SteamyTea

I have just got home, house has been shut up for a week, but the windows have been 'on the latch', so the place is ventilated. 18°C in my kitchen, which is NE facing, so if there was sun today (think it has been rain), the kitchen has not had any since noon. It is 14°C outside. No heating on, not been on since March I think. Where in the country are you?

Yes. There is a reason they are called hydrogen fool sells. Another example of people not understanding the science. The simple answer to to ban combustion technology. That would solve the atmospheric emissions problem.

About 70%. But that is just the conversion, it does not include the water treatment, or compression. I kg of hydrogen takes around 55 kWh of electricity, 1 kg of hydrogen has about 40 kWh of energy. A lot of thermal energy is given off in the process. A fuel cell has ~50% efficiency. A lot of thermal energy is given off in the process. So before compression, storage and transportation, around 35 to 40% efficient. A Tesla Model 3 has a mass of 1850 kg. A Toyota Mirai has a mass of 1950 kg. Similar cars, except one is slower, more expensive, can't be easily refuelled and handles worse.

It don't help having to listen to Tony Blair on Broadcasting House this morning. He may well be right, but I hate listening to him.

Unless you believe in the multiverse, then there will be ~26x500 of them, in any combination, including not having any.

If I could go back to the second second of the universe's creation, I would edit it. But we are only given half an hour. Richard Feynman was asked to explain his Nobel award winning research in 2 minutes. He rightly pointed out that if he could do that it would not have been worth a Nobel.

Got out of mine in the wrong county, Buckinghamshire.

Yes. Try and establish if there is soakaway nearby. My basement used to get a good 6 inches of water in it.

Not one of the Isles of Scilly @pocster the pimple.

Welcome Which island will that be then?

@IanR I have to agree with you. Not sure how we are going to get the message across, hopefully the economic argument will do it, though this nation has a bit of history of making itself poorer.

A gas boiler could be converted to run on just about any fuel. Hydrogen has some specific challenges that need to be overcome first: Production in a zero carbon and energy efficient manner. This is not easy as there will be many calls on power being generated, and until some catalyst made from unobtanium comes along, it is more efficient to just store thermal energy in bricks and water, like 7 million homes already do. Transmission. Natural gas is a large molecule that is fairly inert, so is easy to pump, pipe and store. Hydrogen, at 101.3 kPa has a 0.01188 MJ.l-1, Natural Gas, at the same pressure, has 0.0364 MJ.litre-1. So you have to pump more litres as the existing gas system cannot be run at a greater pressure than it already is. Hydrogen Embrittlement. Because hydrogen is a tiny molecule/atom that is reactive, it wants to attach to other molecules/atoms. This can significantly change a material's properties. So reliability could be a problem (though I am told gas boilers are pretty unreliable anyway, usually the control systems). Cost. Even the cheapest hydrogen is expensive, and then the CO2 has to be captured and processed and put into long term storage (some real prices in this show https://www.bbc.co.uk/sounds/play/m0010qb7 ) It sounds a great idea, couple of wires into a bucket of water, tap of the gas from one electrode and put it into the gas grid. If it was that easy, we would have done it decades ago. Not as if we have just discovered hydrogen, been about since the second second of the universe's creation, well the middle bit was, the outer bit took 370,000 more years to combine with it.

I think our old mate Jeremy Harris had a Stiebel Electron one that was plumbed in after his cylinder. I think he found he did not need it and someone on here had it off him. @ProDave I think.

@Dave Jones will do it in 2, and fit you a new gas boiler during his tea break.

Too right. Could fit something like this:

Played with one of these, connected to a Raspberry Pi. http://plantower.com/en/content/?106.html It has a built in fan, but I am told the accuracy soon drops off. Some of those Honeywells seem good value.

Yes. Just calculate the energy in the tank, calculate the energy needed to raise the slab temperature, then work out at what rate you want to deliver the power. So if you start with 10 kWh in the tank, and it takes 1 kWh to raise the slab 1°C, and you transfer at 3 kW, then it will 20 minutes. The tank will therefore last 200 minutes, or 3 hours 20 minutes. The thing that is important is the starting temperature of both the tank and the slab, plus (well minus really) the losses they both experience.

Put me off my partner. Was hot 35 years ago, when Jane was almost 50.

84 now. May rattle and wheeze like a fridge.

Yes. It is identical to working out the heat loss through a wall. You need to calculate the total surface area, work out the U-Value from the materials used. Usually just the insulation type and thickness is close enough. Then work out the temperature differences between the water (take a mean temp) and the surroundings. Then multiply the lot out. That will give you the power loss. Then calculate how long it will sit idle for i.e no input or usage. When I get some free time I may write this out with a worked example.

Wow, what fantastic timing for TP. Large, short term, price rises a while back, then the summer holidays when sales fall, so no need to reduce prices because sales volumes are low. Now they can offer, in celebration, 20% of materials that they have never reduced the price off. £100 + 30% = £130 £130 - 20% = £104

Will be interesting to see what they have on offer.

It is worth remembering that it is very rare that a hot water cylinder will drop to the incoming mains temperature. Mine rarely goes below 30°C and I only heat my water to around 45°C, so about 3.5 kWh. This is double checked with my energy meter and is about right (I am all electric so easy to monitor). When I get back home, after a week away, my cylinder will be cold, I shall check the temperature if I remember as I have some probes on it, so easy to do. Then I can see what the overnight electricity usage is. My system is a vented system, so the 100 litres in the loft header tank is often above 20°C. This is, in effect, passive solar heating. That changes during the winter though. Not had a full year logging the loft tank temperatures yet, but the data is being collected. I have posted up my water temps somewhere on here. Here it is. I cannot remember what time period this chart comes from, I should have put it into the title.

https://www.engineeringtoolbox.com/thermal-conductivity-d_429.html Easy to check out.

Why, are you diabetic? The '8 glasses of water a day' is a total myth.