In this paper, the mathematical model was founded taking the heating index ξ and the equivalent thermodynamic coefficient ξs as the thermo-economic evaluation index for the dual source heating/air conditioning (AC) system. Each parameter that has effect on these thermo-economic evaluation indices is analyzed as well. According to energy flow of the system and relating to specific equipments, five schemes of dual source heating/AC systems are proposed, on ground of which, live schemes and diversified heating indices^of traditional heating and cooling schemes, as well as the equivalent thermodynamic coefficient ξs are calculated and analyzed with comparison. A mathematical model is set up which is for evaluating the system's environmental performance indicated by the reduction of emission of SO2, NOx, CO2, and dust. In the form of case study, the environmental performance index of this dual source heating/AC system is analysed and calculated.

On how to use natural gas in a highly efficient and rational way in heating, this dissertation proposed a dual-source heating system with gas internal-combustion engine as thermal power equipment and set up a mathematics model of economic evaluation criterion for this system. Applying to concrete cases, the authors analyze the environment temperature t, the COP (coefficient of performance) of heat pump, the power generation efficiency ξw of gas internal-combustion generating set, which are the main factors that influence the economic evaluation criteria of the system. Under certain conditions, the operational economy of this system is higher than that of heating by natural-gas-fired central-heating boiler.

The dual source air-conditioning system(DSACS) based on distributed energy system(DES) can perform cooling or heating independently.It has the DES's advantages,and can avoid the problem of interconnecting with public power grid because it has only one product.The performance of internal-combustion engine dual-source system was full studied.The sensitivity analysis of DSACS showed that its efficiency is influenced remarkably by the heat pump's coefficient of performance(COP) and the generating efficiency.Then,the DSACS off-design performance was analyzed by utilizing the typical analytical solution of internal combustion engine,and by considering variation of input power of heat pump and the heat source temperature of waste heat lithium bromide water chiller/heater.The DSACS has a better off-design performance compared to the performances of ground source heat pump and direct-fired lithium bromide water chiller/heater.Consequently,DSACS is a worthy and remarkable energy saving system.

The dual source air conditioning system(DSACS) based on distributed energy system can perform heating or cooling independently, and temper the situation of inadequate electric power supply and yet relatively redundant gas supply in summer. The operation characteristics of the gas turbine DSACS with 24-hour cooling/heating load were analyzed by applying the second law of thermodynamics based on specific consumption analysis. Using the gas turbine DSACS on large public buildings with designated cooling/heating time section, can maximize its energy utilization efficiency. DSACS is significant to shift peak load and optimize the structure of energy consumption, especially in summer with peak cooling load.

Puts forward a dual-source heating system with gas internal-combustion engine as thermal power equipment and establishes a mathematical model of economic evaluating indexes for this system. Applying it to an actual case, analyses the main factors—the environmental temperature, the COP of heat pump, the generating efficiency of gas internal-combustion generator—that influence the economic evaluating indexes of the system. Under certain conditions, the operating economic efficiency of this system is higher than that of natural gas-fired central heating boiler systems.

In the paper, the theory and analysis of fuel specific consumption of energy utilizations are first introduced and applied to a boiler and power plant, so that their second law efficiencies are easily deduced. The results show that the second law efficiency of the boiler depends not only on its thermal efficiency, but also more importantly on the quality of its thermal product. The economizer has always been indispensable in a boiler. However, the further study shows that heat exchange in the economizer is the low temperature section of thermodynamic cycle in the power plant, so that it is improper to regard it as the economizer. In fact, the economizer becomes a factor restricting optimal matching of the boiler and turbine thermodynamic parameters and improvement of the second law efficiency of the boiler and power plant. Based on the theory and analysis of fuel specific consumption, the economizer should therefore be removed from the boiler. The thermodynamic parameter matching of a boiler and turbine and the approaches of improving the power generation efficiency of USC units are researched in this paper.

On the basis of the "unit consumption analysis" theory, this paper sets up a multi-heat-source and multi-cold-source unit fuel consumption model and a unit cost consumption model for natural gas distributed combined cooling, heat and power system (CCHP) running under two common operation modes. The unit consumption models are utilized in case calculation, the results of which are analyzed and are capable of demonstrating clearly the distribution of the unit fuel consumption accrual of each subsystem (equipment) of the system. The models lay foundations for future energy savings and operation optimization of system equipments.

<正>1引言能源利用的效率问题是一个重要而不容易说清楚的问题。在很多时候,人们喜欢用效率来描述能源利用,但又时常面临着热力学第一定律效率失效或不科学的尴尬境地。众所周知,热力学第二定律是分析能源利用的有力武器,但是由于第二定律和(火用)概念抽象性和复杂

As a high level application module of SIS system, the on-line monitor and analysis system for energy-saving is widely applied to power plants. But the corresponding guide system which applied effectual guidance to realize optimal operation is still lack of sufficient research. The main purpose of the guide system is to confirm the certain reason which leads to energy loss among various reasons. Then the effective operating adjustment or timely maintenance could be implemented to reduce losses. As the symptoms, the operating parameters always depart from their target values. And the symptoms have determinated logical relations with certain reason which leads to energy loss. With detail description of the function and structure of the guide system, the concepts of operating target value and parameters' offset degree are put forward in this paper for the first time. And the curves of some important parameters' operating target values are obtained by off-design condition analytic method with analysis of historical data. Furthermore, the logical matrixes which quantitatively describe the logical relations between symptoms and reasons are established by the method of symbolic logic. The research of the paper provides the important theory foundation to the exploitation of the guide system for energy-saving in power plant.

Nowadays, the on-line monitor system for energy-saving is widely adopted in power plant. But the corresponding guide system which applied effectual guidance to optimal operation is still lack of sufficient research. The main purpose of the guide system is to confirm the certain reason which leads energy loss among various reasons. Then take effective operating adjustment or timely maintenance to reduce the losses. As the symptoms, the operating parameters always depart from the target values. And the symptoms have determinate logical relations with certain reason which leads energy loss. With detail description of the function and structure of the guide system, the concepts of operating target value and parameters' offset degree are put forward in this paper for the first time. Then the curves of some important parameters' operating target values are obtained by variation work condition analytic method with help of the history data. Furthermore, the logical matrixes which quantitatively describe the logical relations between symptoms and reasons are established by the method of symbolic logic. The research of the paper provides the important theory foundation to the exploitation of the guide system for energy-saving in power plant.

Due to its merits such as high-efficiency and low-pollution, distributed energy system(DES) has become a main development tendency of future power generation system. On the basis of the integration idea of total energy system, this paper analyzes the essential characteristics of distributed energy system(DES) as follows: DES is essentially total energy system; with effective integration, it possesses the biggest potential of the performance improvement; on the basis of the idea of cycle economy, it is also advanced energy system adaptive to the sustainable development; with multi-production output, it can meet different need of energy users. The main integration technology and integration principle of DES are studies in this paper. The paper proposes the integration idea of DES: “multi-energy input, synthesis complementation”, “cascade utilization of energy according to energy level”, “multi-production output, reasonable distribution”. Some conclusions obtained here will provide the valuable reference for further study of distributed energy system with high efficiency.

Under premise of guaranteeing the unit operating safely, make the unit maintaining at optimal operating mode, thus maximumly reduces the coal consumption is the pracitical request of market economy to the electricity generation enterprises. The choice operating mode is a important topic relates to the security and economic performance of unit. At present,there are still many arguments about which operating mode is more beneficial to the unit's. The concept of optimal initial steam pressure is put forward under thorough research on this question in this article.Furthermore, the mathematical model is built for selecting the optimal initial pressure of the coal-fired power unit, with the method of systemic analysis for the first time. Through quantitative calculations of N600-16.7/537/537-Ⅰunit of a certain thermal power plant, the optimal initial pressure is obtained by method of exhaustion. It is the foundation of the optimal control in the whole power plant. The limitation of optimal operation curve provided by manufactory is also analyzed in this paper.Which proposed a new mathod to optimize operation of the thermal power unit.

The emergence of distributed energy system is a matter of great significance relating to implementation of sustainable strategy. As proposed by the author, distributed energy system(DES)is defined as an electric power total system compatible with environment, sited in or in the vicinity of the consumer center area without bulk and/or remote power transmission. The DES concept allows people to build and operate energy system on total energy basis and thus facilitates demand side management as well as a more intelligent use of energy. It is considered essential for fossil fueled DES that energy is utilized in a cascade way matching the energy quality supplied and needed. DES also opens the most effective way of implementation of Combined Heat & Power as well as multi-generation. While the preferable choice of primary energy might be the clean fuel such as natural gas, but from the long-term point of view, the clean coal technology should not be excluded from the DES category. Although there is a great deal of interest in micro-turbines at the moment, combustion engines still have their tremendous potential for DES application.

Due to its merits such as high-efficiency and low-pollution, distributed energy system (DES) has become a main development tendency of future power generation system. On the base of the idea of total energy system, this paper mainly studies the integration mechanism of DES. The essential characteristics of DES have been revealed in this paper. The main integration technologies applied in DES have been analyzed. The integration mechanism applied in DES: "multi-energy resources input, synthesis complementary", "cascade utilization of energy according to energy level", "multi-production output, reasonable distribution" has been proposed in this paper. The research results show that enhancing the total performance of DES relies on the effective system integration and parameter optimization. The development of advanced devices and technologies applied in DES makes system integration possible. System integration provides a powerful tool for the development of DES. The research results obtained in this paper will provide the valuable reference for further study of distributed energy system with high efficiency.

For an established fault diagnosis system which is based on it own expert system, it is usually incapable to diagnosis the new operating conditions, of which the knowledge has not been explored by the system. It is the purpose of the paper to develop the approach of identifying new fault and self-learning for diagnosis based on non-linear fractal theorem. It has been generally accepted that the vibration series has obvious fractal feature, which can reflect the essential characteristics of new fault. When the novel fault is taken place in the system, a related sub-net is increased to the system and trained with this sample. We have verified experimentally that the fractal dimensions of the same class faults are distributed approximately around a definite value that can represents the dimension of the standard sample for the novel fault. Based on non-linear theorem, the approach of identifying new fault and self-learning for diagnosing is put forward.

Distributed energy system (DES) is defined by author as a electric power total system compatible with environment, sited in or in the vicinity of the consumer center area without bulk and/or remote power transmission. Based on the proposed definition, distributed energy system is viewed as a special type of power system different from the current conventional ones with gigantean capacity. The paper points out that DES is a type of energy system most suitable for implementation of the total energy system concept. It is also a most suitable type for the use of renewable energy. It is expected that joint development of both types of energy system in an appropriate way would greatly promote China's power industry construction.

在培训用仿真模型的基础上,将工程上性能计算方法融入回转式空预器动态仿真模型中,从而提高了模型的精度.在STAR-90仿真支撑软件提供的建模环境下,将所建立的数学模型转化成一个具有标准化结构的通用算法模块.采用模块化建模方法,复用此算法模块,并通过各模块输出、输入变量名的连接的方式,建立了三分仓回转式空气预热器的多段仿真模型,从而校正了单段集中参数模型动态趋势中存在的某些错误响应.所建仿真模型,既可用于电站仿真机的开发,又可用于工程上对空预器的性能设计、分析.

A new fast solution method for lumped parameter dynamic model is put forward, and is applied to lumped parameter dynamic model for single-phase temperature in boiler. In this method, variables of the model are analyzed and synthesized firstly, and relations between the precise solution and variables of the model are found. Then the model is calculated by the relations, not be solved directly any longer. An example indicates that error between results of the new method and precision solution is little and calculation speed is improved obviously.