SteamyTea

Rather that think about our current standards and how badly they are inspected and enforced, would we not be better off thinking about ways to create good housing that also meets the current standards as a by-product? Now there is a challenge. I am sure it is not hard to exceed many of the standards at no extra cost. So why don't we start by making a list of what would make a difference? As Jeremy has shown, it is possible to build down to a price without sacrificing quality, even allowing for the mistakes/change of mind/nice to haves (I still think a tap that boils water is a bit silly ). I have stated several times in the past that a house is a pretty simple structure, both structurally and thermally, I still fail to understand why people think that it is really complicated. It is just an airtight, insulated box with ventilation introduced at the design stage, not as an after thought. Challenge 1. I don't bother to read the building regs very often, but when I have, there has never been anything that seems difficult in them. As and example, I seem to remember that when hanging joists they have to be 150mm or half way though the wall build up (can't really remember), but why are we sticking timber though a wall in the first place? What is the reason for not using hangers for every joist to reduce the thermal bridging to virtually zero? Challenge 2. A similar things with MVHR, people seem to try and get away with the smallest system they can, may be easier and simpler to just oversize i.e. larger ducts, bigger heat exchanger/fan unit. Shopping around will often find a suitable unit for a similar price. I also think that a simple self calibrating controller could be made, we know the rules, we know how to measure airflow and control fans/flaps, so a simple feedback system is all that is needed. Challenge 3. Doors and Windows also seem to be an issue with people. It is a simple calculation to work out if double or triple glazing will make much of an impact, just do the calculations. But probably the most important point is the fitting. This is where detail is important and needs thinking about before the wall is built, not after. And why are the windows on my 1987 house not electrically operated, they were on my car. It cannot be hard to design this into a house. Challenge 4. Why not have MVHR built into the lower part of a door, I am sure there is enough room and it is easy to make them a little thicker and it would stop all that faffing about in the loft. Challenge 5. Heating and hot water systems seem to be a very popular area for confusion, why? All you need to do is heat some air, either directly or indirectly. This is not hard. To me, under floor heating is the best system, and the pipework seems a lot simpler, just a few loops back to a couple of manifolds with valves on them. George Wingrave, Carl Hentschel, Jerome K Jerome, to mention nothing about the dog Montmorency, may have got lost in Hampton Court Maze, and most plumbers seem to get lost with others pipework, so it is just a case of keeping it simple (and unpressurised if you want to DIY it). Design a simple system. Challenge 6 Wiring, again this is pretty simple. Radial systems with a large consumer unit. OK it uses a bit more wire and RCBO's, but is really simple to understand, kind of thing that we learn at Primary School in the 1960's (along with binary and matrix mathematics for some reason, I can still remember the classes). We have very clear and simple rules to follow with electrical work, I fail to see why people make it harder than it is. Rather than fret over whether a 32amp breaker can run your kitchen, spend the extra few quid and put in another circuit. Same with lighting, people really do go over the top with this, often spend thousands and not get what they expected. Half the time you should not need lighting on. Design a simple system, forget about 'mood lighting' your mood will change, as will your eyesight. Answers by 10PM tonight.

I think we should keep this to thermal properties and not my eyesight. There are 1200 words there if anyone wants to edit it.

Yes right, never thought of that, it is at the lowest setting.

Why have I got a trike though in the last bit. I can't get rid of it either. Seem to have sorted that using Word. I may have to edit the above later when I can see again.

I was pondering this yesterday (actually be thinking about it for a decade). The really hard thing to understand about thermodynamics is fivefold. You have power, energy, mass, temperature and distance. So 5 dimensions, and we are not very good at thinking in 5D, most if us struggle with 3D and we live in that universe, stick on a 4th (time) and our brains start to seize up. So back to basics. 2D Imaging an insulating material that allows no energy to be transferred and has no dimensions. You can pump in as much energy, as fast as you like, into one side of it, and there is no change the other side of it. Quite easy to imagine this (even though it is totally impossible, but then I like 6 impossible things before breakfast). Now imagine a dimensionless material that has the ability to absorb no energy at all so no changing temperature, so you can pop this into the sun and nothing changes (my second impossible thing). Now put the two imaginary materials together, so you have new material that neither transfers or changes at all, no matter that you do to it. What will happen? Well nothing, it will just sit there. We could give it some other dimensions i.e. length, width, height, mass, and still nothing would happen because any energy absorbed, will instantly be transferred though the material and come out the other side. So let us change the material a little bit. We add something that slows down this process, so in effect we change it from a perfect conductor to a less perfect conductor, so now it has a real thermal conductance. This changes the way we calculate it, rather than thinking of energy passing though instantaneously, we now have to think of power. Power is energy per unit time (time is just another dimension). But as our material still absorbs all energy without changing at all i.e. no temperature rise or change in shape, we now have something that can suck in everything, just a bit slower, in effect it stretches time, which affects power (my third impossible thing of the morning). So we are still no closer to really understanding normal material thermodynamics, so we shall change the material slight to allow it to not just absorb energy unchanged, but to heat up a bit. We know this as heat capacity. So for any level of energy we pump in, we get a temperature increase, we usually measure his in one of two ways, by volume or by mass. But at the moment, out material does not have either of those properties, it is still imaginary remember. But no matter, we can still observe what will happen if we increase the energy level now that it has the real properties of conductance and absorption, basically it will take a bit of time to warm up. This is now in the real world and something we observe all the time. The difference between say a kettle warming up and out imaginary material is now only the dimensions of distance and mass. So let us think about distance for a moment, while remembering that we are still working in 2D only. Keeping the intrinsic thermal properties of the material the same, we will give it length only to start with, another impossible thing, my forth. What will happen is that if we add a packet of energy at one end of the material, it will slowly, or quickly, travel to the other end. The thermal conductance sets how long this will take for any given length (W.m-1, as W is energy [J] per unit time ). So shorten the length, it gets to the end faster, lengthen it, it takes longer. That is easy to understand, so not an impossible thing at all. At the same time our material is absorbing some of the energy at increasing in temperature (J.K-1). This is known as the conservation of energy, there is the same amount of energy, it has just changed form (to thermal, I never specified what form it was in at the start). So for every increment along the length, there is less energy to move, so the next bit of the material warms up less. So now we have two ways of describing our material, the conductance and the absorption and you can see that they are linked by 2 dimensions, power and length (W.m-1.). So hopefully you can see that, at this point in this essay, mass makes no difference. So now let us add this mythical material property, mass. Mass is an easy way to describe something on Earth. We don't talk about how many grains of sand we want, or how many atoms are in a person, but we could. So mass is really just an easy method of describing one property of a material. In some ways it would be much easier to think of relative density to a hydrogen atom (or silicon). Oddly mass is the one SI unit that is not defined yet (and is odd because we use the kilogram rather than the gram). Now the real trouble starts as materials, even our imaginary material, do not have consistent thermal properties. Take a kilogram of water at 4°C and it has different thermal properties to a kilogram of iron at 4°C. The water will absorb more energy for the same temperature increase. This is all do do with the internal structure of pure materials and makes it impossible to just use mass alone as an indicator of all thermal properties (the fifth impossible thing, though not one of mine). So you can see why we dislike using mass as a descriptor for thermal properties and how it affects the temperature within a building. To describe what is going on we need to use two equations, thermal conductivity [W.m-1.K-1] and heat capacity [either specific J.kg-1.K-1, or volumetric J.m-3.K-1]. Now it is possible to combine these two for any given material, within a fixed temperature range, by just multiplying them together. It is also much easier to do this using volumetric heat capacity as no density conversion is needed, but either can be used. I = W.m-1.K-1. J.m-3.K-1. This needs a bit of jiggling about to get to something that is understandable to end up with I = J.s-1.m-1.K-1.J.m-3.K-1 which looks like an impossible formula (almost my 6th of the morning), but is really similar to acceleration and can be thought of in the same way. But may be easier to rearrange it to: I = J.m-2.K-1.s-1/2 So you can see that rather than think of mass being the overriding factor, it does not even feature in a formula that fully describe the thermal properties of buildings. Now that really is my 6th impossible thing before breakfast. (I do have a 7th impossible thing, get the effing forum colours sorted out, it has taken me an hour to type up and I have a migraine now, all it needs is a pale grey or pale blue background where you type, that cannot be hard to sort out).

I shall try. What I think would happen is that the HP would run for longer, using more energy. I tend to think of a HP working with 'packets' of energy. So imagine you have a large box of cool air, you squeeze it down, thus making it smaller, but hotter. We have a simple formula for this PV/T = C. So now imagine that you are about to squeeze the box even smaller, you will need more power to do that (but you don't have a bigger motor), and it will take longer, bit like sitting on a packed suitcase to close it. C stays the same (think of this constant as your CoP, so Cn, where n=0 to infinity). So yes, you can make your own 2 stage pump, but you will gain nothing (you will actually loose to general thermal losses).

A lot of it depends on the nature of your business and the organisational skills of the office manager/administrator. And the motivation of the staff. I used to just use lists of what needed doing and trusted my staff to do what was needed in the easiest manner for them.

I think it would kill the heat transfer. When water 'falls' down a vertical pipe, it actually swirls around the inside of the pipe wall. Put that same pipe horizontally and you create a D shape (twiddled over 90°), this has a much greater volume to area ratio. That will ruin the heat transfer. When we discussed this a few years back, I took a different route from Jeremy and looked at transferring heat in a batch method. Basically the waste goes into a holding tank, then via a heat exchanger into the cold water storage. It worked, but was slow, needs space and was not cost effective at all. This idea could be modified with a W2WHP, but then getting even more costly. Main thing is to do the sums first. A normal shower should not need more that about 50 kg of water at 38°C max. Incoming mains in winter is probably very rarely below 8°C. So: 50 [kg] x (38 - 8)[°C] x 4.2 [kJ.kg-1.K-1] = 6300 kJ or about 1.7 kWh That is about 32p at my expensive day rate, 14p at my night rate. Now a 250lt tank to service 4 people with hot showers is right at the limit of its capability, so probably storing at 65°C (or maybe a bit more), but the mean temperature will probably be nearer 55°C, so that is 49350 kJ or 14 kWh. This will probably give you standing losses of around 4 kWh/day so you have 10 kWh of usable energy in the hot water (losses between 32p - 72p.day-1 or £117 to £265.year-1). So look at insulating the store more and reducing the temperature a bit. A couple of sheets of Celeotex type material will cost 50 quid. Turning down the temperature costs nothing. Another method is to get an aerating shower head, had one when I lived in the USA (it also pulsed and did wonderful things on other settings). it worked well, but the flow was still very high. I would like to try one out on my lower (11 kg.min-1) flow shower here. Another alternative is to bite the bullet and get instantaneous water heating (maybe in series with a Sunamp/PV). If that costs £7000 to install, and you can save close to £300 a year, then 'only' 23 years till you hit break even. Easier to use less.

Maybe a quick diagram would help.

Me too, have never worked out the sentimental attachment to pets. Why can't we have a referendum to ban all pets. Would get my vote.

If we all worked 4 days a week only, we would all be better off, and reduce transport costs by about 20%. When I introduced 4 day weeks at my factory 25 years ago there was great resistance to it, even though the 'lads' had to work for 1.5 hours a week less for the same money. Productivity shot up, factory costs went down and eventually people became happier.

Not looked at anyone else's answers, but have seen this before. Change the + to * and add one to the second number. so 8+11 = 8*(11+1) = 8*12 = 96

We used to install SMA's and Fronius, both are good and you can get the data off either. Unless you have shading problems, I cannot see any advantage of micro-inverters.

If you are not too bothered by the accuracy, you could use current clamps and an appropriate reader/logger. The ones I use allow 9 clamps to be wirelessly connected. It will give you a good enough idea about what is happening.

I think this is the wrong way around (and I think I may have posted it originally too) Square meter is shape dependant, e.g. a rectangle of 1 m length by 1 m width. A metre square is not shape dependant, e.g. the surface area of the Cornwall (as it is a really odd shape) 3.563824e+9m²

This highlights the difference between Power and Energy. If you draw power that is greater than the wind turbine is producing, then it tops up from the grid (an import), regardless of how much energy the turbine produces over a year. You also need a high windspeed to get close to the maximum generation capacity of a turbine. You may well find that the load factor is quite low.

Do they now

Is that why we have the most expensive water and sewage costs in the country, they need to buy a lot of sunglasses!

This highlights the problem of subsidies. I have often thought it is wrong to pay people to add extra load on the grid, but I suspect that it goes back to the old 'nationalised' National Grid. It was considered a market failure, so the cost was covered by the state. Since privatisation this has changed and it is very easy to charge to generation companies for the service as there are not too many of them. The administration costs of charging 1 million plus private generators is a different matter. I think I currently pay £0.18/day for my meter rental, so that is about £65/year. If I am also paying £140/year to the National Grid, that is a total of £205/year. This is equivalent to about 1,367 kWh/year, or about a third of my usage. I could buy 200 lt of diesel (2,000 kWh/year) and generate my own electricity and thermal energy (circa 1,200 kWh/year), so getting close to parity before capital expenditure and maintenance to go off grid. But a lot of faff to do so.

"Friends from all over the world, non from this country"

When your PV system was installed, a design drawing of the system should have been sent to the DNO. It would show location of modules, inverter, isolators, meter... as well as the type approval. I have no idea what they do with this info but I do know, that if it is not correct, the system needs to be shut down and rectified. So adding 'something else in' still needs notification. I see it as akin to driving with a bald tyre. Most of the time it is fine, but you can get pulled up for it (administrative) or have an accident (safety).

It is sending out the wrong message though. The consequences if something goes wrong, either administratively, or safety, would be tiring at best, prison at worse. Have a word with the DNO and see what they say.

Called a weighing scale on WeightWatcher day isn't it

Can send it to me too and if I get time, I will show you some different results

Put in 3 or 5 sensors in a diagonal line from the brightest corner to the darkest corner. That way you can get a gradient across the slab and eventually just use the one that gives you the closes match to what you need to control. Make sure you know where they are, so if you place any furniture or extra runs over them, you know. If you have MVHR, put the air temp sensors in the room outlet, will almost certainly give a better result, except above a cooker.