Ed Davies

Yes, it's odd that that Emerald Geyser label sort-of implies that it should be mounted horizontally with the “side” connection downwards (assuming writing upwards). I'd think if you wanted to put one on its side, which seems sensible to me from the point of view of avoiding an air pocket but not having electrics under water, you'd put that connection on the top. I also wonder why they say “vented system only”. Do they really mean max pressure 1.5 bar or something like that?

To put this in context, storing 1 data point every 10 seconds with a reasonably generous assumption of 50 bytes per sample comes out to just under 160 MB per year which is trivial compared to any disk you can buy this century. Why wouldn't you, just in case? E.g., I recently added a temperature sensor on the DHW cylinder coil. It's giving some odd readings which I'd like to look into more closely (my first thought is that the 2-port valve in the circuit must be letting some water through) but it's handy to be able to look at the power consumption at higher time resolution to be able to see when the circulation pump and the actual boiler come on and stop.

Why not, instead of discarding data, reduce it over a fixed period (1 minute, 5 minutes, …) by averaging, summing/integrating or whatever is appropriate to your data? Keep the full data but run the reduction pass once each time before you start to play with the data. That gives you the option to go back and change the way you do the reduction if you decide some other way is more appropriate. My CurrentCost uses a current-transformer clipped round the meter tails and reports the power in watts every 6 seconds. I keep all the samples plus log quite lot of other things mostly on 1 or 2 minute intervals. From November 2016 that's 3GB [¹] in my sqlite3 database which is indeed a bit intractable. On the other hand, it's sometimes handy to be able to go back and look in detail at the data so, as it's not very large by the standards of modern disks, I'm happy to keep it all. I'm planning a complete re-write of the system (in Rust rather than Python) which will keep the data in flat text files. I have in mind with that to also keep all the data but have automatically cached versions with reduced time resolution, maybe 1 minute, 5 minutes, hourly, 6 hourly, daily… particularly for graphing periods longer than a day or two. [¹] An average of 1GB/year but that's a bit misleading as I've been adding more data series as time's gone on.

Next I suppose we'll hear arguments for not using nuclear or wind either because the grid's decarbonizing anyway. Why does PV have to have any embodied carbon? I.e., if you fully decarbonise your energy supply don't you also fully decarbonise your PV manufacturing?

When a cable carries current it lets off heat. The more current the more heat [¹]. If it's exposed to the air it can get rid of the heat easily so won't get so hot for a given current. If it's buried in insulation it can't get rid of the heat so well and will get warmer for that same current, or to keep the maximum temperature the same it can carry less current. There are tables showing how much current different sized cables can carry in different circumstances (e.g., clipped to the outside of a wall, clipped to the top of a ceiling under insulation, buried in insulation, …). Your electrician will deal with this but it's worth bearing in mind if you're going to have any high-power tools in your workshop. [¹] Proportional to the square of the current, so, e.g., 32 amps results in 4 times as much heat per metre of cable as 16 amps so, for any given level of insulation, 4 times the temperature rise.

Had scrappies knocking on the door the other day to ask if I wanted to get rid of my van. Is that about right?

OK, you're silly. More seriously, I've read a piece ages ago where a company with a lot of drives kept careful records and found there was no real difference between the major manufacturers over the long run. Particular manufacturers have periods where their drives are a bit more flaky, presumably as they push technology, but then they get it sorted.

Excellent, look forward to it. Interesting contrast: up this end of the island my perception is that November was particularly cloudy, probably the worst month I can remember having lived in the north of Scotland for nearly a decade, but December had quite a few decent sunny days, though chilly - e.g., heavy frost overnight which didn't clear during the day except for surfaces particularly pointing towards the sun. On the other hand, November was very windy here. I calculated that a little 1kW wind turbine (Futurenergy Airforce1) would have produced all my electricity needs for the month though would have needed a big battery to get over a gap in the middle but there were a few sunny days then.

Depends on the drive. Ones sold as “portable” USB drives should be OK as they're low enough power to run off the USB connection, others sold as “desktop” have a separate power supply.

Thanks @Jeremy Harris, very useful figures. Any chance that in 6 weeks or so you could do similarly for Dec/Jan/Feb? Insert obligatory rant that even in the middle of the night incremental demand will usually come from CCGT (gas), particularly on days when the PV hasn't filled the Sunamp anyway.

Yes, I'm sure I remember seeing a lot more than that hand sketch - photos of the actual windows, etc.

Thought we'd discussed it before but my memory really is getting very wobbly if it was that recently.

Didn't @tonyshouse house do that with his basement windows, or something? On brick rather than timber, IIRC.Can't find it on his web site at the moment.

Depends on which council, I suspect. I submitted mine to Highland Council on August 5th, got the acknowledgement on the 13th and the reply on September 24th so 7 weeks and a day. IIRC they're supposed to respond within 8 weeks but maybe that's just Scotland.

Probably need to check that thread on the tripod is really 5/8th. Should be 27 threads per inch, might be easier to check that.

Yep. AIUI, that's how they work in practice anyway. Each time the primary water flows through the heat pump it only rises a few degrees so, assuming the return temperature is pretty much the tank temperature the flow will be UVC +5 °C so you'll get the better CoP anyhow.

@Tom's Barn

A commonly used rule of thumb is 3 kWh/person/day. Adjust to suite shower/bathing habits - more if anybody habitually takes half-hour showers with boiling water at flow rates comparable to Niagara falls or whatever. That's common with oil or gas boilers but not such a good idea with ASHPs because that would mean that the ASHP would always be running at DHW temperatures whereas normally you want it running at lower CH temperatures to get a better CoP.

By the way, my rule of thumb for off-grid power is that it costs about £30/W so going from 44 W for the standard Biopure down to 27 W for the -E model drops the cost by about £500 less whatever the extra cost of the lower-power pump might be. Sometimes the equation is not so simple because the extra power is dissipated in the house so contributes to the heating but that doesn't make much sense from a practicality and noise point of view in this case.

Biopure do an option with lower-than-standard power consumption which I'll look into when it comes time to order for my off-grid house. https://webuildit-ltd.co.uk/domestic-sewage-treatment-plants/running-costs/

It takes time for droplets of water to fall out of the air; small heat exchangers won't be all that efficient at extracting latent heat. Also, there could be condensation in the inlet pipe if, e.g., it's been cold outside for a while so the pipe is cold then then weather changes to warmer damper air.

I've no practical idea but it seems to me that it ought not to work for the inlet/supply path as the units are not supposed to mix the incoming and outgoing air.

So, still configured for a US keyboard then? Strange coincidence but I also ordered a 2GB DIMM last night. I have an oldish Acer Aspire One netbook (bought 2012) with 1GB of RAM which I use for odds and ends away from my desk or home which has been running Debian/LXDE for a while. For no immediately apparent reason I decided to update it from Debian 9 (Stretch) to Debian 10 (Buster) but it failed for some reasons. I'm getting pretty fed up with Debian package management breaking all the time (have had problems on Raspbian as well, Ubuntu is Debian based but is fine) so decided to give Manjaro/XFCE a play. Ran OK booting from a USB stick but refused to install as it says it needs 1GB of RAM - I guess there's some shared video RAM or something which means it's just under its requirement. So watched a couple of YouTube videos, opened it up, took the existing RAM out, put it back in, rebooted OK, so ordered the maximum it can take, 2GB. Bit more expensive (£16) but coming from the UK so should be here at the end of the week or early next week.

https://www.amazon.co.uk/NICEYRIG-Thread-Adapter-Microphone-Female/dp/B07646GV3W Difficult to be sure from the photo if you need a 5/8th male or female. I assume female but if male then there are probably more adapters available.

That wasn't when it was subsidised, was it? Was done by the energy companies to get their green credits of some sort, like they've been doing EWI more recently. Was supposed to only be used for retrofit in existing property but I bet a lot went into new build.