SteamyTea

But less wrong that armchair commentators.

Have to look 3000 miles to see one here, unless I look towards Goonhilly and see the 20 year old land based ones. I have mentioned this before, but about 17 years ago, I added up the capacity of the wind turbines in Cornwall, and worked out that they could be replaced with just 1, 5 MW one. As that was based on installed capacity, that 5 MW turbine would have produced about 30% more energy, and been half the price.

Mathematics is applied philosophy. That will be subtraction then.

That is because we had a moratorium on building them, thanks to Cameron's 'Greenest Government Ever', it is not because of technical problems. And the medium term to ordinary people.

How I miss the beechwoods down here.

I prefer arithmetic for most of it. The geometry, trigonometry, statistics and calculus can wait for another day.

Getting a corded Shark for home, it is lighter than the rechargeable ones. They are good vacuums, but I know from experience that we would get though 4 a year at work, because we have just replaced, for the third time, the work Shark in 8 months. Sooner or later they will stop replacing them under the 5 year warrantee (which has another 4 and a bit years to run).

No it isn't. We are moving towards distributed generation. I don't often see new pylons where a new wind or solar farm is built. Most of those cables are underground. I am surprised that you keep saying this as you understand demand diversity very well: we don't put in new cables to houses when they add an extra lightbulb. And show me the times, from the UK grid data, when solar, hydro and wind fail to supply because of winter high pressures. Actually don't bother as I have already looked for it. It does not happen. Yes we have reduced RE output, but your installed RE capacity is still quite low. As is most of the rest of the world. The UK is not working in isolation on Climate Change policies. I sense that change is the biggest problem, not the technology. As for What you mean is wasteful. Thankfully productivity and energy use are decoupled now. We make a lot more with a lot less.

Those Numatics are mean suckers. Tried to do the restaurant carpet with one (410m2), nearly killed me. Went to buy a new vacuum for home yesterday as I bust my 20 year sold Hoover at work. Curries had been broken into, so nothing till Wednesday. Then my comments about fitting it outside may be useful. Wood pellets are about 12p/kWh once delivery, VAT and efficiency is taken into account. Which is about the same as I pay for my E7 night rate. Except that electricity prices are artificially high because they are based on gas prices. This could change, and must change, if we are to tackle climate change, especially if around 70% of our generation is now low carbon. It is wrong to blame renewable energy on high prices. It is now the cheapest form of electricity.

Why is the path on the left a bit patchy, is something running under it line a sewer?

MGH Where M is mass flow rate kg.m-1.s-1 G is gravitational constant 9.81 m.s-2 H is head height in metres, m So say you want a 2 kW generator. 2000 [W] = M x 9.81 [m.s-2] x 15 [m] 2000 / 9.81 x 15 = 15 kg.s-1 With a 500,000 litre store you can generate for 33,333 seconds, or 9 hours.

I bet if we could be bothered to go back into the history on Buildhub, a decade ago, people where saying that where we are now was impossible. Any new generation from now on will be low carbon, except for maybe some replacement CCGT. I am currently condensing the last decade electrical generation data down to half hourly means, mins and maxes, it takes a while, but will be useful information.

May be better to fit some outside temperature sensors to the exposed walls, then solar gain can be taken into account. The difference between the NE and SW sides of my house is often over 3K depending on time of day.

I was going to go out yesterday afternoon. Did not bother. Not as warm as you yet 05/01/2025 08:35:50,10.125°C

Not great really. I have had an early morning rant about it already.

As usual, when the weather gets chilly, people start to think of getting a wood burning stove and extracting as much energy out of it as possible. Now there are many reasons to not use a WBS which are well documented on here, and it seems to me there is only one reason to have them. But regardless of all that, my concern is that people think they can successfully make their own, or modify existing ones. A bit of physics. When a carbon based fuel is combusted in air, there is a rapid rise in temperature as the carbon atoms in the fuel (usually a molecule of carbon, hydrogen and other trace elements) combine with the oxygen in the air mixture (around 21% oxygen, 78% nitrogen, 1% argon and traces of the rest). This mainly produces carbon dioxide, some water vapour and a lot of nitrogen. Because these gases are at a high temperature, they have a lower density than the surrounding air, so rise up the flue and are expelled to the atmosphere. What really happens. As a combustion process is not 100% efficient, temperature is not even, the fuel is not homogenous (randomly lumpy) and the airflow is turbulent, many other chemical reactions take place. There are three reactions to be wary of. Carbon Monoxide. This is a killer. Now many things produce CO, car exhausts being a major concern. A modern car produces about 5-15 ppmv (parts per million by volume), and WBS 5000 ppmv. The LC50 number (lethal concentration to kill 50%) is 3614ppm. Nitrogen Dioxide has an LC50 of 176, this does not seem particularly high. The problem is that NO2 is a secondary by-product that is created from nitric oxide (NO, aka NOX). This gas has an LC50 of 1739. Then there are the PM10 and PM2.5 particulates. This is a huge problem with about 22% of the total emissions coming from domestic stoves and fires. There is a lot of nonsense spoken about them i.e. the levels where higher in the past (when people frequently died from heart attacks in their 40s) to "I only use properly dried timber" (particulates can form after combustion though chemical reactions), and my favourite "I live in the countryside" (as if there are no pollution problems there). A problem when extracting energy. As a rule, you cannot extract all the energy from combustion, entropy (a fascinating subject) does not allow it. With thermal combustion, and especially with small domestic burners, the incoming air is at a higher density than the outgoing gases (they are not as as we think of it any more). This difference is created by the higher temperature in the grate and is what 'draws the gases up the flue'. Energy is effectively extracted from these gases after the combustion process has taken place (though there is a small radiative effect from the points of combustion). If too much energy is removed, the difference between the incoming air and the outgoing gases temperatures, and therefore density, is reduced. This stalls the airflow though the combustible material, creating more pollutants. This is why the advice is to burn fiercely for a short time. This does not happen in reality though. The initial period of combustion is slow (maybe an hour) and the tail end is slower still (grate is still warm in the morning), maybe several hours. This means that optimum combustion times are very short, and the more energy extracted, the longer the partial combustion periods are. Concluding. There are many DIY stove designs available, then someone comes along and suggests adding a water jacket to heat water, adding mass around the stove increases the efficiency (it does not), then someone else suggests that more energy can be extracted from the 'waste' flue gases ("my exhaust temperature is only 26°C, how good is that"). These are, without proper understanding and design (which generally does not come from a bearded sage on the internet) potentially deadly heating equipment. So if you really must, usually for vanity purposes, fit a WBS, get a properly designed and built one, fitted correctly (even though we all hate legislation), maintained properly (we spend hundreds doing that to our cars, and are thankful that aeroplanes are services), use only small amounts of timber, that is properly dried (not just one end and assume the fire will dry the rest out). I have suggested in the past that WBS could be fitted though the wall, with a sealed window on the inside. You get your focal point but all the shit is kept outside for the rest of us to enjoy. It is a similar idea to fitting out ASHPs, PV modules and Wind Turbines outside

Yes. Just some cheap styrene sheet, a frame made from thin moulded timber and stick on foam draught excluder. As I have wooden window frames I just screwed them in place.

Right, not read everything in detail. Rather than fixate on one components i.e. your windows. Work out all the external areas i.e. walls, windows, doors, roof/ceiling, floor. Get an idea of what the U-Values are and then work out the losses. It does not have to be very accurate, just a good estimate. You will probably find that your roof/ceiling is the largest area, so improving the insulation there with some properly fitted wool will help a lot. 3 winters ago I made some very cheap secondary glazing to cover my old timber framed double glazed units. This is the difference it made.

Well not at 573 K, it would be a steam engine then. But yes, you can store energy effectively in water. The big advantage is that everything is easily purchased. I will say that if energy storage in fluids and solids was effective, we would have been doing it for centuries, burning fossil fuels is relatively recent.

Can you design a system for showers. That is probably the biggest energy usage. A combination of solar thermal, PV and heat pump. Or, get them to build a fire with a large pot over it, just like Baden Powell did in Africa. It can be lit by rubbing Boy Scouts knees together. Image for illustrative purposes only, not to scale.

We gave Canada away after we decimalised and agreed to use the SI system (1982, 1972)

Terms are important. Specific Heat Capacity of Materials, with the 'specific' being mass, as opposed to Heat Capacity which is by volume. Often a subscript is used to denote if it is at constant pressure or volume so cp and cv. So for water c = 4184 J.kg-1.K-1 where J is joule, the SI unit for energy, kg is kilogram and K is temperature. Best to stick with kelvin as multiplication and division may take place. Sand (quartz) is 830 J.kg-1.K-1 Then you have to get the energy into and out of the material, with water this is easy, sand not so easy as the thermal conductivity comes into play. Thermal conductivity has the unit k and is measured in W.m-1.K-1 where W is a watt, which is a joule per second, J.s-1, m is metre and K is kelvin. Sand has a thermal conductivity k = 0.25 W.m-1.K-1. Now you mention 'thermal mass'. There is some debate about this term as it is a bad term. When it comes to storing and releasing energy, the correct term is Thermal Inertia or Thermal effusivity. This has the symbol e and the units are (kpc)0.5 with p being density. This washes out, by dimensional analysis as J⋅m−2⋅K−1⋅s−1/2 where s is time in seconds. Now after over thirty year of thinking about this, I still do not understand the square root of time, but you will notice that there is a m-2 which is area, which makes shape important as this affects the surface area. The surface area is where the energy transfer takes place. This means that there is no general formula for 'thermal mass'. So don't use that term, ever again. To get to the important part, which is for how long can you get energy out of a store, you can rearrange the above to make time, s, the subject. s = (e / J.m-2.K-1)0.5 Now the above is just about the potential energy levels You then have to think about power delivery. Water is easy, you just put it in a pipe, pipe it to where you want and then use gravity and density difference (thermo-syphon) to move the fluid, or pump it. With a sand store, you have to introduce a heat exchanger, the design if which will change depending on temperature and power delivery. This is not unusual in a water based system, but is much harder with a higher temperature store. What fluid will you use at 573 K (300°C), not water. As it will be a pressurised system, safety becomes important. Especially if you are working close to a phase change temperature. Now you may have got this idea from some recent developments where high temperature sand storage is being proposed. These are industrial units, designed by experienced engineers in thermodynamics, materials, safety compliance, etc. They are not small either. Thermal losses are a function of area (A) and temperature difference ΔT. This means that a lot of insulation is needed the higher the temperature and the smaller the store, negating any space saving advantages on a small unit. Finally, and maybe this should have been the opening statement, temperature is not energy. Don't confuse the two.

They sent a new bench, like the old ones, which have lasted well. I don't think they replaced the other 'two hole' ones, would need to check on that.

It does. And during the off season they 'take in laundry' for pin money.

I find doing things without moving parts best. Why I have added more secondary glazing. Door glass and an opening window this time. I have enough plastic sheet left to do one more window. I have 3 windows that are the escape route in case of fire. I do have a door between porch and living room which I will do as well. I am sold on triple glazing now.