| China is one of the most serious water shortage countries in the world. With the continued development of society and economy and sustained growth of population size,water consumption is growing. Consequently, water shortage and water pollution have become one of the main factors restricting the development of human society. There are many problems in Gansu Province, such as shortage of water, uneven geographical distribution,extensive mode of water resources utilization, water inefficiency, serious waste of water,reduced rainfall because of climate change, significant increase of sewage discharge with economic development and over exploitation of groundwater. There is large water-saving potential in current state of water use in Gansu Province. In order to achieve the green development of construction industry and sustainable use of water resources,strengthening the economic study on water-saving technology of green buildings is particularly important.This research is based on the requirements of "evaluation standard for greening building" in the index of water saving. Research subject is water-saving technology system of green buildings. From the perspective of the whole life cycle and combining with the current situation of water resources in Gansu Province, the researcher analyzes water-saving technology of green buildings in Gansu Province, study water-saving incremental costs and benefits of green buildings and analyzes the economy of specific water-saving technology.With characteristics of long life cycle of water-saving projects, the lack of historical data and various factors which are hard to quantify, this paper adopts the method of system dynamics and analyzes the structure and factors of water-saving incremental costs and benefits of green buildings. Therefore, SD model of water-saving incremental costs and benefits of green buildings is built. Green buildings certification program in Gansu Province as the example,the simulation is conducted. According to the simulation results, the corresponding research results are concluded. The main research conclusions of this paper are as follows:(1) According to the specific rules of "evaluation standard for greening building" in the index of water saving and combining with the present situation of water resources in Gansu province, technology system for water-saving technology development of green buildings is established which is suitable in Gansu Province. After the economic analysis of water supply network, indoor and outdoor water-saving appliances and non-traditional technology of water use, that is, the contrast with the ordinary buildings, the quantized values of the corresponding incremental costs and benefits are concluded.(2) With features of the water-saving incremental costs and benefits of green buildings,the method of system dynamics is adopted to establish the SD model of water-savingincremental costs and benefits. This study analyzes the increase or decrease change rules of water-saving incremental costs and benefits of green buildings in the life cycle of the architecture. Through simulation curve, researcher can visually see the water-saving technology incremental costs of green buildings occur mainly during the construction. That is to say, technology incremental costs have a higher proportion of the total incremental costs.After water-saving projects putting into use, incremental costs remain stable in the operation period, and have a smaller proportion of the total incremental costs. Economic benefits of water-saving technology increase gradually after the operation period. That is, after having water saving and improving water use efficiency, economic benefits begin to make. As the processing of operation, the cumulative value of the water-saving incremental benefits gradually reach that of water-saving incremental costs which achieves the break-even situation of water-saving incremental costs and benefits.(3) Comparative analysis of the impact of different water-saving technology for green building water-saving incremental cost-effectiveness, in order to represent the input-output ratio, wherein the non-traditional water-use technology high proportion of incremental costs,the government should be in non-traditional water technologies utilization play a supervisory role, and subsidies or incentives. Through the analysis of the incremental cost-effectiveness of each technique, it allows developers to more accurately filter out the incremental cost-effectiveness of water saving greater impact on water-saving technologies and the corresponding control costs, maximize the saving benefits. |
