低温热能发电的研究现状和发展趋势

低温热能种类繁多,数量巨大,利用这部分能源意义重大。介绍了低温热能发电技术的研究现状和发展趋势。低温热能发电技术主要应用于太阳能热电、工业余热发电、地热发电、生物质能发电、海洋温差发电等方面。现阶段低温热能发电的研究重点有:工质的热物性和环保性能、循环优化研究;提高低温热能发电效率的研究,包括混合工质循环、Kalina循环、回热、氨吸收式动力制冷循环等;基于有限时间热力学的系统最优控制等方面的研究。     

能源工业的可持续发展

利用低温工质制冷发电的方法，以低温工质为循环制冷作功工质，依托具有低品位热能的太阳能，地热能，工业余热与低污染的低品位工业热能为热源，建设发电站与制冷发电站，用以制冷与发电。以此来减少煤炭，石油，天然气的消耗量，抑制大气中ＣＯ２气体浓度的增加，减缓全球气候变暖。     

低温热源喷射式发电制冷复合系统的(火用)分析

根据热力学第二定律,对一种新型低温热源喷射式发电制冷复合系统进行了(火用)分析,并以R600a作为工质对系统进行了仿真计算.结果表明:在热源入口温度为420 K、热源热水流量为0.2kg/s、热源蒸发温度为370 K的标准工况下,系统净发电量为2.74 kW,系统制冷量为11.99 kw,系统的(火用)效率达到25.83%,系统能量利用率为45.34%;系统(火用)损失主要发生在蒸汽发生器和喷射器中.在热源蒸发温度提高过程中,系统内部工质流量发生改变,导致系统净发电量和(火用)效率小幅下降,制冷量和能量利用率先增后降.当热源蒸发温度为370 K时,系统能量利用率达到最大值.     

内燃机缸套水余热有机朗肯循环发电系统设计与优化

以某分布式能源系统内燃机缸套水为余热为低温热源,设计了适用于该热源条件的有机朗肯循环(ORC)发电系统,使用Ebsilon软件模拟并分析了提升工质过热度对ORC系统性能、组件?效率及局部?损失率的影响,系统优化后,使系统?效率从39.50%提升至41.58%,系统净电效率从9.27%提升至9.77%。     

低品位热能制冷发电站

以低沸点工质为循环制冷作功工质,以低品位热能为热源,建设低品位热能制冷发电站,用以制冷、发电。     

低品位热能制冷发电站

以低沸点工质为循环制冷作功工质,以低品位热能为热源,建设低品位热能制冷发电站,用以制冷、发电。     

变工况下有机朗肯循环发电特性的实验研究

有机朗肯循环是利用中低温热源的重要技术之一。基于R245fa为工质的低温热源驱动有机朗肯循环发电系统,通过改变电加热器功率来研究其在变工况下的发电特性。结果表明：热源热量变化12%时,系统最大净发电量为7.8 kW,发电效率为8.7%;系统最小净发电量为6.9 kW,发电效率为8.26%;系统重新达到稳定状态的时间为35 ~ 45 min,相同时间内,系统对热源温度降低的响应更迅速而对热源温度升高的响应速度较慢;在此热源的改变条件下系统仍能稳定运行。     

喷射式制冷利用技术研究综述

在简要介绍喷射式制冷循环的原理组成和工质类型基础上,分别从运行参数、系统优化(改进系统循环形式)、主要应用领域和低温热源适用性等方面进行了讨论和研究。最后,认为喷射式制冷具有广阔的应用前景。     

低温余热发电系统板式蒸发器过热度控制策略研究

板式蒸发器过热度是低温余热发电系统中的重要参数,以低沸点有机物R600a为循环工质,结合200℃以下的低温热源进行研究。首先介绍了过热度控制理论及其控制策略,结合异步电机矢量控制方法,进行了Simulink仿真验证。以低温余热发电系统平台实验,通过热源变化引起的系统过热度的动态响应分析,验证了过热度作为控制对象的可行性。     

有机朗肯循环系统损实验研究

可再生能源及余热发电是低品位能源一种高效利用模式,有机朗肯循环发电系统比水蒸气发电机组更适用于低温热源发电。设计并搭建了热源功率为100kW的导热油模拟热源的有机朗肯循环发电系统,研究冷热源参数恒定不变、膨胀机转速变化时发电系统主要设备的损失和所占比例。主要结论为:当膨胀机转速增加时,蒸发器、膨胀机和工质泵的损失增大,而冷凝器设备损失减少;定量分析膨胀机转速为3000r/min时,蒸发器损失为51.8%,占有机朗肯循环系统损失的1/2以上,工质泵损失最小,仅为1.8%。     

Thermoeconomic analysis of SOFC-GT-VARS-ORC combined power and cooling system

The integration of the gas turbine cycle and organic Rankine cycle with the solid oxide fuel cell for power generation is quite prevalent. However, the need is also felt for systems capable of providing power with cooling. Therefore, it is proposed to integrate solid oxide fuel cell with gas turbine cycle, vapour absorption refrigeration system and organic Rankine cycle through the heat available with fluid in the cycle. Here intercooled and reheat gas turbine cycle is integrated with solid oxide fuel cell. Heat rejected in intercooling is used in vapour absorption refrigeration system for cooling. This paper presents thermoeconomic analysis. Results show that the combination of solid oxide fuel cell-gas turbine-vapour absorption refrigeration system-organic Rankine cycle yields increase in efficiency to 68.79% as compared to 58.88% from combined solid oxide fuel cell-gas turbine cycle. The cost of electricity per unit power output is found as 1939.93 $/kW.     

A finite time analysis of a cascade refrigeration system using alternative refrigerants

The performance of a three stage cascade refrigeration systems employing two different environmental friendly refrigerants has been examined with a view to determine the best combination of modern environmental friendly refrigerants to produce the minimum power consumption for a given refrigeration rate. The refrigeration system examined employed two stages on the high-pressure side and a single stage on the low-pressure side. The effect of overlap temperature and the efficiency of the compression processes feature in the analysis.     

Development and applications of solar-based thermoelectric technologies

In this paper a survey of solar-based driven thermoelectric technologies and their applications is presented. Initially, a brief analysis of the environmental problems related to the use of conventional technologies and energy sources is presented and the benefits offered by thermoelectric technologies and renewable energy systems are outlined. The development history of solar-based thermoelectric technologies is introduced together with the discussion of the existing drawbacks of current systems. Typical applications of the solar-driven thermoelectric refrigeration and the solar-driven thermoelectric power generation are presented in order to show to the reader the extent of their applicability. The application areas described in this paper show that solar-driven thermoelectric technologies could be used in a wide variety of fields. They are attractive technologies that not only can serve the needs for refrigeration, air-conditioning applications and power generation, but also can meet demand for energy conservation and environment protection.     

高温燃料电池与燃气轮机相结合的混合发电系统

高温燃料电池与燃气轮机相结合的混合发电系统具有高效、环保和可靠的特性,这种新颖的混合发电系统在未来分布式发电领域具有广阔的应用前景。有不少专家和学者对其系统构成度匹配、系统性能等问题做了大量研究。目前已有高温燃料电池与燃气轮机混合发电系统成功运行,但仍有很多问题需要进行进一步的研究和探索,以使该混合发电系统早日实现商业化运行。本文综述了高温燃料电池与燃气轮机混合发电系统的研究现状,展望了该混合发电系统在未来的研究度发展前景。     

Efficient use of energy by utilizing gas turbine combined systems

The gas turbine engine is characterized by its relatively low capital cost compared with steam power plants. It has environmental advantages and short construction lead time. However, conventional industrial engines have lower efficiencies especially at part load. One of the technologies adopted nowadays for improvement is the “combined cycle”. Hence, it is expected that the combined cycle continues to gain acceptance throughout the world as a reliable, flexible and efficient base load power generation plant. In this article, 12 research investigations, carried out by the author and associates during the last 10 years are briefly reviewed. These cover 12 gas turbine systems which would contribute towards efficient use of energy. They entail fundamental studies in addition to applications of combined systems in industry including: the closed gas turbine cycle; the organic Rankine cycle; repowering; integrated power and refrigeration; cryogenic power; liquefied natural gas (LNG) gasification; and inlet air cooling.     

A comparison of the performances of adsorption and resorption refrigeration systems powered by the low grade heat

In order to study the refrigeration performances of the resorption refrigeration technology, the resorption working pair of BaCl₂–MnCl₂–NH₃, which has the similar working requirements for the heat source and cooling source, and also could satisfy the similar refrigeration requirements with the adsorption working pair of CaCl₂–NH₃, is studied by simulation and experiments. In the simulation the mass transfer resistance is not considered for the systems, and the refrigeration performances related with heat transfer performances are studied, results show that the resorption refrigeration system has a higher refrigeration power and COP (coefficient of the refrigeration performance) because the refrigeration effect is generated by the reaction heat compared to the latent heat of evaporation. After the simulation the experimental test unit is constructed, and the experimental data are analyzed. Results show that the resorption rate is influenced by the critical mass transfer performance very much, and the refrigeration performance is lower than that of adsorption system. The resorption system also has the problem of the larger refrigeration power loss for the reason of the sensible heat requirement of low temperature adsorber. How to improve the mass transfer performance of resorption system and decrease the influence on the refrigeration power by the sensible heat requirement of low temperature adsorber will be the key research directions for the application of resorption refrigeration systems.     

Thermodynamic analysis of load-leveling hyper energy converting and utilization system

Load-leveling hyper energy converting and utilization system (LHECUS) is a hybrid cycle which utilizes ammonia–water mixture as the working fluid in a combined power generation and refrigeration cycle. The power generation cycle functions as a Kalina cycle and an absorption refrigeration cycle is combined with it as a bottoming cycle. LHECUS is designed to utilize the waste heat from industry to produce cooling and power simultaneously. The refrigeration effect can be either transported to end-use sectors by means of a solution transportation absorption chiller (STA) as solution concentration difference or stored for demand load leveling.     

大冷量制冷机组匹配实验

依据多联式空调(热泵)机组及实验室设计相关要求初步选取制冷机组类型,根据实验室负荷计算确定制冷机组的容量,采用变频与定频相结合技术选取匹配的制冷机组.通过极限低温工况试验、工况调整速度试验检测制冷机组的匹配性并在试验的基础上进行能耗分析.试验结果表明,采用变频与定频相结合技术比定频机组在冷量测试时节能13%以上.合理高效的匹配制冷机组有助于改善各种工况的稳定速率,同时有效地控制制冷系统能耗,节约能源.     

A comprehensive review of solar thermoelectric cooling systems

The negative environmental impacts of burning fossil fuels have forced the energy research community seriously to consider renewable sources, such as naturally available solar energy. This paper provides an overview of solar thermoelectric (TE) cooling systems. Thus, this review presents the details referring to TE cooling parameters and formulations of the performance indicators and focuses on the development of TE cooling systems in recent decade with particular attention on advances in materials and modeling and design approaches. Additionally, the TE cooling applications have been also reviewed in aspects of electronic cooling, domestic refrigeration, air conditioning, and power generation. Finally, the possibility of solar TE cooling technologies application in “nearly zero” energy buildings is briefly discussed, and some future research directions are included. This research shows that TE cooling systems have advantages over conventional cooling devices, including compact in size, light in weight, high reliability, no mechanical moving parts, no working fluid, being powered by direct current, and easily switching between cooling and heating modes.