Research On The Acceleration Methods Of The Optimization Design Of Buildings-Level Combined Cooling, Heating And Power Systems

With the development of social economy, modern buildings consume a huge amount of energy to meet its functional and comfort requirements. Currently, energy and environmental issues become more and more serious that make energy saving and emission reduction increasingly urgent than ever before in the field of construction. Along with the popularity of domestic natural gas, building loads center arranged natural gas combined cooling, heating and power supply system(buildings-level CCHP system), has received worldwide attention due to its energy-saving, economical and clean performance. Because of numerous internal and external factors. The optimization design calculation of Buildings-level CCHP system's is extremely difficult with huge of variables and complex optimum mathematic model. Based on this, this paper presents a study on acceleration methods for optimization design of buildings-level CCHP systems. The aim is to construct a simple optimization design method for buildings-level CCHP systems with little calculation, high accuracy, wide adaptation. In this paper, with theoretical analysis and numerical calculation study, the main work and results are as follows:(1) Energy consumption model of three typical building such as shopping mall, office building, and hotel has been established under climate of Chong Qing and Beijing. The results has been used for optimization design method research of CCHP system as the load model.(2) On the basis of the classical CCHP system, a more flexible hybrid CCHP system is proposed, and the energy-saving, economical performance of the two systems are compared. The research shows that electric chiller of hybrid CCHP system with high efficiency can consume excess power generated by hybrid CCHP system, which makes hybrid CCHP system more efficient and economical than the classical CCHP system.(3) The design and operation level optimization model of hybrid CCHP system is established with solving method of genetic algorithm and MILP programming. This solving method is called GB method. The optimization results of the GB method in the following studies are used as a reference to verify the validity of the other methods.(4) A working condition diagram analysis method is proposed for the first time to analyze the optimization running mechanism of the hybrid CCHP system. Based on this, a heat & power demand point optimization shift and optimal operation point determination operation strategy optimization method for hybrid CCHP system is proposed. This method can greatly simplify the operation strategy optimization calculation.(5) Based on the studies upon, the acceleration methods called DPOP method and S_DPOP method for optimization design of buildings-level CCHP systems are proposed. The validity verification of this two method indicate that the DPOP method not only has the same and even better precise optimization results, and has higher reliability, shorter computation time, in comparison with GB method; the S_DPOP method originated from DPOP method is more simple and has the same precise optimization results, and most importantly it is adaptable to different types of buildings and climates.(6) Cost-effectiveness analysis of hybrid CCHP system corresponding to three types of constructions in Chongqing including annual total profit, internal rate of return, dynamic investment recovery period show that the hotel has better economic indicators than other two kinds of constructions, and thus it is more suitable for using hybrid CCHP system; Shopping mall has longer dynamic investment recovery period, but can be thought to be in an acceptable range. Due to dynamic payback period is too long, whether to adopt CCHP system in office buildings need to further analysis with other type of the indicators.