SteamyTea

A GRP tray, which is the same material that fishponds are often made from will last decades. Probably because the environmental rules have changed a lot and it is easier to just buy credits and let some farmer turn his unproductive land into a weed patch.

All it is really saying is that between known limits, the total mass and the total flow will vary disproportionately. As the mass increases (more water soaked into the soil), then, until total saturation happens, the flow decreases. At total saturation, the mass is known (soil + plants + water) the flow will increase in proportion to the rainfall. If it freezes, which will probably happen when the weather is drier, ice can build up if it does rain. Heavy snowfall it probably the biggest structural risk (flat roofs are not as good as pitched roofs for distributed solid loads, why they have deeper joists). All in all, best avoided, or just create a small patch of greenery on it.

Think that should be price. Price is the nominal value is currency i.e. bag of 100 nails for £5. Cost includes the externalities i.e. pay someone to bang in nails after you have hit your thumb badly. So the price is just the nominal value of all the materials, cost includes materials and all the services to build a house, these days it also needs to include environmental charges.

I would have though that the first thing to know is by how much you need to reduce the light transmission to reduce the overheating risks. A random google though up this. Picking the first on the list got this. Silver 20 TECHNICAL SPECIFICATION Total Solar Energy Reduction 80% Solar Energy Reflected 50% Solar Energy Absorbed 39% Solar Energy Transmittance 11% Visible Light Transmittance 16% Visible Light Reflected 58% Ultraviolet Light Reflected 99% Shading Coefficient .28 Solar Heat Gain Coeff. (g Value) .24 Emissivity .70 Winter U-Factor (W/m² ºC) 2.82 Glare Reduction 82% I suspect that actual product would make a room quite gloomy, but there are other products. Maybe our resident glazing man @craig can throw some light (or paint) on it.

Darcy's Equation is all you need, probably.

When it is really cold, it is winter. The instantaneous power from the sun is quite low, maybe maxing out at 600 W/m². As the panels will only get about 20% efficient, that is 120 W/m². So while the voltage will be at maximum (PV modules are fixed voltage devices), the current is low, the MPPT will do it's thing and adjust the internal resistance to get the most out of the system. So should never become a problem. Panels are rated, and tested, at a standard temperature, irradiance and air mass. It is extremely rare in the UK to breach those limits. If you do get lucky, the inverter will 'clip' the power initially (the fan speeds up and dumps the excess power as thermal energy, and then will eventually disconnect if it cannot reduce the output voltage and current to the agreed limits (usually 253Vac and 16A per phase.)

Have we heard from @Garald recently, he probably knows about ladders.

The English make a simple job complicated.

Regarding the PV, Building Control may also want structural calculations i.e. wind and snow loadings. If a new build then the Structural Engineer should be able to supply the right paperwork.

Never looked into this, but have heard of it being done. You could split the system into two strings, with each string consisting of 6 panels paralleled up to another 6. That would halve the voltage while doubling the instantaneous current. That inverter can take up to 44Adc, but is designed to operate at 26Adc input. So it really comes down to what your panels can do, what is the maximum amps they are rated at?

It is, generally, not the ones that know we need to worry about. I work with some completely uneducated numptie, if they get away with something just once, that becomes policy, regardless of how often it has failed before or after.

You could look at single room dMVHR. When it comes to the heat recovery of the ventilation, you really need to know how airtight your property is. The only way to do that is to get it tested. If it not that air tight, a positive pressure ventilation system may be enough. There are lots of nuances when it comes to ventilation policy i.e. where are the air leaks, what do they leak into, fraction of overall losses...

I seem to remember that they do get taught it if they do a proper Level 3 apprenticeship. We were taught it on our Part P (limited scope) and that was specially designed for plumbers, PV installers, HVAC etc. Steico do this useful guide. Site_Guide_A6_online.pdf It is wrong that technicians, from other trades, should be making decisions about structural elements. We would not expect a painter (which has Level 3 qualifications) to be making changes to structures.

SMA are a bit iffy about people tinkering with their inverts. Is it still covered by warranty. Seem to remember they offered replacement once the old one is sent back. Call the local agent and see. That would fry it for sure, especially when written correctly, kW. But you mean kWh.

Should have painted it before foaming.

Do you hear that tapping sound, it is the hammering of the coffin nails.

Integral skin polyurethane foams do that. Used for making chair arm rests, and costing the steel hoop in car steering wheels. If you cut it open, you will find a 2 or 3mm thick skin. It is created by temperature difference between the injected liquids that react and foam, and the tooling temperature. With a bit of experimenting you can find the best temperature to heat the can up to get it to either skin on the contact surface or the air interface. Alternatively, and maybe easier, foam up with something strong enough, then coat the outside with non foaming PU. In effect, creating your own skin on outside. (Thinking while typing the above, paint the joint with non foaming PU, foam, then paint outside with non foaming)

Was a problem with honeycomb aluminium and composite plastic structures. Was fine for making the 'tub' of a racecar, but heat shielding was needed in the engine bay. Some of those impressive supercar fires on in YouTube are caused by heat induced delamination. Use with caution. There is a reason SpaceX use stainless steel for rocket bodies.

Will have to say the word sperm, so will get in trouble. Softwoods are gymnosperm, hard woods are angiosperms. Now it is early in the morning to be thinking about wood.

Often wondered about that. I did ask for my system to be completed flushed out at the 100k mile service (and it was). Think it is pink.

There are many answers. Can you temporarily bolt wheels to an axle and fit that at one end, or even bolt wheels to the side.

We have been discussing this here. Hoping to find answers as well.

@Marvin While I can see people's concerns about lack of space heating when the DHW is heating, I can't recall a time that people have actually had a problem. There is no reason that DHW cannot be heated in smaller time steps i.e. half hour here and there, this is what PV to DHW diverters do. One if the things I have tried to do at home is limit the maximum current that my house draws. So when the DHW is heating, I don't have the storage heaters recharging. This is purely a game I play as my supply, at 100A is not at risk. The other game is increasing the length of time that my house draws zero power (well less that 1 Wh). I think 3 hours is my record. Must have had something defrosting in the fridge. Putting those two games together means I can get a picture of how much energy needs to be stored, and how little needs to be delivered to keep the same living standards. Do you have monitoring equipment that logs at the Wh level, or are you using the smart meters half hour averages?

A boy from St.Austell. There is a reason we call it St. Awful. He supported Liz Truss, and was chairman of the ERG. Seems an odd person to appoint.