SteamyTea

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.

So true. Even passing air though 20mm granite chippings, inside a 100mm pipe in a experiment was hard.

Yes you need a license. You also need a decent mass flow rate. It is the kg of water flowing over the turbine that is important. Then there is a lot of formula about rotational speed. Unless you have a few tonnes an hour passing at 5 m/s, put a solar panel in its place.

Right. Found this page. https://www.waterfilterman.co.uk/121-uv-lamps-water-sterilisation They have, what seems to me, cheap, low powered units. No idea what the technology is. I like old Jeremy Harris's ozone treatment, when he was showing me it, I asked if it could have been smaller, and he said yes. An old customer of mine had a commercial laundry (quite big business down here) and they used ozone and a lower temperature to save energy. Needed a special license/approval, but that was a formality, so nothing special. Meant they could wash at 55°C with water heated from a CO2 heat pump.

Can you change, what I assume is a fluorescent light to an LED one? That may save a few quid a year.

I was only teasing about summarising it in 500 words. Do you ever sleep. Odd you mention pendulums, I have always thought that the simple harmonic motion was not intuitively correct.

Hello We use some different terminology over here, and try very hard to stick to SI units throughout. A couple of decades ago I did my BSc thesis in this very field. While there is some space saving to be made, compared to using water, once insulation, extra floor reinforcing, pumps etc is included, there is no real benefit. Water is cheaper than sand as well (I used granite chippings as it was a forced air design). Which part of Canada are you in, it is a large country.

General consensus is that multifoil insulation is not effective. On the space station it works, not when buried in the ground.

But do you get hiccups when you go from a warm, humid environment to a cold dry one (I know why it happens). I do, as does a workmate (who had a great fit of it today). Just had a look on Nullschool. Air temp is 6.3°C, sea surface temperature is 11.5°C. We should be pumping seawater as a thermal source for water source heat pumps.

We have some shipping containers that we use for storage. Popped outside with a mug of tea for a quick break at about 7AM this morning. It was very cold. There was a very loud bang. I can only assume it was some thermal expansion/contraction from the shipping container. Being a brave and reckless idiot, I went to investigate. Then realised it might be an intruder and I was alone on site. So went back inside the main building and locked the door.

Shit (expletive deleted)ing autocorrect

@Garald I have been pondering your mathematics and how it fits in with structures. I found this, but thought I would let you digest it and write up a in less than 500 words for the rest of us to read in the morning. https://cdn.ima.org.uk/wp/wp-content/uploads/2018/02/MT-2007-Nonlinear-Mathematics-in-Structural-Engineering.pdf This one is interesting as well. It is about teaching. https://peer.asee.org/using-engineering-mathematics-to-learn-structural-analysis.pdf

The original poster has not been back on here to check any answers, they only asked one question, then vanished (back in June) It is kWh for storage (the energy) and kW for the generation (power). A lower case k, for kilo, 1000, not an upper case one, that is for temperature (kelvin, not Kelvin, that is the man it is named after). May seem minor, and a bit anal, but actually quite important to save confusion.

kWh

The ethics of 'life' is such a complicated business. While I am sure that in some circumstances child labour is used, it raises questions. What is a child? There is some basic information here, but I have not checked how accurate it is. https://www.hcamag.com/us/news/general/your-guide-to-minimum-age-requirements-around-the-world/155912 So taking Sri Lanka, children can work at age 10, United Arab Emirates it is 21. Now these are sovereign states, and is it ethical for the UK to interfere. There is also the productivity side. Mining, processing and manufacturing, even in developing countries, is now a high tech business. 12 years olds are not very productive. Why would a company employ them. I know that there are some crook than keep slaves, and others that may pay 'piece work', but it is not very productive. But generally, you employ people that are useful, not ones that get in the way. When considering the environmental damage, should we be comparing it to the best we already have, or what we most frequently use. So taking energy production, natural gas is probably the best we have, and in Europe, probably the most used (certainly is in the UK). So is it really a problem to dispose of a few tonnes of batteries until we have a viable recycling industry (which is already happening) when comparing it to just the atmospheric damage caused by methane leaks and carbon dioxide emissions. Without a lot of data, and very serious statistical modelling, that answer is very hard find. One way to value nature is to ask a series of questions to different groups of people. We did this down here (a holiday area) about access to beaches when the National Trust took over a lot of the car parking areas. Started off asking how often people visited the beach, then asked if the trip was solely to visit the beach or part of another trip. Then we asked how they got there and how far they travelled. Were they willing to pay to park near a beach. After quite a long survey, we asked if people where willing to pay to access a beach, regardless of how they got there. We also asked if they should be compensated, financially, for being denied access (that question was worded carefully and part of a 'scenario'). The conclusions were, if I remember correctly, was that local residence wanted totally free access, and would want to be compensated around £20/trip if denied, holiday makers were willing to pay £12 per visit, and were not bothered about compensation. The actual cost of a visit to the beach was around £8 per person. Though for many locals it was free i.e. a very short walk, and holiday makers it was a long journey. My view is that we have to let the industry develop, accept that there will be some terrible mistakes (Bopal/Union Carbide has been in the news recently.learn from those mistakes, legislate as bets we can, then fine tune all the processes.

How builders read drawings and look for faults.

I have heard they are quite bad around Manchester. We got Prince William to do that for us.

Was showing lower than this when I drove into work. I don't live down here for this sort of thing. Makes this more concerning Last hottest ten years on record have been, the last ten years.

Old people fall for shite as well. People still want to believe that Walt Disney was frozen. Strange that, I failed English 'O 'Level (both of them). But then it was really the third language I learnt after Chinese and Dutch. After that we lived in French and Spanish speaking places, so all got muddled again when I was 10. For a laugh, and it was a real laugh, I learnt British Sign Language about 25 years ago. Now that is a sensible and logical language, and you don't have to write anything.