By Eric Lanke, CEO, National Fluid Power Association

One of the primary research challenges identified on the Technology Roadmap for the Fluid Power Industry has to do with increasing the energy storage density of fluid power systems. Hydraulic accumulators can store a lot of energy, but unfortunately are still too big for widespread use in applications like hybrid passenger cars and medical assist devices.

So it was a rare treat for me to be able to participate in an ideation session at the Fall Annual Meeting of the Center for Compact and Efficient Fluid Power (CCEFP) focused on generating new approaches to this difficult problem. (Truth be told, I was more of an observer than a participant, but it was a treat all the same.)

Brainstorming Energy Storage SolutionsGuided by Barry Kudrowitz, an Assistant Professor of Product Design at the University of Minnesota, about 20 industry engineers, university professors, and graduate students split off into three work teams and tackled the problem with surprising enthusiasm and creativity.

The guy in the first photo is Professor Jim Van de Ven, also of the University of Minnesota—whose lab, by the way, is already working on a novel approach to the problem: a flywheel accumulator. But I really want you to look at all the yellow post-it notes on the wall behind him. Each one contains another new idea for how to increase the energy storage density of fluid power systems.

Brainstorming these new ideas was fun, but it was just the first step of the process. Once the teams had their ideas up on the wall, it was time to select the best ones and create some prototypes—not out of iron castings and high viscosity fluids—but out of plastic cups, cardstock, straws, balloons, and any of a number of household items Barry had brought expressly for that purpose.

The objective was not to create a working model, but to create a 3-dimensional representation of the idea—which research shows is more likely to communicate the basic concepts and make them stick in your brain.

Phase Change AccumulatorThe second photo is one of the projects developed by the team I was on—this one ably led by Spencer Stober of ExxonMobil. He calls it the Phase Change Accumulator, and if this non-engineer understands it correctly, it works—theoretically—by having different fluids with different phase change properties in each of the balloons.

When materials change phase—go from a liquid to a gas, for example—they release a tremendous amount of energy. Problem is, they release it all at once, so if the fluid in your accumulator changes phase, you’ve got this sudden burst of energy that is difficult (and dangerous) to control. But if your accumulator has different fluids that change phase at different temperatures and pressures, than you should be able to better control a cascade of small releases of energy as you take the overall accumulator through a set pattern of pressure changes.

No prizes were given out at this Science Fair, but based on the reactions from the real engineers in the room, this seemed like an idea with real potential.

It was a fun afternoon, but more importantly, the sheer number of creative ideas produced demonstrated to me that the challenges facing the fluid power industry are temporary. As we continue to add more young engineers to the team, the solutions will inevitably come.