| In today's world, people pay great attention to global warming gradually, which promotes rapid development of low carbon economy, and low carbon research has become focus at present. In architectural field, research on building energy efficiency, green building and ecological building has made great progress but that on low carbon building, residential area and city has developed just in recent years. Low carbon comprises two factors which are carbon sink and carbon source, and building could fall into the factor of carbon source but residential area and city included two of them. Residential area with middle scale was selected as research object by the author so that research finds in the dissertation could give some guides to low carbon building and lay a foundation for low carbon city. Carbon sources in residential area include building and society carbon source,and green space is the main carbon sink on the other side. In residential area, there are much basic data for carbon sources calculation but little for green space sink calculation. Therefore, low carbon research on residential area in the dissertation was mainly based on green space sink.Research on microscopic mechanism for plant photosynthesis, plant respiration and soil respiration begun many years ago so a great deal of relevant finds have been obtained but that on calculation methods of green space sink started just decades of years ago. Among those methods, the quantitative biomass examinations and plant photosynthesis examinations could be representatives. In the quantitative biomass examinations,calculation is made only considering start point and end point with intermediate state ignored,and on the contrary,intermediate state is taken into account for plant photosynthesis examinations which could not precisely depict all the intermediate points either because it is difficult to get data of all intermediate points. Then it could be concluded that neither of them could precisely depict green space carbon sink instantaneously and continuously. Thus, the purpose of the dissertation is to describe carbon emission and absorption of green space hourly in residential area,so that hourly mathematic model of green space all year round in typical meteorological year becomes the specific goal. This model consists of hourly carbon emission equations for plant respiration and soil respiration and hourly carbon absorption equations for plant photosynthesis. Moreover, equations of hourly plant photosynthesis rate, hourly plant respiration rate, hourly soil respiration rate and hourly leaf area are the basis for them. Water, Sunshine and temperature are the key environmental factors for plant growth and those factors would also affect green space carbon sink. Consequently, three key environmental factors of light intensity, temperature and humidity are chosen to be variables for those equations. Examinations were taken to build those equations so as to establish green space mathematical model based on regression analysis on those experimental data. Because it will spend too many resources for people to acquire datum of the whole year hourly in natural state, the writer advanced a new method to solve this problem based on the datum of typical meteorological year.The new method is simulation experiment, which is applied for equation establishment of hourly plant photosynthesis and hourly plant respiration. This method means to acquire test data in artificially simulated environment in order to build quantitative relations between environmental factors and plant photosynthesis and respiration rate. If taking experiments in natural situation, those environmental factors should not be adjusted freely. In the plan of simulation experiment, uniformity design was introduced for variable design so lots of experiment works were reduced. Contrast experiments of plant photosynthesis and plant respiration were taken to prove the validity of the simulation experiment. It means to compare plant photosynthesis and respiration rate in natural environment with that in artificial simulated environment and the result would show whether it is rational to replace actual experiment with simulation experiment. Ordinary experimental measures were taken for plant leaf area and actual experiment for soil respiration due to limitation of actual equipments. These two experiments are used to build plant leaf area and soil respiration equation hourly in order to establish green space mathematical model based on the datum of typical meteorological year.Analysis on the experimental data shows that all the expected aims have been achieved. According to analysis on data of contrast experiment for plant photosynthesis, it verified the feasible of simulation experiment for plant photosynthesis that data of plant photosynthesis in simulation experiment could match that in actual experiment very well. Those data involve six different kinds of plants in Litchi Park, eight different kinds of plants in a residential area and seventy-eight different kinds of plants in Meilin Park. Having verified the validity of simulation experiment, simulation experiment for seventy-eight different kinds plants was taken and finally obtained equations of hourly photosynthesis rate for those plants with high fitness. According to analysis on data of contrast experiment for plant respiration, it also verified the feasible of simulation experiment for plant respiration that data of plant respiration in simulation experiment could match that in actual experiment very well. Those data involve six different kinds of plants in Litchi Park and eight different kinds of plants in a residential area. Having finished the verification, simulation experiment for seventy-eight different kinds plants was taken and finally obtained equations of hourly respiration rate for those plants with high fitness. Based on analysis on data of leaf area and soil respiration experiments, leaf area equations for seven-eight different kinds of plants and respiration equations for seven-eight different kinds of soils were built also.Having presenting calculation framework for whole life circle carbon budget in residential area based on building system, social system and green space system, this dissertation detailed the calculation method with research finds on green space carbon sink above. This calculation method illustrates four basic principles which are all objects, whole procedure, dynamics and accuracy. It means that all objects of carbon behavior regarded, the whole life circle of residential area covered, dynamic change of objects included and hourly calculation introduced. The example demonstrates details of the calculation procedure whose results show ratio of carbon source to carbon sink is 29:1 and that of society source to building source is 4.6:1. So it can be concluded that serious imbalance exists between carbon sink and carbon source in residential area and society source is a key factor for carbon budget balance.Zero and low carbon residential area construction were discussed at last. It shows that by reducing population and increasing area of green space, zero carbon can be realized but in this situation it does not make full use of land because land per capita is 13/17 times of stipulated specifications and green space ratio even reaches 97/75 percent. It is obvious that this practice have contradicted the goal of land saving in city. Thus, the conclusion could be made that zero carbon is not practicable in city with so large population. Also, calculation of low carbon residential area was made to establish a low carbon standard for this residential area. With the absence of relevant codes to support low carbon appraisal, it becomes the difficulty and emphasis to build those codes.This dissertation was subsidized by national 11th Five-Year Plan major scientific and technological project of No. 2006BAJ02A13-5.
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