分布式供能系统及应用

文中对分布工供能系统概念及优点进行了阐述，对四种不同原动机的分布式供能系统分别加以说明，并通过两个应用燃气内燃机的实例分析了分布式供能系统工作情况，最后针对分布式供能系统特点得出几点结论。     

燃气分布式供能系统工程界面研究

分布式能源系统的工程界面以保证分布式供能工艺完整性为原则,包括以燃气发电和余热利用为主要工艺过程的动力、暖通、通风、电气、自控等专业相关的设备、仪器、管路管线,以及分布式能源系统部分的燃气配套、电力配套、机房土建和机房公用设施(消防、照明、给排水)。若有电制冷、锅炉、热泵等其他供能系统与分布式能源系统共同构成的能源中心,其他供能系统     

冷热电三联供系统的优化研究

冷热电联供系统主要应用于大型集中性供能系统中。作为分布式能源的一种,冷热电联供系统具有节约能源、改善环境、提高电力综合效益的优势。一般情况下,三联供系统是以天然气为燃料带动燃气轮机、微燃机或内燃机发电机等燃气发电设备运行,产生的电力供应用户的电力需求,系统发电后排出的余热通过余热回收利用设备(余热锅炉或者余热直燃机等)向用户供热、供冷。通过这种方式提高整个系统的一次能源利用率,实现能源的梯级利用,还可以提供并网电力作能源互补,经济收益和效率均得以提升。研究较为常见的燃气轮机中的一种蒸汽型吸收式冷热电联产系统,对不同配置方式和运行方式进行横向与纵向交叉比较,以完成系统优化研究。     

内燃机耦合溴化锂机组调试关键技术分析

针对某冷热电三联供分布式能源站系统,对燃气内燃机的缸套水、中冷水及润滑油系统冷却模块进行了系统的介绍与分析,内燃机耦合吸收式制冷机组调试过程进行研究,进一步地针对余热利用设备烟气热水型溴化锂机组调试过程中发现的问题进行分析,并提出解决办法,最后总结并出该类型内燃机耦合溴化锂机组调试过程的关键步骤,为同类型机组初期调试及商业运行提供经验。     

内燃机分布式冷热电联供技术应用及发展趋势

分布式冷热电联产技术符合"温度对口,梯级利用"的科学用能原则,是实现节能减排的重要途径。以内燃机为动力装置的冷热电联产系统在国内外已有一定的应用,但在单元技术和系统集成技术上仍处于较低水平,系统节能率较低。新一代内燃机分布式冷热电联产技术通过吸收式除湿技术、升温型热泵技术等对内燃机缸套水低温余热进行更为有效的利用,使系统节能率上升至25%以上。本文介绍了内燃机分布式冷热电联产技术的研究现状和应用现状,对新一代内燃机分布式冷热电联产技术应用的发展趋势进行了系统分析。     

关于提高建筑冷热电联供系统能源综合利用率的思考

建筑冷热电联供系统(又名分布式能源)通常以能源综合利用率来评价它的节能特性。行业标准《燃气冷热电三联供工程技术规程》也明确规定系统平均能源综合利用率应大于70%。然而,由于各种原因,分布式能源系统有时达不到上述要求。本文分析了分布式能源烟气温度对余热利用的影响及如何提高分布式能源的能源综合利用率。     

分布式供能系统中生物质气内燃机的动力性优化研究

本文将生物质燃气作为分布式供能系统内燃机的替代燃料,并利用GT-Power软件对该种内燃机进行性能模拟和动力性优化,以达到节能减排的目的。模拟结果显示,生物质气的燃烧压力较低,使得生物质气内燃机的有效功率偏低,中速时仅为天然气内燃机的1/3。在1500r/min固定转速下,优化压缩比、点火提前角和空燃比等参数的取值能够有效提高生物质气内燃机的动力性,同时改善燃料消耗和排放性。因此多参数优化的方法可以提高生物质气内燃机的综合性能,使其满足分布式供能系统的特殊要求。     

采用燃气内燃机、燃气轮机的燃气安全及消防问题

本文主要讨论发展分布式供能系统采用燃气内燃机、燃气轮机在安全、消防方面的主要障碍及解决方案。     

内燃机分布式供能系统发展现状及案例研究

针对使用内燃机作为原动机的分布式供能系统进行研究,对该技术在国内外的研究进展、应用情况进行综述,对比了3种在不同负荷要求下,结合不同余热回收方式的内燃机分布式系统。并将内燃机与燃气轮机2种天然气分布式原动机进行对比,前者发电效率更高、初期投资更少,适合应用于5 MW以下规模的分布式系统中。以上海某分布式项目为例,对具体的内燃机分布式冷热电联供系统组成、技术参数进行介绍,并通过计算三联供系统一次能源节约率对其节能效果进行计算分析。结果表明:该分布式联产系统夏季典型工况能耗为分产系统的65.41%,冬季为56.58%,节能效果明显。     

燃气内燃发电机与燃气轮发电机的技术特点 及其在分布式发电领域的应用对比

4燃气内燃机与燃气轮机的热效率对比内燃机和燃气轮机的余热利用形式不同。燃气轮发电机发电后的余热以排烟形式排出,排烟温度在450~550℃,而内燃发电机余热的一半以400~450℃的烟气形式排出,还有一半以80~90℃的冷却液排出。由于燃气轮发电机的余热品位较高,易于回收,因此其余热回收利用效率高于内燃发电机。     

Performance of a gas engine driven heat pump for hot water supply systems

The present work aimed at evaluating the experimental performance of a gas engine heat pump for hot water supply. In order to achieve this objective, a test facility was developed and experiments were performed over a wide range of ambient air temperature (10.9-25.3 °C), condenser water inlet temperature (33-49 °C) and at two engine speeds (1300 and 1750 rpm). Performance characteristics of the gas engine heat pump were characterized by water outlet temperatures, total heating capacity and primary energy ratio. The reported results revealed that hot water outlet temperature between 35 and 70 °C can be obtained over the considered range of the operating parameters. Also, total heating capacity and gas engine heat recovery decrease by 9.3 and 27.7%, respectively, while gas engine energy consumption increases by 17.5% when the condenser water inlet temperature changes from 33 to 49 °C. Total heating capacity, gas engine heat recovery and gas engine energy consumption at ambient air temperature of 25.3 °C are higher than those at ambient air temperature of 10.9 °C by about 10.9, 6.3 and 1.5% respectively. Moreover, system primary energy ratio decreases by 15.3% when the engine speed changes from 1300 to 1750 rpm.     

燃气机热泵变负荷特性的试验研究

燃气机热泵是一项高效节能技术，在试验条件下其一次能源利用率PER为1．13～1．79。为了解交负荷时燃气机热泵的性能，通过试验得到了燃气机热泵的发动机负荷特性、发动机余热回收和燃气机热泵的总体特性曲线。结果表明：随着发动机转速的增加，燃气机热泵的COP和PER是下降的，但下降的幅度较为平缓，且保持较高的数值。通过对IPL Vcop值的分析，发现燃气机热泵的IPL Vcop比热泵系统的大，这说明燃气机热泵的部分负荷性能好，可以很好地实现交负荷运行。     

一种新型压缩空气储能系统的理论分析

根据中国西部干旱、缺水、高风沙和限制使用天然气的地区特点,提出了一种压缩空气储能的技术方案,并对其储能过程和发电过程进行了热力学分析,重点分析了压缩过程指数、最高储气压力和透平进气温度对系统能量转换效率的影响规律。研究结果表明:(1)系统电耗随多变指数的升高基本保持不变,能量效率都随多变指数的升高而增加,而热耗随多变指数的升高而大幅减小。(2)系统电耗和热耗都随压缩空气储能系统高压储气室内压力的变大而增加,而系统的能量效率随压缩空气储能系统高压储气室内压力变大而减小。(3)系统电耗和热耗都随高压气体透平进气温度的升高而下降,而系统的能量效率随高压气体透平进气温度的升高而升高。该研究对在中国开展和大规模推广应用压缩空气储能技术具有一定的参考价值。     

Experimental study of gas engine driven air to water heat pump in cooling mode

Nowadays a sustainable development for more efficient use of energy and protection of the environment is of increasing importance. Gas engine heat pumps represent one of the most practicable solutions which offer high energy efficiency and environmentally friendly for heating and cooling applications. In this paper, the performance characteristics of gas engine driven heat pump used in water cooling were investigated experimentally without engine heat recovery. The effects of several important factors (evaporator water inlet temperature, evaporator water volume flow rate, ambient air temperature, and engine speed) on the performance of gas engine driven heat pump were studied in a wide range of operating conditions. The results showed that primary energy ratio of the system increased by 22.5% as evaporator water inlet temperature increased from 13 °C to 24 °C. On the other hand, varying of engine speed from 1300 rpm to 1750 rpm led to decrease in system primary energy ratio by 13%. Maximum primary energy ratio has been estimated with a value of two over a wide range of operating conditions.     

六缸柴油机冷却系统流动与传热的数值模拟研究

冷却水的流动与传热直接影响柴油机的冷却效率、高温零件的热负荷、整机的热量分配和能量利用。在冷却系统传热计算时，利用流固耦合的方法，较为准确地确定了缸体水套的传热边界条件。采用CFD商用软件STAR—CD对直列六缸柴油机的冷却系统的流动与传热进行三维数值模拟，给出了整机冷却水套内冷却液的流场、换热系数及压力场分布，为柴油机冷却水腔的优化设计提供了理论依据。     

Exergy analysis of the woody biomass Stirling engine and PEM-FC combined system with exhaust heat reforming

The woody biomass Stirling engine (WB-SEG) is an external combustion engine that outputs high-temperature exhaust gases. It is necessary to improve the exergy efficiency of WB-SEG from the viewpoint of energy cascade utilization. So, a combined system that uses the exhaust heat of WB-SEG for the steam reforming of city gas and that supplies the produced reformed gas to a proton exchange membrane fuel cell (PEM-FC) is proposed. The energy flow and the exergy flow were analyzed for each WB-SEG, PEM-FC, and WB-SEG/PEM-FC combined system. Exhaust heat recovery to preheat fuel and combustion air was investigated in each system. As a result, (a) improvement of the heat exchange performance of the woody biomass combustion gas and engine is observed, (b) reduction in difference in the reaction temperature of each unit, and (c) removal of rapid temperature change of reformed gas are required in order to reduce exergy loss of the system. The exergy efficiency of the WB-SEG/PEM-FC combined system is superior to EM-FC.     

Performance analysis of an industrial waste heat‐based trigeneration system

The thermodynamic performance of an industrial waste heat recovery‐based trigeneration system is studied through energy and exergy efficiency parameters. The effects of exhaust gas inlet temperature, process heat pressure, and ambient temperature on both energy and exergy efficiencies, and electrical to thermal energy ratio of the system are investigated. The energy efficiency increases while electrical to thermal energy ratio and exergy efficiency decrease with increasing exhaust gas inlet temperature. On the other hand, with the increase in process heat pressure, energy efficiency decreases but exergy efficiency and electrical to thermal energy ratio increase. The effect of ambient temperature is also observed due to the fact that with an increase in ambient temperature, energy and exergy efficiencies, and electrical to thermal energy ratio decrease slightly. These results clearly show that performance evaluation of trigeneration system based on energy analysis is not adequate and hence more meaningful evaluation must include exergy analysis. The present analysis contributes to further information on the role of exhaust gas inlet temperature, process heat pressure, ambient temperature influence on the performance of waste heat recovery‐based trigeneration from a thermodynamic point of view. Copyright © 2009 John Wiley & Sons, Ltd.     

模拟多种发动机尾气热源的吸附制冷试验台研究

研究建立了一个模拟多种发动机尾气热源的试验台。通过理论和经验数据相结合的方法确定了试验台的热流量、出口温度及压力等参数。试验台的热源由燃油燃烧提供，能够模拟出和实际发动机工作时尾气特性(温度、压力、流量)相似的热烟气。模拟的发动机尾气热源和吸附制冷系统相结合，可以降低试验成本，并使试验的可信度更高。为给定热源条件下设计吸附发生器提供一定的理论和实验依据。     

Experimental investigation on heat recovery from diesel engine exhaust using finned shell and tube heat exchanger and thermal storage system

The exhaust gas from an internal combustion engine carries away about 30% of the heat of combustion. The energy available in the exit stream of many energy conversion devices goes as waste, if not utilized properly. The major technical constraint that prevents successful implementation of waste heat recovery is due to its intermittent and time mismatched demand and availability of energy. In the present work, a shell and finned tube heat exchanger integrated with an IC engine setup to extract heat from the exhaust gas and a thermal energy storage tank used to store the excess energy available is investigated in detail. A combined sensible and latent heat storage system is designed, fabricated and tested for thermal energy storage using cylindrical phase change material (PCM) capsules. The performance of the engine with and without heat exchanger is evaluated. It is found that nearly 10–15% of fuel power is stored as heat in the combined storage system, which is available at reasonably higher temperature for suitable application. The performance parameters pertaining to the heat exchanger and the storage tank such as amount of heat recovered, heat lost, charging rate, charging efficiency and percentage energy saved are evaluated and reported in this paper.