The evolution of the overall current density distribution over time remains similar during the successful cold start process; the current density is the highest near the flow channel inlets and generally decreases along the flow direction.
During the failed cold start process, the highest current density is initially near the inlet region of the flow channels, then it moves downstream, reaching the outlet region eventually.
Moreover, this approach does not suffer from the cold start problem, which is common to most current TBSs, since it was able to use the terms extracted from the Web resources to guide its first recommendations.
The ice melting and liquid formation during the successful cold start process have negligible influence on the general current and temperature distributions.
Dynamic distributions of current and temperature in PEMFC during various cold start processes determine the cold start characteristics, and are required for the optimization of design and operational strategy.
This study focuses on an investigation of the cold start characteristics of a PEMFC through the simultaneous measurements of current and temperature distributions.
As discussed in Scenarios 5 and 6, the variations of the Scenarios 1 and 2, where the cold start problem normally happens in the recommender systems of the current TBSs, the use of the Web resource as a source of information allows the system to deliver recommendations to users, avoiding the cold start problem.
This is another instance of the cold start problem and also happens in most recommender systems in the current TBSs.
The newly developed isothermal cold-start protocol is used to explore the basic physics of cold start, and the effects of purge methods prior to cold start, startup temperature and current density, and the membrane thickness are shown.
The experimental data also confirm the current density effect predicted earlier by a multiphase model of PEFC cold start.
In contrast, increasing the cell current in the freezing stage has a negative impact on the PEFC cold start in that the oxygen reduction reaction causes the water production rate to increase, leading to more rapid ice growth.
