Alternative Energy – 20 April 2009
One of the main hurdles in the field of hydrogen car research is the development of a good fueling system. Professor Issam Mudawar along with his research team has developed a hydrogen storage system that would allow a car tank to be filled in five minutes and you can drive on that fuel for 300 miles.
But turning the above abstract idea into a reality was not a cakewalk for the project team which is funded by the General Motors Corporations. The biggest obstacle was the problem of heating while one is refueling the tank. According to Issam Mudawar who is the Purdue University (PU) Professor of Mechanical Engineering , “The hydride produces an enormous amount of heat. It would take a minimum of 40 minutes to fill the tank without cooling, and that would be entirely impractical.”
These hard facts posed a great challenge to the Purdue University research team. The heat effect has to be countered and the time limit for refill has to be shorter. For refueling they have used a very fine powder, known as metal hydride. This powder absorbs hydrogen very efficiently but can’t do anything regarding the release of huge amount of heat. Therefore a very good cooling system at all the refueling station is of vital importance.
The research team was working on a solution which can do something substantial concerning heating. They needed accessory connectors that can work at the same time to take away the heat while refueling process was on. So the researchers have to overcome this hurdle and design an efficient heat exchanger. They have to be a pioneer in the field because no one had treaded on that path before.
Keeping the complications in mind the team has developed a system where metal hydride is placed in small “pockets” inside a pressure chamber. They injected hydrogen in pressure compartments and it gets absorbed. But the wonderful thing is this reaction is reversible. Therefore the hydrogen gas is released from the metal hydride by lessening the pressure in the storage vessel. They fixed the heat exchanger inside the hydrogen storage pressure vessel.
Mudawar explains, “Due to space constraints, it is essential that the heat exchanger occupies the least volume to maximize room for hydrogen storage.” The cooling system utilizes the regular automotive coolant which flows inside a U shaped tube between the pressure chamber and the aluminum heat exchanger. The exchanger is designed in such a way that when the hydrogen enters into the metal hydride, a smooth temperature absorption mechanism starts functioning. Darsh Kumar, a researcher at General Motors Corporation is hopeful, “As newer and better metal hydrides are developed by research teams worldwide, the heat exchanger design will provide a ready solution for the automobile industry.”