SteamyTea

I think the problem is that the quantity of energy from spare domestic properties is relatively small, and not when it is wanted. And why bother to offer more, they are getting it for 50 quid a MWh, which is slightly higher than the recent (before the silly rises) average price.

I like cutting in. Do it right it makes the rest of the job a doddle.

My sprayer is still in the box, lovely and clean.

Wow, that is the posh version of kW/h. Shall add that to my list.

And then store enough thermal energy for the next 17 hours. My off peak E7 is now 14p.kWh-1, so gas will have to more than triple in price to equal it.

There is a guy on here, from Wales, that refused point blank to try that. He gets upset that his ASHP is useless. Glad you got it sorted.

Gas was so cheap, doubling the price still makes it a third of the price of electricity. Get a heat pump if you don't have gas.

And, at night, you can pretend you are s sniper. Best buy at Lidl mine was. That's your neighbour that is, checking up on you.

Yes, and design it to make full use of the PV modules on the roof. Could make something really quite good and useful, and a place to put lots of batteries/heat store in to soak up some excess generation. May even be able to 'split' a system so some is totally off grid, therefore keeping within the 16A per phase generation limit. On my weekly trips up country, I stop for a coffee in the Cotswolds.

Shame the one @PeterWsuggested only has a 2 year warranty. My twin impeller show pump has lasted over 13 years now. Was a 100 quid from Screwfix.

Why is your usage so high if you do not have an EV already?

Totally different dynamics. Lots of windows, very leaky, small volume, so disproportionate large surface area, floor area open to the elements. And an inch or two of insulation. They really can't be compared to even a 1970s house.

Your best options are to reduce losses as much as possible, then find a way to self generate. Some PV and a couple of small wind turbines, around 4 kW each, would supply you with a fair amount of power.

Been like that all day. Basically, 1 kWp of installed capacity will generate 1000 kWh.year-1. A single module is about 1 m by 1.6 m, so an area of 1.6 m2, and has a peak power of 330 W. So 3 modules gets you close to 1 kWp. 4.8 m2. These have to be set at at optimal angle, luckily PVGIS can sort this out for your location. If you have ever driven past a large solar farm, you may have wondered why there are large gaps between the rows of modules. This is to reduce shading when the sun is low in the sky. Shading is a real killer for PV, you don't need much of a shadow on module to seriously reduce performance. That is any shadow, it does not have to be contiguous. So trees, shrub, hedges, houses garden furniture or flag poles can cause a problem. This basically means that ground mounted takes up more surface area than roof mounted, so what may seem like a large area, may not allow that many modules on it. Can you put some on your roof?

I seem to remember that anything over 9 m2, which is under 2 kWp, needs planning permission. I may be wrong on that, rules change.

I think a few institutions, government agencies and architects have tried. None have worked as designed as the parasitic losses and large temperature differences in winter put a stop to this. But why try, get a HP and use energy that is already stored in the ground, water or air. My house needs around 25 kWh.day-1 in the depth of winter i.e. half of December, all off Jan and half of Feb. So around 1500 kWh. If I could store that in shortage heater bricks which have a SHC of around 2 kJ.kg-1.K-1 and charged them with solar thermal to 70°C, (actually does not matter how they are charged) but using a minimum draw off temperature of 40°C, I would need 90 tonnes of them. Around 30 m3. To reduce the losses to an average of 2 kWh.day-1, and assuming a cube for the store (3.1 m each side), the surface area would be a shade under 58 m2. Using a thermal conductivity of 0.02 W.m-1.K-1 for insulation, the insulation would need to be 0.62 m thick, that would increase the sides of the cube to 4.34 m, and the total volume to 82 m3. This would fill the ground floor of my house. And it would still not be enough in reality. So to store enough energy to run a house, you have to fill the house with storage.

Genetics. Kids generally take the average height of their parents. Always tease my tall mates about their eldest being the mean height between myself and his wife. It is great when looks are exchanged and the conversation dies.

No, just (expletive deleted)ing short.

A really strong light will make your pupils like pinholes. That gives your vision a greater depth of field. It is really quite amazing that we can see in such low light levels, less than a W.m-2, and also in extremely bright light levels, greater than 1000 W.m2. Imagine having a heart that could do that, pumps around a little blood at rest, then 1000 times more when we are running. The human body should not work at all.

This is the whole point. The time it takes to cool is governed by the thermal conductivity, not the heat capacity. When in a steady state, the temperature of the mid point of the wall will be the mean temperature of the wall i.e. 10°C for an internal temperature of 20°C and an external temperature of 0°C. This has the effect of halving the stored energy in the wall. Because of the high thermal conductivity of stone, as the energy escapes to the environment, that 10°C point moves inwards, reducing the stored energy even more as heat only moved from hotter to colder. It effectively reduces the thickness of the wall, so what energy there is stored, is released to the room faster. It follows the Cooling Law, which is an exponential decay that is proportional to temperature differences. It is this proportionality that often causes confusion. It is not just the temperature difference between the inside and outside face of the wall, it is also to do with the temperature gradient inside the wall. If you really want to stabilise temperature, get an oversize MVHR unit and scavenge the energy out of the air, easier and more controllable.

My intuitive feeling is that separate HPs for Space and Water heating. They are different things, at different times and at different temperatures. My thinking is that you can get a small, but better, modulating one for space heating and a non modulating one for water heating. The reasons being is that weather effects both the HPs performance and the house heating load, but water heating is generally quite fixed in the amount of energy needed. So you can find HPs that better suit the two separate tasks, rather than compromise. And you could divert, via a buffer tank the DHW HP to space heating during exceptionally cold spells. But if it is worth it financially, I am not so sure.

If you have a buffer fitted, would there be any advantage in adding a low loss header, and visa versa? A buffer is a simple, cheap and easy to understand bit of kit, I would have thought it was one, or the other, but both is, if correctly sized, unnecessary.

Well that is wat all this debating is about. Built two equally well insulated cartoon house out of stone and timber, ventilation rates identical, and input the same energy to warm them, and you will not see a difference. This is what Physics tells us. Now if you build a stone wall, of normal dimensions i.e. 0.12 m thick, in the stone house and the timber house, you will see no difference. But if you built a timber wall in the timber house, you may see a slight variation, probably too small to notice. This is an interesting topic, skewed greatly by the local build types, but the Physics are the same. If I get time later (feeding my Mother at the moment and then exercises/looking up tax information) I shall sketch up some scenarios to highlight the problems in calculation all this (there are a couple of different ways to calculate it all, the energy model and the power model). No promises though.

Yes, but that is more to do with the energy input and the absorption. If you pump 800 W.m-2 into something that absorbs 95% of all the energy hitting it, it is going to get hot. Very different climates, why most of the studies are done in cloudless places. Go to undeveloped equatorial regions i.e. rain forests and the building style is very different. It is a balance, and non linear, between the heat capacity, shape, thermal conductivity, area exposed to energy inputs and outputs, it is not as simple as just mass. This is why there are no units for 'thermal mass'. Granite has a thermal conductivity of between 1.7 and 4 W.m-1.K-1 so yes, it does slow thermal transfer. But then Oak has a conductivity of 0.16 W.m-1.K-1. So it slows at least 10 times more. So even if, for the same raise in temperature stone stored the same amount of energy per unit mas or volume, which it does not, it also looses to the semi infinite heat sink that is the environment at a faster rate, leaving very little energy left to be transferred to the interior. Quite simply, if just adding mass to a building stabilised the temperature, we would all have been doing it for millennia. Part of the reasons that in the UK we think that adding mass helps is that we have an odd climate for our geographic location, stick the UK 1000km East and we would not be building in the same method. Find a low lying island 1000 km West and thing would be different again. There are also historic reasons that the UK likes 'brick', some go back 1800 years, other just 80.

Temperature is not energy.