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ABSTRACT
Comprehensive performance evaluation is a fundamental part of the design and operation optimization of distributed integrated energy systems (IES), and the evaluation is currently focused on three types of elements: economic, energy efficiency and environmental protection. In this paper, energy use quality elements are proposed from the high energy supply requirements of users for distributed IES and characterized by the supply-demand imbalance rate indicator. Then the Analytic Hierarchy Process (AHP) and the information entropy method are combined to form a combined evaluation method by weighing the subjective and objective methods. The comprehensive performance evaluation of distributed IES with nine indicators considering four elements of economy, energy efficiency, environmental protection and energy use quality is realized. The feasibility and validity of the proposed indicators and the difference between the proposed combination method and the existing combination method are verified by the calculation examples. In the single-objective optimization with optimal energy use quality, the supply-demand imbalance rates for heat and cold are −0.05 and −0.035, respectively, which are the best among the five optimization schemes and fully guarantee the stability and quality of energy supply. However, its CO2 emission of 5738.91 (t/year) shows that this indicator is not suitable for the limitation of single-objective optimization, and it would be more suitable for comprehensive optimization with the above three indicators. The weights of operation cost, heat and cold supply-demand imbalance in the AHP method are 0.2247,0.0539,0.0539. The corresponding weights in the information entropy method are 0.0930,0.1670,0.1864. The corrected values are 0.1999, 0.0861, 0.0961. The results show the corrective effect of the information entropy method on the AHP. In addition, the combination method proposed in this paper corrects the configuration cost term to 0.2032, which is larger than both 0.1588 in the AHP method and 0.1388 in the information entropy method, highlighting the difference from existing combination methods. The above data show that the comprehensive evaluation by the AHP-information entropy method can effectively consider the four elements’ role. It provides a new idea for the research on the impact of distributed IES energy storage on the energy use quality of the system and the construction and operation optimization of the comprehensive performance evaluation indicator of the system.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Nomenclature
| IES | = | Integrated Energy System |
| TOPSIS | = | Technique for Order Preference by Similarity to an Ideal Solution |
| AHP | = | Analytic Hierarchy Process |
| FHL | = | Fixing Heating Load |
| CHP | = | Combined Heat and Power |
| = | evaluation indicators | |
| = | total number of micro gas turbine models | |
| = | number of configurations of a certain type of micro gas turbine | |
| = | total number of capacity continuous equipment | |
| = | cost factor¥/kW | |
| = | equipment capacitykW | |
| = | annuity present value coefficient | |
| = | number of days in the season at time t | |
| = | gas consumptionm3 | |
| = | electricit ykWh | |
| = | heat/cool energy kWh | |
| = | primary energy utilization | |
| = | electricity, heat and cold energy load kW | |
| = | coal-fired cogeneration unit coal consumption for power generation kg/kWh | |
| = | coal-fired received base heat kg/kWh | |
| = | electricity purchase from grid kWh | |
| = | calorific value kJ/kg | |
| = | grid transmission line loss rate | |
| = | exergykWh | |
| = | electricity, heat, cold exergy coefficient | |
| = | natural gas chemistry, coal exergy coefficient | |
| = | CO2，NOx，SO2 emissions | |
| = | pollutant emission factor kg/kWh | |
| = | equipment load rate | |
| = | the start and stop state of equipment | |
| = | imbalance energykWh |
Subscripts
| confc | = | configuration cost¥/kW |
| oc | = | operating cost¥/kW |
| f | = | fuel |
| om | = | operation and maintenance cost |
| sub | = | subsidy |
| ac | = | absorption cold and warm water unit |
| gb | = | gas boiler |
| hp | = | air source heat pumps |
| ec | = | dual working condition chiller |
| sto | = | energy storage equipment |
| pv | = | photovoltaic equipment |