Anyone interested in discrete renewable projects

HI,
I have a pretty large garden and 'er indoors has banished me to the bottom of it for my polytunnel...this is now out of grid electric range and difficult to get mains water (that's not a bother anyway have plenty of shed roof etc to collect water)
The other benefit being down there is it gets just about every scrap of sun in the day...
It's also pretty exposed there and therefore a good area to collect wind.

I would like to set up a discrete power system to use for lighting and propagator and also pump for watering system. Have looked around net and it all seems to be pretty much either 240 stuff including inverters and connecting to grid or basically designed to run in boats etc and is 12v...this is then a bit of a problem finding heaters and stuff.

anyone any ideas??
ps I have a similar requirement for the fish pond for the pumps and filters and oxygenators as well

I would like to do all of these with renewable energy if I possible can but I don't want to pay out thousands.....


regards

les

 

Hi Les,

You'd be hard pressed getting enough current for heating from solar pv. I have an 18 watt panel that charges 2 12volt leisure batteries, but its only really for emergency lighting & running a laptop during powercuts.

Was thinking about building a wind turbine using an alternator from a car to charge the batteries too, running that through the same controler to prevent overcharging. That would be cheaper than the solar pv panel. Wont get around to that now as i'm selling up, so probably will take the system out & re install it in my caravan.

If you get a lot of sun down there, might be worth considering a solar thermal store, using a colector to heat up rocks in an insulated tank for release at night.

 

If you get a lot of sun down there, might be worth considering a solar thermal store, using a colector to heat up rocks in an insulated tank for release at night.

Sounds like a storage radiator :D

 

It is

 

lesdyork, that's a commendable idea, lets have a look in more detail.

Solar

Lets say you want to collect rain in a low barrel (on in or near the ground) and pump it to a bigger one that is mounted say 6 feet up. (To give pressure on your hose) lets say the barrel is 4 feet tall. So that means the top of the barrel is now 10 feet above the ground. As you will fill it from the top (you have to) you will need a pump that can pump water to a minimum height of 10.1 feet (its called "head height") and you want it solar, something like............



Looks promising, now lets read the small print. "Water Lift (Jet Height): 1 meter."
1 metre is just about 1/3 of what you need so that's of no use.

I Have searched some more, and I have found one that claims to be able to pump upto 30 feet, it costs £250 + battery still want one?

Oh, and what happens when its dark, snows or rains? (The solar panel can not charge)

Wind

Unlike solar, wind is available 24/7. You can buy a "wind turbine" as used on caravans, they charge batteries all the time, the batteries feed an inverter and ............
Actually, no they don't.

Ever had a push bike with a dynamo? The light works but it never comes on bright unless you really pedal fast. Same with a wind turbine. The sails will turn, but unless its windy you are not going to get enough out of it.
Or if you opt for a car alternator, imagine how fast it will have to turn?

You may find THIS CLIP interesting.

Heating

No matter how you supply it, a small 1kw fan heater needs 1kw of electricity, you are not going to get that from a 100w solar panel or a small wind turbine.

Over all
As I said at the top, its a commendable idea, its just not (yet) practical in the UK. Sorry.

(Oh, it can be done, it is in some very remote places, but it costs thousands to do)

 

Have a look at this thread about passive heating on Tomatoville: earth tunnel house - Page 2 - Tomatoville® Gardening Forums



There's also some usefull stuff on the Permaculture Mag website that I'll try & checkout.

 

Roam the country side and most of the remote, speed warning signs and advice signs have a Voltaic Cell mounted on top
(Well they used to on my way to work each day, Twenty are missing presumed dropped off :-)
Then one of these in car heaters £20 each that they flog, would keep your greenhouse and shed frost free at least

Hire a white van, where a yellow hard hat and high vis jacket whilst checking the poles :-)

Jack McH

 

I've had a couple of those little in-car heaters. Unfortunately they were both completely useless.

It seems to me, that for heating a polytunnel, one of those chimenia things might be the solution, as long as adequate measure were put into place to prevent any mishaps. Gardens produce quite a lot of clippings that, when allowed to dry for a few weeks, make good solid fuel. Woody clippings from hedges are a nightmare to compost, so why not burn them? Then you get the heat off it, and lots of potash rich ashes to help your plants flower and set fruit.

If the goal was simply to keep the frost away, then you wouldn't need to keep it burning constantly. I good heavy unit would retain heat for ages. Not enough to make you feel toasty, but enough to keep the frost away.

Low tech, cheap, easy to implement, free to fuel, and fuelled by stuff you would normally throw away. surely it doesn't get better than that.

Lighting is a different story. If we're on about lighting so you can see well enough to not break your neck while trying to potter about after dark, then I guess its easy. You can get very low power LED lights that cast enough light to prevent you standing on an ill-placed rake. Such lights could easily be powered by a car battery that's been trickle charge during the day by a small solar panel (might need to do some very simple electronics to lower the voltage, depending on the lights).

If we're talking grow lights, or lights bright enough so you can reasonably comfortably work at night, then something much more beefy is called for, and I think the solar and wind options would be prohibitively expense for anything useful.

 

Whatever happened to COKE the fuel type ?

Ah we do not produce coal gas anymore

Jack McH

 

lesdyork, not that you mentioned lighting, you can obviously get solar lights, and yes you can get some that have several LED's but as clueless1 said, even with several LED's they are really not that much use. (Most decent LED lamps have multiple LEDs, solar lights don't) The other thing is ready made solar lights have a get out clause. "Lasts up to 8 hours"
For an experiment I brought some and they are in the garden, yes they do last up to 8 hours, about 15 minutes to be precise. That's because 15 minutes is up to 8 hours. (They don't say lasts minimum 8 hours)

To get anything "decent" to be solar you need a big solar panel, a big battery and protection / charging circuit. Its the battery and solar panel that are very expensive, and even if you did it, you would be able to see the thermometer says its very cold, as there is no heating.

I am just trying to be practical about it, its a shame, but unless you have deep pockets solar is not for the UK

 

Thanks for all the posts - some interesting points

Thanks everyone- I will check out Solar Thermal collector.....it sounds pretty useful

AS far as pump is concerned I am currently rebuilding all the sheds and an old 'lean-to' greenhouse so for water collection (i have two 45 gall drums plus two large and one medium size water butts) I can more or less put them as high as need to use- providing I have enough power I wouldn't need much as flow will be downwards and by connecting all feeds I can get enough head pressure (I think) to be able to water using an electric timer to open and close feed.Solar PV panels of C. 250 watt can be got for about £80 and I really only want to heat the propagator so as to give me and extra few weeks start on some stuff (unfortunately she who has a bloody big stick won't countenance anything growing in the house)... the tunnel is too large to be thinking about complete heating. What I am not sure about is how to rig it all up - what else do I need, what battery and do I need a controller/ inverter or a power sink if battery full up.


les

 

This is not coming from my experience, but if the only heating you're after is for propagators, is it an option to rewind the clock to Victorian times and make a hot bed of fresh manure, then a layer of straw, then a layer of soil?

Like I said, I have no experience in that area so it might be a silly idea. I've only ready about them.

 

Where from? Please show me a link, I would love one for that price.


Size of other parts required are determined by what you want to run with it, if its all 12v no inverter required, you also need a regulator and deep cycle battery. In short the bigger the better