SteamyTea

Windows has it built in. Movie Maker

I have often wondered if there is a real benefit from using aluminium. Depending on grade of aluminium and the steel, you may get almost 5 times more heat transfer, trouble is, the temperature differences are relatively small, and they are in effect, in a steady state. Aluminium has a k = 230 W.m-1.K-1 Steel k = 50 W.m-1.K-1 I don't know what thickness the material will be but a steel radiator is probably thinner than an aluminium one. This is only half the story though. When a radiator is cold, it takes energy to heat it up. Aluminium has a SHC of 0.921 kJ.kg-1.K-1 Steel is 0.502 kJ.kg-1.K-1 But the water that is pumped around takes 4.2 kJ.kg-1.K-1 I think the thermal properties of the water will tend to swamp any advantages that the radiator material will make in reality. It would be nice to see a proper study on this as there may be marginal cases where an aluminium radiator does have an advantage i.e. small radiator heating a small volume. I suspect that there is a greater advantage to the manufacture than the user. Aluminium is easily extruded, so more interesting designs can be created quite cheaply. Nothing wrong with that, but it would be good to see some genuine like for like comparisions.

It is Ws, for watt second, which is energy, not power. Why we should really use J, joule, for energy and not any other units. Assuming all things being equal in the pan materials, and allowing for different masses due to size, I will take a guess that there will be an optimum size of pan base for a particular induction coil. If the pan base is smaller than the coil, then some back electromotive force (BMF) may happen in the 'uncovered' portion of the coil, reducing efficiency. There may also be a reduction in power, but overall the efficiency will be less. To test this would mean going out and buying more pans, but others may like to give it a go with what they have, and then we can see what comes out of the data. A quick plot of this very limited data shows a power ratio (exponent has the same R2 value as well). So: Measured Value = 0.0078x2.1118 Where x is the theoretical value. Now what was the question. (We used to call these Silly Sunday Experiments)

Plan it right and the BEV will easily suck all the juice out the modules. All you have to do now is find a decent day rate, or accept that you may still need to charge the BEV at night (on E7) and just take the hit if the ASHP needs to heat DHW (lower CoP than space heating) during the day.

Not so fast. Second set of results. I have reset my energy monitor as it was miss reporting for some reason, and now I have noticed that there is a 0.15 kW fan on when the hob is running. I also timed how long it would take to heat 500 g of water. Full Power: Small pan, small ring, 1.63kW, 3m 20s (200s) Full Power: Small pan, large ring, 1.93kW, 2m 16s (136s) Full Power: Large Pan, small ring, 1.63kW, 3m 35s (215s) Full Power, Large Pan, Large Ring, 1.93kW, 2m 25s (145s) To just boil 500 g of water should take 0.0511896 kWh (assuming incoming is at 12°C), this is 184,282 Ws. Multiplying the time taken by the power of the ring, in watts, but minus the 150 W for the cooling fan gives: Small Pan, Small Ring, 296,000 Ws, 60% more energy needed Small Pan, Large Ring, 242080 Ws, 30% more energy needed Large Pan, Small Ring, 382700 Ws, 73% more energy needed Large Pan, Large Ring, 258100 Ws, 40% more energy needed Some of that extra energy is needed to heat the pan and lid, and when the large pan was on the smaller ring, it only boils vigorously in the middle of the pan. So, to boil faster, and use less energy, match the pan to the ring, and the task. Don't boil peas in frying pan, try and use a smaller diameter pan if you can. There is not a huge difference between my rings, ~300W.

Maybe no one told them it was a Bank Holiday.

Or the better fitting pan takes more power.

Maybe I can time a fixed amount of water until it boils. But going to eat some supper instead.

Interesting question. I shall see if I can test it, right now. Well, weird results. Both pans had pint of water in them. Half Power: Small pan, small ring, 0.869 kW Half Power: Small pan, large ring, 0.805 kW Full Power: Large Pan, small ring, 2.28 kW Full Power, Large Pan, Large Ring, 2.65 kW More testing needed, but warming supper now.

No you haven't. kWh is energy, kW is power.

Yes. Still, should be the first of the year to get deleted. Better take some screen captures. Going to catch the news to see how our mate Andy Windsor got on today.

Was it too slack for you Tiny?

My arse you will. (expletive deleted)in blown my New Years Resolution already.

Could embed your rocks in resin, maybe a few LEDs as well. That would look very 'Essex' and keep people away.

Too right, they are for scattering your seed in.

Except sleep at night.

Open the window then.

I think the physics us pretty basic for buildings. It is the 'solutions' that are confusing, and often wrong. Then add in a couple of layers of legislation, followed by manufacturer's warranties, then a builder's opinion, it surprising that we don't all live in rammed earth hovels with roofs made from stalks.

You can design a switch that looks at the rate of change, rather than the absolute change.

Dont most grid tied inverters also sense the grid impedance? Which can be tricked as well.

Yes, and it is still best to insulate what you can, even when I side the heated envelope. In my old house, there was a ceiling fan, that was quite good at forcing some of the higher than mean temperature air downwards.

A kW is power, the rate that energy is delivered at. So in this context it is the rate that thermal energy is delivered to the house. If you break down a watt, it is a joule per second, a joule, which is the proper unit of energy, is a kg.m² / s². Which is quite hard to visualise.

Just a thermodynamics book will do. Density, heat capacity and conductivity are not related to each other for any given material. It is all to do with energy levels in the atomic shells. Gets a bit quantum at the lowest level, but does describe what us happening nicely. Not sure, there are probably better people to ask.

Whale Oil Beef Hooked.

Work on half the output, won't be far out. The maximum theoretical output only matters in extreme weather.