Last week the word was out that Promethean Systems, an MIT spinoff, is developing a high-tech solar thermoelectric solid-state refrigerator, a new kind of renewable device, for use in rural India. Visions of an ice cream stand in the middle of a jungle, or possibly a desert? It's no mirage.

It's for profit, but they also want to bring a better life to the developing world by letting people keep their perishables from perishing and their life-saving medicines from losing effect. Promethean is motivated not only by capitalism but also by altruism. Good for them.

Promethean is using thermoelectric technology, originally discovered by Jean Peltier and Thomas Seebeck in the early 19th century, and which is now being rediscovered, refined and improved at the atomic level, thanks to extraordinary leaps in materials science and nanotechnology.

HOT OR COLD

Thermoelectric devices transform electric current into either heat or cold, depending on the direction of the current, like magic. For Promethean's solar refrigerator to work, all you need is a thermoelectric device with pellets of bismuth and telluride, semiconductors, wired to photovoltaic cells. And presto, a useful device completely independent of the grid.

These MIT guys are going further, of course. They are coding software for embedded electronics that will control the current to achieve maximum efficiency. The device will create ice to maintain the temperature from day to night. The people in the village are going to be really impressed.

Promethean is not alone. GMZ Energy, a Boston University spinoff, just received funding to develop thermoelectric materials with nanotechnology that can be used for refrigeration, air conditioning, waste heat recovery and solar thermoelectricity (turning solar energy directly into electricity).

It gets better. A thin new polymer being developed at Penn State changes temperature in response to changing electric fields. Changing the field rearranges the atoms in the polymer, which govern its temperature. This is called the "electrocaloric" effect, and it's way beyond the 19th century.

Penn State researchers, reporting in the journal Science last week, say this polymer will lead to better technologies for cooling computer chips and for building even better solid-state refrigerators. This polymer is a breakthrough and could move thermoelectrics ahead that much faster. Promethean may want to contact them for a license.

THINGS ARE HEATING UP

Things are definitely heating up in thermoelectric cooling. But what do these new technologies mean for us? Start with renewable cooling and heating units, without moving parts or maintenance, anywhere in the world, oil free and forever. Then think of other creative applications in remote places, the military, disaster relief, even ice cream in the jungle.

Let's go further. Think of creating a perfect environment —when it's too hot, the embedded software turns the current one way and your house is cooled. When it's too cool the embedded software turns the current the other way and your house is heated. That's thermoelectronics for you.

Perhaps this is a harbinger of a new paradigm on energy. Sure you can have a whole neighborhood cooled by deep sea water, in the way planned by Honolulu Sea Water Air Conditioning, but maybe you'll also be able to cool one building at a time without attaching it to a large scale system.

All you'll need to do is put PV cells on the roof and then wire them to a thermoelectric device that will cool a heat exchanger and provide chilled water. This would result in an air conditioning chiller with no moving parts or maintenance, at a substantially reduced expense, without oil.

IT GOES BOTH WAYS

While the science and energy journals are filled with daring exploits in thermoelectric technologies, there are offshoots in related directions as well, offshoots so close that they suggest the possibility of convergence.

It goes both ways. We have electricity-to-heat, and we also have heat-to-electricity. ElectraTherm has recently installed a 50-kilowatt machine at Southern Methodist University in Dallas that uses industrial low temperature waste heat as its fuel. SMU will recoup its acquisition costs in three to four years with electricity costing three or four cents per kilowatt-hour during that time.

General Motors and BMW are likewise trying to find a useful outlet for waste heat from cars. Next year, their researchers will be testing devices that will convert excess heat from a combustion engine into electricity. GM's prototype is a metal-plated device that fits on the exhaust pipe.

These researchers estimate that 60 to 70 percent of the heat from a car's engine is usually lost, and they expect that their new device will capture that and improve fuel efficiency in a Chevy Suburban by some 5 percent, or one mile per gallon. The benefit would be greater in smaller, more fuel-efficient cars.

HOW WE PARTICIPATE

We know that Hawai'i, the Tropical Energy State, is moving into solar, wind, ocean energy and other renewables, and that's great. But is Hawai'i also getting into thermoelectric technology? Perhaps some of the electrical engineers at our UH College of Engineering can make strides down the paths forged by MIT, BU, Penn State and SMU.

For now, these new technologies seem most useful in developing nations. Indeed, Hawai'i can lay claim to a homegrown company called Safe Water Systems, which has provided solar water purification systems that have prevented disease and saved lives in remote areas since 1996.

Their systems are a study in simplicity and ingenuity, with few moving parts and little or no maintenance, and they offer integrated solar devices that provide power for pumps that distribute water they have purified.

Perhaps Safe Water Systems can show Promethean Systems a thing or two about selling renewable devices to enhance lives in remote areas. That would be a noble contribution.

At the same time, the MIT guys seem to have no trouble raising capital. We need to work harder on venture capital so we can fund our renewable energy entrepreneurs. Yet another reason Act 221 is so important and another thing we need to do to realize our rendezvous with energy.