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SteamyTea last won the day on December 18 2017

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About SteamyTea

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  1. I feel am I am not privy to this running joke
  2. Solar PV - are they worth fitting?

    Get intouch with the MCS and see what it costs to be registered. Only a phone call away.
  3. Solar PV - are they worth fitting?

    Those DIY kits are probably not available all the time though as they will be bankrupt stock. The only way to find out for sure is to call the people up and ask what the price is delivered to your door. I will admit that the price of PV from the government data was higher than I thought We were selling installations at that price 5 years ago (probably because the company did not pay suppliers, staff, failed to correct faults, was run by an idiot...). When I was involved with PV, the largest single, non hardware, expense was the sales commission, often about £800. I doubt if anyone gets that sort of cash these days. I never remember the MCS costs being an issue. The fact that I cannot remember what they are means they were never an issue. No one ever mentioned that we can sell at a premium because we had MCS, probably because everyone had MCS. It was possible to win or lose a sale on a fiver back then (just as the rate changed from 41 to 22p). The company of thieves I worked for (I left for ethical reasons) would usually 'throw in' an extended inverter warrantee and some data logging, but never actually deliver it.
  4. Solar PV - are they worth fitting?

    I am not sure that the MCS premium is anything like £2000. If the installer can get modules at 50p/W, then that is a couple of grand for a 4 kWp system. 2 guys to install going to be £200, electrician about the same, so £400 Rail and fittings probably about £300 Inverter about £1000 Scaffold maybe £300 if easy, £700 if hard, let us say another £400 Office costs around £200. So we are up to £4300 There may be some sales commission that needs to be added on and I have not added any profit for the company yet. But let us say that the cost of install a system is around £5000 to £5500. There is not going to be another £2000 added to that, the market would not stand it (actually it might once I saw some data). I suspect that companies that are installing PV these days are just paying the MCS registration charge out of normal profit and not charging a premium. I seem to remember that the fee was not that high (a few hundred quid). If that is the case, short of fitting yourself by ignoring most normal rules for health and safety, or you already have everything in place because it is a new build, I don't think that it is worth not getting an MCS system and claiming FiTs. I think it is way too easy to find 4 kWp of modules on eBay for a very low price and assume that a registered installer is paying no more. The very cheap modules are probably from a bankrupt company, so they distort the market. I found these at 40p/W But that would only reduce my fag packet estimate by £500. A quick look at the government data (I like data, takes the guess work out) Show that in 2016/2017 the mean price was £1866/kW installed for up to 4 kW2 systems. So around £7500. There is quite a variation £1749 if installed in January, £1977 if installed in April. Choose your installation date carefully. There is less of a variation between the upper and the lower prices, around £36/kWp on average, but goes to £41 in December, January and February. Now those prices are not from all the MCS installation and are just prices reported. Most, I suspect, will be retrofits, so more expensive, and a lot will be sold to greedy people that want to convert low returns on cash savings to a slightly better return (spending an extra £7500 on a hybrid car would give a better return). So while the prices are probably near enough right, they are not representative for people like us that take a detailed interest.
  5. Solar PV - are they worth fitting?

    They are pretty relaxed about it. They eventually take you to court for theft. They don't often lose. So how would you feel about it?
  6. Yet another Heating + DHW design!

    Not sure what that really is. watts (W) is power day (24 hour) is time So do you mean 2100 [W] x 24 [h] = 50.4 kWh/day
  7. Solar PV - are they worth fitting?

    Does depend what you mean by an immersion. Assuming that you mean a traditional hot water cylinder, then you can think of it as just a large kettle. You put cold water in, heat it up with a 3 kW element at the bottom (or midpoint/top depending on design), once the water is hot enough, you use it. Then it gets refilled with cold water (does this without you knowing as it is just replacing the hot water that you need) and either automatically turns the heating element on, or waits until the timer says it is time to switch on and heats the water if it needs it (think Economy 7 after midnight). There are generally two ways to 'manage' domestic hot water (DHW) in a cylinder. One it to use the water that is actually in the cylinder, the other is to have a heat exchanger that separates the cold mains water that you want to heat up from a volume of static stored water in the cylinder. The heat exchanger does not have to be very fancy, often just a coil of pipe within the cylinder. The Sunamp is basically a box of 'heat' that cold water is passed though to get warmed up via a heat exchanger. The difference between a normal cylinder is that the substance holding the heat (heat is the old word for energy) is not water but a phase change material (PCM). PCMs are sometimes a little hard to understand, but the easy one is water changing from solid ice to liquid water at 0°C. So imaging that you have some ice at exactly 0°C, as it changes into liquid water, the temperature stays at exactly 0°C. As it changes state (called phase in grown up science) it releases energy. We call this melting (or latent heat of fusion for lab coat wearing grown ups). The energy released can be transferred, via a heat exchanger, to 'something else', usually the air around the ice. The really odd thing is that a disproportionate amount of energy is released as materials change state. So imaging that solid ice can store 2.1 kJ/kg.K (J, joule, is the unit of energy) and liquid water can store 4.2 kJ/kg.K of energy you may think that as it fuses it would be somewhere between the 2, well it isn't. It is 334 kJ/kg, or about 100 times the difference (note that there is no K (kelvin) as the temperature stays the same at 0) The Sunamp does a similar trick but at a higher temperature, about the temperature you want your hot water at (that was lucky or it would be useless). So, when you want some hot water, though some sciency magic and trickery, the material in the Sunamp changes state and releases energy though the heat exchanger, warming up the water. If you want to know exact details, ask Sunamp or a Physicist, or at a push a Chemist (not Boots or Lloyds). This allows the Sunamp to store a relatively high amount of energy is a small box. There are some other odd things that happen with PCMs, one is the ability to store a lot of energy at a low temperature i.e. room temperature, but still release the energy at a higher temperature when needed. This reduces the need to have lots of insulation around the store. To give you an idea of how high thermal losses can be with a traditional hot water cylinder, I was loosing more energy from mine than I actually needed to bathe every day (reduced it with extra insulation, so not insurmountable). Some things just need lots of insulation, a DHW cylinder is one of them. A Sunamp is not much good in an airing cupboard as it looses little thermal energy to the air around it. So pros and cons. A normal water cylinder is well understood by most people, is simple (if electrically heated) and relatively cheap to install. The downside is that they are large, can be noisy (if you have a bad installation), heavy when full of water and can have very high thermal losses. A Sunamp is much smaller and lighter and has much lower losses. It is more complicated as there is a pump and control systems, and can seem, in isolation, more expensive, but that is down to installation and location to a certain extent. I do not have any connection with Sunamp, but have seen @JSHarris installation and was quite impressed with the unit (apart from the old bleed valve position which I think is now improved). There is probably a lot more to discus about the two different technologies, and I may not have got everything correct, or may have got muddles. But basically they are both ways to make cold water into hot water, which is very basic technology and engineering, so don't fret too much when comparing systems/installations.
  8. Wireless broadband pricing

    JFGI, all the info is there, but will take some time. You may find that your main router has something to show data usage, my old TalkTalk one did. Try logging in with and the supplied password
  9. Wireless broadband pricing

    You can check what your PC is using easily enough. Settings-->Network & Internet-->Data Usage
  10. Solar PV - are they worth fitting?

    It is kWp really
  11. Solar PV - are they worth fitting?

    I might be wrong as I do not know the finer details, so that was just generic advice really. The main thing to always remember are the laws of thermodynamics, no one ha managed to break them yet.
  12. Adhesive for EPS

    I used Resintite, it is pretty cheap and can be made just about as thick or thin as you like. It is waterproof as well. No idea of the EPS density, was just something I had kicking about.
  13. How I feel about U2 tunes, but then found out I there was nothing to miss. @recoveringacademicWhere is this going?
  14. Solar PV - are they worth fitting?

    I think that @AndyT is saying that you use the immersion heater when the PV is only producing a small amount of excess energy, when the PV produces more it disconnects the immersion and helps run the heat pump. But you can only use either the immersion or the heat pump, not both. This is because there is a secondary electrical element in the heat pump and it may overload the eddy box of tricks, or kill the CoP as the stored energy is at a too higher temperature to get a decent CoP from the heat pump, which would cause the heat pumps internal immersion to kick in. Ideally you never want to use the heat pumps internal immersion heater. If you are using a thermal store then the water that you use (what comes out the tap) and the stored energy (which may be a brick, PCM or a fluid) can be separated with a heat exchanger. This gets rid of the Legionella problem (not that it is a real problem anyway, but that is another debate).