SteamyTea

Nothing dedicated to modelling, there may be some interesting stuff in Boffins Corner. No secret knowledge between members. The ones of us that are interested/trained in it tend to give our tuppence worth. It is often hard to trust models, especially ones that are hard to verify against real world conditions, all models are wrong, but some models are useful. The man thing is to stick to basic engineering principles and physics. A house is not really complicated after all, try modelling a car, boat or an aeroplane, and they work.

were you awarded many points?

Yes, but it is much better to learn it yourself. All you need is the material properties. The Conductivity, the SHC, the density and an hour on Google. But having said that, like cars, people will not be convinced as we know lightweight is hopeless. Keep adding mass, hang the extra energy needed and eventually you will have a cold cave.

Right, as I am an early riser, and am waiting for my 92 year old mother to get up (oh how things have changed in 50 year), I thought I would do some 'trivial' calculations on the difference between concrete and wood. I used the following thermal properties. Concrete Density 2700 kg/m3, SHC 0.88 kJ/kg, Thermal Conductivity 1 W/(mK) Wood Density 600 kg/m3, SHC 1.85 kJ/kj, Thermal Conductivity 0.147 W/(mK) For a 1K (or °C in Roman Catholic) a 1m by 1m by 0.1m slab of concrete will store 238 kJ (0.07 kWh). For a 1K (or °C in Roman Catholic) a 1m by 1m by 0.1m slab of wood will store 111 kJ (0.03 kWh). The time to gain, or loose, all that energy, (but radiating/conducting from all sides) will be Concrete 6.6 hours Wood 21 hours That is a 3 fold difference in time, so reducing the wood to 0.0314 m (oh a pi number, don't read anything into that) the time constant will be the same. Mineral wool for the trivial case, would have a time of nearly 3500 hours. This is why we use insulation, it stops the energy flowing (Q). (as usual, I may have made an error, and this is for 'trivial' cases i.e. a simple slab with a constant Q, no other inputs, and energy can leave all sides of the slab, the ratio of energy loss/gain is treated as linear, when in truth it follows Newton's Law of Cooling)

They are bellow set standards if used correctly, and anyway, it is just shifting the problem. Concrete manufacture has health risks for some people that work in the industry. https://www.haspod.com/blog/health/concrete-cement-dust-health-hazards Wood dust is pretty nasty as well if not controlled. What were the before and after mass differences? Seems odd that with water being about the best material to store energy in, people dislike a bit of moisture in insulation.

How good is the correlation between thermostat settings and actual room temperatures? At my mother's at the moment and it is sweltering.

Yes. It is all in the units. Energy (heat in Roman Catholic) is measured in joules, J. Thermal conductivity is measured watts, W. Now a watt is a joule per second. So there is the difference, and is where the time element comes from.

No it isn't. This is where the myth comes from. See my earlier reply.

I am with you on this. But, if people want to open windows, maybe because they like a breeze as well as fresh, but pollen and particulate polluted air, then they can. Without MVHR, you only have one option, and that is to open windows. Seems to be the case. Architects seem to 'like light', and that has filtered down to peoples idea of normal (we don't want post 1973 oil crisis USA housing). But since then we have upped air tightness and insulation levels, by law. Add in more days over 30°C, and overheating can be a real problem. I think people forget how powerful the sun is. If the morning sun is low in the sky, but chucking out 300W/m2, and you have 4 m2 of openings that allows in 1200W. Many modern houses only need that sort of input when it is cold. Storm Alex has now hit me proper, my solar radiation is at 202W/m2. Not dark. @joe90 hope your pond is large, there is a lot of rain.

https://thehum.info/newhummap/html_docs/

All materials hold heat, and all have thermal conductivity. It is the product of the two that is important, as well as the shape they are formed into. Then you have to take into account mass and volume, and the practicalities of using those suitable materials.

Don't change the physics though. I have lived in places where the temperature hardly changes seasonally, let alone diurnal, as have many millions of others.

I am of the view that as renewables, mainly wind and solar are now the cheapest energy source to deploy, and still getting cheaper, there is no need for energy costs to rise above their current level of around 5% of median household income.

A good sheep will step backwards.

Oh dear, where have your read this.

https://www.ofgem.gov.uk/environmental-programmes/fit/fit-tariff-rates

I don't now either, but there may well be a price on the electricity bill, or a date on the consumer unit.

If you know when the system was fitted, it will be possible to work out what scheme it is on and what the payments are.

A thermal store is an insulated box with something in it to adsorb the energy, then a hole to let it out again in a controlled manner.

The less blade protruding the less force there is on the saw base plate. This is a safety issue. I set the depth to maximum as it 'pulls' the work piece onto the base plate better. Do get a rougher cut. Opps, thought it was a hand held circular saw you were using.

What @ProDavesays. Basically you want to dump the power into appliances. Then use Economy 7 as your back up option for winter.

Thanks That looks better than Wagos and a bodge. I was very reluctant to pull the cable out. Shall pop out to Screwfix fairly soon.

Yes, what I thought. I have to jiggle the wires about a bit as they come out of the wall socket/cooker switch into the wall, then reappear about a metre away behind where the cooker was. I am reluctant to pull the old cable out with some string attacked to it, and then pull the new wire though (I am on my own so will be tricky really don't want to cut the wall open and then repair it). So intend to fit a new wall box and connect to the old cable below the hob.

I can usually work these things out, but just to be on the safe side I want to double check before I pump 7kW into it. My new induction hob has 4 wires, blue for neutral, black and brown for live and an earth. The blue is labelled N, the black and brown are taped together and labelled L. But, in the wiring diagram it shows Black as L1 and Brown as L2. L1 is 380V to 415V, L2 is 220V to 240V. The instructions show only 3 wires on the diagram, with 220-240V between the L and N, but next to it it shows L1 and L2 connected together (and the neutrals). Now i think that L1 and L2 do need to be joined (so have ordered some Wago connectors). Does anyone think differently?

No, it was a small, 1 bed, place about 30 metres from the harbour. Was actually £103k. Or about £20k more than my place. There is Cornwall, and then there is the real Cornwall, the bits people don't visit, or even know about.