onlyme2 Posted July 8, 2014 Share Posted July 8, 2014 £6k ?! I've got a system for my shed with a couple of deep cycle batteries, a charge controller, some salvaged solar panels and a cheap 1kw inverter (not pure sine wave). It'll run loads of power tools, chargers, lights and a hoover. It owes me a few quid for the controller but the rest was free to me. I reckon you could do a home supply for very little as long as you don't demand heat. Batteries don't need to be fancy. The more basic the better. Flooded lead acid batteries are cheap and easily maintained. Don't worry about weight or space, you just need cheap capacity. I wonder what they do with the batteries from the hunter-killer submarines they decommission? 2v (or other) sub batteries would be very good. Problem is, again, a standalone off grid system is one thing (where you have contrlo over what is attached), Linking to house supply is different ballgame, needs complete isolation and switch in of off grid type inverter and switchover or go grid tie inverter route. There are so many issues with usign an off grid system, switching over and then running everything reliably without discharging the batteries within minutes/hours becuase something has been left on I don;t think it is a good solution unless you are going all out with a very hefty (and expensive) system. You just cannot afford to be reliant on battery power and then lose central heating control, fridge etc, Unfortunately cheap and cheerful does not apply to replacing whole house supplies, best bet would still probably be a genny and crossover / isolator switch properly installed. For the porch maybe look up something like Enecsys plug in solar. Link to comment Share on other sites More sharing options...
Rave Posted July 9, 2014 Share Posted July 9, 2014 £6k ?! That was literally the second link on a quick ebay search, I'm sure it could be done cheaper. Interested to know where you 'salvaged' the panels from though? Anyone know the 'capacity factor' or whatever it's called of solar panels in the UK? I was of course extremely critical of the ludicrous 30p/KWh FIT the government introduced for domestic installations a few years ago, and then quickly retreated from. But now the price of panels has dropped well under a pound a watt I'm wondering if they're a sensible investment even at wholesale rates... I live in my mum's house which doesn't have much south facing roof space, and which is in a 'conservation area', so I don't think roof mounted panels are allowed in any case . There is a small area of flat roof on top which we might get away with installing panels on, but I'd only get a single row on there if they were oriented efficiently. However- my Grandad bought a 4 acre paddock behind the home he bought when he sold his farm and retired, to keep his two remaining farm ponies on. The ponies lived a long time (both well into their 20s IIRC) but both predeceased him, and he died in 2011. My aunt and uncle moved into his house, and now I think they let a local farmer graze his sheep on the paddock just to keep the grass down. My mum passed her inheritance from him directly on to my brothers and I, so now I have the thick end of £100k cash sat about that I'm not going to put into a house purchase until things return to normal. So I'm wondering if I should have a chat with them about building a little solar power station... There's a field full of panels next to the Mid Norfolk Railway that I had several opportunities to observe while anorak-ing at their Diesel Gala, so someone obviously thinks its a sensible idea... Link to comment Share on other sites More sharing options...
SarahBell Posted July 9, 2014 Share Posted July 9, 2014 A caravan? How will that help? You can't use as much electric in a caravan as a house. The washing machine and full size fridge freezer weigh it down a bit. Link to comment Share on other sites More sharing options...
RDW Posted July 9, 2014 Share Posted July 9, 2014 I've got one of these http://www.immersun.co.uk/ It works a treat I'm also considering putting deep underfloor heating in the living room, controlled by the immersun above, to heat underfloor during the summer which will release slowly over the winter, abit like a big storage heater. Link to comment Share on other sites More sharing options...
StainlessSteelCat Posted July 9, 2014 Share Posted July 9, 2014 I've got one of these http://www.immersun.co.uk/ It works a treat I'm also considering putting deep underfloor heating in the living room, controlled by the immersun above, to heat underfloor during the summer which will release slowly over the winter, abit like a big storage heater. Would be interested in seeing how you get on with that as I have the immersun too and have been thinking the same. Link to comment Share on other sites More sharing options...
onlyme2 Posted July 9, 2014 Share Posted July 9, 2014 Don't see why that Immersun unit could not be used as the charge controller for a battery bank - It is doing all the necessary power reading to then basically switch a relay/semiconductor switch for the immersion heater - that output could be used to power a battery charger. Link to comment Share on other sites More sharing options...
corevalue Posted July 9, 2014 Share Posted July 9, 2014 The best solar capture system I have seen is a guy who built his own house. Under the house he built a thermal store by having an insulating basement retaining wall, trapping a few hundred cubic metres of soil. This he heated with a hot water array on his roof all summer, he told me it got up to about 30C in the second year. He then ran a heat pump from this thermal mass during the winter, getting a much better COP (coefficient of performance) than the usual pipes in the garden heat source. His maximum heating demand was 1 kW for a large detached house. Batteries by comparison are crap. A 100 Ah battery stores about as much energy as a small cupful of diesel, however, start/stopping a genny and putting up with the noise and fumes (let alone the cost of the things) is a major drawback. People I have known who tried batteries as solar storage - charge all day from solar and use after work - found that it simply wasn't sustainable, you couldn't achieve enough storage. By contrast, they work OK as smoothing devices, powering appliances beyond the output of your solar array for short period e.g. boiling a kettle. During sunny days, "free" boiling water is our major weedkiller/ant killer. Link to comment Share on other sites More sharing options...
inactionman Posted July 9, 2014 Share Posted July 9, 2014 Fascinating! But I suspect that the total power that could be stored (for each unit at least) isn't going to be that great?? Depends how fast you want the flywheel to spin and how heavy it is (1/2mv^2 in a near vaccum after all!). Here's a CAT unit. Designed for Datacentres though (3 phase power, etc.) Link to comment Share on other sites More sharing options...
whitevanman Posted July 9, 2014 Share Posted July 9, 2014 That was literally the second link on a quick ebay search, I'm sure it could be done cheaper. Interested to know where you 'salvaged' the panels from though? Anyone know the 'capacity factor' or whatever it's called of solar panels in the UK? I was of course extremely critical of the ludicrous 30p/KWh FIT the government introduced for domestic installations a few years ago, and then quickly retreated from. But now the price of panels has dropped well under a pound a watt I'm wondering if they're a sensible investment even at wholesale rates... I live in my mum's house which doesn't have much south facing roof space, and which is in a 'conservation area', so I don't think roof mounted panels are allowed in any case . There is a small area of flat roof on top which we might get away with installing panels on, but I'd only get a single row on there if they were oriented efficiently. However- my Grandad bought a 4 acre paddock behind the home he bought when he sold his farm and retired, to keep his two remaining farm ponies on. The ponies lived a long time (both well into their 20s IIRC) but both predeceased him, and he died in 2011. My aunt and uncle moved into his house, and now I think they let a local farmer graze his sheep on the paddock just to keep the grass down. My mum passed her inheritance from him directly on to my brothers and I, so now I have the thick end of £100k cash sat about that I'm not going to put into a house purchase until things return to normal. So I'm wondering if I should have a chat with them about building a little solar power station... There's a field full of panels next to the Mid Norfolk Railway that I had several opportunities to observe while anorak-ing at their Diesel Gala, so someone obviously thinks its a sensible idea... I got the panels off my yacht! To clarify, as yachts go there's less sitting in a jacuzzi and more sitting on a bucket Googling submarine batteries it seems that each 2V cell weights nearly a ton and can deliver 7500amps. Might be slight overkill for a domestic system but apparently it has been done! More sensible might be industrial lead acid batteries as found in forklift trucks. Lots for sale secondhand or new if you have the cash. They are very resistant to deep discharge and can be maintained and bad cells bypassed. As for your solar power station? They seem to be everywhere, with farmers and industrial landlords cashing in. I understand that once you've signed up the feed-in tariff is guaranteed for the life of the installation. Plenty of people have obviously decided it does pay. Get in there before they drop the rates further! Link to comment Share on other sites More sharing options...
onlyme2 Posted July 9, 2014 Share Posted July 9, 2014 The best solar capture system I have seen is a guy who built his own house. Under the house he built a thermal store by having an insulating basement retaining wall, trapping a few hundred cubic metres of soil. This he heated with a hot water array on his roof all summer, he told me it got up to about 30C in the second year. He then ran a heat pump from this thermal mass during the winter, getting a much better COP (coefficient of performance) than the usual pipes in the garden heat source. His maximum heating demand was 1 kW for a large detached house. Batteries by comparison are crap. A 100 Ah battery stores about as much energy as a small cupful of diesel, however, start/stopping a genny and putting up with the noise and fumes (let alone the cost of the things) is a major drawback. People I have known who tried batteries as solar storage - charge all day from solar and use after work - found that it simply wasn't sustainable, you couldn't achieve enough storage. By contrast, they work OK as smoothing devices, powering appliances beyond the output of your solar array for short period e.g. boiling a kettle. During sunny days, "free" boiling water is our major weedkiller/ant killer. I was wondering about that last year - specifically increasing the COP with a thermal heat store, 1KW for a detached is great. Collecting thermal heat with solar thermal collector is the way to go too, using 20% efficient PV for the job is not the way to go if this is specifically what you are after, although as a dump for excess PV 100% better than gifting it back to the grid. Link to comment Share on other sites More sharing options...
John51 Posted July 9, 2014 Share Posted July 9, 2014 Not sure about domestic use but Vanadium Flow Batteries are getting used more for larger setups. http://www.bbc.co.uk/news/magazine-27829874 Link to comment Share on other sites More sharing options...
onlylooking Posted July 9, 2014 Share Posted July 9, 2014 This chap has built this to store solar power for later usage: http://www.diyesskit.com/ Nissan have already launched a electric vehicle to home system in Japan to get the power back out of the Leaf. Would love to have that made available over here. Link to comment Share on other sites More sharing options...
Grandad Posted July 9, 2014 Share Posted July 9, 2014 I have a couple of solar panels by the stream at the bottom of the garden. In the summer they are coupled to a car battery then in turn, to a marine sump pump in the stream. This provides me with lots of water for my veg patch. Been very handy these last few weeks. During the winter the panels are directly coupled to kettle elements, these are immersed in a pond keeping part of it ice free helping to keep he pond oxygenated. I have been meaning to make a fancy fountain for a couple of years but haven't got around to it yet. Link to comment Share on other sites More sharing options...
SNACR Posted July 10, 2014 Share Posted July 10, 2014 I got the panels off my yacht! To clarify, as yachts go there's less sitting in a jacuzzi and more sitting on a bucket Googling submarine batteries it seems that each 2V cell weights nearly a ton and can deliver 7500amps. Might be slight overkill for a domestic system but apparently it has been done! More sensible might be industrial lead acid batteries as found in forklift trucks. Lots for sale secondhand or new if you have the cash. They are very resistant to deep discharge and can be maintained and bad cells bypassed. As for your solar power station? They seem to be everywhere, with farmers and industrial landlords cashing in. I understand that once you've signed up the feed-in tariff is guaranteed for the life of the installation. Plenty of people have obviously decided it does pay. Get in there before they drop the rates further! Really not sure you would get hold of any decent forklift batteries that cheap or easily. Also they will be a PITA to move without a forklift and it does seem inevitable they eventually piddle battery acid out. Link to comment Share on other sites More sharing options...
Rare Bear Posted September 12, 2014 Share Posted September 12, 2014 The best solar capture system I have seen is a guy who built his own house. Under the house he built a thermal store by having an insulating basement retaining wall, trapping a few hundred cubic metres of soil. This he heated with a hot water array on his roof all summer, he told me it got up to about 30C in the second year. He then ran a heat pump from this thermal mass during the winter, getting a much better COP (coefficient of performance) than the usual pipes in the garden heat source. His maximum heating demand was 1 kW for a large detached house. Batteries by comparison are crap. A 100 Ah battery stores about as much energy as a small cupful of diesel, however, start/stopping a genny and putting up with the noise and fumes (let alone the cost of the things) is a major drawback. People I have known who tried batteries as solar storage - charge all day from solar and use after work - found that it simply wasn't sustainable, you couldn't achieve enough storage. By contrast, they work OK as smoothing devices, powering appliances beyond the output of your solar array for short period e.g. boiling a kettle. During sunny days, "free" boiling water is our major weedkiller/ant killer. Any reason not to use a basement full of water as the heat store? Serious question. Link to comment Share on other sites More sharing options...
rxe Posted September 13, 2014 Share Posted September 13, 2014 Unless you have a pressing need to go off grid, don't bother. To run a normal house (not some hair shirt place with a single LED lamp), you need several thousand amp hour of batteries and several kW of inverter. This will run to many thousands of pounds, and you still need to pay the standing charge of the grid because you will run out in the winter If you want to fully utilise the power generated, then make sure all your big loads come on during the day. DHW - on a time switch is fine, washing machines etc. Using a basement of water as a thermal store - you may have humidity issues when you get the water above about 20 c Link to comment Share on other sites More sharing options...
MrPin Posted September 13, 2014 Share Posted September 13, 2014 I got the panels off my yacht! To clarify, as yachts go there's less sitting in a jacuzzi and more sitting on a bucket Googling submarine batteries it seems that each 2V cell weights nearly a ton and can deliver 7500amps. Might be slight overkill for a domestic system but apparently it has been done! Way to go! I know somebody that took that path! You need a big shed! Link to comment Share on other sites More sharing options...
ChumpusRex Posted September 13, 2014 Share Posted September 13, 2014 Any reason not to use a basement full of water as the heat store? Serious question. Damp, humidity, corrosion, microbes. You can use large thermal tanks - unpressurised tanks of water with corrosion inhibitior/biocide chemicals. A better option is wax filled tanks - this way you can utilise the latent heat of fusion to store heat at a preferred temperature (a big advantage, as the latent heat of fusion of 1kg wax is about equal to the thermal capacity of 50 kg of water). Link to comment Share on other sites More sharing options...
AteMoose Posted September 13, 2014 Share Posted September 13, 2014 Any reason not to use a basement full of water as the heat store? Serious question. very sensible, a couple of 'grand designs' used an indoor swimming pool as a heatstore. The second advantage is you also get a heated swimming pool Link to comment Share on other sites More sharing options...
Tiger Woods? Posted September 13, 2014 Share Posted September 13, 2014 You might consider a commercial product like this: http://www.resau.com.au/ Not sure if there issomething equivalent availablein the UK though. Link to comment Share on other sites More sharing options...
oracle Posted September 14, 2014 Share Posted September 14, 2014 Unless you have a pressing need to go off grid, don't bother. To run a normal house (not some hair shirt place with a single LED lamp), you need several thousand amp hour of batteries and several kW of inverter. This will run to many thousands of pounds, and you still need to pay the standing charge of the grid because you will run out in the winter If you want to fully utilise the power generated, then make sure all your big loads come on during the day. DHW - on a time switch is fine, washing machines etc. Using a basement of water as a thermal store - you may have humidity issues when you get the water above about 20 c so boil it first and then get several sachets of gelatine/wallpaper paste before you put it int the basement. that should stop future humidity issues. Link to comment Share on other sites More sharing options...
anonguest Posted September 14, 2014 Author Share Posted September 14, 2014 I'll just chip in again here, as thread starter, to say thanks to all for the discussion - and also interest shown. Lots of ideas/food for thought, useful inks, etc so far to mull over...... One point I suppose I'll concede is that, although I referred to specifically solar power, the problem applies to energy generated by any means (wind, solar, etc) - its just about storage. Link to comment Share on other sites More sharing options...
19 year mortgage 8itch Posted September 14, 2014 Share Posted September 14, 2014 so boil it first and then get several sachets of gelatine/wallpaper paste before you put it int the basement. that should stop future humidity issues. The sort of quantities of matter and energy we're talking about for a thermal store, I'm not sure that boiling it is the sort of thing that. Makes sense. Link to comment Share on other sites More sharing options...
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