Ed Davies

I've found my Lidl chain hoists very useful for this sort of thing. Bit worried I haven't seen them on sale for quite a while, hope it wasn't too many liability claims.

Interesting, I wonder if one could use the same stuff as a prefilter in the MVHR and in a rainwater harvesting system. Having a good stock of spare material for both uses would encourage keeping both clean and changing before it all gets too icky.

Trivial and irrelevant, but how do you convert a mass of 405 kg to a weight of 3924 N? That would imply a gravitational force of ~9.688 N/kg (i.e., an acceleration of 9.688 m/s²). The more usual figure to use is 9.81 N/kg so the weight would be ~3973 N. Is there a 405 vs 400.5 kg confusion in here somewhere? Or are you in another Leicestershire on a slightly lighter or less dense planet, but still with a higher surface gravity than that of Venus where CF would presumably melt, anyway.

I always carry my phone around with me on site. It would be somewhat disappointing to be lying on the floor with broken bones and not be able to call for help. It's also why I have a cheap and relatively small phone: a) because I won't care too much if I break it and b) it's more likely to survive an accident which breaks me.

The Simpson Strong-Tie range includes various concealed hangers intended to go in the end of glulam or well-dried timber joists. E.g., https://www.strongtie.co.uk/products/detail/concealed-beam-hanger/57 https://www.strongtie.co.uk/products/detail/concealed-beam-hangers/59 https://www.strongtie.co.uk/products/detail/concealed-beam-hanger/481 I couldn't find any for bolting to steel backing. Still, that might be a help to find some. Alternatively, you could discreetly bolt a timber backing plate into a steel I beam or onto another shaped beam then nail to that.

Most likely they're not a specific voltage but a specific current (perhaps 350 or 700 mA). Running LEDs from a constant voltage source is not likely to be very satisfactory, either they'll be too dim or they'll go pop, maybe as the temperature changes.

Pity.

Sounds like the impact of defrosting is very device dependent. Still, even on ones where it's significant there must be quite a lot of the year where it doesn't defrost at 60°C so maybe on balance full ASHP heating would still be a win or maybe a bit more intelligence could be used deciding on the cut over temperature, depending on the outdoor temperature and humidity. Given that in a well-insulated house DHW is a major part of the energy consumption this seems to be an area where fine tuning would be worthwhile. @ProDave, do you log your heat pump's power consumption with short time resolution (e.g., every few seconds)? That'd give a hint as to what it's doing when defrosting.

We've discussed this before. Surely the HP CoP wouldn't go below 1 even at 60°C so, remind me, what is the point of switching to direct electric heating?

Anyway, I thought this was the world's first actually solar powered train: https://www.popularmechanics.com/technology/infrastructure/a14506568/worlds-first-solar-train-running-in-australia/

It seems to me that for moderately complicated household wiring and plumbing you need lots of diagrams of three sorts: Logical: nice layout to understand the logic of the system with high voltage/pressure at the top, current flowing downhill, cause and effect going from left to right as is often used for electronic circuits. Mechanical: showing the actual wiring with some indication of the layout, e.g., if there's a row of MCBs in a box then they're shown in a row on the diagram, as in @JSHarris's diagram in his water-treatment shed. Geographical: showing where the wires actually run throughout the house. At the same time software will need to know configuration information about the system. E.g., 1-wire sensor 28E3F2C7010000 measures the study radiator flow temperature. A key tenet of software engineering is the DRY principle [¹] = don't repeat yourself. If there's one file to update when a change is made it might actually happen; if there are three or four then it's likely some will be missed some times and the whole lot will degenerate into a mess. So, what I'm envisaging is a single text file (maybe actually split into multiple files but processed as one) which sets up the software configuration and also produces various diagrams which could be printed or viewed online. The online views could be “live” in that they'd show actual states of temperature sensors, valves, pumps, batteries, etc, at least as far as the main computer knows them. E.g., I think somewhere on her web site Elke Stangl had a version of these diagrams which showed the actual temperatures and flows in their heat pump system live but I can't find it now. Thinking about this sort of thing is why I'm not overly interested in the existing home automation systems. [¹] I shared an office and house with Dave Thomas when I was a postgrad student.

My assumption, above, was that you're talking about a small turbine up to around 1 kW or a bit larger. If you mean something bigger then a 2.4/3.2 kW Proven/Kingspan turbine seems like the answer but that's quite a big bit of engineering to DIY. Multiple cubes of concrete for the base, for example.

Because they have to charge VAT on the plot but can zero rate if it's locked in as a self-build residential?

I'm not convinced there is a good solution in the small wind turbine area. AFAICS, none are well engineered to withstand windy sites or work well on sheltered sites. My site is about as good as it gets for wind [¹] other than bits of the west coast of Scotland but I'm not planning a turbine for my off-grid house until I've experienced a winter or two in it to see how necessary/useful one would be. If you're grid connected small turbines are, IMHO, pointless. Even off grid it's not obvious whether just adding more PV is more cost effective. Obviously long runs of dull weather in winter are difficult but even still… [¹] 100 metre high hill top overlooking the Moray Firth with about a hectare of land available to site the turbine, no trees of any significance around and no other occupied properties within 100 metres so would be permitted development.

Have I missed something? What's this “golden brick” thing about? Is it just to lock in the planning permission before the sale is finalised or something more useful?

https://cloudconvert.com/svg-to-dxf Don't know how much extra information DE will put in the SVG and how much of that will be picked up by cloudconvert but it could be a possible route to at least get basic 2D geometry converted across. SVG won't do 3D.

CO (carbon monoxide) and CO₂ (carbon dioxide) are quite different things. CO kills you fairly quickly (e.g., overnight) though chronic exposure is also a problem, AIUI. CO₂ just makes you feel a bit groggy (unless it's up to ridiculously high levels) and warms the planet. High CO levels are a result of badly set up combustion appliances. Indoor CO₂ mostly comes from breathing and high levels are indicative of poor ventilation. CO should be at much lower concentrations (parts per billion) than CO₂ and is lethal at concentrations which are normal for CO₂ (500 to 1000 parts per million). It'd be quite common for a modern house to have separate sensors for CO and CO₂. CO sensors are required in (most or all? new build and rental? dunno) houses with combustion appliances. CO₂ sensors and loggers are required in some houses (recent new builds in Scotland). The CO sensor may or may not be wired into the fire alarms. CO₂ sensors usually won't be.

Do unvented systems have a vent? E.g., one at the top of the system you can open manually when draining and filling? More than one if there's more than one high point?

Wikipedia lists 5 windfarms in Morecambe Bay, total nameplate capacity 1745 MW. Long-distance HVDC cables have losses of about 3%/1000km. I think it's reasonable to assume that the short cables from the windfarms would have similar orders of magnitude but slightly higher losses, maybe 5%/1000km. If they all come ashore through one cable (which I doubt) the heating at full capacity would be 87.25 W/m. It's hard to imagine a string of incandescent lightbulbs, one every metre, having much effect on the temperature of a salt marsh.

Intriguing. It's probably more obvious to you from walking past and seeing it from different angles but is that three storey or two storey with roof space or what? Is it a conversion or purpose built? Infill replacing an old garage, perhaps?

Yes, but even in quite humid air there's only a few grams, or tens of grams of water vapour for each kg of dry air so the extra heat capacity will have little effect. E.g., air at 25°C, 100% relative humidity (a moderately extreme case for a house in the UK) would only have 20 grams of water vapour for each kg of dry air. I think (but I'm not completely sure) that you can just add the heat capacities in the obvious ratio so, using the approximate heat capacities of the gasses given above, its specific heat capacity would be (1 + 0.02 * 1.8)/1.02 ~= 1.0157 kJ/kg·K. I.e., not much more than the approximation of 1 kJ/kg·K of dry air. https://upload.wikimedia.org/wikipedia/commons/9/9d/PsychrometricChart.SeaLevel.SI.svg

Why do you think drier air takes less energy to heat? Normally wet things are harder to heat because you first have to put in quite a bit of energy to evaporate a lot of the water but with humid air the water's already evaporated so that's not an issue. The specific heat capacity of water vapour (at constant pressure) is a bit higher than that of dry air (about 1.8 kJ/kg·K vs 1 kJ/kg·K) but with the very small quantities present I'd think that would only make a tiny difference, not worth considering. Is there another relevant consideration?

… and materials. Even Gods, with capitalized pronouns, don't take precedence over HMRC.

Don't use a metal tape measure when you check. ?

I think you're right to be concerned about getting this right. I too think that's a good plan. My floors will be similar: 150 x 19 or 22 mm [¹] sarking boards under the joists, full fill with mineral wool, VCL over then 22m chipboard and finish floor. The warrant specifies a membrane across the bottom and in the middle of the mineral wool to prevent wind washing and support the mineral wool. I'm having second thoughts, though and may well just use 25mm EPS sheets taped at the edge. Given the reduction in the amount of mineral wool required it works out cost neutral and gives slightly better insulation and will be a little less fiddly to install, I think. I'll run that by the BCO when he comes to peer at my timber before I start adding insulation. [¹] It varies. I started with 19mm but for the last batch I bought the timber place didn't have 19 to hand so I got 22.