A Dynamic Analysis of the Multi-Stack SOFC-CHP System for Power Modulation

Abstract

This paper performs a dynamic analysis of a 10-kW solid oxide fuel cell/combined heat and power (SOFC-CHP) system with a multi-stack module via numerical simulations. The performance of stacks, tail gas burners, heat exchangers, and fuel reformers are modeled by the MATLAB/Simulink module. The effects of fuel and air maldistribution on SOFC-CHP systems are addressed in this work. A two-stack module for 10-kW power generation is adopted to represent the multi-stack module with high power modulation. The air flow rate and operating current, which are related to the fuel use rate of an SOFC system, should be optimally regulated to perform with maximum power generation and efficiency. The proposed dynamic analysis shows that the operating temperatures of the two stacks have a difference of 33 K, which results in a reduced total power generation of 9.77 kW, with inconsistent fuel use (FU) rates of 78.3% and 56.8% for the two stacks. With the optimal control strategy, the output power is increased to 10.6 kW, an increment of 8.5%, and the FU rates of the two stacks are improved to 79% and 70%, respectively. As a potential distributed power generator, the long-term effects of the studied SOFC-CHP systems are also investigated. The dynamic analysis of the long-term operating SOFC-CHP system shows that the total daily output power can be increased 7.34% by using the optimal control strategy.

A Comprehensive Review of Thermal Management in Solid Oxide Fuel Cells: Focus on Burners, Heat Exchangers, and Strategies

“…This is crucial for stability and performance optimization of SOFC systems. Yang et al [93] conducted dynamic analysis on a 10 kW SOFC-CHP system, finding the need to optimize adjustments to airflow and operating current related to fuel utilization for maximum power generation and efficiency. Hartwell et al [94] investigated the effects of system design modifications, environmental variables, and fuel composition on SOFC performance.…”

Modern Small and Microcogeneration Systems—A Review

“…As SOFC fuel cells are one of the most popular types of fuel cells, there have been many studies and publications on combining these fuel cells into systems for the simultaneous generation of electricity and heat. Basic information on such systems can be found in [215][216][217][218][219][220].…”

Design and Experiment of a Power Sharing Control Circuit for Parallel Fuel Cell Modules

“…To illustrate the effect of employed FCs having different characteristics, two FCs are assumed to have the same characteristics before 4 × 10 3 s, but differs in their internal resistance (r 0 in Equation ( 7)) after 4 × 10 3 s. Table 2 lists all the parameters of FCs used in this simulation. These parameters can be obtained from published articles [24,25], except the internal resistance. Figure 8 shows the output power (left plot) and temperature response (right plot) of each cell, where the FC #1 is drawn in blue and FC #2 drawn in dashed green lines.…”