Study On Optimal Design Of Mechanical System For A Green Building Based On Project Economic Evaluation Theory

Mechanical system energy consumption of large public buildings is the main component of building energy consumption,promote the development of large public green energy-saving building evaluation standard,is the objective requirement of the implementation of national energy production and consumption revolution strategy.During the period of 12th Five-Year,great progress has been made in building energy conservation and green building in China,and the building energy efficiency standards have been continuously improved.In the process of planning and design of green building,it is very important to select the building mechanical and electrical system,especially the HVAC system.This paper from the perspective of life cycle of green building,using the theory of economic evaluation of life-cycle cost theory and the construction of the project,selected that is consistent with the cold source of air conditioning requirements of green building technology has the optimal economic evaluation index.Cold source of air conditioning systems for green building electromechanical system,the identification of the cold source of air conditioning systems in the building life cycle in different stages of the cost structure and calculated at the same time;scheme of economic benefits,externality and environmental benefits were identified for all kinds of benefits are calculated and monetary,in order to build cost effectiveness of the scheme evaluation model.This paper is based on the actual data of a commercial complex building in Fuyang city of Anhui Province in five star hotel project,the use of Dest-C building energy consumption annual cooling and heating load of the structure of the computer simulation software,designed with three star green building evaluation standard of cold source of air conditioning air conditioning cooling load data.Respectively the conventional air conditioning system,ice storage air conditioning system,CCHP system.Three options for cold source program based on the life cycle cost theory,three alternatives to the life cycle cost benefit and incremental costs and benefits are calculated respectively,provide the basic data for the evaluation of the project economic benefit.Based on the.calculation of net present value,internal rate of return and dynamic payback period,the economic benefits of single and multiple schemes are studied for the three schemes.The results show that the net present value of the conventional refrigeration and air conditioning system is less than zero,and the internal rate of return is less than the industry benchmark rate.The net present value of the difference between the CCHP system and the ice storage air conditioning system is greater than zero,and the difference in the internal rate of return is greater than the industry benchmark rate of return,which is the optimal solution of the three alternatives.Based on the analysis of the two factors of electricity price and natural gas price,the sensitivity analysis of CCHP system is carried out.The analysis results show that the sensitivity of the change rate of the financial indicators of the CCHP system is significantly higher than that of the natural gas price changes.Finally,review and prospect of the research content and development trend in the future,and puts forward the method of green building evaluation and selection of cold source of air conditioning system of economic benefits and theoretical basis,which has a certain guiding significance for guiding engineering practice.