scholarly journals Waste heat recovery for fuel cell electric vehicle with thermochemical energy storage

2016 ◽  
Author(s):  
Mounir Nasri ◽  
Inga Burger ◽  
Schier Michael ◽  
Horst E. Friedrich
Keyword(s):  
Energy Storage ◽  
Fuel Cell ◽  
Electric Vehicle ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Fuel Cell Electric Vehicle

Hybrid direct carbon fuel cell-thermoradiative systems for high-efficiency waste-heat recovery

2019 ◽  
Vol 198 ◽  
pp. 111842
Author(s):  
Xin Zhang ◽  
Jianying Du ◽  
Yee Sin Ang ◽  
Jincan Chen ◽  
Lay Kee Ang
Keyword(s):  
Fuel Cell ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
High Efficiency ◽  
Waste Heat ◽  
Direct Carbon Fuel Cell

Design and Performance of a Fuel Cell Plant Heat Recovery System

2007 ◽  
Author(s):  
Robert G. Ryan ◽  
Tom Brown
Keyword(s):  
Fuel Cell ◽  
Latent Heat ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Operating Conditions ◽  
Hot Water ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Heat Recovery System

A 1 MW Direct Fuel Cell® (DFC) power plant began operation at California State University, Northridge (CSUN) in January, 2007. This plant is currently the largest fuel cell plant in the world operating on a university campus. The plant consists of four 250 kW DFC300MA™ fuel cell units purchased from FuelCell Energy, Inc., and a waste heat recovery system which produces dual heating hot water loops for campus building ventilation heating, and domestic water and swimming pool heating water for the University Student Union (USU). The waste heat recovery system was designed by CSUN’s Physical Plant Management and engineering student staff personnel to accommodate the operating conditions required by the four individual fuel cell units as well as the thermal energy needs of the campus. A Barometric Thermal Trap (BaTT) was designed to mix the four fuel cell exhaust streams prior to flowing through a two stage heat exchanger unit. The BaTT is required to maintain an appropriate exhaust back pressure at the individual fuel cell units under a variety of operating conditions and without reliance on mechanical systems for control. The two stage heat exchanger uses separate coils for recovering sensible and latent heat in the exhaust stream. The sensible heat is used for heating water for the campus’ hot water system. The latent heat represents a significant amount of energy because of the high steam content in the fuel cell exhaust, although it is available at a lower temperature. CSUN’s design is able to make effective use of the latent heat because of the need for swimming pool heating and hot water for showers in an adjacent recreational facility at the USU. Design calculations indicate that a Combined Heat and Power efficiency of 74% is possible. This paper discusses the integration of the fuel cell plant into the campus’ energy systems, and presents preliminary operational data for the performance of the heat recovery system.

scholarly journals Optimal Design of Combined Two-Tank Latent and Metal Hydrides-Based Thermochemical Heat Storage Systems for High-Temperature Waste Heat Recovery

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4216 ◽  
Author(s):  
Serge Nyallang Nyamsi ◽  
Mykhaylo Lototskyy ◽  
Ivan Tolj
Keyword(s):  
Energy Storage ◽  
Melting Point ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Heat Storage ◽  
Waste Heat ◽  
Storage Systems ◽  
Storage System ◽  
Metal Hydrides ◽  
Thermochemical Heat Storage

The integration of thermal energy storage systems (TES) in waste-heat recovery applications shows great potential for energy efficiency improvement. In this study, a 2D mathematical model is formulated to analyze the performance of a two-tank thermochemical heat storage system using metal hydrides pair (Mg2Ni/LaNi5), for high-temperature waste heat recovery. Moreover, the system integrates a phase change material (PCM) to store and restore the heat of reaction of LaNi5. The effects of key properties of the PCM on the dynamics of the heat storage system were analyzed. Then, the TES was optimized using a genetic algorithm-based multi-objective optimization tool (NSGA-II), to maximize the power density, the energy density and storage efficiency simultaneously. The results indicate that the melting point Tm and the effective thermal conductivity of the PCM greatly affect the energy storage density and power output. For the range of melting point Tm = 30–50 °C used in this study, it was shown that a PCM with Tm = 47–49 °C leads to a maximum heat storage performance. Indeed, at that melting point narrow range, the thermodynamic driving force of reaction between metal hydrides during the heat charging and discharging processes is almost equal. The increase in the effective thermal conductivity by the addition of graphite brings about a tradeoff between increasing power output and decreasing the energy storage density. Finally, the hysteresis behavior (the difference between the melting and freezing point) only negatively impacts energy storage and power density during the heat discharging process by up to 9%. This study paves the way for the selection of PCMs for such combined thermochemical-latent heat storage systems.

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