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在设备全寿命管理过程中,存在大量有待决策的问题.为此必须建立决策准则和应用适当的决策方法.国家计委关于建设项目的有关规定明确要求,经济评价应以动态为主,以定量分析为主、以全过程效益分析为主、以宏观效益分析为主、以价值量分析为主和预测分析为主.寿命周期费用分析完全能体现这“六个为主”的要求.一、设备技术经济评价准则与寿命周期费用经济建设项目追求以最小的投入谋取最大的收益.可以用两者之差或两者之比作为权衡的准则.基于收益与投入之差的准则,以寿命周期内每年的收益B_t减去每年的投资费I_t和年度费用C_t,贴现到基准年,叠加起来,得到以现值表示的净收益,称为净现值NPV:NPV=sum from t=0 to a(0/t)[(B_t-I_t-C_t)(P/F,i,n)](1)这里,投资费包括设备的购置费及相关的论证、设计、运输、安装等费用,即费用分解结构中的研究与开发费和投资费两个主费用单元的总和.年度费用即设备的使用与维修费.两者之和即寿命周期费用.收益为各年的增值部分,即销售额减去原材料费.若以年度销售作为收益,则年度费用中还应包括所消耗的原材料费.符号(P/F,i,t)表示在已知利率i,年数t下,由终值求现值的系数,称为现值系数,如第二讲中所述.在净现值计算的基础上,可以求出使寿命周期内净现值为零的年数t,也?
In the process of equipment life-cycle management, there are a large number of problems to be decided. To this end, decision criteria must be established and appropriate decision-making methods must be applied. The relevant provisions of the State Planning Commission for construction projects clearly require that economic evaluation should be based mainly on dynamics to quantify. Mainly in analysis, mainly in the whole process of benefit analysis, mainly in macro-benefit analysis, mainly in value analysis and forecast analysis. Life cycle cost analysis fully reflects this “six-based” requirement. Technical Economic Evaluation Criteria and Life Cycle Costs Economic construction projects pursue the greatest gains with minimal input. The difference between the two or the ratio of the two can be used as a trade-off criterion. Based on the criteria of the difference between income and inputs, in the life cycle The annual revenue B_t minus the annual investment cost I_t and the annual fee C_t are discounted to the base year and added together to obtain the net income expressed as the present value, which is called the net present value NPV:NPV=sum from t=0 to a( 0/t)[(B_t-I_t-C_t)(P/F,i,n)](1) Here, the investment fee includes the purchase cost of the equipment and the related costs of argumentation, design, transportation, installation, etc. Research and Development Fees in Structures Investment cost The sum of the two main expense units. The annual fee is the equipment usage and maintenance. The sum of the two is the life cycle cost. The gain is the value-added part of each year, ie the sales minus the raw material costs. If the annual sales is taken as the For income, the annual expenses shall also include the raw material costs consumed. The symbol (P/F, i, t) represents the coefficient of the present value of the final value at a known interest rate i, years t, called the present value coefficient. As described in the second lecture, based on the calculation of net present value, we can find the number of years t that makes the net present value zero in the life cycle.