SteamyTea

I forgot to put any CDs in my car so had to suffer listening to Radio 4 all day (actually my station of choice). Today is Any Question/Answers. So the Tory MP Jeremy Wright and the Labour MP Chris Bryant (won't bother with the other MP on the show as she was irrelevant to this part) were bickering over the targets for Leicester and Warwick. Apparently Warwick is going to have to build twice the number of homes, Leicester half. So I thought I would look at the actual figures. Warwick is going from 653 to 1086, 65% increase. Leicester is going from 2435 to 1690 -31%. Now if both these MPs had bothered to do their homework, they could have told the truth. Warwick, in the 2021 census had a population of 148,500, Leicester 559,017 (2021). So Warwick is 3.7 times smaller. The two places are not comparable in the slightest. But why should facts get in the way of politicians bitching at each other.

Ask your Dad, he is very good at science communication. Failing that, You said what I thought you meant, just needed that extra bit of clarification as you are showing that using one technology, with a CoP of 1, and, in some circumstances be thought of as equivalent to another technology with a CoP of 2. Yes, this is a problem as we introduce more weather based generation. It is interesting to look at the phase out of coal generation, some days coal only produced into the grid for a few hours. While this looks good on the reporting, those power stations were still burning coal as they cannot go from zero to almost 1 GW in half an hour. What is known as hot spinning reserves or in the case of the zero periods, probably just spinning reserves. Wind is probably, at the moment, doing the opposite i.e. overproducing and has to be curtailed, sometimes, to allow the larger gas plants to reintroduce power in an orderly manner.

Things can only get better. One of my favourite programmes.

Yes, I think that is right. And then you need to cheat the CoP values at the extremes. It all boils down to the energy/power. As mentioned, percentages are very misleading. Get the absolute numbers. In statistics, which energy transferred in the biosphere is all about, always ask is it a big, or small number, then ask if it is relevant.

When I was a lad and did my apprenticeship at a company that made material testing machines, many if which were hydraulic, we used to pulse the pressure up and down in quick succession. This was part of the rapid aging of components (odd to test the strength of a machine that is made to test strength). Static over pressure testing is a very crude test, and you have to take temperature extremes into account, and vibration. Vibration can cause havoc with drawn steel pipes. Quick thought on the calculations. There are two elements, the stored energy due to the pressure/volume curve plus the energy from the change in temperature. You can probable treat the PV as a constant flow i.e. mass times velocity, and just find the mean dT and use that as the starting point for the real thermodynamics heat capacity of the steam. And stand well back during testing.

Not sure I understand the last bit about getting an effective CoP of 2 by charging when grid intensity is lower than the mean. Are you using emissions as a proxy? i.e half the emissions is the same as a heat pump's CoP of 2.

Seems to have been forgotten how good analogue can be for some calculations. Most of the circuits in a mobile phone are analogue, and extremely low power now.

The royalty of all science.

Water vapour can change to liquid water for a number of reasons. Temperature, air pressure and particulates in the air. That last one is often overlooked and it had a cousin. A solid surface will have a roughness to it, this can cause water vapour to transition to liquid. Also worth noting that if you see steam, the water vapour has already condensed. Just thought of more. Temperature is a measure of mean 'free path' speed. So when a pan boils, some of the water will be below 100°C, and some above. Water vapour is the same, but a larger temperature range (up to about 374°C I seem to remember). There is also a triple point where water can be a solid, liquid and a gas.

Start by taking some internal and external temperature and RH readings. It may just be bathroom condensation.

"All models are wrong, some models are useful" Easy enough to get the weather data.

Yes, that is at elevated temperatures, how about at sub 20°C.

Does it include VAT?

(expletive deleted)

A watt, which is power, is a joule per second, which is a N.m/s. Or, and it is the same thing, kg.m2.s-3. The N.m.s-1 is the easier one to understand as we all remember that force is equal to mass times acceleration.

There are evaporation losses as well. https://www.thermexcel.com/english/program/pool.htm

There is. Read a report 2 decades ago when I was at university about how raising RH when cold can sometimes make a difference, but cannot remember if it feels warmer or colder. Was an American report about large public buildings.

It is kWh, not Kelvin rotational velocity.

It is kWh, not Kelvin rotational velocity.

That is an important point. I limit the charging time to 1.5 hours, so 4.5 kWh(ish), I don't run out of hot water. When there was 2 of us in the house, and once I had trained my lodger not to stand under the shower until it ran cold, I limited the time to 3 hours, but raised the temperature up by 5°C to 52°C top of tank temperature. Never ran out and could get two bathfuls and a shower out of that.

Took my car in for some minor MOT work today. The bush extraction tool is broken, so got to rebook. They called me.

Except we are adding more storage and better management. That has to be paid for somehow. But imagine of it was the other way around and all we had were renewables and someone came along and said we can off the same with natural gas. We would have to issue drilling licences, drill holes, get planning permission for pipes and onshore terminals, build all the infrastructure, deal with all the safety aspects, change all the heating systems in houses and so forth. And after 60 years, deal with the associated pollution and climate change.

Only when the friction between the water and pipe changes from laminar to turbulent. If you can find a formula for it that holds true for every situation, you will win a prize. https://en.wikipedia.org/wiki/Navier–Stokes_equations https://en.wikipedia.org/wiki/Reynolds_number

Other way around would be better. Use the PV to power some LED panels, or a screen with a camera outside.

Get a new architect.