SteamyTea

They draw so little power that they do not register at the Wh level very often. Unlike when I first started data logging and was using an old desktop that was pulling about 200W. They obviously do take some power. Looking at the data from 2019 to now, the mean 'no power' is 53.7% of the time. This does give a quirk to mean averages, so I calculate the total mean and the 'power draw only' mean, 0.44 kW and 0.62 kW respectively. Maximum power is obviously the same for both, 13.16 kW, but minimum power above 0W is different, 0.001 kW, or a watt. That is probably the logging power usage, radio alarm clock and washing machine on standby. As I am on E7, time of use gives different numbers depending on time. During the E7 window, they are 1.14 kW and 1.47 kW, higher number excluded 0 power draw times. During the 'day' the numbers are 0.1 kW and 0.19 kW. 84.6% of my usage is at night. Would be hard to justify a battery system to offset 15.6% of my usage as the marginal price difference is 18.9p/kWh, and I only use 1.6 kWh during the day (over the last 6 years), and last year, I got that down to 1.26 kWh. So would only save about 29p/day. I am not sure how much it would cost to cobble together a battery system, got to be £1000, so would take 11.4 years to recoup my costs at today's electricity prices. Fun to do though.

I am staying silent on this one.

Plenty of jerky videos today was there?

There is a lot more to it than just the ability to time shift. Start with looking at your current usage patterns, download your half hour usage if you have a smart meter. Then see if you can get a better tariff that will fit your usage better, or if some simple changes will make a difference. The biggest thing you can probably change, for nothing, is reducing parasitic loads. Half the time my house pulls no power at all. Many battery systems have a minimum load requirement, so running a laptop and a light may not be enough to start the battery system.

I had a leak about 20 minutes ago. If I drive up to yours, I will be ready to do another one. More that willing to test all your handy work with my aqua vita.

I see that Rebel Energy have gone into administration.

So have others had trouble logging on today?

While I like this idea, and had a similar one for heating my fishpond, it may be better to just find ways to stop the energy getting into the shed. PV on the roof will reduce the input, as will a mirror.

I cannot be bothered to go though your shopping list in detail. But a couple or three things. What is your expected electrical usage? Are there any panel optimisers in there? Why not go for microinverters?

I tried to pronounce that, in Welsh, all I got was (expletive deleted)

Puts a new slant on a drink problem.

Far and few between. I would say maybe only 2 days like that over the past year A heating system is designed to supply the correct amount of thermal power, 99.5% of the time. 2 day below -3°C is 0.55% of the time. So that looks good. Most of the heating season time the outside air temperature will be between 10°C (very little heating needed) and 5°C (not that much in reality). We do get weeks where the temperature hovers around freezing for 4 or 5 days (when the Thames freezes over) but not seen any of those weeks since the early 1980s (worked in Marlow back then). The worse that will happen is that your internal temperature will drop a couple of degrees, say to 18°C, then plug in a fan heater. If the domestic hot water becomes a struggle, turn the immersion heater on. Don't fret over the extremes, they are called extremes for a reason.

I wish there was a standard. Not as if it is difficult as all manufactures will know the ΔT curves of their products.

Just had a look at your heat loss calculations. Says that there is no insulation under the solid ground floor. Is that correct, I though floors had to have a minimum of 0.13 W.m-2.K-1 I think. Better to have more if UFH is installed.

You have to check that the heat pump can deliver 5 kW (now kw) at -3°C. Not sure if this is the model you are getting. https://www.vaillant.co.uk/product-images/0020330791-03.pdf.pdf but it shows a power output of between 2.1 and 6.9 kW. The 2.1 will be when the temperature is cold. Update This https://www.plumbnation.co.uk/documents/vaillant-arotherm-plus-information-sheet.pdf Shows different numbers.

I downloaded Them as got a new laptop. It then wanted me to download extra programs, .net and a Fortran on I think. Downloaded them, installed them, got asked for a serial number. Don't seem to remember having that trouble last time. What am I missing?

Not my favourite experience. Mine are over a decade old and all still working. The only failure was about 15 years ago, and that was the bathroom one. I think my disabled lodger bashed it with a bit of towel flicking. Aren't the actual 'bulbs' or strips standard items. Some may be easier to change than others, but should all be changeable.

Generally, the cheaper, 2 part, exothermic resins have a low (sub 60°C) temperature rating. There are higher rated resins, usually epoxy or phenolics, that are much higher rated. There is a reason that SpaceX makes rockets out of stainless steel and not carbon fibre, it can take thermal cycling. Even if you can find a cheap, high temperature resin, it will almost certainly discolour if something hot is placed on it. Another problem with thermosetting resins is that they absorb moisture, you to about 10% by mass. I used to make steam rooms from composites, too me ages to find a suitable mix of materials, and we still had the occasional problem caused by over temperature, both during manufacture and usage. Thermo plastics are a different kettle of fix, many are designed to be formed at higher temperatures, around 140 to 200°C. If anyone knows of a thermoset resin that is stable at higher temperatures, let me know.

Does rebar help with catastrophic failure? i.e. holds chunks of concrete together. When carbon fibre composites were first used as structural elements in vehicles, Kevlar was also put into the weave. Kevlar yield point was 'further up the scale' than CFs. Going back a bit further, when Kevlar was first used in composites, glass fibre was include. There were times that a very flexible weave called Diolen was used to hold all the bits together when failures happened. We had lots of failures when we first used more advanced composites back in the 1970 and early 1980s. Thankfully the knowledge base is huge now, back then there were only about 3 UK based companies doing it, and we're did not discuss our failures with each other.

It is down to marginal costs. Probably cheaper to give a few thousand customers £200 a year than actually change systems.

Not as many sheep though. Probably work it out roughly. Grass converts about 0.2% of the total annual irradiation to dry mass, dry mass has an energy content of around 3.5 kWh/kg. Halving the amount of sunlight will not halve the growth rate, but will, at an educated guess, reduce it by a third, so somewhere around 2.3 kWh/kg. To get better figures I would have to look at the UN FAO database and see how latitude affect crop growth. But I am too busy at the moment.

If we had a true carbon tax (it is levied on the big generators, a bit), then the economics would change. But I agree, roof top is the most expensive way to install solar. You can easily get 0.5 MWp on a hectare (10,000 m2) Bit more on sloping land. To put that into perspective, it is the same as 125 roofs with 4 kWp systems.

Looks like they're now targeting end of June 2025 They totally lied to me about the switch off date, and failed to mention that my billing would go to monthly, even after they assured me I was on quarterly billing. EDF had to give me £250 quid compensation.

I think they use the lack of airtightness to control condensation, they are/were an HVAC company really. Have you thought of making your own, it is only a periscope after all.

Not had a chance, sorry. But I think you are right about a 15 minute total runtime per hour. What will affect the frequency is the temperature difference between flow and return temperature, as that is what sets, in part, the energy needed.