| Archive for Downsizer For an ethical approach to consumption |
| mochyn |
What acreage of solar panels...Would I need to run a washing machine and three freezers? Photo voltaics, obviously, although I suppose I could have a hot water one for the WMC. Rebuilding the wash house, and might as well go the whole hog. |
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| Helen_A |
We've been told that we would need about 10sq grid-tied meters to cover our 'permanent' power needs (i.e. fridge, freezer, washing machine and internet, plus occasional lighting). But that it wouldn't do it all year round as we'd also need about 8 hours daylight, and of that at least 3 hours decent sun.....
I'm not so sure that its an accurate survery though... Last summer a 15W solar charger in a case was keeping my laptop nicely charged so..... Helen_A |
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| dpack |
imho solar is good for warming things a bit
for power you want gravity moving water |
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| dougal |
Forget any idea of driving things directly from the panels.
Just think of the freezers. In the dark. Or on a dark January day. If you are on the electricity mains, it makes massive financial sense to use the grid as your "battery". You can export to the grid in summer/daytime and import from it in winter/night. Don't get involved with batteries and stuff unless you really must. !! So, its not really a matter of sizing things against your electricity load. More a matter of what is financially possible/sensible. And a lot of the financial viability depends on Grants, subsidies and whatever deal you can make with an electricity company. Remember "Alternative-Energy"? He spent something like £17k. He got a grant for about £8k, leaving him £9k out of pocket. He's just finished his second year with his system. Personally, I think his means of calculating payback makes very little sense* - but he has generated 6100 kw/h units of electricity in 2 years in Kent (there may not be as much light energy in Wales - further North and more clouds!). He seems to actually use very little electricity, hence his bill was minus £200 for the year (they pay him), and he gets a £150 RoC subsidy as well. See how the subsidy is almost half the income? http://www.alternative-energy.co.uk/Daily%20Outputs.html And on those figures, it really doesn't look daft. But miss out on the Grant, take away the RoC subsidy and get a less-good deal out of an electricity company, and it becomes a very different story. * He's not including the cost of the capital to install the thing. And he's factoring in interest on the income. But he doesn't seem to be recognising that his benefit includes money that he isn't paying out for the electricity that he uses himself - let alone that the saving is of money from taxed income. Or that his new income as a generator presumably ought to be accounted for income tax... |
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| vegplot |
It's best to get a professional requirements survey done. This doesn't necesarily mean paying professional rates just someone who knows how to correctly size your system against your requirements (on/off grid, reserves required etc.) and the availability of natural resources to do this properly may need a site visit - especially true for solar hot water in order to make best use of the system.
Also don't think about it in payback terms. PV may take 5-15 years to pay back they have a (life of about 25 years to 80% efficiency). Instead think of it from an independance and/or enviromental point of view. Solar thermal hotwater will have a payback time much short than PV perhaps as little as 2 years. Wind turbine can be as little as 5 years or as long as 20 years depending on the size and usage of the system. Capital expenditure may be high so you may need to factor in interest payments on loans as well. For solar PV a basic rule of thumb is that your get, on average, at this latitude about 1 peak hour sunshine per day in winter and 4.5 hrs per day in summer. That means for a 60 Watt panel (running at 100% efficiciency) you'll get 60 Watt.hrs per day in the winter and around 250 Watt.hrs per day in the summer. If your needs are 3.5kWhrs per day (average small house) that means 14 PV panels will be sufficient to meet your needs on an average summers day but you'll need a lot more in winter. I haven't taken into account losses in the system. A 60 Watt panel costs around £300 so that's a capital outlay of £4,200 minimum. Just to give you a very broad idea. Usually you don't try and meet all your energy needs using one system. Wind turbine and solar PV compliment each other well, solar PV supplies electricity during sunny windless days in the summer and wind turbine on cloudy windy winter days. This complicates calculations but can work in your favour. |
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| James |
aren't you on a windy hill in cloudy wales?
hmmmm...... |
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| vegplot |
Oh yes, rarely cloudy though. I qualify that by saying where we live is often cloudy due to being very close to the mountains but where we're building has a martime climate and is clear for a lot of the time. Great thing about this area is the huge variety of microclimates in such a small area. |
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| Northern_Lad |
She lives in Wales - they don't need to switch their freezers on in January. |
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| JB |
Basic figures are that solar radiation delivers about 1Kw / m2
Half of the time it's night Half of the day your solr panel isn't square on Depending on where you can site it it may be even less efficient Solar panels are not 100% efficient It could be cloudy Over winter you could get even less solar radiation and fewer daylight hours in which to capture it. So at best you could only use solar power to supplement other power sources, unless you were willing to use a large storage system and cut your power usage dramatically over winter. I looked into this a while ago and unfortunately it worked out that by the time I had accounted for all the above the payback time was longer than the solar panel lifetime! Having said that there are these guys who have come up with cheap PVs that bring the cost down dramatically. If that starts producing in any quantity then PV will certainly be worth installing. Alternatively if you are willing to accept that it will only supplement it and don't need to fit it to a roof then it could be viable but wouldn't be a complete solution. |
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| mochyn |
Why I thought of solar was because we're having the wash house rebuilt, which is where all those machines are and the roof gets a reasonable amount of sun. I'd also just saved us quite a bit of the cost by getting slates from Freecycle, so was going to use that saving to offset the cost of the panels.
I'll have a rethink. |
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| dougal |
If you are having roof work done (or need to change your hot water tank) then installing solar *thermal* (ie water heating) can be done for even less extra cost than it would cost to do the job entirely on its own.
Navitron (last time I checked) would supply evacuated tube (ie good) solar collector, controller/pump/gubbins kit and a super-insulated replacement hot water tank for about £1000 total. Installation extra, and up to you. This is pretty fuss free, and nowhere near as major an investment decision as solar ("PV") electricity. It should also be possible to organise the bits quite quickly. |
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| vegplot |
That sounds like excellent value. |
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| mochyn |
Now, that sounds an even better idea, Dougal. At the moment the washing machine heats its own water, albeit only to 40*, but having that done through solar would make a lot of sense. It only works that way because the wash house is 'outside' and it would be difficult to pipe hot water from the Rayburn to it.
More thinking needed now... |
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| JB |
Bear in mind that if you replace your washing machine many washing machines now only take a cold water supply so if you connect that to a solar heated water tank you might no longer have the option of a cool wash. | ||||
| vegplot |
Do you have a budget? I think it's important you set yourself one then see what you can acheive within that budget then revise if necessary. You can make resaonable effective solar thermal hot water collector and storage out of an old radiator, hot water tank and some plumbing. Not as effecient as a evacuated tube collector but could be a lot of fun. |
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| mochyn |
Thanks for that, JB: I'll have to find the instruction book thingy. |
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| dougal |
I wouldn't be thinking only in terms of using solar heated water for the washing machine - though if that's what you want to do, and only want to get up to 40 degrees, then a pretty *tiny* system would do the job (at least for most of the summer).
You could fit a 'blender' (thermostatic) valve to limit the maximum water supply heat to, say 40C ... CAT (nearby?) run courses & do leaflets on mini DIY solar water heating. But, having *house* solar hot water (evacuated tube/big tank/etc) would let you shut down the Rayburn for most of the summer... *if* that were what you wanted... |
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| dpack |
this stuff is good cos it saves buying energy to heat water and is fairly quick to repay outlay . |
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| mochyn |
Nooooo! Don't shut my Rayburn down: no cooking!  That's why solar HW seems a good plan for the washing m/c: it's the only thing that needs HW that isn't connected to the Rayburn.
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| JB |
If that's the only thing that needs it is it really worth installing solar heating or power just for that? If heating the water takes 1 KWh and your solar panel costs £1000 to install it's still going to have to take 10,000 laundry cycles before it pays for itself. I've no idea if those numbers are right but I wouldn't install solar _just_ for the laundry. |
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| mochyn |
I know what you mean, JB, but it really annoys me every time I use the washing m/c to think that the water's being heated by grid electricity. 
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| Chez |
Ours is a Navitron system, it's fab. The solid fuel stove and the central heating and the solar all put heat in to the water tank in separate coils.
I think HHW has a set-up for her cold-fill washing machine where the hot and cold water both run through a shower mixer valve - so if you need a cold wash you can turn it right down. I've got one that I intend to do the same with when we finally get around to deciding where our cold-fill washing machine will permanently go. |
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| dpack |
you said what i meant ,thanks
if you live in a wet ,sloping place is a micro turbine or wheel possible for lectrickery ? |
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| RichardW |
Not far out most a rated washers are about 1kwh per washing load (not boil washes obviously). But not all of that will be the hot water. Justme |
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| Brandon |
If you are merely keeping your rayburn going throught he summer for cooking, then I would go for solar hot water, and shut the rayburn down, and use propane through the summer. What do you power the rayburn with? Wood or oil? |
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| mochyn |
Anthracite. I certainly can't afford to convert it to propane: nor do I want to! I'm looking at changing over to all wood, though. I don't only cook for us: I bake for Country Markets too, so baking is often going on all day. |
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| Brandon |
I was not suggesting for a minute that you would convert the rayburn, but rather install a propane hob, but if you NEED the rayburn to bake daily, then there may not be much in it.
How far is the wash house from the house? an insulated main (hot) to the wash house wouldn't be too dear... cheaper than a solar install if the distance isn't massive. |
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| mochyn |
I don't suppose you do that sort of thing, do you? Insatllation etc. I mean. The problem is that the wash house is a lean to, on the right end of the house (that is the rayburn is the other side of the wall) but the wall is very thick, stone, and rather old. I've often wondered whether it would be possible to get the water from the rayburn to the washing m/c, but couldn't see how. |
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| vegplot |
I had this problem and got over it by tunnelling a small hole through the wall removing rocks. Actually it wasn't small hole by the time i'd finished but it was a lot cheaper than using a diamond drill |
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| mochyn |
That's my big worry: that the small hole will expand and bring the house down! |
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| Brandon |
Mochyn, Yes, PM me. |