Comprehensive performance evaluation of Wind-Solar-CCHP system based on emergy analysis and multi-objective decision method

Abstract

Abstract To make full use of abundant new energy sources and meet the diverse energy demands of users, a system with new energy resources could be used to realize a combined cooling, heating, and power (CCHP) system. Environmental pressure can be reduced when new energy is used as a heat source or auxiliary power source. However, many kinds of energy can lead to uncertainty, low energy utilization rate, and high cost with the increasing types of energy. Therefore, an evaluation method of the advantages and disadvantages of a CCHP system coupled with wind and solar (Wind-Solar-CCHP) is needed. Firstly, emergy theory is introduced to evaluate the sustainable development level of the two systems, and a new comprehensive evaluation index system is established by combining emergy indexes with traditional indicators. Secondly, a multi-objective decision-making (MODM) method is proposed based on fuzzy-analytic hierarchy process (Fuzzy-AHP), anti-entropy weighting (AEW), and game theory to calculate the weights of these indexes. Then, the Kendall rank correlation coefficient is used to determine the correlation between the CCHP and Wind-Solar-CCHP systems. Taking the CCHP system as a reference, the integrated performance of the systems is analyzed by using the fuzzy comprehensive evaluation (FCE) method. Finally, an example of a hotel in a city in western China is selected for verification. The accuracy and robustness of the proposed method were verified by sensitivity analysis. The obtained experimental results indicate that the comprehensive performance of the Wind-Solar-CCHP system was superior to that of the CCHP system. Compared with other methods in the literature, the proposed method could achieve unification of subjective and objective attribute weights, overcome the limitations of the existing single evaluation method, and make the evaluation results more accurate. Moreover, these research results can provide a reference for the comprehensive utilization of new energy in China.