined cooling, heat, and power system, Scenario II is supplemented with renewable solar and wind energy, and Scenario III includes electrical, heat, and cold storages in addition to renewable sources and combined cooling, heat, and power system. Results reveal a decrease in total productivity cost by 12.2% in Scenario II versus Scenario I and 10.9% in Scenario III versus Scenario II.