RobLe

We got Octopus to remove our gas meter a year and an half ago, they do it for free, can’t say fairer than that! They took the meter itself, capped off the plastic pipe inside the meter box outside our house, turned off the pipe shutoff and took the lever away for good measure. I think a year after it had gone we got a letter from Cadent saying they’d come and inspect - and that if they thought it was unsafe they’d charge to take out the pipe all the way to the road - and that would be the pricey bit(£1500 ish I think). The pipe was still nicely protected in the meter box, so they went away happy - no charge 😇

When propane is cold and/or compressed, it will be a liquid. When it’s hot and or at low pressure it will be a gas. The chart shows the transition from gas to liquid, which is at a certain pressure at every temperature. Tbh it’s all quite non intuitive, but that phase transition is where most of the energy is stored enabling heatpumps to operate. Generally heatpumps are refilled at the cold low pressure side, when they are on, so that the low pressure there allows the fluid to be pushed into the system.

I suggest to liberally spray suspect joints with a water/washing up liquid mix. If there is a leak, you generally get a bubble forming. Our R290 system generally runs at around 13bar (hot), 3bar(cold) - of course the actual values depend on the temperatures involved - the temperatures should be slightly above the saturated values in the snip below at the measured pressures - the compressor in and out always has gas in it, never liquid. Snip from a handy free danfoss ‘ref tools’ app. My gut feeling from what you’ve said though is that the compressor is suspect or the metering device is too open - I would expect pressure post compressor(guess that’s what you measured- normally you would measure both ports simultaneously, and also temperatures at the compressor) to increase rapidly after switch on. 5bar at 9C ambient is I think the expected pressure….I am at the limit of my knowledge I’m afraid though. I assume you know r290=propane…. so don’t even think of getting a spark / flame anywhere near it.

I found exactly the same. That is, anecdotal use involved an osb sandwich, while the actual bba certification calls for the waterproof layer to be directly on top of tr27. I think osb under the tr27 is in a danger zone, should anything go wrong with the vapour barrier below or the waterproof layer above, and will rot. However practically not doing that makes for a springy roof surface that can easily get damaged by foot traffic. I went with osb under epdm, put lots of solar panels on it, walk about on it, I’m happy with it. I especially liked the osb tg4 interlocking as it made for a nice flat surface which I might not have got with tr27 directly as I was doing a refurb, and not starting with a perfectly flat surface. The only thing I’d do differently is choose a lighter colour membrane, what little of the epdm is visible around the PV gets hot in the summer sun.

Short cycling of heat pumps was a real issue, back in the bad old pre-inverter days. The rule of thumb was that greater than 6 start-stop cycles an hour was likely to lead to fatigue failure of copper joints near the compressor due to the start up impulse. I would expect that particular issue isn't much of a concern with a modern ASHP inverter drive, which I would expect to soft start. GSHP are often still on/off relay driven simpler units, I think as noise is less of a concern for them, so they are more likely to still suffer fatigue failure with excessive cycling.

So he buys or rents pasture land, mows the grass, biodigests it, cleans up the gas then inject it into the gas network. He’s got a fact sheet: https://www.ecotricity.co.uk/our-green-energy/green-gas-mills-fact-sheet I expect the only thing slowing him down is overall cost/kWh of the product - he claims 7p/kWh, which makes it sometimes profitable, but not at the moment. (Does that include drax style subsidies though?). It seems very cheap up front costs, and easy to scale up. Clearly he’s a vegan, that pastureland has something on it right now! We could however do with eating less meat in the world, for the planet and our health. While I believe wind turbine + heatpump is a better long term heating solution, the capital cost of this makes it just that - long term. Nothing to stop both approaches happening. Dale Vince, eco hero!

Google for your specific meter; our ‘secure 100’ smets1 meter has a led on it that blinks like morse code showing ‘WAN’ signal strength with 1-5 blinks. Solid led =no signal, 1 blink is poor, 5 blinks is max signal strength.

No I’ve not done this but instead I suggest trying a ‘passive repeater’. It’s basically two off 423MHz antennas, linked by a 50ohm coax cable. One of them would live outside high up, the other is next to your smart meter. It won’t be as good as actually connecting it to the smart meter - but it’ll look less dodgy, be simpler to do, and maybe good enough?

With a few caveats, you can estimate the heatpump size from your yearly heat use: Heating requirement (in kW) = Yearly heat use (in kWh) / 2900 There is some maths behind the above, and it relies on: Home heating dominates over hot water South England based HDD (Heating Degree Days) data South England min temps 21C home temps all the time with both heating sources For example, if you use 20000kWh / year of heating, then the maximum heatload is 7kW. Most people would go up a size to a 11kW heatpump because: You do need a little more heat to keep a home at 21C all the time instead of only twice a day (which is common in the UK, and only possible with oversize heating sources). Air source Heatpump nameplate power does not take into account cold weather defrost cycles, so again that needs headroom. maths: https://protonsforbreakfast.wordpress.com/2022/04/05/what-size-heat-pump-do-i-need-a-rule-of-thumb/

Most DG installers used to use pilkington k, a ‘hard coat’ metal layer on an inner glass face, the DG would typically be Ug=1.4W/m2/K. In contrast Planitherm 1 by st gobain is Ug = 1, a significant improvement. Pilkington offer a similar soft coat too; it used to be hard to find (I don’t know now). All the above were with ‘typical’ 4/16/4 thickness DG units. Obviously 3G is better, but again the actual glass coating makes a huge difference - I didn’t find the lower u value glass cost any more, all else being equal.

It would need specifying up front, it is not the norm in the UK (it is in California and South Africa, where there are more frequent power cuts). Quite a few hybrid inverters offer this, eg Sunsynk inverters tend to, and I think Victron. The limitation is that all the current through the consumer unit is then sent through a relay in the Sunsynk all the time, ready for the occasion when it swaps to battery only. The 3.6kW sunsynk that we have specifies a 40A input breaker - if we used it as a UPS, then although we have a 100A mains cutout we would be limited to 40A due to this UPS functionality. I guess you could have two consumer units, a 40A one with and a higher power one without this UPS functionality.

There’s a few different figures for Kg CO2 / kWp in the article, but they all seem very high. 2500kg/kWp is used twice, a lower number later; that 2.5T corresponding to 1000kg for a 400W solar panel which you can buy for £60 these days, ie. 17kg CO2e/£….way higher than buying a barrel of Brent crude oil and burning it (5kg/£). I just don’t get how you can get higher emissions than buying oil and burning it - ok you can, but no legal and sensible business strategies. I think that figure is very old and irrelevant now.

Think there is a humidity sensor in the B plus model (but not the B)

We have PV, heatpump, battery, elec car. It’s actually cheaper, faster, and simpler to charge the car overnight with 7.5p IOG electricity than use ‘spare’ PV electricity (for which we get 15p) - better for us and the national grid to export it. Of course we have measured export, not deemed, which seems more ‘honest’ than deemed and a diverter.

I’ve been converting our flat roof garage into a workshop. It’s adjoined to the house, and has an up-and-over metal door. Ages ago I put 50mm of celotex on the inside of the metal door, giving it a calculated U value of around 0.5W/m2k - of course this ignores draughts around it. Calc: celotex lambda=0.025W/mk, so U=0.025W/mk / 0.05m=0.5W/m2k The outside wall has 100mm celotex, floor 50mm, roof 150mm equivalent. The insulation is mostly internal - likely I’ll only heat it locally when needed with IR panels rather than with a thermostat. For comparison with the U values you gave; an old single glazed window U value is 6W/m2k, modern double glaze is 1.2W/m2k. I think you’ll be disappointed with a 5W/m2k ‘insulated’ door.