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Hydrogen and Fuel Cells
Published in Muhammad Asif, Handbook of Energy Transitions, 2023
Saeed-ur-Rehman, Hafiz Ahmad Ishfaq, Zubair Masaud, Muhammad Haseeb Hassan, Hafiz Ali Muhammad, Muhammad Zubair Khan
Phosphoric acid fuel cell (PAFC) utilizes phosphoric acid H3PO4 as an electrolyte hence named as PAFCs. This fuel cell typically operates between 150°C and 230°C, with an optimal temperature of 180°C. The greater resistance to CO poisoning and smaller Pt catalyst loading as compared to PEMFCs make the PAFC attractive to AFCs. In addition, the waste heat can be utilized effectively in PAFCs. Due to their higher operating temperatures, PAFCs can be used in the CHP applications (Ito 2017). Major drawbacks of PAFCs are the great price, prolonged start-up time, and low ionic conductivity. Because it is operated at high temperatures than PEMFCs and AFCs, the materials for this type of fuel cell are limited. The thermal expansion coefficient (TEC) requirements further limit the materials to certain choices. The electrochemical reactions in PAFCs are like PEMFCs (Stonehart and Wheeler 2006).
Power Conversion and Control for Fuel Cell Systems in Transportation and Stationary Power Generation
Published in Frede Blaabjerg, Dan M. Ionel, Renewable Energy Devices and Systems with Simulations in MATLAB® and ANSYS®, 2017
Kaushik Rajashekara, Akshay K. Rathore
Phosphoric acid fuel cell (PAFC) uses phosphoric acid as the electrolyte and the operating temperature of these cells is about 200 °C. It uses platinum electrode catalysts to withstand the corrosive acid effects. Because of about 200 °C operation, PAFCs can tolerate a carbon monoxide concentration of about 1.5%, which broadens the choice of fuels they can use. However, the sulfur needs to be removed from the fuel. PAFC was the first fuel cell to cross the commercial threshold. The United Technology Corporation developed and placed a number of PAFC-based 50–200 kW range power units in operation for stationary power applications in the United States and overseas. Most fuel cell systems that were sold before 2001 for stationary power generation application used PAFC technology [6].
Hydrogen
Published in Arumugam S. Ramadhas, Alternative Fuels for Transportation, 2016
Fernando Ortenzi, Giovanni Pede, Arumugam Sakunthalai Ramadhas
There are some possible choices: Alkaline Fuel Cells (AFC): They have been used widely in space in the last few decades. Their terrestrial utilization is limited by their ease of being contaminated: the very CO2 content of the air is a poison for the cell. Their limitations have brought about a progressive abandonment of their use and will not be considered further in this document.Polymer Electrolyte Fuel Cells (PEFC): These are the most widely used in transportation because they operate at lower temperatures (60–80°C); they can be started-up and shut-down very rapidly; they are compact and efficient; and their cost has steadily decreased during recent years, halving each 1–2 years.Phosphoric Acid Fuel Cells (PAFC): These operate at around 200°C and have a technology that is sufficiently mature for stationary utilizations; units with power outputs of a few hundred kW are feasible and increasingly common.Hydrogen Molten Carbonate Fuel Cells (MCFC): They operate at a temperature of around 650°C and are currently being considered mainly for stationary applications.Hydrogen Solid Oxide Fuel Cells (SOFC): They are the highest in temperature (900–1000°C). As with the MCFC, they are currently being considered mainly for stationary applications.
Review on performance analysis in diffusion absorption refrigeration system (DARS) using different working fluids
Published in International Journal of Ambient Energy, 2023
Sreenesh Valiyandi, Gireeshkumaran Thampi
Mohtaram et al. (2019) analysed multi-mixture working fluids such as lithium bromide and water in an absorption system, and the exergy rate was analysed. Exergy destruction has been obtained in different parts of the cycle. The 35.87% of maximum exergy destruction rate was observed from the absorber. Chen et al. (2020) showed that this promised system developed the critical electrical current density. In this absorption system, the phosphoric acid fuel cell (PAFC) performance increases the thermal performance. Lee, Choi, and Kang (2020) investigated the DAR cycle using R600a/n-octane, which performs better than other low-GWP refrigerants. The result proved that the compound of R600a/n-octane has significant potential energy. The observed maximum COP was 0.218, respectively. Takalkar and Sleiti (2021) used different combinations of binary mixtures, where the optimal refrigeration performances are obtained for the system works with H2O-[mmim][DMP] mixtures. Öztas et al. (2019) prepared the ammonia solution blended with different proportions of lithium bromide.
Energy and exergy evaluation of triple-effect H2O/LiBr absorption cooling system
Published in International Journal of Ambient Energy, 2022
Many authors claimed that in absorption system LiBr/H2O and H2O/NH3 working fluids possess some defects and applications of absorption systems are limited (Cera-Manjarres, Salavera, and Coronas 2018; Królikowska, Paduszyński, and Zawadzki 2019; Wu 2019). Thus, the development of alternative working fluids is a new area of research. For instance, Chen et al. (2020) proposed a hybrid system consisting of phosphoric acid fuel cell and triple-effect absorption system. The effect of electrical current density, fuel temperature and compression ratio on operating parameters was analysed. Findings indicate that fuel cell efficiency and heat transfer in system components must be optimised. Mohammadi et al. (2020) analysed the performance of hybrid triple-effect absorption chiller-compression cycle. Particle swam optimisation technique is used for optimisation of operating parameters. Findings reveal with the integration of compressor leads to an improvement in COP of cycle. However, COP decreases with an increase in compressor pressure ratio. The study also suggests that hybrid triple-effect absorption chiller-compression cycle is a promising technique when absorption chiller fails to operate under several conditions.
A combined energy system for generating electrical and thermal energies using concentrating Solar System, fuel cell and organic Rankine cycle; energy and exergy assessment
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Liang Chen, Huan Huang, Panyu Tang, Dong Yao, Haonan Yang, Hadi Roohbakhsh
In order to compare the results obtained from the research, the results reported in the similar literature have been used. For example, for a combined system comprising of a Fresnel technology, TEG and Stirling engine, an electrical efficiency of about 39% was reported (Feng et al. 2021). It was reported that a process based on a polymer fuel cell, solar PV and electrolyzer is capable of producing 230 g/h of hydrogen (Li et al. 2021a). For another similar cycle comprising of the solar thermal system, electrolyzer, and Stirling engine, it was shown that the system was capable of generating 1.46 kW of electricity and 100 mol/h of hydrogen (Dong et al. 2021). The total efficiency (electrical and thermal) for a combined system consisting of Fresnel technology, ORC, phosphoric acid fuel cell, and Stirling engine was reported to be 71% (Sun et al. 2021b). In addition, the electrical efficiency for a combined system consisting of gas turbine, PTC, and a high temperature fuel cell was reported to be 37% (Marefati, Mehrpooya, and Mousavi 2019). Comparison of the results indicates that the research findings can be within an appropriate and sensible range. It is hoped that the energy system and the described results for energy engineers in the development of alternative energy systems will be promising. The provided conceptual design is such that it can be easily generalized to different demands and specific geographical regions.