PEM Fuel Cell Engine Cooling System Simulation And Waste Heat Utilization

Fuel cell fueled with hydrogen,a renewable fuel, characterized by its traits of high efficiency, low temperature, high power densities, quick start as well as its zero-exhaust, attracts highly concerns, It is the most potential powertrain for new energy vehicles. The operating efficiency of such fuel cell engine is about 40 to 60 percent, with 40 to 60 percent of its inner energy being transferred into heat, which is twice as that of engine consuming traditional fuel. The perfect operating temperature for such fuel cell is between 65℃and 70℃. During its operation, it will generate large amount of waste heat, over 95 percent of which will be taken away by recirculated cooling water, so as to assure appropriate temperature to operate. Waste heat in fuel cell engines is lower-value energy,The engergy in thr exhaust gas can be recycled and reused. In this thesis,numerical simulation method is used to reseach the PEMFC engine cooling system,and discuss waste heat utilization.Firstly, fuel stack cooling system modeling method based on GT-COOL software was discussed in this thesis. The main items include the following:the mathematic models applied to simulation were introduced and appropriate physical models adopted in this thesis were analyzed in details which include FC stack model and cooling system model. Then, Through the application of GT-COOL software, a one-dimensional simulation model is made. It is a cooling system engine of PEMFC with a power of 30kw. It is made up of fuel cell stack, a pump, a fan and a radiator. Such model is used to emulate heat radiation of this fuel cell cooling system, thus making a comparison between the results and experimental data, with the relative error being controlled within 5 percent. Meanwhile, in this thesis, it applies GT-COOL to discusses the effect of those major parameters have on its cooling system. Furthermore, it uses GT-COOL to make a choice among kinds of programs on making high power fuel cell cooling system.It is unignored in any dynamic system to recycle and reuse energy. This is also significant for fuel cell system to do so. In this thesis, it provides a way for energy recovery by installing a reclaimer for the water within tail gases. This reclaimer makes use of tail gases to heat the cathode inlet, so as to eliminate noises and reduce tail gas temperature to recycle the water in it. Thus, after the primary supplement of water, there's no need for a second one even during continuous working period.