SteamyTea

I don't think that heat losses from convection are much of a worry.

Generally speaking. PUs don't catch fire these days, they have a retardant in them as part of the mix (remember the Manchester Woolworth's fire 1979). If the celotex, or similar, is not in direct contact with the cans/tubes, then there will be little distortion/melting. http://www.talkcomposites.com/22732/celotex-in-a-composites-oven

I was told that you should never use a soldered joint on solar thermal. May be just on high temperature or pressurized systems though.

Take half an hour out of your life and listen to this: http://www.bbc.co.uk/programmes/b08n2v3f

It seems to me that you are set on a secondary cylinder, so can you lag all pipework well to reduce losses? It is just like electrical wiring, except backwards, you need to insulate it well, odd I know, kind of goes against the grain, even for most plumbers

Are they both used equally as much, or is one for guests or mainly showering?

Make a male and female mould from a resin and stamp them out with a press (hydraulic bottle jack).

Is electrolysis efficient really, I thought it was a pretty poor conversion in reality. Even worse if you have to cool it/compress it to store it. Why we make if by steam reformation from natural gas. https://en.wikipedia.org/wiki/Electrolysis_of_water

Yes it is, but is it is slow and expensive. Thursday on Inside Science (http://www.bbc.co.uk/programmes/b08m8z38) They had a bit about diesel car scrapage. One reason that it may happen is that the product development lifecycle is very fast for cars at around 5 years. Trains are about 20 years. I would hate to think what housing is, 40 years? and a very low replacement rate. I mentioned over at the other place that if we get very low carbon generation, then the DER-TER standard will need updating as it will be irrelevant.

No Athletics, it is windy down here and buildings move

If we forget the dream of being self-sufficient in energy at the domestic level, then you really only need very small scale storage per household e.g. <1kWh This would be enough to run a kettle till it boils (0.2 kWh) , smooth out the peak of a washing machine heating water (1.1 kWh), half an hour vacuuming (0.8 kWh), fridge (0.1 kWh). Those figures are per 'cycle'. What it would not help with is things like cooking, resistance space heating, resistance water heating i.e. showering or vehicle charging. I would need a bit of education to learn to use equipment sequentially with a little bit of recovery time between usage (or circuitry to manage some of it e.g. fridge cannot start if kettle just boiled), but I don't think that is too complicated. It would stop me turning the kettle on as soon as I get in from work and then having a shower while it boils, but I could live with that.

May be easier to just put up a large thermo-nuclear power station and beam the power down via microwave. I think any space based system has a cost issue. I had a 70gm package come from China (5000 miles away) delivered for a fiver, and that included the goods, so about 0.03p/kg.mile. It currently cost around £17,000 to get a kilo of cargo to the space station (£68/kg.mile). So about 24,000 times more expensive.

How hard are these redflow batteries to make, are they DIYable?

Had a quick look at the DECC PV figures and using the criteria of below 50 kWp is not metered i.e. domestic and over is metered, then we have 903,513 MWp as domestic and 4,084 MWp commercial. So if that commercial generated 48,788 MWh on the 19th April 2017, 12 MWh per 1 MWp installed, that seems a bit high to me Domestic would be 11,000 MWh. I may have misread the units of the DECC spreadsheet (https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/603803/Solar_photovoltaics_deployment_March_2017.xlsx) But I am in a hurry to get to the food festival. Others can look at it and put me right. There is a bit in the spreadsheet about where the money comes from i.e. FiT or CfD, that may help clarify it. Edit: Just relaised those calculations above a nonsense, so shall try and have a better look later if no one else does.

I think it is from large solar installations, domestic just shows a drop in other generation, but hard to get a clear picture. But as we know the amount of small and large scale installed, we could take a stab at working out what is happening on the domestic side. The main consequences of a space mirror is someone like Trump. Thankfully it is not really a viable idea.

I am not sure that the air temperature would have a big enough difference to worry about. We tend to think that the North side is cold, but that is more to do with solar radiation than the actual air temperature. And at night (50% of the year), it makes no difference at all. There will always be exceptions i.e. a windless back alley, but that is another story.

Heard this on the news on way home from work last night: http://www.bbc.co.uk/news/business-39668889 I have made a chart of the domestic fuel mix from GridWatch (http://www.gridwatch.templar.co.uk/download.php) I tripped out the interconnects, Oil generation, OCG, Pumped and Other, as they were either so tiny or not really relevant to domestic generation (who knows what the Dutch are really burning). Easy enough to look those figures up if you want to as they are part of the download. Now the really interesting thing is the solar production. It can now peak at nuclear levels, though the yield over a day is a lot lower. Due to the high pressure over the UK at the moment we have had pretty clear skies, and wind production is down. Gas still makes up the lion's share of our generation, not ideal environmentally and politically, but so much better than coal. What did occur to me is that if we can continue down this low carbon route, and there is no reason why we cannot do so for the next decade (there are technical limitations eventually), we may need to rethink our house building from an emissions viewpoint (that DER, TER stuff). There is still a good argument to reduce usage because of cost (Gas is about £40/MWh, Nuclear about £95/MWh, Solar and Wind about £150/MWh), but it shows that with a serious reduction in usage the price need not be prohibitive (maybe a 25% rise in overall electricity costs, I would need to look at figures a bit more on that to get a truer picture). Now the 'Spot the Coal line' chart.

It does start to distort at high temperatures, but probably not a serious problem for this kind of low efficiency design. You need a 'clear as can be' path to the collectors as you are trying to absorb all frequencies (energy is related to frequency, see the ultra-violet catastrophe). Paint the collector matt black.

Yes, I think I could (said Ian) Except it can be totally boxed in, does not need a large open surface or two. I would think that the first person to suggest a balcony got laughed at. Why would you build one when you can have an extra room

Can you build an outside 'cupboard' to house the unit(s)? Treat is as a novel 'feature', rather than an industrial fitment.

'Not even a small, though the wall one (or several)?' Like.....?

Why not separate units for each building?

If you have a new bathroom, do you come out cleaner and sweeter, same with kitchens, does the food taste better, or have more or less calories. Heating a house is a totally different thing, cold, damp houses can kill, a warm cosy one tends not to. What is wrong with a tub in the livingroom.

Just that when people are actually living in a place, habits change. So doors may be left open a bit, windows not fully closed, filters block up at different rates, all sorts of 'other things' go on.

That is the power of algebra. So taking that little heater, was a 12V one that had a power of 200W. We can work out the resistance using the 'orange' part of the chart. R = V2 / P R = 122 / 200 R = 144 / 200 R = 0.72 Now, working out to see what would happen if the voltage was 40V Using the 'blue' bit we can use. P = V2 / R P = 402 / 0.72 P = 1600 / 0.72 P = 2222 That is 11 times the power, so I think you can work out what will happen.