Solar Power-is it worth it?

paceinternet

I would suggest you take some electricity meter readings with single items of equipment running each day and add up where the kwh are going.
In particular switch off the coal and use the immersion heater to see how many kwh this is using and then work out what the effect of an economy 7 tariff would be for water and washing mc, with the balance at a higher tariff.

See if one tank of hot water lasts a day, or would a bigger tank last a day.

Example, if a 3 kw immersion heater runs for 2 hours a day (or night) to heat a tank of water, this costs 3 x 2 x 30 days x say 4p/kwh at night = £7.20 per month, or 11 p/kwh during the day = £19.80 per month.
Add some to it if you need to, but it can't get anywhere near the £125 you are using on coal in the summer.

Someone politely correct me if I am wrong here. Thanks.

mech_2

Cardew wrote: »

Mech,
Without trying to 'knock' your idea, it seems implausible to me; but patent it if it works!!

I'm not sure it will have enough unique features to be patentable. As for plausibility, I'm not sure about that either, but it would be fun to try (or maybe I'm just sad).

Not much sun at night!

6 square metres is big! the size of 2 big fence panels.

Not useful at night, no, but I wasn't envisaging it replacing my central heating entirely.

Six square metres is big. But it needs to be to collect a decent amount of energy in winter. Summer heat is going to be useless to me. I picked six because that will fit comfortably on the back of my house between the upstairs and the downstairs windows. One metre high by six long. I'm thinking of blowing the air horizontally now. I've also decided that insulating the back of the collector is a bit pointless when it's flat up against the house. If I just put draught strip around the edges on the back, any heat lost through the back will just heat up the house wall from the outside anyway. I'm also thinking of abandoning the drinks cans idea that the Canadian design had. It's a neat way to get cheap metal tubes with fins on the inside, but I'd like something lighter and flatter to the wall.

Planning permission required??

I'm not in a conservation area, so unless someone objects I don't think I'll have a problem. As long as it doesn't protrude by more than 200mm it's supposed to be OK. I'd probably build the thing and fit it and then ask if I need permission. If they say no then at least I'll have tried it out, and I'll design it from the outset to be easily removed in case it's useless or there's a problem with the design.

Mounting/fittings to withstand winter winds???

Um... big screws.

If I can make the thing flat against the wall, yet prevent any air getting up behind it I shouldn't have a problem. I tend to over-engineer things anyway.

My main worry is condensation. I suppose I could mount it sloping towards one end and if there's bad condensation build up at night in winter it can drain into the bottom of the manifold at one end and out through a little pipe at the bottom or something. I could even make a little u-bend to stop warm air loss. Trial and error I think.

Good luck

If I ever build it, I'll let you know if it worked.

Welshwoofs

paceinternet wrote: »

In particular switch off the coal and use the immersion heater to see how many kwh this is using and then work out what the effect of an economy 7 tariff would be for water and washing mc, with the balance at a higher tariff.

See if one tank of hot water lasts a day, or would a bigger tank last a day.

Unfortunately it's a small tank. One tank of hot water fills our bath 3/4 way, but that's it. The problem is that the tank's size is due to space constraints, it's jammed into the space between wall and chimney breast in a bedroom. My HETAS engineer told me I couldn't resite it to the attic (to get in a bigger one) as it needs to be on a lower level to some other whopping great water tank in the attic given the gravity heating system.

Believe it or not, the £60 a month is after the electricity company supposedly put me on the best tariff. Before that it was £73 a month...something I've never understood since when I bought this place in Dec 06 there was a card meter in here and we religiously fed it £50 a month until the pre-pay meter was replaced with a normal one. When I queried this I was told that pre-pay was the cheapest way to pay which, frankly, I think is a huge pile of BS.

Granted we could save a bucket or two of coal a day by starting up the fire once in the morning for hot water, letting it burn out and then lighting it again in the evening. However the cleaning out and restarting of one of these things is extremely long, dirty and laborious.

No mains gas in the village and the lane we live down is bordered by stone walls so narrow you can't get anything wider than a family car down. As a result, our little terrace of 3 has no gas/oil tanks. The neighbour runs her gas central heating from bottles.

I often get people go all misty-eyed about the concept of relying on solid fuel stoves to heat one's house but I have to say that having lived with one it's a nightmare. Daily dusting to get rid of the coating of black soot over *everything* (I've had two printers die from it), black ceilings from the smoke which inevitably billows out when you're trying to get the damn thing going, getting yourself covered in soot when giving it the regular clean out/brush down, the dragging in of coal in winter in the !!!!ing rain, the fact that the room it's in is like an oven but rooms nearer the end of the 'chain' are freezing cold. The endless miles of huge, ugly copper pipes gracing every hallway and the inevitable time you forget that you put a pair of knickers on the top to try and you end up smacking out a small fire with a wet teatowel :rolleyes:

mech_2

Welshwoofs:
Check the insulation on your hot water tank. If there is none, get some. If there is already a jacket, check to see if it's a decent one (three inches thick or more). This should cut down on the amount of fuel needed to maintain hot water, at least in the summer when the waste heat isn't useful for heating the house.

Ask around locally. Maybe someone has some unwanted wood you can burn in the stove (I have a stack of it in my garage. Logs from trees I mean, not useful timber). The stove may eat it fairly quickly, I dunno, but if it's free...

Most of my other suggestions are only really useful for the winter...

Are the radiators upstairs getting hotter at the bottom than the top? Maybe they need air bleeding out of them. Alternatively the system may have sludge in it. It might be worth having it power-flushed and the system re-balanced. Might be worth asking a plumber how much that would cost as I don't really know.

Next check for draughts around windows and doors. Draughtproofing is probably one of the cheapest ways of improving the energy efficiency of the house.

If you have a cellar, or a wooden floor on the ground floor with a big enough crawlspace under it, it might be worth considering insulating it from underneath. With the loft insulated, a suspended wooden floor would now be losing more heat than the loft.

If you have solid floors downstairs you can probably get stuff that you can put under the carpet underlay. I haven't investigated, but I wouldn't worry so much with solid floors anyway. They soak up heat when cold, but without air passing under them all the time they're actually not as bad as a wooden floor, even if they're not insulated.

Dunno what else to suggest right now.

amtrakuk

i guess this would be beneficial to me, as I have a cellar and no insulation between the cellar and ground floor. :T

Welshwoofs

mech wrote: »

Welshwoofs:
Check the insulation on your hot water tank. If there is none, get some. If there is already a jacket, check to see if it's a decent one (three inches thick or more). This should cut down on the amount of fuel needed to maintain hot water, at least in the summer when the waste heat isn't useful for heating the house.

No jacket at all so that's a good start

Ask around locally. Maybe someone has some unwanted wood you can burn in the stove (I have a stack of it in my garage. Logs from trees I mean, not useful timber). The stove may eat it fairly quickly, I dunno, but if it's free...

I don't know anyone with free wood...but I do have 25 massive Leylandi trees I want felling in the garden so that'll be a good supply once seasoned.

Are the radiators upstairs getting hotter at the bottom than the top? Maybe they need air bleeding out of them. Alternatively the system may have sludge in it. It might be worth having it power-flushed and the system re-balanced. Might be worth asking a plumber how much that would cost as I don't really know.

Unfortunately they're pretty much luke warm all over. When we moved in the solid fuel stove was replaced, along with the pump and every radiator we have by an engineer. I don't know if he 'power flushed' but as had to change all the rads you'd have thought he'd have done something of that ilk.

Next check for draughts around windows and doors. Draughtproofing is probably one of the cheapest ways of improving the energy efficiency of the house.

We're good on that one. All the windows and doors were replaced so there's draft strip things around everything.

If you have solid floors downstairs you can probably get stuff that you can put under the carpet underlay. I haven't investigated, but I wouldn't worry so much with solid floors anyway. They soak up heat when cold, but without air passing under them all the time they're actually not as bad as a wooden floor, even if they're not insulated.

Our property had a meeting of minds with a spring tide some years ago (we're within 800m of the sea and below sea level) and in the clean-up they took up all the boards downstairs and pumped the cottages full of concrete. We laid an engineered oak floor down on top of some fairly think insulation but I have to admit the floors always feel cold. The old folk round here say it's because the tide comes in below the houses and I was advised never to dig more than 2ft down in the garden! :eek:

I have tinkered with the idea of a wind turbine to bolster electricity, but whenever I go to the Government site to get my average windspeed by postcode it tells me that it can't get a reading because the coordinates put me in the sea! All I know is that it's bloody windy round these 'ere parts.

dekh

Move your computer into the warmest room.

When I were t'lad my parents house had 1 gas fire in the living room and nowt elsewhere. Everything happened in the living room or kitchen.

Thankfully central heating arrived when I was about 9, but I can't remember ever being cold - I can remember the nice warm electric blanket though, probably an unsafe fire hazard by todays standards

Cardew

mcptech wrote: »

Solar thermal works a treat. Solar PV, technology not quite there yet. The only reason solar thermal won't work right is if it's been spec'ed or install wrong. Modern solar thermal panels will do 70% of your annual hot water if spec'ed right.

Money saving
:money:

This is a money saving site and your spam is the usual rubbish peddled by salesmen.

dekh

I'm currently doing a website for a guy specialising in industrial heat exchangers.

He just laughed at the mention of solar panels.

Sarjsmith

Hi, please don't maul me Cardew!!
we live in Germany and last year had a new oil condensing boiler plus 21 sq mt of solar panels which are intended to heat the pool, support the hot water AND central heating with a 400 litre hot water tank and 800 litre support tank ( I don't know what 'speicher'is in English) We have had savings of 50% in the first year on our oil consumption (which is probably in large part to replacing a 22yr old boiler) however we have reduced our oil usage from April to October by an average of 80% meaning big savings for hot water and the pool. If oil prices don't rise from today for the next 10 years, we will have repaid our loan well within that time. The government here gives a 1.95% fixed loan for solar and condensing systems. From then on the summer months pool and water heating is vastly reduced. PLease don't ask me for kwh etc I just know we were paying out a lot more before!!