Solid Oxide Fuel Cells as Promising Candidates for Distributed Generators

Abstract

SOFCs have a potential of showing extraordinarily high electric conversion efficiency. Thus they are considered as promising candidates for future distributed generators. However operations of SOFCs are not simple compared with the other generators such as gas engines or gas turbine since SOFCs have to be operated at a high temperature. It is difficult to start up SOFCs rapidly and thus they are not suitable for situations where there is a large fluctuation of demand. This limits the application of SOFCs and the introduction is restricted within a narrow market. In order to promote the introduction of SOFCs to a market, how to make use of SOFCs is a very significant factor. Techniques to operate and control SOFCs are key factors to draw the potential of SOFCs. Therefore information technologies are expected as a powerful tool to improve the total performance of SOFCs.

Numerical Calculation for Fuel Depletion State of SOFCs

“…This test was performed using hydrogen as the fuel at 750 deg in an electric furnace, and the temperature distribution under the test was numerically simulated. The detail of the simulation method was similar to that reported elsewhere (4). Figure 3(a) shows the simulated temperature distribution inside the stack under the operation.…”

“…One of reasons of the uneven distribution of the fuel to each cell is originated to a temperature distribution at the stack. At a high power generation under a stack operation, a large temperature distribution occurs at the stack inducing the uneven fuel distribution (4). With an increase of the temperature, gases become viscous and the density of the gases decreases (5), thus the relative mass flow rate decreases at cells where the temperature is high.…”

Distributed Generation by Solid Oxide Fuel Cell: A Review

“…Yakabe.H et al [47] explained operational complications of SOFCs compared with gas turbines and the difficulties encountered at the time of start up of generation particularly when there is a large fluctuations in load demand. Since the SOFCs are operating at high temperatures, the response time against the change of inlet air flow rate takes long time to stabilize.…”