Research In Investment Decision Based On The Life-cycle Cost Of Energy Efficient Residential Buildings

Saving Energy is an inevitable choice that will promote the continuous development of our country. The state, developing trend and characters of buildings energy-consuming in our country make the residential buildings become the key field of Saving energy. However, because of the lack of correct concept on energy efficient residential buildings in the view of the life-cycle cost, the exploitation and construction of energy efficient residential buildings have been in a devil of a hole.In this paper, based on the importance of research in life-cycle cost of energy efficient residential buildings, the theories and the methods of investment decision are researched entirely based on life-cycle cost. The conclusions are as follows:(1) The meaning, constitution, analyzing process, characters and analyzing time of energy efficient residential buildings is confirmed.Starting with the meaning of life-cycle cost from inside and outside of our country, it is confirmed that the discount life-cycle cost is composed of preparing costs, construction costs, using costs and disposing costs and is discussed in detail. And then, making reference to the general process of life-cycle cost from inside and outside of our country, the analyzing process and general characters is concluded on the life-cycle cost of energy efficient residential buildings. At last, it is put forwarded that the analyzing time of life-cycle cost should start from the beginning of investment and run through projects, but design stage is the key point, as well as the opinion that the analyzing of life-cycle cost should be combined with effecting analyzing of energy efficient buildings.(2) Establishing a dynamic, opening and considering real options' life-cycle cost estimation modelCutting in the defects of traditional life-cycle cost estimation model and the practical situation of the current residential buildings' life-cycle cost constitution in our country, the estimation model of residential buildings' life-cycle cost is established, and thoroughly explains the concrete estimation method of each cost involved in the estimation model, such as initial outlay, special maintenance and repair cost, property management cost, owner's annual operating cost, abandonment and disposal cost, residual of fixed assets and cost real options. At last, it puts forward the scientific reference of choosing parameters involved in the estimation model, such as discount rate, life cycle and residual rate and makes the model more maneuverable.(3) The appraisal and optimized methods of designing energy efficient buildings are put forward at design stage.Through the comparison of two appraisal target systems, the view of using capability appraisal target is put forward. Two defects of this system are pointed out. One is incomprehensive, the other is too simple. Aiming at the above defects, the solving methods of appraisal target in energy efficient design plans are put forward. Based on the method of entropy proportion, the best-selecting model of appraisal decision is established and does well in practice.(4) The appraisal target systems and methods of saving energy effectiveness are established, and the conception is put forward in which cost effectiveness analysis in exploration and construction of residential buildings is combined with the idea of entropy.Cutting in three aspects of energy efficient residential buildings' effectiveness, the appraisal target systems of energy efficient residential buildings' effectiveness and the method-hierarchy fuzzy comprehensive evaluation based on the idea of entropy are established. In the end, through comparison of cost effectiveness ratio and the demonstration of entropy, the conclusion is drawn and put in practice that energy efficient residential buildings is a construction product of being pursued, continuous development and subtract entropy.(5) Research in Hongyunrunyuan Housing based on life-cycle cost and drawing some conclusionsRegarding energy efficient residential buildings in Lanzhou Hongyunrunyuan as object of the example study, first, through the demonstration research in design plan using the method of entropy proportion, it can be drawn a conclusion that the method is suitable. Second, through careful analyzing in the construction cost, using costs and the input of energy efficient technique, some conclusions are as follows: the investment of energy efficient residential buildings increases 35.8～99.87 yuan/m~2 than non-energy efficient residential buildings, the investment ratio of construction project is 3.3%～9.3%; the investment increases about 35.8～99.87 yuan/m~2 in each increase of energy efficiency ratio, the investment ratio of construction project is 2.3%～3.4%. In the mean time, through comparison of the energy efficiency residential buildings with 65% and non-energy efficiency residential building, the conclusion is drawn that life-cycle cost of the former is lower, Although the initial investment of the former increases 99.87 yuan/m~2, the ratio increases 9.3%. further more, the life-cycle is longer, the effect is more available. Considering real options, the life-cycle cost of energy efficient residential buildings is much less than that of non-energy efficient residential buildings. At last, the demonstration research in effect of energy efficiency and ratio shows that the ratio of energy efficient residential buildings is much less than non-energy efficient residential buildings. It will be the decision foundation and great promotion to the exploration and construction in Lanzhou region as well as our country.