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small project with a very small budget
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blah



Joined: 12 Jun 2008
Posts: 5

PostPosted: Thu Jun 12, 2008 7:53 pm    Post subject: small project with a very small budget Reply with quote

Hi all, im interested in what solar energy could do for me in growing mushrooms...nothing fancy just button mushrooms instead of spending nearly ?1 a week on them from the stores i want to grow them. but to grow them the soil temp must be right.

I have the most meagre of budgets for this but just need to know a ballpark figure given that i want to run a soil warmer shown here

http://www.garden4less.co.uk/proddetail.asp?prod=WP012-65

during the winter and probably all day as the air temp would be too low to grow the mushrooms.

not the biggest project you have ever seen but people have to start somewhere Smile
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Andy Hunt



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PostPosted: Thu Jun 12, 2008 9:04 pm    Post subject: Reply with quote

I've often wondered about mushrooms actually, they don't exactly keep over the winter.

No idea how you might go about it though, it will be interesting to see the responses! Smile
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hardworkinghippy



Joined: 16 Aug 2007
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PostPosted: Thu Jun 12, 2008 9:40 pm    Post subject: Reply with quote

Using the sun to convert to electricity then converting again to heat isn't very efficient and will cost you quite a bit - but a project like that is easy to do using solar.

It would be better to use a primary source of energy like wood - possibly used to heat a thermal mass near your mushrooms and they'd have an almost constant heat.

Better still would be to grow your mushrooms in the warm months and either dry them or bottle them to keep them for use in the winter.

The ideal situation of course would be to go and pick them in the woods - if that's possible.

Irene
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blah



Joined: 12 Jun 2008
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PostPosted: Thu Jun 12, 2008 9:54 pm    Post subject: Reply with quote

hmmm...but if its not very efficient to convert it then why do people consider solar water heating?

its the winter growing thats causing me the issue hwh as the spores wont grow they will go dormant. im growing them in my shed sooo i dont really want to place combustables i there either.

i would pick them in the woods but in scotland it gets too damn cold in the winter and i wouldnt know what i was looking for. at the moment im dabbling and looking for sustainablity if thats remotely possible Question
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hardworkinghippy



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PostPosted: Thu Jun 12, 2008 10:02 pm    Post subject: Reply with quote

I'm Scottish, so I know how you feel !!

Solar water heating isn't electric, it's done by the sun heating a fluid which moves around in a circuit to a heat exchanger to warm the water in a tank.

Solar panels for electricity are best used for lighting and music and computers and tellys - things that need a little bit of electricity to make them work.

Can't you move the mushies to inside - near a radiator or behind a fireplace or even under your bed?

And... why mushrooms ? (Tell me off if you think I'm too nosey ! Rolling Eyes )
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Bandidoz
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PostPosted: Thu Jun 12, 2008 10:11 pm    Post subject: Reply with quote

...but at least with solar PV it would be possible to have a controlled, regulated heat (without needing lots of mass), which would probably be much more difficult with solar thermal.
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hardworkinghippy



Joined: 16 Aug 2007
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Location: Bergerac France

PostPosted: Thu Jun 12, 2008 10:50 pm    Post subject: Reply with quote

You're right bandidoz, and that's why grid electricity is so bloomin' useful but with solar you still have to store the electricity somewhere when the sun's not shining.

For the 14watt heater in the link, you'd need a set-up at least four times larger than that described by Adam in the "basic lighting" thread - you'd need more panels and more battery storage - say minimum five days cover for Scotland.

The system would have to balanced to make sure your batteries got a good charge and a good "clean up" - normally done automatically by a good controller - every so often.

But, if it were just for germination (short term) you could use the system for lights and other things as well.
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blah



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PostPosted: Fri Jun 13, 2008 6:33 pm    Post subject: Reply with quote

hardworkinghippy wrote:
I'm Scottish, so I know how you feel !!

Solar water heating isn't electric, it's done by the sun heating a fluid which moves around in a circuit to a heat exchanger to warm the water in a tank.



aaaahhhh my bad

Quote:

Solar panels for electricity are best used for lighting and music and computers and tellys - things that need a little bit of electricity to make them work.


I was hoping that by insulating the container that they are in i wouldnt require the heat to be on constantly
Quote:

Can't you move the mushies to inside - near a radiator or behind a fireplace or even under your bed?


nah, i cant see my other half agreeing to that and as you know they grow in manure...i dont know if i could stand the smell Very Happy

Quote:

And... why mushrooms ? (Tell me off if you think I'm too nosey ! Rolling Eyes )


well i can keep them in the shed to grow and all they need is to be at about 15 degrees so i figured that since i want them all year round i would need a way to stop them getting cold and if that meant an outset of money for all year round crops then it might be worth it Smile
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blah



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PostPosted: Fri Jun 13, 2008 9:40 pm    Post subject: Reply with quote

a search of the forum didnt show a basic lighting thread Question
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contadino



Joined: 05 Apr 2007
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PostPosted: Fri Jun 13, 2008 10:27 pm    Post subject: Reply with quote

Depending on the volume of mushies you want to grow, maybe you could consider something like a PV-powered electric propagator (somewhere in the region of 17w) or a modified beer-making keg (with an electric blanket-esque heater drawing somewhere approaching 30w). Anything beyond that, I think you'd be better off with a large thermal store and using solar thermal for your heat as the battery storage would be uneconomical.

What sort of volume would you be seeking to heat, to what temperature (16?C-ish?), and what would be your average ambient temperature?
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kenneal - lagger
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PostPosted: Sat Jun 14, 2008 4:42 am    Post subject: Reply with quote

You will need a highly insulated container with plenty of thermal mass underneath and not much free air space inside. One way of producing a lot of Thermal Mass cheaply is to use the ground and this paper tells you how to:- http://www.greenershelter.org/TokyoPaper.pdf (good diagrams on page 5)

If you use a green house, a length of 100 dia plastic pipe, a 5W PV panel and a 12V computer cooling fan and the above paper you could construct a heat source under a shed, or better still, a box, which could then be highly insulated from the sides and above.

Better still why not just enjoy mushrooms when in season? Or extend the season slightly by using a greenhouse or polytunnel?

Wanting something that is seasonal, all the year round, smacks of clinging onto the BAU lifestyle.
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blah



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PostPosted: Sat Jun 14, 2008 8:06 pm    Post subject: Reply with quote

contadino wrote:

What sort of volume would you be seeking to heat, to what temperature (16?C-ish?), and what would be your average ambient temperature?


the spores came in a 0.5m pack so i really dont need a vast system.

im thinking of using a plastic storage box with a lid from the local supermarket. Into this placing around 2 inches of prepared compost (staw manure from horses) and placing in the soil warmer. i know you said about a propagator but no-one seems to actually make them so this is kinda a home kit...which is perhaps what you mean? anyway...on top of the soil warmer add another 4 inches of compost.

My thinking is that the box itslef will probably have a 17L capacity and more than half of this will be used for the bedding material which we need to keep at around 15-16 degrees celcius.

from what i can gather i would need a panel - a power invertor as the warmer would need a mains plug - a regulator for the temp - the soil warmer - loads of luck as it would seem this is probably going to be a non-starter
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contadino



Joined: 05 Apr 2007
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PostPosted: Sat Jun 14, 2008 8:49 pm    Post subject: Reply with quote

Look at the mash kegs that homebrewers use for making beer. They sound about the right sort of size, and have a low power, thermostaticly controlled electric blanket surrounding them. Shouldn't be too much of a job to retrofit it to a battery, and have that charged by a panel.

It doesn't sound like a non-starter to me.
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Andy Hunt



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PostPosted: Sat Jun 14, 2008 9:11 pm    Post subject: Reply with quote

You can get heat mats for vivaria and the like - instead of keeping lizards warm you could heat your mushrooms.

You could run it off a battery and appropriately sized PV panel, it might not be that efficient though.
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adam2
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PostPosted: Mon Jun 16, 2008 8:36 am    Post subject: Reply with quote

As others state, PV is not the ideal energy source for this application, not only will it prove rather expensive, but the available rescource will at at its lowest in the short, dark winter days, just when the demand will be greatest.

You may achieve a much greater saving by useing grid electricity for this purpose, put the money saved on PV modules and batteries towards improved insulation, or perhaps grid tied PV to offset the power used from the grid.

Another possibility would be to use a small wind turbine, with battery storage. I suspect that a given sum invested in wind power may, in Scottish winter weather, give more power than the same spent on PV.
The advantage of windpower is that it produces the most in winter, just when heating is needed. This is equally true for a few watts to heat a propagator, or a few kilowatts to heat a house.

Another possibility is to use a very small oil burning heater as sold for the purpose in garden centers.
Although oil burning may seem a strange recomendation, the oil used is much less than a litre a week. Such heaters are safe if used correctly and with care.
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