SteamyTea

Not for long

Thanks for the tip about Googling DP, I may be gone some time

Not much of a turnkey service they offer.

As you say, the direct comparison is not fair. Two way you could compare this is to look at the total energy yield for the given area between technologies. Another way would be to compare the amount of energy you can store from your short rotation coppice and then calculate the area of PV needed to supply the same energy at the same time of year i.e. winter time. So for a giggle, let us assume that that you can harvest between 8 and 18 tonnes of dry mass per hectare (https://en.wikipedia.org/wiki/Short_rotation_coppice) That will be between 0.8 kg/m2 and 1.8 kg/m2. If the usable energy content is 4 kWh/kg, then that is somewhere between 3.2 kWh and 7.2 kWh. I do not know the real energy content of short rotation willow (SRW) in real life, maybe someone else can waste time looking that up. Now a quick look at John O'Groats in PVGIS and using a 250W 1.6 m2 PV module, which is 156 Wp/m2, will give a yield of in kWh/month: Nov 4.46 Dec 2.69 Jan 4.01 Feb 4.86 Total of 18.02 kWh So a lot better than the best that SRW can supply (7.2 kWh).

I don't know, especially as they are not so different. It could be that Newtonian stuff is easy to see, energy stuff is not. Purely as an aside, we have a card machine at work and it accepts contactless payment. Many people do not trust it and will put their card in the slot and punch in the PIN. I have christened contactless payment as "Voodoo", as it is black magic and not to be trusted.

Almost certainly. It is an issue of the disconnect more than the software. Maybe I was not making my self clear at the beginning.

That is the point I am making. Glad we agree on it. There seems to be a lot of people that think because they can make a nice shape in a 3D package it can be translated into reality.

And then the second bit is how to rotate and move it into place, which is where I fall down. And then make one end small than the other. When I did a course in SolidWorks I never seemed to get to grips with the idea of starting with a block of material and then cutting bits away, even though that is how things are made (3D printing aside). Just my experience. It seems to me that there is often a disconnect between the designer/drafter, the engineer and the supplier. If I drew a wall 6 metres long, 2 metres high and 0.15m thick with a tolerance of -0 +0.01m, that is what I would expect to be build, not something to the nearest bricks worth.

I spoke to the customer too, he had resigned himself that he had lost about 50k on the project. I don't want to get into slagging people off, but when I meet for a coffee with a local member of other place for a chat said. "I stick to the laws of thermodynamics, usually sorts it out" There are still people trying to break them (a good thing), but so far they have been very robust (the laws), even as we get a better understanding of the quantum world (which really plays no part in observing everyday life). Maybe we need a 'sticky' (whatever that is) with a brief description of the laws and why they are important. Would save a lot of trouble.

Was that the same idiot that I used to row with, the one that could grow an energy crop in the winter and then drag PV onto the same field to get electricity. The same one that thought David MacKay was a fraud and that grass cutting could power a house. If it was, he was not alone in his thinking, I went to meet a couple of contributors from the other place who thought a few kilos of household waste could power a house. The whole thing was a joke (as the guy who bought a system found out).

I am the same re 3D. I think 3D is really for people that don't understand technical drawings (no criticism intended). I also think that 3D can create a lot of problems between industries/suppliers. There are standards and conventions used in drafting, and these are often not the same as what an industry will use. Take a brick or a bit of timber, they may specify a size, then you get the goods and they are different. This is a serious problem for those that do not know about tolerances and how to use them. That example of the RSJ fitted wrongly is probably a misunderstanding at the drawing level, then the 'builder' has tried to make the best of a bad job.

John You could look here for a course: http://www.passivhaus.org.uk/page.jsp?id=24 Though in reality it is just basic physics and engineering, there is no magic involved. If something, say a bit of timber, goes from a hot area to a cold area, heat will travel from the hotter part to the colder part. So insulating the colder part will reduce those losses. Bit like putting gloves and a hat on when it is cold and windy. There are two reasons to do this, one is to lower energy losses and the other is to reduce the condensation risk at the colder end.

I have the Tarot cards out and the chimpanzee is dealing.

For a light hearted view on the market place. Note what an investment really is. http://www.bbc.co.uk/programmes/b0435p0k

The real problem is that even if the logs/pellets/chippings are at the correct moisture, the stove fitted correctly and used right, they still pollute like hell. I think that message is not getting across.

And when it don't smell, it ain't right either (I am allergic to fish).

Not easily as far as I know. Was the main reason for the MCS system. The only way I know of is to contact a power company and see if they want to buy some, then pay your tax on it.

As far as I know you can export to the grid without a MCS certificate. You need to contact your local Distribution Network Operator (DNO) who should be able to advice on what paper work is needed (every PV, wind/water turbine, diesel generation system is logged with them). You will also need to use certified equipment to automatically disconnect in case of a fault.

One of the things that the report highlighted is that it is not just a problem for neighbours (or from neighbours). Even using an approved stove the pollutants may be staying in your own house. " Press-Kristensen has been measuring that pollution inside homes in Copenhagen. In three out of seven tests done so far, he has found very high levels. In one home with a modern log-burning stove, he found particulate levels several times higher than the highest ever recorded outdoors there (see diagram, above). " And why would people collect timber when the weather is wet and cold. Surely the idea is to get it when the weather is warm and dry and dry/store it until it is needed.

I tend to agree. There are some almost generic abbreviated terms is common use, PV, ST and DHW. But when we get to component level, it gets messy.

At that price, buy two.

Welcome John There are some of us on here that are interested in very low energy usage housing, domestic generation technologies and making things as easy as possible. Sometimes it can get good fun. We try hard to only criticise an idea, not the person, but things sometimes stray, especially if a car get mentioned. So were are you based?

I seem to remember that the Barratt problem was really a site problem. The 'builders' were tearing the vapour barrier and not repairing it. Hard to stop things like that. Down here there is quite a large TF company, the production manager said to me. "we make them to a 3mm tolerance, then the plumbers come along and drill a fxxxing hole though the wall'.

Most of the new builds down here seem to be timber frame, so maybe it is a regional thing. Or the Cornish are just a bit more advanced.