SteamyTea

Not always. It is hard to calculate as it is marginal generation that counts. So if you swap your FF energy supply to a finite RE supply, the difference is made up by either someone else swapping to FF or extra marginal FF generation. In reality, as we are heading to a low CO2 generation system, electrification is the best way forward, as well as energy reduction.

What sort of drill bit are you using, and are you using the hammer attachment on the drill?

Why they have such good weather.

Not really the UFH that is expensive to run, it work just like a radiator. It is really down to two things, the thermal losses to the ground/building periphery and what temperature it is run at. Covering an UFH system with underlay and thick carpet, could cripple a system quite quickly, it would be like replacing a window with a radiator, then shutting the curtains. I am not sure, but maybe your local Building Control has some details, they almost certainly signed off the development, though it could be a private company.

Start butting some numbers on the design. Store volumes, mass flow rates, temperatures and then calculate the energy levels. Lower storage temperature just mean lower potential energy, not less energy per se.

Have to question why steel houses are not made. https://en.wikipedia.org/wiki/BISF_house

It is used as a filler with some paints and resins. Comes in a large bag and goes everywhere as soon as you open it up.

The trouble is that this is heading into 'off grid' thinking. When off grid it has to be accepted that there are times when there is just not enough stored energy, so compromises have to be done. It really does not matter what sort of storage is used, if it is empty, it is empty. One problem with water storage is that there is a minimum temperature, below which, say 30°C, it is just an efficiency loss. Chemical batteries suffer less from this, but you have had efficiency losses during charging and discharging, so may all even out. That would require a lot of real data. What may be possible, with a bit hardware and plumbing, is to preheat the air entering the ASHP, from excess stored energy. A truck radiator and fan, placed in front of the ASHP intake, fed from a thermal store that is heated when there is excess solar, would warm the intake air. It would also reduce the inefficiency of the storage by allowing the store temperature to go as low as ambient. A bit madcap maybe, but the science is sound.

Good man. Once set up I find making repeat items quite relaxing.

Vacuum is best. In reality, when you look at the numbers, there is not much in the normal range of insulation and other losses will soon dominate. Material Thermal conductivity [W·m−1·K−1] Notes Silica aerogel 0.02 Polyurethane foam 0.03 Expanded polystyrene 0.033–0.046 Fiberglass or foam-glass 0.045

Welcome Janner. Quite a few people on here are near you.

Having followed this a bit, but not really understood it, I think I am now getting to see the problem. Does the wall face the prevailing wind? Causing rain to get blown under the membrane.

I have a 'Nigel in the Arches' feeling. (The 'pips' are 100 years old at 9PM today)

I have just noticed that I made an error in working out the volume of the water cylinder, this changes the heat capacity to 0.701, which is over double the 0.301 I originally posted. So that line is now. Properties Water Cylinder (Kingspan 250 lt AU12250ERP) Sunamp (Thermino 210e) Storage Heater (Creda TSR12) kWh/m3.K 0.701 8.736 3.940 Still looks pretty poor in comparison but that cylinder has the expansion chamber built it, so it bigger than it needs to be to hold 250 litres of water. If it was just the water, then the volume would be 0.35 m3 rather than the 0.41 m3 that it works out as with the expansion vessel and insulation. Floor loading becomes 12.6 kN/m2 as well.

Yes, why it is a big K for kelvin. No. Specific means by mass, kg, small k as it is 1000. Every material will have a different specific heat capacity and it is not based on material type i.e. gas, liquid, solid, density shape, metallic, non metallic, natural or man made, pure or alloy etc, and just to make it worse, most materials will vary the SHC with temperature and what phase they are in i.e. gas to liquid. This is also known as sensible heat. Wedged in between phases, the place where the state changes, but the temperature remains the same, will also have a different heat specific heat capacity, this one is called latent heat. Basically yes, when half the energy has gone, there is only half of the original to loose. This is where shape comes in, and is why surface area is important. The larger the surface area, the faster the energy can be lost, why we have large surface area radiators with low temperature systems. What is really happening is that it is giving up its sensible heat, specific heat is basically fixed. Heat is only the old word for energy and has nothing to do with temperature. This often causes confusion, just remember, if you see the word heat, replace it with the word energy, and see if it makes sense, if it does not, then replace it with temperature. I tend to think in terms of energy and power for most thermodynamic 'things'. All that means is how much of something do I have to play with, and how fast, or slow, can I get rid of it. Bit like budgeting at the end of the month when you know you have a bill or two to pay.

This is quite difficult, but only because it is laborious. I made a matrix of some common properties of a water cylinder, a Sunamp and a storage heater, all with a similar nameplate thermal capacity. I converted the values into rated capacity in kWh, cubic metres, litres/minute flowrates, input power, dimensions, volumes, mass, standing losses (though not relevant for a storage heater), kWh/m3.K and kWh/kg.K, floor loading and recharge times. Then it is just a matter of picking from the lists the properties that best suit the installation i.e. floor area, height etc. I have not put any prices in as they are way to variable and very specific to the installation i.e. pipe runs, cabling, floor reinforcement. A quick not on a storage heater. These work by loosing heat at a controlled rate, which is why the numbers look a bit strange. I made an assumption that there are no losses during the recharge period (even though this is not true in practice, but more closely matched the way water storage is measured), then worked out an equivalent amount of water storage (the Equivalent Storage /lt row), which was divided by 17 hours discharge time, then converted to litres per minute. This is not really a fair comparison and only really relevant for water delivery. Another way to look at it is to divide the storage capacity by 17 hours (the usage period) and get a kW delivery (they are all pretty similar). The biggest problem is know what temperature difference to use, so I picked 35K for water storage (maxing out at 65°C), 5K for the Sunamp (delivery is 40° after all) and 45K for the storage heater (the bricks get very hot). These numbers are very much open to debate and are really, in this instance, something to work to. They can be adjusted. Properties Water Cylinder (Kingspan 250 lt AU12250ERP) Sunamp (Thermino 210e) Storage Heater (Creda TSR12) Input kW 6 2.8 1.7 Height m 1.744 0.87 0.705 Diameter/Width m 0.55 0.365 0.56 Depth m 0.757 0.17 Mass kg 305 178 77 Equivalent Capacity lt 250 210 208 Standing Losses W 84 32 N/A Flow Rate lt/min 12.5 20 0.01 Rated Capacity 10.2 10.5 11.9 Power kW 0.60 0.62 0.70 Volume m3 0.91 0.24 0.07 kWh/m3.K 0.317 8.736 3.940 kWh/kg.K 0.001 0.003 0.001 Floor Loading kN/m2 5.7 6.3 7.9 Recharge Times /h 1.7 3.8 7.0 A kettle is a good thing to play with. You can easily check the input power, it is written on the base, easy to put different amount of water in, what a Pyrex jug is for, the starting and ending temperatures will be the same (run the cold tap for a few seconds first) and then time the time to boiling. If you want to get a much better feel for what heat capacity is, every 10 minutes after boiling take some water temperature readings, then plot them. It won't be a straight line. Will be, roughly, 3 times longer for every 10K temperature drop. Actually

And plenty of polyurethane adhesive.

May be worth having a look around here: https://www.structuralbasics.com/ https://www.structuralbasics.com/timber-column-design/ There is a reason that beams and columns have different names.

Most hydrogen would be run though fuel cells.

Generally, apart from coal powered generation, the efficiency gains more than offset the emissions. But we really need to stop combustion technologies.

When I get around to making my new shed, this is how I intend to do it. For a house some analysis of buckling will have to be done. Adhesive bonding.

Your dead right, I was eating a kebab while watching the sun set. Timber has a lower density, so larger volume for the same mass. Does highlight why it is not a good idea to mix units, until the very end.

Well this is the problem if using one, undefined, word to describe complicated physics. The right questions have to be asked. Depends on the chemistry, but water vapour has a global warming potential (GWP) of between 0.001 and 0.0005, CO2 is 1 (it varies a bit depending on the timescale monitored). Methane is 82. So On just the GWP metric. Hydrogen quickly reacts with other atmospheric elements that caused it to have a GWP of 5.8 (over 100 years). Hydrogen, while better than methane/room temperature liquid fuels, is not problem free even if we got it at no cost. Like most combustion technologies, it is rather 'last century' and globally not needed. This does not mean that all renewable technology is 'good', large scale hydro is horrendously damaging at the local scale, but it is still much better than nuclear and combustion. The main thing is we have to electrify quickly as we can take advantage of the improved efficiency and vastly reduced emissions.

It gives you the information to compare with other storage systems. This comes down to context. I tend to use SHC as I can think better in mass than volume, all mass is equal. Heat capacity depends on material density, so varies, a m3 of timber is physically larger than the same volume of stone. Sometimes you just have to pick the most appropriate unit.

Heating and cooling seem to be fundamentally different, not opposites Conventional thermodynamics says that heating and cooling are essentially mirror images of each other, but an experiment with a tiny silica sphere suggests otherwise By Alex Wilkins 29 January 2024 Conventional thermodynamics explains why hot tea gets cold – but those laws don’t tell the full story In Green/Shutterstock Heating something up will always be quicker than cooling it down on a microscopic scale, according to a proposed new principle of thermodynamics. The two processes, long thought of as two sides of the same coin by physicists, seem actually to be fundamentally different. While most people have an intuitive understanding of what temperature is, physicists have argued over a precise definition for centuries. A school textbook might say it is a measure of how much atoms jiggle around in a system. But thermodynamics, the study of the relationship between heat and other forms of energy, describes temperature as a measure of how many different arrangements of values, such as speed or energy, all the atoms in a system can have. These arrangements are called microstates. Based on this understanding, conventional thermodynamics says that heating and cooling are essentially mirror images of each other. However, this theory assumes that temperature changes happen either slowly or over small increments. When systems heat up or cool down over very large intervals, the physics is less well understood – and the outcomes can be counterintuitive. For example, hot water freezes faster than cold water, a phenomenon called the Mpemba effect. Now, Aljaz Godec at the Max Planck Institute for Multidisciplinary Sciences in Göttingen, Germany, and his colleagues have found that a microscopic sphere of silica that is rapidly heated or cooled by an electric field appears to do so in a lopsided way, heating up faster than it cools. “This is very surprising,” says Godec. “So far, we know that this is true because we have shown it, but I don’t think we can claim that we understand why this is the case.” Godec and his team placed the tiny sphere in water and trapped it in place using a laser. They then applied an electric field to heat or cool it and measured how much the particle jiggled and moved. They repeated this process tens of thousands of times. Measuring a single particle in this way is equivalent to measuring a single microstate. This is impossible to do for a material consisting of many particles because of the vast number of possible configurations they can take. But by making many measurements for a single microscopic particle, the team was able to map out the possible number of microstates it can take. The researchers then measured how many different microstates the particle would have to go through when transitioning between two temperatures by heating or cooling. They found it had to travel through fewer possible microstates when heating up as opposed to when cooling down, which translated to a faster heating speed. While it isn’t clear why there should be this fundamental difference, it should be present in any system that heats or cools by a sufficiently large amount, says Godec, though it would usually be difficult to see. This is because such large temperature changes normally induce phenomena in the system itself, such as freezing or boiling, that obscure this newly observed effect. Despite this, the asymmetry could be important for improving the efficiency of microscopic systems such as tiny heat engines or motors, he says. “It’s really interesting work,” says Janet Anders at the University of Exeter, UK. “It’s really important to think about what this could explain in nature.”The effect that Godec and his team have discovered could almost be considered an extra law of thermodynamics, says Anders. It expands upon the second law of thermodynamics, which says that hot things always cool unless you do something to stop them. “The second law doesn’t say anything about speed; it says something about possibility,” she says. “This second-and-a-half law, as I’m calling it, says you can do all these things, but some of them will take a lot longer than the inverse.” Journal reference: Nature Physics DOI: 10.1038/s41567-023-02269-z Toxic mud from aluminium production can be used to make greener steel Producing steel generates huge amounts of CO2 emissions. These could be reduced with a technique that repurposes the hazardous red mud generated when refining aluminium By Andrew Rosenblum 24 January 2024 Aluminium refinement produces a hazardous red sludge Ajdin Kamber/Shutterstock The huge reservoirs of hazardous red mud that are produced as part of refining aluminium could be used to make greener steel. There are roughly 4 billion tonnes of red mud stored around the world, which is an environmental hazard that can lead to deadly accidents. And producing a tonne of steel generates nearly 2 tonnes of CO2 – that is because most steel production involves burning fossil fuels to react carbon with the oxygen in iron ore, yielding iron but also carbon dioxide. Read more A hydrogen fuel revolution is coming – here's why we might not want it Isnaldi Souza Filho at the Max Planck Institute for Iron Research in Germany and his colleagues have come up with a way to tackle both problems. They have devised a method to extract iron from red mud by exposing it to a plasma of hydrogen and argon, and then using this iron to produce steel. Key to the process is that red mud contains between 30 and 60 per cent iron oxide by weight, alongside hazardous elements such as arsenic and lead. The researchers heated up red mud in a device called an electric arc furnace to a temperature of roughly 1850°C (3362°F), with a blend of argon and hydrogen to react with the oxygen. The resulting melt was then cooled, crushed and separated into iron pellets ready to be turned into steel. Co-author Matic Jovičević-Klug, also at the Max Planck Institute for Iron Research, says that given the amount of red mud there is, the process could produce between 748 million and 942 million tonnes of steel, which would result in over a billion tonnes less of CO2 compared with conventional methods. However, this scale would still only be a fraction of the steel produced globally each year. Using green hydrogen as part of the refining process is not a new idea, says Mark Jacobson at Stanford University in California. In 2021, a Swedish consortium called HYBRIT demonstrated a trial run that lowered the carbon footprint of steelmaking by up to 98 per cent. What is new is using the hazardous red mud as a feedstock, he says. “Whether it is less expensive than the first process is difficult to tell,” says Jacobson. “The authors claim it is inexpensive, but more information is needed to determine this.” Journal reference: Nature DOI: 10.1038/s41586-023-06901-z Toxic mud from aluminium production can be used to make greener steel Producing steel generates huge amounts of CO2 emissions. These could be reduced with a technique that repurposes the hazardous red mud generated when refining aluminium By Andrew Rosenblum 24 January 2024 Aluminium refinement produces a hazardous red sludge Ajdin Kamber/Shutterstock The huge reservoirs of hazardous red mud that are produced as part of refining aluminium could be used to make greener steel. There are roughly 4 billion tonnes of red mud stored around the world, which is an environmental hazard that can lead to deadly accidents. And producing a tonne of steel generates nearly 2 tonnes of CO2 – that is because most steel production involves burning fossil fuels to react carbon with the oxygen in iron ore, yielding iron but also carbon dioxide. Isnaldi Souza Filho at the Max Planck Institute for Iron Research in Germany and his colleagues have come up with a way to tackle both problems. They have devised a method to extract iron from red mud by exposing it to a plasma of hydrogen and argon, and then using this iron to produce steel. Key to the process is that red mud contains between 30 and 60 per cent iron oxide by weight, alongside hazardous elements such as arsenic and lead. The researchers heated up red mud in a device called an electric arc furnace to a temperature of roughly 1850°C (3362°F), with a blend of argon and hydrogen to react with the oxygen. The resulting melt was then cooled, crushed and separated into iron pellets ready to be turned into steel. Co-author Matic Jovičević-Klug, also at the Max Planck Institute for Iron Research, says that given the amount of red mud there is, the process could produce between 748 million and 942 million tonnes of steel, which would result in over a billion tonnes less of CO2 compared with conventional methods. However, this scale would still only be a fraction of the steel produced globally each year. Using green hydrogen as part of the refining process is not a new idea, says Mark Jacobson at Stanford University in California. In 2021, a Swedish consortium called HYBRIT demonstrated a trial run that lowered the carbon footprint of steelmaking by up to 98 per cent. What is new is using the hazardous red mud as a feedstock, he says. “Whether it is less expensive than the first process is difficult to tell,” says Jacobson. “The authors claim it is inexpensive, but more information is needed to determine this.” Journal reference: Nature DOI: 10.1038/s41586-023-06901-z