China
Africa
Explore chapters and articles related to this topic
Stationary Fuel Cells and Hybrid Systems
Published in Viorel Badescu, George Cristian Lazaroiu, Linda Barelli, POWER ENGINEERING Advances and Challenges, 2018
A. Moreno, V. Cigolotti, M. Minutillo, A. Perna
Another new market segment for stationary fuel cells application is the energy storage of renewable energy sources such as wind and solar that are significantly increased in the last decade, and a further growing is expected in the next years. Their integration in the power grid is problematic and presents a great challenge in energy generation and load balance maintenance to ensure power network stability and reliability. Amongst all the possible solutions, Electrical Energy Storage (EES) has been recognized as one of the most promising approaches. Recent studies demonstrate that an EES system based on fuel cell technology offers a potentially high efficiency, low cost, and scalable distributed energy resource. Thus, a new market segment can be found in this application field for stationary fuel cells. In particular, PEMFC and SOFC, operating either as a fuel cell (generating electric power) to electrochemically oxidize fuel species (i.e., hydrogen or syngas) or as an electrolysis cell (consuming electric power) to electrochemically reduce reactant species (i.e., water or water and carbon dioxide) are under R&D as EES systems. If steam is the only reactant, the process is typically referred to as electrolysis, while co-electrolysis refers to simultaneous reduction of H2O and CO2 to produce syngas. A ReSOC energy storage system is well suited for energy management applications because it can operate over a wide range of energy-to-power ratios by sizing the energy and power ratings independently, and is expected to have high energy storage efficiency and energy capacity suitable for storage duration in the order of hours to days.
Energy Storage
Published in Mukund R. Patel, Omid Beik, Wind and Solar Power Systems, 2021
The energy storage efficiency of the compressed-air storage system is a function of a series of component efficiencies, such as the compressor efficiency, motor–generator efficiency, heat losses, and compressed air leakage. The overall round-trip energy efficiency of about 50% has been estimated.
Performance comparison of sensible and latent heat-based thermal storage system during discharging – an experimental study
Published in Experimental Heat Transfer, 2022
Based on the literature, it has been found that few numerical studies have been carried out for comparing the performance of latent and sensible TES systems with different geometric configurations and operating conditions. Gao et al [33] compared the performance of latent and sensible TES system under similar geometry and operating conditions. The authors reported that latent TES has greater energy storage potential and lower thermocline degradation as compared to the sensible TES. Yang et al. [34] performed a comparative assessment on latent and sensible TES under similar system and operating parameters. The results showed that latent TES has higher HTF temperature and lower thermocline degradation than the sensible TES. Limited experimental studies are found to compare and analyze the instantaneous energy and effect of thermocline degradation of latent and sensible TES system under similar operating and geometric conditions. Therefore, the current study presents the comparison of two configurations such as sensible TES (concrete sphere) and latent TES system (paraffin encapsulated spheres) under similar geometrical and operating conditions with medium size elements. The performances of the storage system are analyzed with respect to discharge time, instant energy recovery, storage capacity, and storage efficiency. The temperature profiles for both configurations are evaluated and compared under different mass flow rates. The experimental findings may be useful for developing the TES systems for given solar thermal applications.
Diffuser design and experimental research of a large-scale chilled water storage system
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Jiali Tang, Zhengrong OuYang, Yuyang Shi
There are many ways for researchers to evaluate the stratification effect or efficiency of a naturally stratified water storage device in a certain period of operation (Panthalookaran, Heidemann, and Müller-Steinhagen 2007; Haller et al. 2009). The main performance evaluation indexes include the storage efficiency (Bahnfleth and Musser 1998) and the thickness of the thermocline (Bahnfleth and Song 2005; Consul et al. 2004). The storage efficiency is defined as the ratio of cooling effect removed from the storage during a single, complete discharge cycle to the cooling effect deposited during the immediately preceding complete charge cycle (Wildin and Truman 1985). In this paper, storage efficiency refers to the ratio of effective chilled water to total storage capacity. The definition of thermocline is the temperature transition area between the hot and cold water in storage tank, removing a certain tolerance, corresponding to the height of the water.
A rolling penalty function algorithm of real-time pricing for smart microgrids based on bilevel programming
Published in Engineering Optimization, 2020
Li Tao, Yan Gao, Ying Liu, Hongbo Zhu
The pursuit of sustainability has driven increased interest in developing renewable energy sources (RES), such as solar, wind, biomass and geothermal. In addition, recent technologies have improved energy storage efficiency. Currently, there are more and more RES and storage devices integrated into the current main power grids. These distributed RES and storage devices are beneficial for grid dependability and resiliency (Hu et al. 2018; Miner, Walter, and Nicolson 2012; Wei, Ozdaglar, and Jadbabaie 2010). Meanwhile, due to the variability of distributed power generation and the uncertainty of demand, power market faces great challenge in energy supply and demand.