Johnson thermoelectric energy converter

Transcription

LONNIE JOHNSON: I'm going to talk about something that has been touched on routinely throughout this conference-- the fact that we're in an unsustainable situation with respect to energy. We're hooked on dirty energy sources. And we have inefficient means for converting those images sources to work or power, even for refrigeration. Imagine what would happen if we had a universal engine that's more efficient than any engine that's been built before and that would be versatile enough that it could be used for large-scale power plants for converting heat to useful power, but yet small enough that you could actually use it convert body heat to power to power personal electronics or even harvesting energy from ambient environment using the temperature variations in our environment that we routinely take for granted. Energy that could be used irreversibly for refrigeration and air conditioning applications-- we could actually power and provide power and refrigeration to remote, undeveloped areas of the world. When you think about energy-- and the ideal sustainable energy source is, of course, the sun-- there's enough energy falling on a small area of desert, as shown here, that could supply all of the needs of the world, but yet we don't have the efficient conversion technology and the cost effective technology that would be able to do it. So imagine if you could have an energy conversion system that could convert this energy to useful power at a cost that's competitive with coal, natural gas, and fossil fuels. I get very concerned when I hear people talk about clean, natural gas, clean burning natural gas. The fact is, natural gas is a hydrocarbon. When you burn it, you get two reaction products. The hydrogen reacts with oxygen to produce water, good. The carbon reacts with oxygen to produce CO2, bad. So you don't get around that. So we really do need a sustainable energy source that's really good for the environment. Aside from having an effective, clean way of supplying and sustainable way of supplying energy, we also have an engine that could allow us to use that energy more efficiently. For example, buildings-- and it's been talked about before here-- consume about 40% of the energy that's produced in this country. About 2/3 of that is used for heating, refrigeration, air conditioning, those kind of things. If we had an efficient technology, we could actually cut that consumption in half. That would be a profound effect. I'm a proponent of electric transportation. In fact, I'm developing battery technology that could take that to another level. But if we had to rely on fuels, if you had a more efficient engine, what if we could cut the amount of energy consumed for transportation in half, almost 30% down to about 15%? That would have profound implications for us. When we think about engines, we generally think about mechanical devices. And the way they work is you compress a working fluid at low temperature. You heat it up and expand it at high temperature. That hot temperature expansion gives you a lot more work out than it takes to compress it at low temperature. All engines work this way. They generally do it by turbines, pistons, and things like that. Even refrigeration systems operate in reverse. You compress the gas-- it actually gets hotter when you compress it-- you dump that heat off, bring it back to your ambient temperature, then you expand it. When you expand it from that ambient temperature, it cools, and that's how you get to refrigeration effects. So it's all about compressing and expanding working fluids. We're taught in thermodynamics that the Carnot cycle is the ideal cycle for converting heat to work. It's represented by a rectangle and if temperature entered the space, you'd have a high temperature expansion and a low temperature compression. This is an ideal curve for a Carnot cycle. What's significant about it is that if you look at it, internal combustion engines burn gas at temperatures that are way off the scales here, up around 2000 degrees centigrade and higher. Yet the efficiency that you get here from an internal combustion engine is only about 30%. And you can get that with an ideal Carnot engine on a heat source for about 200 degrees centigrade. So it's a lot of energy loss, the engines that we presently use are very inefficient. So the JTECHH is basically an engine that operates the same way. We have a membrane electrode assembly stack, not too different from what you would find in a fuel cell. It's a proton-conducted membrane with a couple electrodes on either side. By applying power to this membrane, you're able to drive hydrogen from low pressure to high pressure. That hydrogen goes through a heat exchanger to the high temperature section of the engine, where you have another stack that's at high temperature, and you allow the hydrogen to expand from high pressure, high temperature to low pressure, high temperature. Here is the high temperature expansion where you get a lot more energy out, and energy comes out directly as electricity. You have enough that you can supply some back to the low temperature stack and keep the compression process going so you have a continuous supply of high pressure hydrogen to the high temperature section of the engine. Not too different from what you'd find in any conventional engine. For example, I've got a jet engine here. I've talked about internal combustion using pistons for this process. But here, you have a jet engine. You're pulling air in at ambient temperature. You have a turbine that's compressing it to high pressure. You supply the fuel, you burn the fuel, you heat the gas up. Now it's expanding at high temperature from high pressure to low pressure. As it expands across the exit turbine here, some of that work energy is extracted, and it's coupled back to the front of the jet engine to keep the supply of compressed air coming in. So it's a self-sustaining process. So you can see the similarities between the two engines. The significant difference, though, is that this engine operates on what's called a breaking thermodynamic cycle, which is less efficient than Carnot. The JTECHH operates on the Ericsson thermodynamic cycle, which is equivalent to Carnot. So we have the potential for really achieving a very high efficiency. Here's an example. The sun, as I referred to earlier, is the single source that will be able to meet the terawatt levels of power that are going to be needed by the world in the future. Here is shown the high temperature stack as I just described it, and the low temperature stack here, where we're cooling it using ambient air. Here your stacks focus solely energy onto the high temperature stack. Here's a practical implementation of the engine. Interesting thing about this. Solo sales were attractive, competitive, even though their efficiency is low. But they're attractive because they are solid state. They're very reliable. There's nothing really there to fail mechanically. You don't have an ongoing maintenance problem rather than cleaning them. On the other hand, the sterling engine is a mechanical device. It operates on the thermodynamic cycle. It's a lot more efficient than solar sales. But the problem with it is that it's mechanical. It requires maintenance. Things are going to break. And so the maintenance cycle for that system makes it less than ideal. The JTECH, of course, offers the best of both worlds, because it's all solid state so you have a higher reliability. It operates on the thermodynamic cycle so you have the high efficiency. Here's a chart here showing some examples. I've got an internal combustion engine here, a car engine. You can see the efficiency, around 30%. This is a state-of-the-art power plant, about 40%. JTECH operating on heat, coming in at about 1,000 degrees as the solar powered JTECH is the example here. Our model suggested we can achieve about 85% of Carnot, in terms of our conversion efficiency, because in the real world, you will have lost this. If I were to take the internal combustion engine and add a JTECH on top operating on waste heat from the internal combustion engine, you can get some pretty impressive efficiencies here. When I do this chart, sometimes people say well, how do you exceed Carnot efficiency? That's really can't be. But remember, the internal combustion engine is actually burning fuel up here at about 2000 degrees. So your Carnot potential is a lot higher. You get high quality waste heat from it, and use that to power the JTECH. Any refrigeration applications? The US, back in 2006, the government increased the seasonal energy efficiency rating for air conditioning systems from 10 to 13, and they projected that that would avoid the need to construct 39 400-megawatt power plants, and that we would reduce the CO2 emissions by 33 million metric tons. The JTECH could increase that CO2 to about 26, which would avoid 130 400-megawatt power plants, and 110 million metric tons of pollution to the environment. Aside from the fundamental advantages and benefits from the JTECH itself, being able to do the research, just conducting and developing the technology, will have a number of spin offs, not only for pumping hydrogen, but actually-- hydrogen production, electrolysis, compressing hydrogen, storing it, supplying it. So if we do go to a hydrogen economy, this technology would benefit that. But cryogenic cooling, refrigeration, a wide range of applications that would come as a result of that. So to sum up, the JTECH is a universal engine that has benefits across the board just about anywhere you would have an engine application. The really neat thing about it is not only does it allow us to get green, environmentally sustainable energy sources, but it also improves the efficiency by which we will be able to use that energy. Thank you.