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1.
This study represents the results of the analysis and optimization of an integrated system for cogenerating electricity and freshwater. This setup consists of a Solid Oxide Fuel cell (SOFC) for producing electricity. Unburned fuel of the SOFC is burned in the afterburner to increase the temperature of the SOFC's outlet gasses and operate a Gas turbine (GT) to produce additional power and operate the air compressor. At the bottom of this cycle, a combined setup of a Multi-Effect Desalination (MED) and Reverse Osmosis (RO) is considered to produce freshwater from the unused heat capacity of the GT's exhaust gasses. Also, a Stirling engine is used in the fuel supply line to increase the fuel's temperature. Using LNG and the Stirling engine will replace the fuel compressor with a pump which increases the system performance and eliminates the need for the expansion valve. To study the system performance a mathematical model is developed in Engineering Equation Solver (EES) program. Then, the system's simulated data from the EES has been sent to MATLAB to promote the best operating condition based on the optimization criteria. An energetic, exergetic, economic, and environmental analysis has been performed and a Non-dominated Sorting Genetic Algorithm (NSGA-II) is used to achieve the goal. The two-objective optimization is performed to maximize the exergetic efficiency of the proposed system while minimizing the system's total cost of production. This cost is a weighted distribution of the Levelized Cost of Electricity (LCOE) and Levelized Cost of freshwater (LCOW). The results showed that the exergetic and energetic efficiencies of the system can reach 73.5% and 69.06% at the optimum point. The total electricity production of the system is 99 MW. The production cost is 11.71 Cents/kWh, of which 1.04 Cents/kWh is emission-related and environmental taxes. The freshwater production rate is 42.44 kg/s which costs 4.38 USD/m3.  相似文献   
2.
由于能够减小系统自身的热噪声和提高系统信噪比,低温光学是实现高灵敏度红外探测的必要手段。提出了一种将脉冲管制冷机用作冷源的透射式低温光学系统。这种新型低温光学系统可用于体积和重量受限而又需要进行高灵敏度红外探测的场合。从光学设计、光机结构设计和内部热噪声分析等方面说明了透射式低温光学系统的设计过程。搭建了用于对脉冲管制冷机冷却光学系统的可行性进行验证的试验系统,并从系统内部热噪声的角度对低温光学的有效性进行了验证。实验结果表明,经过3 h,透镜温度由300 K降至设计温度150 K,继续降温则可达到最低温度105 K。测试过程中,透镜保持完好,验证了将脉冲管制冷机用作冷源的可行性。用黑体和320×256元碲镉汞探测器对光学系统自身的热噪声进行了测试。结果表明,当光学系统的温度从300 K降至215 K时,其自身热辐射减少了75%。这与理论分析结果一致,验证了低温光学降噪的有效性。  相似文献   
3.
杨森  刘碧强  蒋珍华  吴亦农 《红外》2018,39(5):25-30
针对一台U型一级斯特林二级脉管混合制冷机,分析了一级冷量对二级脉管预冷对制冷机整机性能的影响。制冷机一级制冷温度为80 K,二级制冷温度为30 K,通过将一级冷指和脉管热桥连接,利用一级提供的冷量对脉管进行了预冷。通过计算流体力学(Computer Fluid Dynamics, CFD)仿真研究了脉管预冷对脉管内部温度场和速度场的影响。研究发现,对脉管进行预冷会改变脉管工作时的内部温度分布,对二级制冷能力有巨大影响。在不采用一级冷量对脉管中段进行预冷时,制冷机以二级0.7W@30 K和一级7W@80 K同时进行冷量输出,压缩机输入PV功为133 W;通过热桥将一级冷端换热器与二级脉管中段连接后,保持输入PV功为133 W,输出冷量变为二级1.2W@30K和一级6W@80K同时进行冷量输出。研究发现,U型一级斯特林二级脉管混合制冷机采用中段脉管预冷可大大提高二级的制冷能力。  相似文献   
4.
A Stirling/pulse tube hybrid cryocooler (SPC), comprised of a Stirling cryocooler as the first stage and a pulse tube cryocooler as the second stage, features the ability of shifting cooling capacity between stages by adjusting the movement of the displacer in the first stage. Such an ability allows an SPC to accommodate itself to time-varying heat loads at different temperatures, which makes it a competitive candidate in space applications. However, due to the gas coupling, there exists a significant mutual effect between stages which endows an SPC with special thermodynamic characteristics and has a significant effect on the SPC’s capability of shifting cooling capacity between stages. With the phasor analysis and the thermodynamic analysis, this paper establishes an idealized model of an SPC. The model is then used to study the effect of the second stage on the first stage and reveal the condition that an SPC is able to shift cooling capacity between stages. Also, the model is compared with a Sage numerical model and the two models are consistent on the overall trend. Though it is unable to reflect reality precisely, the idealized model can interpret the mechanism and highlight some of the essential nature of an SPC, which will eventually benefit the appropriate design of an SPC.  相似文献   
5.
α-Stirling engines are receiving more and more attention for applications of concentrated solar power in small power installations (15–30 kW). The design of these engines has not experienced in recent years the breakthrough needed to deliver close to the Carnot Cycle energy conversion efficiencies. The delivered efficiencies are limited to mid-to-high 20% in the typical installations “Dish Stirling”. Here we review the latest studies made on α-Stirling engines, unfortunately mostly based on theoretical models of limited reliability, but also including very few examples of Computer-Aided Engineering (CAE) modeling followed by prototyping and testing. Finally, we present in detail one CAE model of an α-Stirling engine delivering energy conversion efficiencies of 42% with hydrogen as working fluid and adopting one hot cylinder, one cold cylinder, and one regenerator, with the hot fluid temperature of 800 °C. This efficiency is much higher than current air microturbines, which may deliver efficiencies of only about 20% working at much lower temperatures.  相似文献   
6.
The Stirling engine is an environmentally friendly external combustion heat engine and reduces the complexities of the combustion process, and indirectly helps in reduction of CO2 emission. Modelling based on cyclic analysis is performed for a Beta configuration Stirling engine of 1.5?kWe capacity using a rhombic drive for the solar-dish-supported Stirling engine. The analysis helps in estimating the overall efficiency of the system using the experimental correlation of the solar concentrator ARUN160 at the engine operating temperature. The analysis shows that the system will have overall efficiency around 25% in the range of 750–1050?K at the expansion space. The degradation of performance compared to that at an operating temperature of 1025?K is only marginal and makes 750?K a more preferred temperature. The present study evaluates a range of possible design goals and provides suitable alternatives and thus provides a clear understanding of the system design considerations.  相似文献   
7.
High-frequency pulse tube cryocooler (HPTC) has advantages of compact structure, low vibration, high reliability and long operation time. In this study, Theoretical analysis and experimental tests have been conducted in four aspects based on a developed 4 K HPTC. Firstly, a compressor with larger power output capability was employed and the impedance match between the cold head and the compressor was discussed. Secondly, simply using inertance tube configuration to replace the traditional inertance tube-gas reservoir structure. Then, the type and the size of the regenerator materials working at 4–20 K have been experimentally optimized. Finally, the performance of double-inlet working at as low as 20 K has also been tested for the first time for the HPTC. The present prototype achieved a no-load temperature of 3.6 K, which is the lowest temperature record ever reported for HPTC using helium-4 as working gas. A cooling power of 6 mW/4.2 K was also obtained with 250 W input power and a precooling power of 12.1 W/77 K.  相似文献   
8.
汪宁  张学军  赵阳  甘智华  张春伟  余萌 《化工学报》2020,71(z1):179-186
博物馆文物保存过程中相对湿度对文物的影响尤其重要,因此针对目前小型展柜广泛采用的半导体制冷存在制冷量小的缺点,结合斯特林制冷机制冷量大、寿命长、安全可靠等优点,设计并搭建了一台基于斯特林制冷的文物恒湿展柜装置,实现对微环境中相对湿度的精确调节。将斯特林制冷机的冷头置于优化设计的水槽中用于控制水温,采用空气与水直接接触的方式控制展柜内空气湿度。结果表明:使用散热片以及小型循环水泵可以大幅提升冷头与水之间的换热效率;合理的风机控制策略可以有效提升展柜湿度调节速度,维持湿度稳定,降低系统能耗;展柜内的相对湿度在45.0%~65.0%之间连续可调,并能保持稳定。  相似文献   
9.
针对某型热气机发电机组建立了电机和热气机发电机组的有限元模型,用模态分析进行试验验证,进而得到了缩减模型.进行了同时考虑径向电磁力与机械载荷的电机多体动力学计算,及有无考虑电机激励的热气机发电机组振动响应计算;对比分析了热气机发电机机组振动加速度的计算值与实测值,试验验证了计算模型的正确性.研究成果可为发电机组电磁力的计算提供参考.  相似文献   
10.
A system consisting of a last-generation Stirling engine (SE) and a fuel burner for distributed power generation has been developed and experimentally investigated. The heat generated by the combustion of two liquid fuels, a standard Diesel fuel and a rapeseed oil, is used as a heat source for the SE, that converts part of the thermal energy into mechanical and then electric energy. The hot head of the SE is kept in direct contact with the flame generated by the burner. The burner operating parameters, designed for Diesel fuel, were changed to make it possible to burn vegetable oils, not suitable for internal combustion engines. The possibility of adopting different configurations of the combustion chamber was taken into account to increase the system efficiency. The preliminary configurations adopted allowed to operate this integrated system, obtaining an electric power up to 4.4 kWel with a net efficiency of 11.6%.  相似文献   
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