scholarly journals CFD-subset-FVM-based MATLAB-simulation of Heat Transfer in High Grade Cold Storage Augmenting Cryogenic Energy Storage System by Circulating Natural Gas as Working Fluid

Cryogenic Energy Storage (CES) improves power grid application with renewable intermittent power sources. In CES, off-peak excess electricity liquefies air or natural gas. Cryogenic fluid so obtained is stored in large Dewar tanks for long periods of time. Whenever electricity need is in peak, work available in cryogen is recovered by thermodynamic cycle using hot storage waste heat (HSWH) that has been generated by liquefier’s compressor. Many researchers focus on liquid air energy storage (LAES). But, natural gas (NG) is good working substance for CES liquefaction process. This paper reviews NG-CES containing high grade cold storage (HGCS). Cold stored HGCS is utilized to raise CES efficiency and hike liquefier yield. This paper models HGCS unit and compares output with experimental data. Impact of cold recycling is analyzed for liquefier yield and storage efficiency.

2018 ◽  
Vol 44 ◽  
pp. 00190
Author(s):  
Paweł Wojcieszak ◽  
Ziemowit Malecha

Cryogenic Energy Storage (CES) systems are able to improve the stability of electrical grids with large shares of intermittent power plants. In CES systems, excess electrical energy can be used in the liquefaction of cryogenic fluids, which may be stored in large cryogenic vessels for long periods of time. When the demand for electricity is high, work is recovered from the cryogen during a power cycle using ambient or waste heat as an upper heat source. Most research is focused on liquid air energy storage (LAES). However, natural gas can also be a promising working fluid for the CES system. This paper presents a natural gas-based CES system, coupled with a low temperature packed bed cold storage unit. The cold, which is stored at a low temperature level, can be used to increase the efficiency of the cryogenic liquefiers. The model for the packed bed in a high grade cold storage unit was implemented and then compared with the experimental data. The impact of cold recycling on the liquefaction yield and efficiency of the cryogenic energy storage system was investigated


2021 ◽  
Vol 11 (18) ◽  
pp. 8484
Author(s):  
Seok-Ho Song ◽  
Jin-Young Heo ◽  
Jeong-Ik Lee

A nuclear power plant is one of the power sources that shares a large portion of base-load. However, as the proportion of renewable energy increases, nuclear power plants will be required to generate power more flexibly due to the intermittency of the renewable energy sources. This paper reviews a layout thermally integrating the liquid air energy storage system with a nuclear power plant. To evaluate the performance realistically while optimizing the layout, operating nuclear power plant conditions are used. After revisiting the analysis, the optimized performance of the proposed system is predicted to achieve 59.96% of the round-trip efficiency. However, it is further shown that external environmental conditions could deteriorate the performance. For the design of liquid air energy storage-nuclear power plant integrated systems, both the steam properties of the linked plants and external factors should be considered.


2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Cong Zhang ◽  
Haitao Min ◽  
Yuanbin Yu ◽  
Qingnian Wang ◽  
Huanli Sun

Although both battery and super-capacitor are important power sources for hybrid electric vehicles, there is no accurate configuration theory to match the above two kinds of power sources which have significantly different characteristics on energy and power storage for the goal of making good use of their individual features without size wasting. In this paper, a new performance is presented that is used for analysis and optimal design method of battery and super-capacitor for hybrid energy storage system of a parallel hybrid electrical vehicle. In order to achieve optimal design with less consumption, the power-energy function is applied to establish direct mathematical relationship between demand power and the performance. During matching process, firstly, three typical operating conditions are chosen as the basis of design; secondly, the energy and power capacity evaluation methods for the parameters of battery and super-capacitor in hybrid energy storage system are proposed; thirdly, the mass, volume, and cost of the system are optimized simultaneously by using power-energy function. As a result, there are significant advantages on mass, volume, and cost for the hybrid energy storage system with the matching method. Simulation results fit well with the results of analysis, which confirms that the optimized design can meet the demand of hybrid electric vehicle well.


Author(s):  
Simeon Dybe ◽  
Tom Tanneberger ◽  
Panagiotis Stathopoulos

Abstract The expansion of renewable energy generation must go hand in hand with measures for reliable energy supply and energy storage. A combination of hydrogen and oxygen as storing media provided from electrolysis at high pressure and zero emission power plants is a very promising option. The Graz cycle is an oxy-fuel combined power cycle that can operate with internal H2/O2 combustion and steam as working fluid. It offers thermal efficiencies up to 68.5% (LHV). This work applies a second law analysis to the Graz cycle and determines its exergetic efficiency. Exergy destruction is broken down to the cycle’s components thus providing insights on the location and magnitude of the cycle’s inefficiencies. A sensitivity analysis identifies the cycle’s exergetic and energetic efficiency as a function of representative parameters, offering an approach for future improvements. The combination of the cycle with an electrolysis plant is subsequently analyzed as an electric energy storage system. The round trip efficiency of the storage and back conversion system is computed by taking into account the additional compression of the reactants. As part of this analysis, the effect of the electrolyzer’s operational pressure is studied by comparing several commercial electrolyzers.


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