SteamyTea

Apart from installation damage, has anyone every had a PV module break? I have seen one solar slate install that got hit by lightening, but that is the only one I know off.

It is the mas of the thing. One of the criticisms of EVs is that they are heavy because of the battery pack. Mirai has a mass of 1850 kg, Tesla 3 is anywhere between 239 and 3 kg lighter. Now I know it is very hard to compare like for like, but at the moment, HFCEV are just heavy bits of kit. Makes me wonder what they are bothering with all the other drawbacks of hydrogen. I also wonder how fast the hydrogen is produced if done on site. Is it really worth pumping in 100 kW to crack water when it could be shot into a BEV. I know these are relatively short term problems, but there must be a reason why car manufactures have gone down the BEV route, especially considering that lithium cell technology is a lot newer than fuel cell technology.

That could be the Renault influence, which is really the French government, who own most of EDF. I wonder who is pushing hardest for EVs to be the only choice, not that it is a bad thing.

Yes, it was to do with the supply of batteries. But I would have thought that the world's largest car producer (not sure if it still is) could have sorted that in a decade. Tesla have built a factory and delivered cars in about 10 months.

I read a piece in the motoring press that claimed that the reason that Toyota did not make a full EV was because a greater CO2 reduction could be made, overall, with PHEVs. Last week the chairman of Honda said that customers wanted Hydrids at the moment, not full EVs or, the worse of all worlds HFCEV. With a product cycle of 7 years, this is probably a prudent commercial decision.

I was almost directly quoting something I heard recently. I think it was an aging biker in a supermarket carpark. He started then going on about volcanoes and cows, Chinese and Indians. It is that sort of conversation that makes me want to have a reasonable and understandable response to.

As I thought, no.

Says in that link that it is not very good for calculation the liquid phase. So shall reach for the laughing gas. But out of interest, does my part finished explanation above make sense?

But can you say squirrel?

Or St. Ives. Emmets wandering all over the place getting in the locals way. Can't make up my mind what is more annoying, a teenage girl saying "Oh My God" loudly into her phone or Greta.

The initial butter temperature will make s difference. Oddly, I am sitting in the sun reading Randall Munroe's What If? Write to him and ask, Google xkcd for an email.

Or @Ed Davies will explain it with radiation. Trouble is that it is not a controlled environment. Was it the same butter, was it the same dimensions, are there any drafts, sunshine hitting it. I buy Flora as I know it will spread straight from fridge, lasts weeks as well. Not do good for sauteed mushrooms, but then I don't have them at home much.

Or a very fuel efficient car. Possibly a correlation between low level windspeed and temperature at the site. May also be a place to do a Covariance analysts with irradience.

Too large may be a problem if you are trying to maximise on your solar (the 7.3 kWp PV), but I can see your thinking. Should be fairly easy to work that out knowing the fabric areas and the temperature differences.

That such a small molecule, in tiny proportions to the surrounding gases, can make any difference. Right, had a sleep, and a think this morning and I think I shall work on the model in that chem.libretext.org link. I don't fully understand why the shape of the molecule i.e. linear or non-linear makes much difference, that will need more reading, but as it is only two equations to work out, it is easier to remember. For linear molecules like CO2 it is equation 1 3(N) - 5 For non-linear molecules like SO2 it is equation 2 3(N) - 6 Where N is the number of atoms. This does rely on knowing (or finding out) the shape of the molecules, and I am not sure how much difference the angles between the atoms makes i.e. H2) being 104.5°, SO2 being 119°C. Or how much difference the mass of a molecule makes. In classical physics, those two properties should make a difference. (think I may have asked myself the question to explain why the shape may be important) Some molecules like Sulfur tetrafluoride (SF4) have a degrees of freedom number of 9, as does CH4. SF4 has two angles of 101.6° and 173.1° CH4 only has 1 angle, 109.5° There is also a difference in the orbital distance between the nucleus and the electrons. SF4 is 154.5 pm and 164.6 pm depending on the fluorine pair. CH4 is 133.9 pm between the carbon atoms and 108.7 pm between the carbon and hydrogen atoms (this assumes that CH4 is always paired with another). I am starting to remember the real reasons I disliked chemistry at school, I thought it was because the teacher was a religious zealot (a Born Again Christian, whose name a still fully remember) but I think it is really because it was just a memory test.

Think I am going to sleep on it. It is hard to know what is actually happening, and then trying to find a clear and concise explanation for 'the man on the Clapham omnibus'. Probably why: It is not explained often Just expect to be taken on trust People don't believe it

Only 3.3 times worse. Propane molecule followed by Carbon Dioxide.

Bit more hunting around and I found this, but going to have to look up Raman to see what it is all about. https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Spectroscopy/Vibrational_Spectroscopy/Vibrational_Modes/Number_of_Vibrational_Modes_in_a_Molecule I think that I may have been confused in my thinking. Seems that the rotations and vibrations are between the atoms, not within the atoms, which kind of makes sense. Would be nice to work out a simple, but realistic, description or I shall be just like I think the first part is to treat incoming photons as particles, but the emitted IR as a wave (think one is allowed to do that, if you drop a stone in a pond you get a wave, but a wave does not create a stone). Thoughts anyone.

Bloody phone, I put in an autocorrect superscript, seems to want to do it every time I use the numbers 2 and 3.

Cladding Do something really horrible with the cladding, then ask the neighbours/planners if they still love your house.

That was what I first did, left the PC running for a few weeks. Found out that it had done an auto-update and rebooted. So no data. Was then I started to look at Linux, and still struggle with it all, especially as they changed the way that programs can auto start.

Hello Do you have any weather data for where you want to build? Knowing those parameters can help a fair bit, takes the guess work out of it, and solar radiation can add a lot of energy to a place (ask @Jeremy Harris). Also, a small place has a larger surface area to volume ratio, this is a killer when it comes to designing a low energy building, just too much wall.. The physics id pretty basic, two parts, the insulation reduces the power (the watts) that go though the wall, but once though, air movement sucks more power out. This is why there are a two parts to complex construction formula. First thing to look at is the R-Value of materials (make sure you pick the SI ones and not the funny American ones). The K.m2/W. Also air tightness is important, no point having a foot of insulation if there is a window open.

Similar to the light meters I have made using a LDR, and LDR and capacitor, and a webcam (I must get one of those going again as it was fun, but the local WeatherUnderground station with a good light meter on it has vanished, so can't calibrate).

Interesting problem came up today while I was having a coffee with a mate. Knowing that I was interested in climate change (actually it is weather I like) and being a curious fellow, he asked how atmospheric CO2 actually increased temperatures. A good question and one I found very hard to answer. Once, while at university, it was described as such: "It is the shape of the molecule and the degrees of freedom that it can rotate when hit by a photon." Now I quite liked that as it is a very mechanical description and can be used to describe different molecules having different properties. Hitting one end of a dumbbell is not the same as hitting a bicycle (a complex shaped molecule). So when I was chatting to a proper chemist (she has a PhD in it, tall and willowly, so someone worth hitting on), her response was: "don't talk to me about degrees of freedom, I hate them". She then went onto explain that it was do do with frequencies and resonance. This seems to be the usual description i.e. the EM radiation coming in is at a high frequency, so not much wave height/length, so misses the CO2 molecule. After hitting the ground, the EM radiation is reduced in frequency, increasing the wave height/length, so more chance of hitting the molecule. Which also happens to have a a 'gap' between the nucleus and the electrons that just happens to match that frequency, so it resonates. Now to be honest, I don't really understand how something resonates, even though I have seen it happen. So what clever things are happening there then? And is there a better description to how it happens? preferably a 'mechanical' one, as people seem to understand that better than sub-atomic voodoo.

I had a similar problem earlier in the year. But it just went to no readings. Bit of a problem because the batteries can last years, think I once I changed (the white optical sensor) was about 7 or 8 years old.