Loading...

Performance Assessment of PEM Fuel Cell in Extreme Conditions (Sub- Freezing Temperatures)

Shirazi, Peimaneh | 2021

366 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 54111 (46)
  4. University: Sharif University of Technology
  5. Department: Energy Engineering
  6. Advisor(s): Rajabi Qhahnuyeh, Abbas; Ahmadi, Pouria
  7. Abstract:
  8. Fossil fuels provide the most needs of the world's energy, however, continues to lead to two key problems. The first problem is their limitation, and the second problem is the creation of serious environmental issues. Therefore, the need for renewable energy sources is felt more than ever.As an energy source, hydrogen is the lightest, most efficient and cleanest fuel. One of its unique properties is efficiency, the production of electricity by fuel cells through the electrochemical process, has far greater efficiency than of mechanical energy production from fossil fuels in internal combustion engines or energy production in thermal power plants. A fuel cell is a device that converts chemical energy directly into electrical energy through a number of electrochemical reactions. Because of low operating temperature, high efficiency and fast response time, the polymer fuel cells have been noteworthy in the transportation industry.In this study, first, a single-cell polymer fuel cell was modeled under three-dimensional, non-isothermal, single-phase conditions in COMSOL software. The most important factor affecting the performance of the polymer fuel cell at sub-zero temperatures is the presence of ice, which affects the time it takes for the fuel cell to reach optimal operating conditions. Also, the effect of changing the cross-sectional geometry of the gas inlet channel has been studied, and in the final part, the effect of thermal performance of a single cell (primary cell) on other cells has been investigated using the link of COMSOL software with MATLAB. In order to compare the performance of the fuel cell set in parallel and series mode, the simulation of this decimal set has been done, in each case, two operating conditions of existence and absence of insulation have been considered.The obtained results give a good and clear view of the performance and details of the phenomena performed in the fuel cell, such as temperature distribution. At a given time, the volume fraction of the lighter phase is greater at the inlet of the porous media, the higher the inlet temperature occurs faster as a result of the phase change from solid to the lighter phase, and also changes in the vertical direction are obvious. Due to the lack of insulation, the system exchanges heat with the outside environment at a temperature of -15 ° C, causing local ice formation. In the series mode, the final 10th cell determines the performance and intensity of the overall current. Also, the temperature of the first cell reaches -2 degrees Celsius in the first 50 seconds, but due to the lack of insulation, there is still ice in the system and for the next cells the temperature increase process is very slow and for the final cells no temperature change is observed. And the performance of the collection in this case is very poor. In parallel mode with the insulation, all the ice in the system melts in the first 75 seconds, and from this time on, the maximum electric current will be achieved.This time in series mode is 270 seconds
  9. Keywords:
  10. Thermal Management ; Proton Exchange Membrane (PEM)Fuel Cell ; COMSOL Software ; Sub Freezing Temperatures ; Three Dimentional Non-Isothermal Simulation

 Digital Object List

 Bookmark

No TOC