热电冷联产的技术经济性探讨

本文根据制冷技术在我国应用的前景，对可能组成的四种热电冷联产类型从节电、节能和投资三方面进行了综合分析比较，探讨了热电冷联产的有关技术经济问题。     

热电冷联产技术及其经济性分析

本文就热、电、冷联产技术的实质进行了阐述，并结合工程实例，计算分析了联产技术的经济性。     

浅议热电冷联产

文章论述了热电冷联产节能原理,压缩制冷吸收制冷的比较,热电冷联产的市场前景。     

论燃气轮机热电冷联产分布式电源系统

本文论述了燃气轮机热电冷联产分布式电源的系统装置、工作性能、优势及国内外发展现状 ;并从燃料成本、系统能效等方面分析了发展这种电源的经济性 ;建议我省在引进LNG之后 ,应当建设燃气轮机热电冷分布式电源的示范工程。     

论燃气轮机热电冷联产分布式电源系统

本文论述了燃气轮机热电冷联产分布式电源的系统装置、工作性能、优势及国内外发展现状；并从燃料成本、系统能效等方面分析了发展这种电源的经济性；建议我省在引进LNG之后，应当建设燃气轮机热电冷分布式电源的示范工程。     

小型热电站热电联产分析及节能评价

采用平衡分析法,分别对小型热电联产系统和分散锅炉房供热系统进行了流分析,把两者计算所得效率作一对比,从而得出热电联产系统是取代分散锅炉房供热的节能措施之一。同时还对热电联产系统内各环节中的流损失进行计算,得出各热力设备的效率,找出系统用能不合理的主要薄弱环节,为今后设备的工艺过程改进指出了方向。     

热电冷三联产的经济分析

本文简要介绍了热电冷三联产的基本生产工艺，通过对采用溴化锂制冷和中央空调以电制冷两种制冷方式的投资及运行费用进行比较，提出了发展热电冷三联产的良好前景的结论。     

应用溴化锂制冷技术发展热电冷联合生产

对低位热能作为采暖空调的动力─—吸收式制冷的机理、特点、效益等作了简略的介绍，认为溴化锂吸收式制冷技术是实现城市热电冷三联供的有效途径，热电冷联合生产是节电、节能、节省投资、减少环境污染的最佳方法。     

热电冷联产综合节能条件的研究

在对不同供冷方式的耗能情况进行分析的基础上，对热电冷联产的综合节能条件进行了探讨。     

带吸收式制冷的汽轮机热电联产

<正> 许多工业部门或其他部门既需要一定电力,也需要一部分热能。有些单位设置了背压式汽轮机进行热电联产以满足热和电这两方面的需求。为了提高热电联产的效率,足够的热负荷是很重要的。通常热负荷是用于干燥、蒸煮以及冬季供暖等等。在某种条件下,热电联产的热负荷往往不足。近年来,利用低品位蒸汽作为热源的吸收式制冷机在国外已得到普及,在我国的应用也越来越多。今后不但工业部门或者其他部门(如大型宾馆等)有条件的均可采用带吸收式制冷的热电联产,冷天可利用余热进行供暖,热天则由吸收式制冷机利用余热供空调,以及日常过程冷却和冷藏等用。这样就可以大大节省电力,使背压式汽轮机进     

Exergoeconomic analysis of a combined heat and power (CHP) system

This study deals with exergoeconomic analysis of a combined heat and power (CHP) system along its main components installed in Eskisehir City of Turkey. Quantitative exergy cost balance for each component and the whole CHP system is considered, while exergy cost generation within the system is determined. The exergetic efficiency of the CHP system is obtained to be 38.33% with 51 475.90 kW electrical power and the maximum exergy consumption between the components of the CHP system is found to be 51 878.82 kW in the combustion chamber. On the other hand, the exergoeconomic analysis results indicate that the unit exergy cost of electrical power produced by the CHP system accounts for 18.51 US$ GW^?1. This study demonstrates that exergoeconomic analysis can provide extra information than exergy analysis, and the results from exergoeconomic analysis provide cost‐based information, suggesting potential locations for the CHP system improvement. Copyright © 2007 John Wiley & Sons, Ltd.     

Exergetic performance evaluation of a combined heat and power (CHP) system in Turkey

This study deals with the exergetic performance assessment of a combined heat and power (CHP) system installed in Eskisehir city of Turkey. Quantitative exergy balance for each component and the whole CHP system was considered, while exergy consumptions in the system were determined. The performance characteristics of this CHP system were evaluated using exergy analysis method. The exergetic efficiency of the CHP system was accounted for 38.16% with 49 880 kW as electrical products. The exergy consumption occurred in this system amounted to 80 833.67 kW. The ways of improving the exergy efficiency of this system were also analysed. As a result of these, a simple way of increasing the exergy efficiency of the available CHP system was suggested that the valves‐I–III and the MPSC could be replaced by a 3500 kW‐intermediate pressure steam turbine (IPST). If the IPST is installed to the CHP system (called the modified CHP (MCHP) system), the exergetic efficiency of the MCHP system is calculated to be 40.75% with 53 269.53 kW as electrical products. The exergy consumption is found to be 77 444.14 kW in the MCHP system. Copyright © 2006 John Wiley & Sons, Ltd.     

Synthesis and parameter optimization of a combined sugar and ethanol production process integrated with a CHP system

The combined sugar and ethanol production process from sugar cane is a paradigmatic application for energy integration strategies because of the high number of hot and cold streams involved, the external hot utility requirement at two temperature levels for juice evaporation and crystallization, and the electricity demand for juice extraction by milling. These conditions make it convenient to combine the sugar-cane process with a CHP system fuelled by bagasse, the main by-product from juice extraction. The strategies, tools and expertise on energy integration developed separately by the research teams authoring this paper are applied here jointly to optimize the synthesis and the design parameters of the process and of the total site starting from the basic idea of dissociating the heat exchanger network design problem from the total site synthesis problem. At first the minimization of the external heat requirement for the process alone is pursued and results show that a one third reduction can be achieved by optimal heat integration. Then the use of the by-product bagasse for on-site power generation is considered and two bagasse-fuelled CHP systems are optimized along with some parts of the sugar and ethanol production process in order to obtain maximum total site net power. Results show a variety of interesting scenarios of combined sugar, ethanol and electricity production plants with considerably high electricity output.     

Multi-criteria evaluation for CHP system options

Several Combined Heat and Power (CHP) system options have been considered for evaluation with respect to the end-user requirements. These included Internal Combustion Engines (Otto and Diesel), Gas Turbines, Steam Turbines and Combined Cycles covering a wide range of electrical output. Data have been obtained from literature and the CHP systems have been evaluated using different criteria such as overall efficiency, investment cost, fuel cost, electricity cost, heat cost, CO₂ production and footprint. A multi-criteria method is used with an agglomeration function based on the statistical evaluation of weight factors. The technical, economic and social aspects of each system have been evaluated in an integrated manner and the results have been compared by means of the Sustainability Index. Based on the above criteria and depending on the user requirements, the best CHP system options have been established.     

燃气冷热电三联供的能量消耗分析研究

以燃气冷热电联供系统的节能率、总热效率或一次能源利用率的分析研究论证了"三联供"的系统、设备的优化配置的关键技术,并推荐供冷期应以余热吸收制冷机和电动压缩制冷机混合配置方案,该解决方案是节能的.     

分布式供能系统站房布置形式及选用条件

全面阐述了分布式供能系统站房设置的各种形式，提出必要的安全技术措施及其实施的可能性，并列举国内外有关工程实例证明其合理性。分析天然气供应条件、原动机燃气工作压力、单机功率、输出电压等级、排烟温度、余热利用方式及供热介质特性、建筑消防安全间距等多种限制条件，结合国外统计资料，既提出了相应的原动机适用形式，又提出了站房设置在不同位置时的原动机规模限制。     

Performance improvement of a 70 kWe natural gas combined heat and power (CHP) system

Combined heat and power is the simultaneous production of electricity and heat. CHP plants produce energy in an efficient way. A natural gas CHP system based on an internal combustion engine (ICE) is described, which has been set up at the Building Energy Research Center in Beijing, China. The system is composed of an ICE, a flue gas heat exchanger, a jacket water heat exchanger and other assistant facilities. The ICE generates power on-site, and the exhaust of the ICE is recovered by the flue gas heat exchanger, and the heat of the engine jacket is recovered by the jacket water heat exchanger to district heating system. In order to improve the performance of the system, an absorption heat pump (AHP) is adopted. The exhaust of the ICE drives the AHP to recover the sensible and latent heat step by step, and the temperature of the exhaust could be lowered to below 30 °C. In this paper, the performance of the new system were tested and compared with conventional cogeneration systems. The results show that the new CHP system could increase the heat utilization efficiency 10% compared to conventional systems in winter. All the results could be valuable references for the improvement of the CHP system.     

Techno-economic analysis of a coal-fired CHP based combined heating system with gas-fired boilers for peak load compensation

Combined heat and power (CHP) plants dominate the heating market in China. With the ongoing energy structure reformation and increasing environmental concerns, we propose gas-fired boilers to be deployed in underperforming heating substations of heating networks for peak load compensation, in order to improve both energy efficiency and environmental sustainability. However, due to the relatively high price of gas, techno-economic analysis is required for evaluating different combined heating scenarios, characterized by basic heat load ratio (β). Therefore, we employ the dynamic economics and annual cost method to develop a techno-economic model for computing the net heating cost of the system, considering the current state of the art of cogeneration systems in China. The net heating cost is defined as the investment costs and operations costs of the system subtracted by revenues from power generation. We demonstrate the model in a real-life combined heating system of Daqing, China. The results show that the minimum net heating cost can be realized at β=0.75 with a cost reduction of 16.8% compared to coal heating alone. Since fuel cost is the dominating factor, sensitivity analyses on coal and gas prices are discussed subsequently.     

A novel pressurized CHP system with water extraction and refrigeration

A novel Cooling, Heat, and Power (CHP) system has been proposed that features a semi-closed Brayton cycle with pressurized recuperation, integrated with a Vapor Absorption Refrigeration System (VARS). The semi-closed Brayton cycle is called the High Pressure Regenerative Turbine Engine (HPRTE). The VARS interacts with the HPRTE power cycle through heat exchange in the generator and the evaporator. Waste heat from the recirculated combustion gas of the HPRTE is used to power the absorption refrigeration unit, which cools the high-pressure compressor inlet of the HPRTE to below ambient conditions and also produces excess refrigeration in an amount which depends on ambient conditions. Water produced as a product of combustion is intentionally condensed in the evaporator of the VARS, which is designed to provide sufficient cooling for the inlet air to the high-pressure compressor, water extraction, and for an external cooling load. The computer model of the combined HPRTE/VARS cycle predicts that with steam blade cooling and a medium-sized engine, the cycle will have a thermal efficiency of 49% for a turbine inlet temperature of 1400 °C. This thermal efficiency is in addition to the large external cooling load generated in the combined cycle which is 13% of the net work output. In addition it also produces up to 1.4 kg of water for each kg of fuel consumed, depending upon the fuel type. When the combined HPRTE/VARS cycle is optimized for maximum thermal efficiency, the optimum occurs for a broad range of operating conditions. Details of the multivariate optimization procedure and results are presented in the paper.Previous studies have demonstrated the following attributes of the combined HPRTE/VARS cycle: attaining high part power efficiency in a compact package, threefold specific power increase over the state of the art, reduced IR signatures due to lower exhaust temperature, significant reduction of exhaust particulates and smoke, constant high-pressure compressor inlet temperature and order-of-magnitude reductions in emissions such as NO_x, CO and unburned hydrocarbons. The integrated nature of this system allows overall reduction in size and weight of approximately 50% relative to conventional equipment. The combination of positive attributes makes the HPRTE combined cycle engine attractive for future mobile power applications in terms of performance as well as life cycle cost.     

Conversion of Brighton power station to combined heat and power (CHP)

The technology of whole city heating by CHP is well established in Holland, West Germany, Denmark and Sweden. There most big towns have schemes, and the metered hot water that they supply is popular, being cheapest, safest and most trouble-free. The paper describes the technical and economic issues, but concentrates on the institutional and political obstacles to the implementation of CHP in the UK. These are due to the CEGB which wrongly seeks to build electricity-only stations (nuclear and coal-fired) with cheap public money, thus crowding out more cost-effective private investment in conservation (CHP and insulation) and renewables (e.g. tidal power). The author considers that privatisation of power stations, both projected and existing, is the best way to halt the present misallocation of resources and obtain better value for investment in electricity supply.