太阳能电热联产技术研究综述

该文综述了目前电热联产系统(photovoltaic/thermal,PV/T)的研究现状。系统地比较了目前的研究进展,首先概述了PV/T系统的发展,总结了各类(气冷式和水冷式,平板式和聚光式)PV/T系统的结构特点,分析比较了各类PV/T系统的性能。为分析PV/T系统效率,详细介绍了PV/T系统效率的试验测试方法和基于辐射传递模型和热平衡模型的理论计算方法。同时分析了目前的研究热点:与建筑一体化的PV/T系统及聚光PV/T系统。最后,结合各类PV/T系统特点,概述了目前PV/T系统的优点和存在的主要问题。

考虑电热联产的虚拟电厂两阶段鲁棒优化经济调度

为了有效应对能源系统供给侧资源不断丰富,需求侧负荷趋于灵活多变带来的系统运行优化与资源配置的复杂性,提出了一种考虑电、热机组互动的虚拟电厂鲁棒优化模型。针对虚拟电厂内可再生能源和负荷的不确定性,建立了min-max-min结构的两阶段鲁棒优化模型,得到最恶劣场景下运行经济性最优的调度方案;引入鲁棒系数,灵活调节优化调度方案的保守性;基于C&CG(column-and-constraint generation)算法和强对偶理论进行求解;进一步分析了燃气轮机设置价值、蓄电池运行边界条件以及虚拟电厂运行成本灵敏度。

整体煤气化固体氧化物燃料电池电热联产系统分析

整体煤气化固体氧化物燃料电池-燃气轮机混合发电系统(Integrated gasification solid fuel cell-gas turbine hybrid powergeneration system,IGFC-GT)是一种高效清洁合理的煤炭发电技术。混合系统的模型搭建及性能分析对于系统集成和商业运行有着重要的意义。通过查阅国内外在致力于提高SOFC发电效率方面的研究文献,并根据课题组的前期研究成果,基于商业软件Aspen Plus平台,搭建了IGFC-GT混合发电系统的电热联产系统模型图,分析了IGFC-GT电热联产系统的性能,结果表明该系统具有较高的发电效率及总能量利用率。

纳米流体太阳能电热联产系统性能研究

提出了一种具有选择性吸收功能的直接吸收式油基纳米流体太阳能电热联产系统,采用油基二氧化钛纳米流体匹配硅光伏电池板以实现对太阳辐射的分波段利用.通过求解辐射传递方程和能量守恒方程,分析了该系统在不同聚光强度和工质循环速率条件下的工作性能.通过与传统电热联产系统中光伏模块工作温度、循环流体出口温度、光热转换效率,以及光电转换效率的比对,验证了该系统能够在维持良好的光伏电池热管理的同时获得相对高品位热能收集.结果表明,在入射光强小于200 kW/m2工况下,该系统中的光伏电池板的工作温度能够维持在330K以下,其系统总的有效输出能相较于采用导热油作为循环工质的传统电热联产系统可实现16％ ～58％的效率提升.

两级透射-反射聚光分频电热联产系统设计和分析

在传统聚光条件下的太阳能光伏发电系统中,由于太阳光中存在所有波段的光子,而其中只有一部分能够被太阳电池用来发电,其余的部分进入太阳电池之后非但不会被用于发电,反而会变成热量使太阳电池升温,从而使电池光电转换效率下降.本文设计了一种聚光且具有分频功能的太阳能电热联产系统,利用线聚焦菲涅尔透镜和光谱选择性透过涂层改善太阳电池表面的入射光环境,在聚光的同时将不利于光伏发电的太阳光波段反射并加以收集利用.分析结果表明,与相同条件下传统的只进行聚光的光伏系统相比,两级透射-反射聚光分频电热联产系统具有更高的太阳能利用效率.

基于TRNSYS的太阳能电热联产复合系统仿真

为了提高太阳能利用率,结合平板电热联产(PVT)和槽式集热器(PTC)的优点,基于瞬态系统模拟软件TRNSYS建立了太阳能电热联产复合系统仿真模型。采用气象软件Meteonorm提供的典型气象年数据文件,以电效率、热效率以及太阳能保证率等参数为系统仿真指标,对集热水箱容积和供热水箱容积等关键参数进行系统仿真研究,并对系统进行全年性能分析。结果表明:集热水箱容积或供热水箱容积的增大都会引起太阳能保证率的增大,在集热水箱容积6 m^3、供热水箱容积8 m^3的条件下,全年平均PVT电效率可达12.40%,PVT热效率可达18.75%,PTC热效率可达50.97%,太阳能综合利用率可达82.13%,太阳能保证率可达52.21%,其中全年有5个月太阳能保证率达到60%以上。

探索天富电力(集团)煤电热化工一体化多联产新型工业化产业发展之路

新疆天富电力(集团)有限公司(以下简称天富)经过50年的发展,已经成为集煤炭生产、发供电、产供热、天然气供应、房地产开发、高科技等多元化生产为一体的大型国有企业集团。虽然这几年企业发展比较快,但从整体来看,企业发展的后劲不足,发展的空间受到了一定的限制。究其原因,除了天富是一个局部地区的以能源为主的企业,能源的销售仅局限在本地区以外,还与本企业现有的产业结构布局有关。如果公司紧紧围绕新疆的产业结构布局来进行产业结构发展,坚持走新型工业化发展道路,将会迎来又一次大发展的机遇。即公司以现有的主业为基础,集煤炭生产、发供电、产供热与煤化工联合的产业化发展,实现主要产品的市场转移,即主要产品的市场跨越出石河子范围之外,坚持走煤电热化工一体化的产业化发展之路,将是天富再次腾飞的发展之路。

热电联产机组的节能发电调度技术研究与实践

改革开放以来,针对我国能源短缺的现状,节能发电调度技术一直作为我国电力工业和能源行业节能减排的指导思想。热电联产将热能和电能联合生产并辅以梯级利用,是一种高度节能环保的能源生产方式。在当今能源日益紧张的现状下,研究热电联产机组中的节能发电调度技术有利于更有效的提高能源利用率。本文将在节能思想的指导下,先概述节能发电调度技术,在介绍热电联产机组的内涵,然后分析热电联产机组中的节能调度技术,最后根据上文做出总结并提出相应建议。

Parametric optimization of power system for a micro-CCHP system

The universal mathematical model of an engine is established,and an economical zone,in which an engine mainly provides medium output load at medium speed,is presented.Based on the experimental data and the universal model of such an engine above,a mathematical model of a refitted engine is provided.The boundary of the corresponding economical zone is further demarcated,and the optimal operating curve and the operating point of the engine are analyzed.Then,the energy transforming models of the power system are established in the mode of cooling,heating and power（MCHP）,the mode of heating and power（MHP）and the mode of electricity powering（MEP）.The parameter matching of the power system is optimized according to the transmission ratios of the gear box in the power distribution system.The results show that,in the MCHP,the speed transmission ratio of the engine to the gear box（ies）and the speed transmission ratio of the motor to the gear box（ims）are defined as 2.9 and 1,respectively;in the MHP,when the demand load of the power system is less than the low critical load of the economical zone,the speed transmission ratio of the motor to the engine（ime）is equal to 1,and when the demand load of the power system exceeds the low critical load of the economical zone,ime equals 0.85;in the MEP,the optimal value of ims is defined as 2.5.

Simulation and performance analysis of organic Rankine cycle combined heat and power system

To improve the overall thermal efficiency of the organic Rankine cycle（ ORC）, a simulation study was carried out for a combined heat and power（ CHP） system, using the Redlich-Kuang-Soave（ RKS） equation of state. In the system,R245 fa was selected as the working fluid. A scroll expander was modeled with empirical isentropic expansion efficiency.Plate heat exchangers were selected as the evaporator and the condenser, and detailed heat transfer models were programmed for both one-phase and two-phase regions. Simulations were carried out at seven different heat source temperatures（ 80,90, 100, 110, 120, 130, 140 ℃） in combination with eight different heat sink temperatures（ 20, 25, 30, 35, 40, 45, 50,55 ℃）. Results showthat in the ORC without an internal heat exchanger（ IHE）, the optimum cycle efficiencies are in the range of 7. 0% to 7. 3% when the temperature differences between the heat source and heat sink are in the range of 70 to90 ℃. Simulations on CHP reveal that domestic hot water can be produced when the heat sink inlet temperature is higher than40 ℃, and the corresponding exergy efficiency and overall thermal efficiency are 29% to 56% and 87% to 90% higher than those in the non-CHP ORC, respectively. It is found that the IHE has little effect on the improvement of work output and efficiencies for the CHP ORC.

Estimate of China's energy carbon emissions peak and analysis on electric power carbon emissions

China＇s energy carbon emissions are projected to peak in 2030 with approximately 110% of its 2020 level under the following conditions： 1） China＇s gross primary energy consumption is 5 Gtce in 2020 and 6 Gtce in 2030; 2） coal＇s share of the energy consumption is 61% in 2020 and 55% in 2030; 3） non-fossil energy＇s share increases from 15% in 2020 to 20% in 2030; 4） through 2030, China＇s GDP grows at an average annual rate of 6%; 5） the annual energy consumption elasticity coefficient is 0.30 in average; and 6） the annual growth rate of energy consumption steadily reduces to within 1%. China＇s electricity generating capacity would be 1,990 GW, with 8,600 TW h of power generation output in 2020. Of that output 66% would be from coal, 5% from gas, and 29% from non-fossil energy. By 2030, electricity generating capacity would reach 3,170 GW with 11,900 TW h of power generation output. Of that output, 56% would be from coal, 6% from gas, and 37% from non-fossil energy. From 2020 to 2030, CO2 emissions from electric power would relatively fall by 0.2 Gt due to lower coal consumption, and rela- tively fall by nearly 0.3 Gt with the installation of more coal-fired cogeneration units. During 2020--2030, the portion of carbon emissions from electric power in China＇s energy consumption is projected to increase by 3.4 percentage points. Although the carbon emissions from electric power would keep increasing to 118% of the 2020 level in 2030, the electric power industry would continue to play a decisive role in achieving the goal of increase in non-fossil energy use. This study proposes countermeasures and recommendations to control carbon emissions peak, including energy system optimization, green-coal-fired electricity generation, and demand side management.

Model and Design of Cogeneration System for Different Demands of Desalination Water, Heat and Power Production

In order to improve the energy efficiency, reduce the CO2 emission and decrease the cost, a cogenera- tion system for desalination water, heat and power production was studied in this paper. The superstructure of the cogeneration system consisted of a coal-based thermal power plant （TPP）, a multi-stage flash desalination （MSF） module and reverse osmosis desalination （RO） module. For different demands of water, heat and power production, the corresponding optimal production structure was different. After reasonable simplification, the process model ot each unit was built. The economical model, including the unit investment, and operation and maintenance cost, was presented. By solving this non-linear programming （NLP） model, whose objective is to minimize the annual cost, an optimal cogeneration system can be obtained. Compared to separate production systems, the optimal system can reduce 16.1%-21.7% of the total annual cost. showing this design method was effective.

Mathematical model of absorption and hybrid heat pump

Recovering waste heat from industrial processes is bene ficial in order to reduce the primary energy demands and heat pumps can be used to this purpose.Absorption heat pumps are energy-saving and environment-friendly because use working fluids that do not cause ozone depletion and can reduce the global warming emissions.The hybrid heat pump processes combine the conventional vapor-compression and the absorption heat pump cycles.Studies about the simulations and modeling of hybrid heat pumps are few in literature.In this research a mathematical model for single effect absorption and hybrid heat pump is carried out with Chem Cad? 6.0.1.LiBr–H_2O is used as working fluid while electrolytic NRTL and electrolytes latent heat are used as thermodynamic model due to the better results.Binary parameters of activity coef ficients are regressed from experimental vapor pressure data while default constants are used for the solubility expressions.A design of heat pumps is developed and a new modeling of generator is analyzed.The coef ficient of performance of absorption heat pump and hybrid heat pump is equal to 0.7 and 0.83 respectively.For absorption heat pump a sensitivity analysis is carried out to evaluate the effect of temperature and pressure generator,the concentration of Li–Br solution on coef ficient of performance,cooling capacity and working fluid temperature.For hybrid heat pump,the different coef ficients of performance,the primary energy ratio,the generator heat,and the compressor power are analyzed for different values of compressor proportion.Results show that comparing the two systems the hybrid pump allows to save more primary energy,costs and carbon dioxide emissions with respect to absorption heat pump with the increasing of compressor proportion parameter.Future researches should focus on the construction of this heat pumps integrated in chemical processes as a biogas plant or trigeneration systems.

A Novel Solar Driven Micro-CliP System： A State of the Art Review

The state-of-the-art solar power system technologies are presented. Various methods of capturing solar energy using solar collectors such as parabolic trough collectors and dish collectors are reviewed. Combined heat and power （CHP） systems driven by concentrating solar absorbers and supplemented by biomass boilers are proving to be the most promising methods of domestic power generation, μCHP systems eliminate losses associated with power distribution and transmission opposed to the large scale power generation methods. The systems can utilize about 75% of solar energy to provide electric and thermal energy direct to end users. The driving potential behind μCHP systems is the thermal efficiency the systems can achieve and their market significance. Despite huge potential market for μCHP systems, the systems are yet to be seen available in commercial market. Hence the authors of this paper are currently developing such type of CHP system with electricity production being of prime importance.

Building Sector： The Different Ways to Improve Their Energetic Efficiency

The building sector has a significant weight in the global energy consumption in almost of the countries. So, there is a high potential for increasing its energy efficiency. With the enforcement of the energetic certification, it was tried to select different solutions that presents less energy consumption and waste, as well as an effective reduction of CO2 emissions. This work fits in this perspective, since the main goal is to evaluate the contribution of passive and active solutions that can be used in buildings for the improvement of its energetic efficiency, as well as to evaluate the contribution of renewable energy sources. Contribution of solar systems for hot water heating and electric energy production has been studied, as well as cogeneration, Combined Heat and Power （CHP）. The case studied is a hotel. To improve the building performance, there were proposed several changes, with the goal of evaluating the contribution of the different solutions proposed. It was concluded that they contribute to a reduction of thermal needs of 25.2% and avoided emissions of CO2 is 30.4%. The analysis of the implementation of trigeneration, Combined Heat, Cooling and Power （CHCP） turns it executable. The payback period is less than 8 years.

A Cogeneration System for an Apartment Building Based on Distributed Heat Storage Technology

In order for economically viable distributed generation systems for apartment buildings to spread, it is essential to develop an efficient and low-cost heat supply system. We have developed a new eogeneration system called the Neighboring Cogeneration system （NCG）. The key concept of this system is to install a heat accumulator with a hot water supply and a room heating function at each household and to connect different households by a single loop of hot water pipe. As a result, time leveling of the heat supply and heat transferring among households becomes possible. Thus, the costs of the pipe and the heat source equipment decrease. Furthermore, because all of the heat accumulators store heat, the total heat storage capacity is large enough for cogeneration to generate exhaust heat according to the electricity demand and with a high operating rate. In this paper, we report the results of the NCG system for 7 lived-in households. The controlling system worked efficiently. All of the households were able to use hot water without any difficulties. Further, we report the results of the energy saving effect of the NCG system for 50 lived-in households by means of a simulation based on the experimental results for NEXT21.

Integration of a Gas Fired Steam Power Plant with a Total Site Utility Using a New Cogeneration Targeting Procedure

A steam power plant can work as a dual purpose plant for simultaneous production of steam and elec-trical power. In this paper we seek the optimum integration of a steam power plant as a source and a site utility sys-tem as a sink of steam and power. Estimation for the cogeneration potential prior to the design of a central utility system for site utility systems is vital to the targets for site fuel demand as well as heat and power production. In this regard, a new cogeneration targeting procedure is proposed for integration of a steam power plant and a site utility consisting of a process plant. The new methodology seeks the optimal integration based on a new cogenera-tion targeting scheme. In addition, a modified site utility grand composite curve(SUGCC) diagram is proposed and compared to the original SUGCC. A gas fired steam power plant and a process site utility is considered in a case study. The applicability of the developed procedure is tested against other design methods(STAR? and Thermoflex software) through a case study. The proposed method gives comparable results, and the targeting method is used for optimal integration of steam levels. Identifying optimal conditions of steam levels for integration is important in the design of utility systems, as the selection of steam levels in a steam power plant and site utility for integration greatly influences the potential for cogeneration and energy recovery. The integration of steam levels of the steam power plant and the site utility system in the case study demonstrates the usefulness of the method for reducing the overall energy consumption for the site.

New type steam turbine for cogeneration

A concept of energy saving & efficiency improving from cold source for cogeneration steam turbine was discussed herein. A new type "NCB" cogeneration steam turbine was proposed,which could considerably increase heat supply capacity,thermal efficiency and electric power. Taking 300 MW cogeneration steam turbine as an example,the results show that heat supply capacity reaches the maximum,i.e. increases by 30 %,thermal efficiency is improved by 12 %,and electric power is enhanced by 15 MW during peak heat load.