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Whos in to green energy then


pete_b
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Solar Thermal is most efficient energy harvest method. Lowest energy conversion rate and therefor losses.

Depends I spose on what your goals/needs are and how much you can invest out of the gate. Off grid, backup power, backup heat, Domestic hot water, it all depends...

I'm mucking with plate/evacuated tube mixed collection driven by a small PV array to power collection pumps and circulation battery backup for outages. Thermal mass provided by a 1000 gallon milk storage tank and the slab it sits on. Dumping excess charging volatge to a small grid tie inverter when batteries are topped up.

I don't expect it to remove my needs for conventional heat/electricity, but do expect it to drop the cost of those over the long term, and keep the lights on when there is a power outage without a scramble for the generator.

A quarter scale version of this fellow's thoughts:

http://www.earth.org.uk/milk-tanker-thermal-store.html

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Thought about water heating but was looking at Pv first.

I have a very large battery store from a forklift already (about 1600Ah) and a 2500watt pure sine wave inverter.

We use about 5-800 watts Ph unless the washing machine / hover / microwave is on, kettle is on gas cooker and heating is oil.

The first thing I was looking to do was get a genny (Lister) and use this to charge batteries/ supply house loading it up to 75-85% with imertion heater and fan heaters (if needed) which would pre warm the house saving oil.

The genny would run on WVO or WEO with a water heat reclaimer on the exhaust to heat a log briquet making machine which we then use on the fire to further reduce oil usage.

I can get WEO for nothing at the moment :D

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At the risk of sounding "deep", all our energy comes from the sun.

So collecting it and using it the most direct method remains most efficient.

That said, and pending your goals (which I can't glean from your post) you may find that the losses in fuel for the genny to electricity to charging losses to inverter losses may in fact be more expensive then oil and grid costs.

For backup it's the only way, but with the advent of cheap grid tie solutions house loads can be offset somewhat, but taking care of home comes first so only once batteries are floated.

Reads like you've done some math already, and while that can make for justification, that wasn't my motivation to embark on solar storage at all. Goals again.

From my journey so far the rule that has come out of it is to stay as close to the form of collection you start with.

So, if PV is your path, check your utility's net metering plans and / or consider selling your power to someone thru your local grid to avoid the "year end zero" that many utilities use to avoid owing you anything in the advent of excess generation to your needs.

If Thermal is your plan, you need a method of storage or effective shunt at capacity a la briquet.

Any way you go, good on ya for doing it.

I don't have your acronym booklet handy so WEO, WVO are just funny sounds when I say them.

:-)

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I'm currently building a house for myself. I'm going ground source heat pump for my heating. Personally I think solar is a waste of time. With the government grant, I worked out that a solar system would give me 1 free month of electricity per year. Not worth the outlay as far as I'm concerned. Now the grant is reduced, it's definitely not worth it. I'd rather put the £12k towards new toys!!

If you have mains gas, that is still the cheapest way to heat your home, however, if you are off mains, I believe that ground source heat pumps are the way forward.

Thats my penny's worth! :lol:

Chris

PS. Hoping to go flying over Cheshire tomorrow, weather dependant.

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One of the houses in our village has a water wheel that takes power from a MUCH smaller lake fed by a few streams.... ( it runs under his house and he has a glass floor so you can see the wheel in action)

His house is powered from this wheel 100% of the year.

SW :D

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Not sure if it has been on TV ?? It may have been.

There is also a pub in andover which takes 'some' power out of a water mill which runs under it... That HAS been on TV for sure.....

SW :D

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Hi Pete

Our house is run on an air source heat pump. Ground source is quite expensive to install due to all the pipes that have to be placed in the ground.. Where this run the same as an air con unit buy in reverse.

We also have another heat pump to heat our water from the heat from inside the house and utility room. With the New RHI (renewable heat incentives) coming out from the government we should be geting between £800-£1200 per heat pump per year for the next 21 years!!!!! so basically free heating for us for the next 21 years!!!!

You should also be able to get another grant to cover some of the install costs. I think up to £900.

Our system is by earth save products.

we also have a 3500ltr rain water harvest system in the garden that supplies our toilets and for watering the garden and washing the car's. When we run out of water it the turn back to the mains.... I think we ran out once this year due to the lack of rain in the summer.... This has cut our water bill's to next to nothing. My last water bill was for £45.

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Hi Pete

Our house is run on an air source heat pump. Ground source is quite expensive to install due to all the pipes that have to be placed in the ground.. Where this run the same as an air con unit buy in reverse.

We also have another heat pump to heat our water from the heat from inside the house and utility room. With the New RHI (renewable heat incentives) coming out from the government we should be geting between £800-£1200 per heat pump per year for the next 21 years!!!!! so basically free heating for us for the next 21 years!!!!

You should also be able to get another grant to cover some of the install costs. I think up to £900.

Our system is by earth save products.

we also have a 3500ltr rain water harvest system in the garden that supplies our toilets and for watering the garden and washing the car's. When we run out of water it the turn back to the mains.... I think we ran out once this year due to the lack of rain in the summer.... This has cut our water bill's to next to nothing. My last water bill was for £45.

Nice one, I will look in to heat pumps more :D

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Ground source heat pumps work better if the pipes are buried in swampy south facing ground. The idea is that an element of water, on the move, will stop it from freezing up, and so extract heat easier. Ten grand was quoted . That's before all the digging.

Air source is cheaper and easier to install, but when you need the heat most, the air temp is very low. Thermal store might help.

We went for PVC. 43 pence per unit and use most of it for free. Happy days

Coupling solar water heater to my thermal store shortly

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I have looked at heat pumps and do not think they will return the investment quick enough for me.

I am going to possibly go with solar and a large heat store which will pre heat the water going in to the boiler and also the central heating.

Looking at bio mass heating as well (6 foot square compost heap) pipes running through centre to central heating system or heat store, this should also produce enough methane to run a gas ring 24/7.

running a genny to charge my batteries extra power to top up heat store I should be able to save 75% on heating 95% on electric.

But then the running costs of the genny with maintenance will nearly bring this back to break even at the moment.

Not really cost viable but it will get me a bit more out of the matrix :D

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