https://phys.org/news/2021-05-gold-standard-compound-electricity.html People have long desired alternatives to the existing commercial pem thermoelectric generators, the kind you put on top of a woodstove to drive the fan. This material is FLAT and should be significantly cheaper to make, meaning you could line the walls of your woodstove with them and recharge your batteries or whatever. Other advances in the materials used could easily lead to double the performance, but could remain expensive for sometime to come, using the latest metamaterials or whatever. Thermodynamics are an ad hoc theory, and reinventing thermodynamics is like starting the steam age all over again, steampunk style.
Is this similar to what they have in gas water heaters? There's a small plate the size of a quarter I think. The pilot light generates enough electricity to power the electronics.
Their is not a lot of waste heat around these days, even modern boilers recover the heat from the latent. Some years ago, absorption refrigeration became quite popular when powered by waste heat from turbines. Although it was effectively 300% efficient, the temperature differential between evaporator and condenser was only around 30 degrees centigrade. It found very little use outside small air conditioning applications in the offices of factories. It would be interesting to see some output figures, along with required heat and product surface areas for this new device.
That is simply a thermocouple to hold the gas valve open, preventing an escape of gas in event of flame failure. It has no ability to run the spark ignition, since their is no output until the burner is firing.
I'm more interested in its cost. This one is supposedly comparable to the existing ones, which is nothing to brag about, but if its cheap and flat, you can use larger ones.
Try as I may, I cannot think of any practical use for them. Without technical data sheets I do not know the temperature needed to drive them, or whether they work at ambient temperatures. Either way, they cannot convert to below +2 degrees centigrade, or as the ambient air is dehumidified they would ice up, insulating them from further heating. Working between +20 and +2, their is very little energy produced and it would be the same (less conversion efficiency) as their refrigerating effect to their ambient. Energy produced would be a direct current, so inverting it would cause yet another efficiency loss. I must admit that your application made me laugh, thinking about lighting a fire in the height of summer to run a fan. Give some thought to the thermal mass of air, its sensible and latent heat content, then calculate the output in watts per metre square of the panel obtaining it's heat in practical situations. If anything, I can imagine the cooling effect of panel itself being used to cool items such as computer processors and the electrical output being a bonus. However by the basic laws of physics, this could never even produce enough electricity to run the computer that it was cooling. However big or small you make an item, the laws of physics remain the same.
Woodstoves are a practical use for cheap thermoelectrics, which can easily have their performance doubled and cost cut in half. For example, a trailer is a hot box in the summer, and an icebox in the winter, and many use cheap small woodstoves and heat the floors electrically, or they get ice cold. Such people will often invest in solar power, not because they need to, but because it requires so little solar power to heat their trailer and cook or whatever. Thermoelectric woodstoves would allow them to recharge their batteries, for the middle of the night, when the stove goes out. Just having options, is often what its all about.
Their is a serious danger here, since extracting heat from the flue gasses would remove the convection currents that drive the flue. With the resultant incomplete combustion, the embers would produce carbon monoxide that would discharge into the room. Even without the heat absorption, inadequate air supply to wood stoves due to doors and windows being closed, along with ventilation grills to the room being blocked in order to retain heat has caused countless deaths over the years. Adding an ID fan to the stove could resolve the problem, but would the electricity being produced even be sufficient to drive the fan? With a gas boiler, fan failure trips the gas supply, but this is not possible in a wood stove and fans don't last forever. Modern gas boilers already extract the latent heat energy from the flue gasses, leaving little sensible heat to drive any thermoelectric devices. With industrial chimneys, convection heat drives the smoke and toxic gasses into the outer atmosphere. Extracting any of this heat could have disastrous environmental affects. Without knowledge of the output per square meter of these panels and their active temperature range, it is very difficult to attempt to work out a viable use. I suspect that the output would be a parabola on a graph, but most importantly what happens when the maximum output temperature is exceeded. Something makes me think that when you lit your wood stove in the morning and flames were roaring up the chimney, the panels would be burnt to a cinder within minutes, or at least be electrically destroyed. Over the years, almost all attempts to improve heating efficiency, but with the exception of the condensing boiler, few of them have any domestic use. PS, have you ever looked at the original heating plant designed for the Royal Festival Hall in London during it's original construction for the festival of Britain. Basically, it was a heat pump with its evaporators heated by water drawn from the bed of the river. As you probably know, since the coefficient of cubical expansion of water reverses at 2 degrees centigrade as its state starts to change from liquid to solid. (otherwise ice would sink) This results in the bed of a river of lake never falling below 2 degrees. . Extracting this heat without icing the evaporator tubes was a daunting task. With the COP efficiency of the system rarely rising above unity, Following a compressor explosion that cracked an 18 inch thick concrete wall the system was decommissioned. My late father was one of the design team, he was the electrical engineer for the UK government.
If anything, thermoelectrics add heat to the system by adding thermal mass. They only convert a few percent of the heat that hits them into electricity. If we had significantly better thermoelectric materials, we could literally bury them and use the temperature differentials under the ground to generate electricity all year round.
Why don't we figure out how not to throw away 75% of the energy that solar panels absorb...or as important, how not to do that in China.....
Silicon is garbage for most of the things its used for, and the only reason we use it for computers and solar cells is because its cheap. Electronics are garbage for computers, silicon is overpriced and running out, while behind an open door, there lies a million unanswered questions.
Well, there's plenty of beach sand left to crank out silicon wafers.....our shortage today is because of poor planning. God save us if bomb goes off in in the silicon fabs in China or Taiwan...oh wait, Taiwan is China...
Silicon is made from a particular fine grade sand that is running out. If you want, you can crush rocks and make your own sand, but the problem is, the cost of silicon is rising and will never stop rising. It is neither cheap to buy nor cheap to process, and is far from ideal. The alternatives have been slow in development, but it looks like perseveres are poised to replace it for the most part. They're much more abundant and easier to process, and are roughly as good as silicon solar cells.
