Economic Evaluation Research Of Green Building Based On Whole Life Cycle Theory

With the growing issues of environment and resources day by day, many countries are seeking the way of protecting environment and conserving resources to keep sustainable development. Green building as a typical environmental friendly form of architecture, uses fewer natural resources in its construction and service stages, which is being more and more concerned by the communities. The high energy consumption and high pollution of construction are common problems in China, so the implementation of green buildings in China is of great significance. But investors tend to focus only on the increase of the initial investment of green building, and do not realize the long-term benefits of green building, which will hinder the promotion progress of green building’s implementation.This article starts from the concept of green building, by introducing the theory of the whole life cycle assessment, analyzes the composition of the building’s whole life cycle costs, and from the view of the incremental costs and benefits respectively to break down and classify the whole life cycle costs. The author breaks down the incremental cost into the preliminary incremental cost and construction incremental cost, and from six aspects—energy conservation, water conservation, land conservation, materials conservation, indoor environment, the operator—to analyzes the construction incremental cost, with the benefits of green building are broken down into economic benefits, environmental benefits and social benefits, then analyzes the economic benefits from "four-conservation" view, sums up the monetization measurement methods of the green building’s direct benefits and indirect benefits. Afterwards, combining the engineering economics theory, the author selects the most appropriate economic evaluation parameters and targets. Then the establishment of a integrate set of green building economic evaluation method is completed.Afterword, this methodology is applied to the economic evaluation of the green building project which the author participated in. By analyzing the incremental cost of this building, doing the detailed measurement of the key technologies economic benefits and calculating the net present value and payback period of the key technologies, the earning performance of key technologies can be understood fully at one glance, which provides a strong reference to the selection of green building technologies. As the uncertainties of economic evaluation parameters, a Monte Carlo simulation analysis has been done through the application of the crystal ball software.In the end, the overall distributions and means of project’s synthesized net present value, payback period and benefit-cost ratio is obtained, which arrives at this paper’s conclusion.