Newbie here - wants to do diy solar - needs help please!
Synth
I'm a software developer and I'm trying to branch out and get into
solar power projects. I really have no experience and don't even know
where to begin. All I have is the 2 semesters of physics(long ago)
that I took in undergrad.
I was thinking about starting with the $600 diy solar project found
here: http://www.off-grid.net/2005/10/10/600-gets-your-house-on-solar-power/
but its a bit steep for my budget. I was thinking of initially going
with a lower wattage(cheaper) PV module, but then if I want to expand,
the article says I won't be able to string them together if they
aren't the same wattage. I don't even understand why...
Any readings that you all might recommend, especially primers on
electricity concepts. I've googled around and have read many websites
about electricity basics(watts/amps/volts, etc) but I still feel under
prepared to get into this field.
Ultimately, I do have a project in mind: a solar powered hot dog
cart. So, eventually I'll need a setup that can keep several gallons
of water warm all day long - as well as be semi-portable. Also,
seeing as how I'm on a computer all day long, I'll like to get my
computer(~400W) off the grid, if possible.
Thanks!
Mauried
Unfortunately, getting into Solar in a meaningful way is going to be
expensive simply because Solar Panels are expensive.
You need to decide what you ultimately want to achieve then wait till
you have enough money to buy all the necessary components.
trying to go there on the cheap will find you ending up with a lot of
components you will have to junk or replace when you want to make the
whole system bigger.
As a simple example, if you wanted to run your computer off the grid
for say 8 hours a day , since your computer needs 400 watts , thats a
total of 3200 watt hours or 3.2 KWH per day.
To generate this amount of power you would need a solar panel of
approx 600 watts and a battery of sufficient capacity to run the
computer at night if thats when you needed it .
If the computer needs to run for 4 hours at night, thats 1.6 KWH so a
battery of about double this would be needed to avoid completely
discharging the battery.
A 12 volt 300 AH battey would be ok, but this is a big battery.
You also need a 400 Watt Inverter.
The total cost of all this would be around $3500 to $4000.
Its an expensive business.
This is an approximate estimate and you may do things a bit cheaper
but if $600 is beyond your budget then Id wait ill you have some more
spare cash.
Synth
Thanks for your quick reply :)
Ok, so solar pv may not be the most efficient choice for a sustainable
power supply :-) Do you have recommendations on alternative ideas?
The key considerations being that it generates enough power for around
8-12hrs of work(whether it be direct or through batteries) at a clip.
I definitely don't think wind would cut it and bio-desiel doesn't seem
truly sustainable(or am I wrong here). Bear in mind, I'm not really
doing this to create a viable business idea. I'd be completely happy
investing in a moderately pricey setup($3k-$10k) and only operate on
the sunny weekends of the summer in order to spread sustainable
ideas. However, I'd rather get my hands dirty on a smaller scale
project first and extrapolate out before really investing.
Someone who replied straight to my email, mentioned the use of a
heliostat to cook the hot dogs because of the fact that solar energy
is lost greatly when converting the suns energy from light, to
electricity, to heat. In truth, I imagined running a hot dog cart
where they keep the hot dogs in hot water, and that's how they cook.
It seems doubtful that a heliostat could heat several gallons of water
constantly through a day. Anyone want to run the math ;-)
Eeyore
Synth wrote:
> Hey all,
>
> I'm a software developer and I'm trying to branch out and get into
> solar power projects.
Why ? Are you off grid ? If not, don't waste your time and money.
Looks like you're in New York. Don't expect much useful insolation there !
http://howto.altenergystore.com/Solar-Insolation-Map-USA/a44/
Graham
Mauried
<libra...@gmail.com> wrote:
>On Nov 28, 10:58=A0pm, maur...@tpg.com.au (Mauried) wrote:
>> On Fri, 28 Nov 2008 15:24:49 -0800 (PST), Synth
>>
>>
>>
>> <libraris...@gmail.com> wrote:
>> >Hey all,
>>
>> >I'm a software developer and I'm trying to branch out and get into
>> >solar power projects. =A0I really have no experience and don't even know
>> >where to begin. =A0All I have is the 2 semesters of physics(long ago)
>> >that I took in undergrad.
>>
>> >I was thinking about starting with the $600 diy solar project found
>> >here:http://www.off-grid.net/2005/10/10/600-gets-your-house-on-solar-pow=
>er/
>> >but its a bit steep for my budget. =A0I was thinking of initially going
>> >with a lower wattage(cheaper) PV module, but then if I want to expand,
>> >the article says I won't be able to string them together if they
>> >aren't the same wattage. =A0I don't even understand why...
>>
>> >Any readings that you all might recommend, especially primers on
>> >electricity concepts. =A0I've googled around and have read many websites
>> >about electricity basics(watts/amps/volts, etc) but I still feel under
>> >prepared to get into this field.
>>
>> >Ultimately, I do have a project in mind: a solar powered hot dog
>> >cart. =A0So, eventually I'll need a setup that can keep several gallons
>> >of water warm all day long - as well as be semi-portable. =A0Also,
>> >seeing as how I'm on a computer all day long, I'll like to get my
>> >computer(~400W) off the grid, if possible.
>>
>> >Thanks!
>>
>> Unfortunately, getting into Solar in a meaningful way is going to be
>> expensive simply because Solar Panels are expensive.
>> You need to decide what you ultimately want to achieve then wait till
>> you have enough money to buy all the necessary components.
>> trying to go there on the cheap will find you ending up with a lot of
>> components you will have to junk or replace when you want to make the
>> whole system bigger. =A0
Using Solar Power to electricially heat things up is insanely
innefiicient.
Solar cells are around 14% efficient and cost around $5 a watt or
more.
Essentially Solar only makes sense when there is no other options
available.
Whats wrong with just using gas, it will be much cheaper.
Eeyore
Synth wrote:
> Ultimately, I do have a project in mind: a solar powered hot dog
> cart. So, eventually I'll need a setup that can keep several gallons
> of water warm all day long - as well as be semi-portable.
Use solar thermal for that and heat the water directly.
> Also, seeing as how I'm on a computer all day long, I'll like to get my
> computer(~400W) off the grid, if possible.
Have you ANY idea how many sq metres of panels, batteries, charge controllers
and inverters that would take ? And how much it would cost ?
A 1 sq metre panel would power it for about 1 hour in NY assuming no system
losses. And not at all on a cloudy day. You'd pay about $1000 for that approx.
If by 'all day long' you mean say 12 hours multiply accordingly ($12,000).
If you care about energy use get a less thirsty computer. Low power CPUs and
chipsets are available in modern computers. Plus Linux won't need as powerful a
PC as Vista by a LONG way. And get an LCD screen. And insulate your home
properly.
http://www.solarcraft.net/sun-hours-map.htm
Graham
Eeyore
Synth wrote:
> I was thinking about starting with the $600 diy solar project found
> here: http://www.off-grid.net/2005/10/10/600-gets-your-house-on-solar-power/
And WHERE on that page does it state how much power it will deliver ?
Probably reportable to the FTC for fraud.
> but its a bit steep for my budget.
LMFAO !
And to think you write software ! I just hope it's not safety critical if you're
that gullible.
Graham
Eeyore
Synth wrote:
> Ok, so solar pv may not be the most efficient choice for a sustainable
> power supply :-)
It's a positively INSANE one.
> Do you have recommendations on alternative ideas?
Yes. REDUCE YOUR ENERGY *USE* ! Use CFL lighting, LCD TVs and PC screens. Insulate
your property. This can all be done for relatively little money and will 'save the
environment' about 100 times more effectively.
Graham
Eeyore
Mauried wrote:
> As a simple example, if you wanted to run your computer off the grid
> for say 8 hours a day , since your computer needs 400 watts , thats a
> total of 3200 watt hours or 3.2 KWH per day.
> To generate this amount of power you would need a solar panel of
> approx 600 watts
Assumes 5.3 hours per day equivalent peak insolation.
NY gets about 2.7 in winter, so if it's to work all year round multiply your
figures by 2.
Graham
Eeyore
Eeyore wrote:
> Synth wrote:
>
> > I was thinking about starting with the $600 diy solar project found
> > here: http://www.off-grid.net/2005/10/10/600-gets-your-house-on-solar-power/
>
> And WHERE on that page does it state how much power it will deliver ?
Oh here !
"One Uni-Solar 32-watt amorphous-silicon PV module, 12 volts: $180.00
First, the 32-watt amorphous silicon PV module. I chose amorphous silicon, as
opposed to crystalline silicon, for its superior performance in low light
conditions, since you’ll want to capture every ray of sunlight you can. It’s
nominally rated at 32 watts, but for reasons too complicated to explain here, the
most power you’ll ever see it produce with a standard charge controller is around 25
watts. This peak production will be for the two or three hours that straddle midday,
when the sun is highest in the sky. Though output varies with the seasons, this
small module will produce between 0.15 and 0.20 kWh of power each sunny day;
considerably less during cloudy periods."
How much do you expect to run on 32W when you have 2.7 hours of insolation ?
That's less than 0.1 kWh !
"So, in a reasonably sunny climate, you should be able to count on about one kWh of
energy per week, give or take. What can you do with that much-or that little-energy?
Keep reading."
ONE kWh of energy per WEEK ? Worth what ? maybe 20c ? So you get $10 worth of
electricity per year for an outlay of $600.
Even assuming your money earns no interest that would be a payback period of SIXTY
years.
But it's worse than that because after 60 years you will probably have had to
replace the batteries at least SIX times.
Two Deka 92 amp-hour sealed batteries, 12 volts: ($130.00 each) $260.00
That's another $1560. In short it'll never pay for itself and its total
environmental impact will be WORSE than using grid electricity.
Oh and after 60 years that panel might be down to 2/3 output or worse too.
> Probably reportable to the FTC for fraud.
Unquestionably if they think you can power the stuff they mention on it.
This stuff is all 'green propaganda' TRASH.
Graham
David Williams
-> heliostat to cook the hot dogs because of the fact that solar energy
-> is lost greatly when converting the suns energy from light, to
-> electricity, to heat. In truth, I imagined running a hot dog cart
-> where they keep the hot dogs in hot water, and that's how they cook.
-> It seems doubtful that a heliostat could heat several gallons of water
-> constantly through a day. Anyone want to run the math ;-)
Already done, and e-mailed to you.
If you use PV, you'll need tens of square metres of cells to produce a
couple of kilowatts of electric power. How much will you have to sell
the dogs for in order to pay off the cost of the cells in a reasonable
time?!
dow
nicks...@ece.villanova.edu
>I'm a software developer and I'm trying to branch out and get into
>solar power projects. I really have no experience and don't even know
>where to begin. All I have is the 2 semesters of physics(long ago)
>that I took in undergrad.
Solar heat from a sunspace can be 100 times cheaper than PVs per peak watt,
and houses need several times more heat than electrical energy.
>I was thinking about starting with the $600 diy solar project found here:
>http://www.off-grid.net/2005/10/10/600-gets-your-house-on-solar-power/
>but its a bit steep for my budget...
$600 might buy 200 ft^2 of "solar siding," eg a thermosyphoning air heater
with 4 12'x4' pieces of R2 Thermaglas Plus twinwall polycarbonate with 80%
solar transmission. In full sun (250 Btu/h-ft^2) on a 30 F day, you might
collect 200 Btu/h-ft^2 of 150 F air and lose (150-30)1ft^2/R2 = 60, ie 140
net (41 watts), at $3/41 = $0.073 per peak watt. The 7.9 kW output could
heat a house and water for showers, with the help of a $35 car radiator and
its 12 V 20 watt fans and a $60 13-gallon 1`x300' pressurized plastic pipe
coil in a polywood tank with a folded EPDM liner.
>Any readings that you all might recommend, especially primers on electricity
>concepts...
Ohm's law for heatflow is just Ohm's law for electricity with different units.
Nick