SteamyTea

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.

Would you have to be concerned with flow rates in the summer? I often wonder how well balanced a system is after a few weeks of operation.

Does it have beer and kebab stains on it

Can't you just stick a cheap portable aircon unit onto the MVHR inlet to the rooms.

Ohms law will tell you what you can do.

Yes, if anything it could run the pool too hot. I only had a manual OnOff switch on the pump. There is a big difference in running up to 28-30°C for a swimming pool and getting up over 50°C if you want to rely on it for DHW. Easy method for cheap pre-heating when the conditions are right. I used some cheap agricultural semi-rigid black water pipe laid on a gravel bed, then poured dyed concrete on top. If I was doing it again I would put some insulation down instead of gravel. And make a control system.

Not unusual to get the best relative performance this time of year because of the combination of temperature and array angles.

Isn't it Wh?

You're alright, they call it thermal storage. I made a similar system for a swimming pool back in 1984.

How did we end up with terraced houses laid out the way they are? If we turned them 90°, living room to one side, kitchen the other side, stairs in the middle, would they take up more land area in practice. If, say we are trying to build houses with a 5m by 10m footprint, a garden area that is the same, a road/footpath is 6m wide and a parking area at least 4m by 8m (just guessing at these figures) and the total development area is 100m by 100m (a hectare). A traditional terrace would take up a total land area of 155m2, while the 'turned 90°' would take up 170m2, so on a 10,000m2 square development, you would get 65 homes or 59 homes respectively. You would get more 'parking' area with the 'turned 90°' housing, but not enough to get two cars in, and it would probably be wise to put in some alleyway access on the traditional housing, so it would probably even out. All this does depend on having the ideal site to develop, but as England has 130,27,900 hectares of land, this cartoon development is only 0.000008% of the countries total area and about 0.00008% of the urbanised land area (of in other words, f all) Is 5m enough to put a staircase? I know that my 3.5m isn't.

Many people have low expectations of housing and think that what is on offer is the best they will get. Can you put the main door into the kitchen? That does depend on orientation. My car parking is at the back of the house, so the back door is the main door. The main door does have a porch, so not too bad, though hardly gets used.

I am not sure I understand what you mean here. I live in small a 2 bed terrace. It is dreadful. The living room is just a corridor. I think a terrace needs to be 5m wide, that way the stairs can run across the house, this would separate the living room from the rest of the house. The same could happen upstairs, separating the master bedroom from the rest. Ensuite under the stairs if there is a second story. With terraces, orientation is everything. Mine is NE (rear) SW (front). I get no decent sun in the afternoon at the rear (the garden, and f'all grows well there), the front is no good for sitting out on as it is by a road. There is little opportunity for PV as well. The really sad thing is that with a bit of thought, the whole development could have been so much better (there is more car parking than housing area).

I think the basic concept is that any module that is not working at the optimal performance for the conditions i.e. shading, is bypassed. This stops the module being heated up by the other modules i.e. self consumption. This can cause a power drop for the whole system. Micro inverters do the same thing and convert the wild DC current and voltage to regulated AC. If you don't have a shading issue (or only a minor one), there is nothing to be gained by using individual module optimisation. Let a normal inverter deal with it.