While the commercialization of fuel cell vehicles may still be a few years offs, a team at Purdue University has come up with a breakthrough that paves the way for making topping off their hydrogen tanks nearly as quick as filling a conventional car with gasoline. The innovative Purdue technology, which reportedly can port over enough hydrogen in five minutes to yield a 300-mile effective range, relies on the use of fine powdered metal hydride and a special heat exchanger. The metal hydride resides in compartments inside the pressurized storage tank and gaseous hydrogen gas is pumped in at high pressure to be absorbed by the powder.
Issam Mudawar, professor of mechanical engineering who headed the overall research efforts, noted that the heat exchanger is the key to making this system viable. "The hydride produces an enormous amount of heat in the process. It would take a minimum of 40 minutes to fill the tank without cooling. This presented an engineering challenge because we had to figure out how to fill the fuel vessel with hydrogen quickly while also removing the heat efficiently. The problem is, nobody had ever designed this type of heat exchanger before. It's a whole new animal that we designed from scratch." One additional complication: Because metal hydride reacts with both air and moisture, the system itself had to be assembled in an airtight chamber.
Development work on this new system has been ongoing for the past two years. It was done in conjunction with General Motors Corporation, which also provided funding for the program as well as it own team of research directors. One of GM's lead researchers, Darsh Kumar, sees it as a potential game-changer. "This milestone paves the way for practical on-board hydrogen storage systems that can be charged multiple times in much the same way a gasoline tank is charged today. 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."
Photo courtesy Purdue News Service/Andrew Hancock