共查询到19条相似文献,搜索用时 765 毫秒
1.
2.
3.
基于搭建的以R245fa为工质的有机朗肯循环发电系统,通过调节电加热器功率来研究热源温度对有机朗肯循环发电特性的影响。研究表明:当冷凝温度不变时,随着热源温度的升高,蒸发压力升高,冷凝压力基本不变;膨胀机的压比和压差都增大;当热源温度由86℃升到99℃时,净输出电功率从4.7 kW增加到8 kW,发电效率由7.55%升至8.4%,功率和效率都近似线性增加。 相似文献
4.
对柴油机废热驱动有机朗肯循环(ORC)发电系统的4种方案进行了理论分析;并以200,kW柴油发电机废热回收为对象,设计一台以R245fa为循环工质的废热驱动ORC发电系统样机.在柴油发电机输出功率为180,kW时,分别以"发动机冷却液"和"发动机冷却液和尾气"为热源,测试ORC系统的循环性能.结果表明:单独依靠发动机冷却液驱动ORC系统时,节温器开闭导致系统无法稳定工作.当强制开启节温器、R245fa流量从0.32,kg/s增大到0.41,kg/s时,冷却液出水温度迅速下降,而系统净发电量单调递增至3.1,kW;净效率曲线呈先增后减的变化趋势,并在0.35,kg/s时达到3.8%的最大值.当发动机冷却液和尾气共同驱动ORC系统时,系统净发电量可达9.9,kW,净效率为6.3%. 相似文献
5.
本文对四川甘孜的一口地热井进行能量分析和?分析,参考该井地热水的温度115℃,采取的发电方式有单级闪蒸系统、预热有机朗肯系统、闪蒸有机朗肯联合系统。结果表明,闪蒸朗肯系统的?效率最高(47.81%),预热朗肯系统次之(46.31%),单级闪蒸系统最低(42.83%)。对于有机朗肯循环,发生器的影响因子及?损均为最大;而闪蒸部分,闪蒸罐的影响因子最高,但闪蒸朗肯系统将其?损减少64.8%,低于汽轮机。计算结果显示,提高闪蒸/发生温度能够提高效率、减少?损,而闪蒸朗肯系统中发生温度有较好的优化性能。综上所述,闪蒸有机朗肯联合系统具有最大的净功率(360.8 kW)和最高的?效率,而且尾水温度最低,热效率适中,适合用于中低温地热发电。 相似文献
6.
理想发电循环系统仅与系统热源、冷源的温度相关,而实际低品位有机朗肯循环发电系统效率除与冷热源温度相关外,与工质、系统形式等因素密切相关.但是由于受到热源参数及优化目标等因素影响,尚未优选出合适的工质和系统形式.针对不同热源参数特性,研究相适应的系统形式及工质,为有机朗肯循环发电系统应用提供科学依据,是有机朗肯循环发电系统切实可用的关键. 相似文献
7.
8.
9.
《新能源进展》2015,(3)
本文对四川甘孜的一口地热井进行能量分析和?分析,参考该井地热水的温度115℃,采取的发电方式有单级闪蒸系统、预热有机朗肯系统、闪蒸有机朗肯联合系统。结果表明,闪蒸朗肯系统的?效率最高(47.81%),预热朗肯系统次之(46.31%),单级闪蒸系统最低(42.83%)。对于有机朗肯循环,发生器的影响因子及?损均为最大;而闪蒸部分,闪蒸罐的影响因子最高,但闪蒸朗肯系统将其?损减少64.8%,低于汽轮机。计算结果显示,提高闪蒸/发生温度能够提高效率、减少?损,而闪蒸朗肯系统中发生温度有较好的优化性能。综上所述,闪蒸有机朗肯联合系统具有最大的净功率(360.8 k W)和最高的?效率,而且尾水温度最低,热效率适中,适合用于中低温地热发电。 相似文献
10.
11.
Experimental investigation on the performance of ORC power system using zeotropic mixture R601a/R600a 下载免费PDF全文
An experimental study on the practical performance of organic Rankine cycle (ORC) system using zeotropic mixture is performed by using a small scale ORC power generation experimental setup. R601a/R600a is selected as the working fluid. The effects of mixture composition, heat source temperature, and working fluid flow rate on the performance of ORC system are investigated. The experimental results indicate that the net power output first increases and then decreases as the R600a concentration increases. The optimal mixture composition with the maximum net power output is 0.6/0.4 (mass fraction) at the heat source temperature of 115°C. The net power output of R601a/R600a (0.6/0.4) is higher than that of R601a by 25%, indicating that the performance of ORC system can be clearly improved by using the zeotropic mixture. For a fixed working fluid flow rate, both net power output and thermal efficiency first decrease slowly and then drop sharply with the decrease of the heat source temperature. The appropriate superheat degree of R601a/R600a is in the range of 15 to 20°C when the heat source temperature has a small variation. In addition, the optimal working fluid volume flow rates yielding the maximum net power output are obtained for different compositions of R601a/R600a. The experimental results in the study can be of great significance for the design and operation of ORC power system using zeotropic mixture. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
12.
A novel heat pump and power generation integration system (HPPGIS) using solar energy as a low temperature heat source was presented in this study. This system could be operated in both an organic Rankine cycle power generation (ORC‐PG) mode and a reverse Carnot cycle heat pump (RCC‐HP) mode. Compared with a single heat pump and power generation system, this system improved the utilization efficiency of solar energy, thus showing potential for the generation of economic benefits. Contrastive analyses of different working fluids using ORC‐PG and RCC‐HP systems were conducted first, leading to the selection of R142b and R245fa as optimal fluids. Then, an experimental investigation of the system was carried out under different conditions. A heat pump and ORC system model was proposed and validated by comparing experimental and simulated values. The experimental results indicated that the HPPGIS had good feasibility and stability in both modes. In the ORC‐PG mode, HPPGIS had a power output of 1.29 kW and a thermal efficiency of 4.71% when the water inlet temperature of the evaporator was 90.03°C. In the RCC‐HP mode, HPPGIS had a COP of 3.16 and a heat capacity of 33.24 kW when the water outlet temperature of the condenser was 106.23°C. 相似文献
13.
我国的余热资源和可再生能源丰富,但部分余热资源和可再生能源分布比较分散,并存在温度和能量密度均较低的问题。基于传统能源转化技术,利用温度较低的余热资源和能量密度较低的可再生能源进行发电,会降低余热资源和可再生能源的热功转换效率。有机朗肯循环(ORC)系统可以有效利用低温热能进行发电。对于不同温度和形式的热源,采用合适的工质和循环工况,可以提高ORC系统的发电效率。有出口温度限制的热源是一种较为常见的热源形式,在ORC系统中增加回热装置可能会进一步提高热力循环对该类热源的利用效率。因此,文章针对有温度出口限制的热源,建立了亚临界ORC计算分析模型,选取了干流体和等熵流体作为循环工质,以热源回收?效率作为ORC系统的循环性能评价指标,系统地比较了不同回热度条件下ORC系统的循环性能。文章系统地分析了回热流程对ORC系统循环性能的影响规律,并将计算结果进行理论关联,首次建立了依据冷源和热源条件直接选取最佳回热度的定量准则。 相似文献
14.
According to fluid critical temperature and heat source temperature, organic Rankine cycle (ORC) is recognized in two categories: subcritical ORC and supercritical ORC. For a given heat source, some organic fluids not only can be used in subcritical ORC, but also can be used in supercritical ORC. For heat source with temperature of 90 °C, HFC125, HFC143a and HF218 can be used in both ORCs. Performance of the three substances in both cycles, especially in near-critical conditions is studied with expander inlet temperature of 85 °C and hot water mass flow rate of 1 kg/s. The results show that when fluids go in supercritical ORC from subcritical ORC, cycle thermal efficiency varies continuously, while mass flow rate and net power generation vary discontinuously. Maximum net power generation in near-critical conditions of subcritical ORC is higher than that of supercritical ORC. For HFC125 and HFC143a, outlet temperature of hot water decreases with the increase of heating pressure ratio. For HF218, outlet temperature of hot water increases firstly and decreases secondly with the increase of heating pressure ratio, which leads to an increase of net power generation with the increase of heating pressure ratio in high heating pressure ratio conditions. 相似文献
15.
16.
余热利用有机物朗肯循环最佳热回收效率分析 总被引:1,自引:0,他引:1
首先通过分析余热回收动力循环的不可逆损失,得到循环的理想效率。其次,通过分析发现热回收效率随蒸发压力变化存在最佳值,并且最佳热回收效率与最小熵增率是等价的。然后,通过研究两种简化的余热利用动力模型,应用有限时间热力学的相关方法,指出最大热回收效率产生的原因。再次,研究了余热变化时系统最佳工况的变化。结果发现最佳蒸发压力随余热流量、入口温度增加而显著增加,而与余热组分关系不大。最后,研究了工质对系统最佳工况的影响,发现较高临界温度的工质,最佳蒸发压力较低。 相似文献
17.
《International Journal of Hydrogen Energy》2019,44(7):3876-3890
Distributed power generation is gaining attention as a solution for the transmission loss and site selection in centralized power generation. Polymer-electrolyte membrane fuel cells (PEMFCs) are suitable as a distributed power source for residential areas because of their high efficiency and low environmental impact. This study proposes a combined power generation system for recovering waste heat from both the cell stack and the reformer of a PEMFC by applying an organic Rankine cycle (ORC). The best working fluid with the highest ORC power output (i.e., the highest combined system efficiency) was identified through a parametric study of different working fluids. An economic analysis was also performed for different working fluids, waste heat sources, and types of system operation. The results show that the installation cost of the ORC can be recovered within the fuel cell's lifetime in all design cases. Greater cumulative profit can be generated by maintaining the same power output as the stand-alone PEMFC system for greater efficiency than when increasing the power output to sell surplus power. The results demonstrate that the optimal heat recovery from the PEMFC system is both thermodynamically and economically beneficial. 相似文献
18.
This study involves the design of a single flash cycle which comprises a separator, steam turbine, condenser and pump combined with Organic Rankine Cycle (ORC). The ORC has a three-stage heat exchanger. The mass flow rate of the organic fluid varies depending on the type of organic fluid. The system is heated by geothermal water. The effect of changing the geothermal water temperature [200–260°C] on performance parameters including the power output and overall efficiency has been studied. Four working fluids (n-Butane, Isobutane, R11 and R123) were chosen depending on their properties. The results show that a drop in the source temperature (T1) by 10% will result in 9.7% and 25.3% drop in overall efficiency and net power output for Isobutane. Also, Isobutane has a drop of 4.2% in both; overall efficiency and net power output for a 10% drop in pressure ratio (rp). R11 shows the highest overall efficiency and net power output (18.76% and 24.887 MW) respectively at the design point. 相似文献
19.
以太阳能为驱动热源,基于喷射式制冷和ORC,构建一种太阳能喷射式制冷功冷联供系统,该系统分为太阳能集热子系统和功冷联供子系统两部分。以R161为功冷联供子系统循环工质,通过Matlab建立该系统热力学模型,对其性能进行模拟,在设计工况下该系统制冷量为2.893 kW,净输出功为1.594 kW,功冷联供子系统制冷效率为12.47%,发电效率为6.87%,效率为41.45%。通过分析可知,该系统损占比较大的部件依次为太阳能集热器(73.3%)、发生器(12.14%)、蒸发器(5.03%)和透平(4.81%)。考虑到实际过程,分别研究系统内部参数改变和外部环境参数改变,对系统的影响,发现高低压发生器的温升由利于系统性能的提升,同时环境温度的升高以及太阳辐照度的提升均可改善集热器效率,从而提升系统性能。 相似文献