This being hockey playoff season, everyone is talking about scores. In the hope I might be taken as something other than a science geek, I thought I would, too.
So let me tell you what the score is regarding SCORE–the Stove for Cooking, Refrigeration and Electricity.
SCORE is a joint research project by four U.K. universities, numerous universities in Asia and Africa, the international charity Practical Action, the Los Alamos National Laboratory in the U.S., and the multi-national company GP Acoustics.
It’s the name of that last unlikely seeming partner that actually gives a hint as to the science that make it possible to talk about a stove for refrigeration without getting funny looks. SCORE, you see, is based on thermoacoustics.
Glassblowers sometimes hear their creations emit pure musical tones, and a couple of centuries ago scientists figured out that was because the heat causes the air close to the gas to expand.
It took a lot longer for scientists to realize that the reverse was also true, that sound changes the temperature of a gas, because the sound wave compresses the gas as it passes through.
It’s not much: ordinary speech heats up the air a miniscule amount (about one-10,000th of a degree Celsius), and even painfully loud sound has a miniscule effect–you won’t get scorched if you sit in front of the speakers at a Rolling Stones concert (otherwise a large number of Regina residents would recently have been reduced to ash).
But you can concentrate the thermoacoustic effect by putting the gas in contact with a solid, because solids can hold a lot more heat in a given volume than a gas, and heat up and cool down more quickly.
At the heart of a typical thermoacoustic device is a stack of many layers of solid material, separated by gas-filled spaces. If you put this stack in a closed tube, and pump in sound, the sound bounces creates a standing wave in the tube. As the gas is pushed in one direction, it heats up and deposits that heat into the slightly cooler solid layer in that direction. When it moves the other direction it expands and extracts heat from the slightly warmer layer in that direction. Like a bucket brigade, the layers of gas thus pass heat the length of the stack. As a result, heat comes off one end of the stack, while the other end acts as a cooler.
It’s not hard to make a thermoacoustic refrigerator if you have the materials. I found plans for one made for less than $25 from a boxed loudspeaker, acrylic tubing and sheet, a roll of film, fishing line, an aluminum plug, and two homemade thermocouples.
Most of the world doesn’t have those materials, though, or the electricity to power the device. Mostly, a lot of people in the developing world wood, which they burn in open fires for cooking and heating.
SCORE will be a wood-burning thermoacoustic cooker, refrigerator and electrical generator (Los Alamos Laboratory has done a lot of work on using thermoacoustics to generate electricity for satellites).
If it works, if it can be made cheap and durable, and if it can be introduced in a way that overcomes the natural reluctance of people to try something new–all goals of the SCORE team–it could improve life for millions of people.
Dr. Artur Jaworski, an expert in thermoacoustic engineering at the University of Manchester who will lead research into the design of the SCORE engine, puts it this way: “The benefits could be huge, ranging from better health due to the correct storage of medicines, to improved education through electricity for computers and lighting, to a higher standard of living through the creation of employment opportunities and associated businesses.”
There’s a lot of work to be done, but it’s an exciting project.
I suspect, however, that despite the project’s promising name, my writing about it has not had the desired effect of making me appear to be a jock-type guy.
Well, you can’t win them all, but at least I gave it 110 percent.
