British Petroleum and the Sun

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We're helping some people next week set up their solar array on Mackin Creek Farms, an organic vegetable farm. They have 4 acres of garden. They want to power their 240 volt (60hz) walk-in fridge, lights around their barns, washing areas and have the option of easily being able to add on to their system as they expand and bring the sun's energy into their house. Photovoltaic systems allow this kind of flexibility depending on your needs.

The great thing for them is that they work hard outside in the months when the sun is high in the sky. That is when their fridge demands power. As the farming season winds down, the air cools outside and the days become shorter. Their fridge demands less and less power until it is turned off for the season. They don't realize it yet but the system we are setting up will be all the power they need all year.

They are connected to the grid which will make the whole experience easier for them as they make the transition into a lot more freedom.


Here is their system and a list of prices:

three 175 watt Sharp panel ($633 ea.), $1899 (525 watts of power)

one 30 amp 24 volt controller, $156

one 3000/6000 watt 220/240 volt inverter, $499

twelve 6 volt 12 volt HD batteries($143 ea), $1716
(1320 amp hours of 12 volt storage)

$4270
for the main components

miscellaneous cables, fuses, switches, $500

Shipping, $250

Grand total, $5020


With a 110/120 volt, 3000 watt inverter ($500) they'll be able to power their house.

Our own system, which we built over a 5 year period (half of the power they are going to have) cost $5000 10 years ago. We live comfortably in the bush and run a small shop. Our panels were made by Bp and came with a 25 year
guarantee. 13 years later they are as efficient as the day we bought them.

The technology now is trying to mimic photosynthesis. Using organic and recyclable materials. Should be available very soon, within the next 5 years.

Right now panels use silicon as their semiconducter material. Silicon is everywhere but to use it as a semiconducter material it has to be 99% pure. That means furnaces, smelting, tailings etc... The backing ( it must be able to withstand hot temperatures for a long period of time. 25 years is the standard guarantee) that holds the semiconducter materials in place is made from a polyvinyl. Hard to recycle and toxic but there are companies recycling it. 5NPlus is one of them. .

I've read that the real cost of a panel pays for itself in 10 years. Soon that will be 5 years with the technologies being developed. I wonder if human life was factored into that.

It is tempting to say" I'll wait for equipment to get cheaper and safer". Personally I think that is only an excuse to bury one's head in the ground. For sure we live in a market driven society. Along with the crap the market brings solar power will only get safer and cheaper faster if that's what we want.

We have been living and hopefully spreading some freedom.

It is breathtaking how long this transition is taking when one considers it could literally happen overnight for most in North America. "Tomorrow I will buy a solar panel".

Scott

http://aki-and-scott-fireweed.blogspot.com/
http://www.caribooblades.com/newknives.html
 

Tony

White bear (Admin)
Admin
Apr 16, 2003
22,628
1
928
50
Wales
www.bushcraftuk.com
I think that's really interesting Scott, I like the breakdown . I was looking at some stuff for my place a little while ago and came back with £30,000 to take us off grid, I'm sure it could be done cheaper. I need to look into the whole thing more.

Some pictures would be good as well :D
 

Matt.S

Native
Mar 26, 2008
1,075
0
33
Exeter, Devon
I wonder if using DC appliances would be worthwhile, in terms of using a smaller (cheaper) inverter) and power economies (no inverter losses).
 

andy r

Tenderfoot
Apr 13, 2010
86
0
Torquay
I have done some research into building a generator room for an old style diesel with a modern genny attatched, ruuning on used veggie oil, watercooled with the coolant system running to the house to heat the water tank and radiators, the 2 factors that are causing me problems are noise and smell !
 

drewdunnrespect

On a new journey
Aug 29, 2007
4,788
0
teesside
www.drewdunnrespect.com
andy in regards to smell pass now noise i can help what to is either sound proof the room or build on a spercific room thats fully sound proof like radio booth or buy a canal boat spercific one cos the are really quiet but are expensive as u probably guessed.
now then sound proof according to my dj and music creating mate. what you need is polystyrene blocks that you can glue to the walls and ceiling because supposedly it deaddens the noise.

anyways it might help but i bet there will be some one along to help you more than me
 

Tengu

Full Member
Jan 10, 2006
11,266
704
48
Wiltshire
Thanks for saying that.

I have met so many people telling me its not possible.

And companies that will rip you off
 

ged

Bushcrafter (boy, I've got a lot to say!)
... if it's a long narrow boat ... you get a lot of voltage drop.

The voltage drop is proportional to the current drawn. If you use normal domestic cabling and low-current lighting like light-emitting diodes, the voltage drop will be negligible. LEDs work on a low voltage anyway (two or three volts), so a device which conditions the power for LEDs can easily cope with something less than 12V.
 
Apr 14, 2006
630
0
Jurassic Coast
The voltage drop is proportional to the current drawn. If you use normal domestic cabling and low-current lighting like light-emitting diodes, the voltage drop will be negligible. LEDs work on a low voltage anyway (two or three volts), so a device which conditions the power for LEDs can easily cope with something less than 12V.

You're not allowed to use domestic cabling in canal boats, it's considered dangerous although in other situations it's probably ok. Most people use multi-strand wire and go for the thickest they can afford, 10mm is normally sufficient for 12v


.
 
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ged

Bushcrafter (boy, I've got a lot to say!)
Apr 14, 2006
630
0
Jurassic Coast
No Ged I haven't the time to look it up but I did live on the canal for 10+ years and can say with confidence that if you were to hardwire household domestic wiring in a boat it would fail the test, mine did!


Back on topic... Cariboo those prices seem very good, particularly the solar panels.


.
 
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Aragorn

Settler
Aug 20, 2006
880
2
47
Wrexham, North Wales
multistrand "flexable" cable is also prefered in caravans, the reason being it has a bit of give in it, caravans and I suppose boats move and flex, solid t+e domestic cable would tend to pull out of fittings and connections, whereas flexable cable would not.
 
I think that's really interesting Scott, I like the breakdown . I was looking at some stuff for my place a little while ago and came back with £30,000 to take us off grid, I'm sure it could be done cheaper. I need to look into the whole thing more.

Some pictures would be good as well :D

I purchased the Sharp 175 watt 24 volt panels from these people,
http://www.renewcanada.com/spring_specials.html

Panels are in over supply and the price of silicon is way down. Silicon is 40% of the panel cost. Producers are selling at almost 1/2 price. Panels in the UK should be much cheaper. If they aren't your being shystered.

The batteries are 6 volt 220AH heavy duty Battery Direct (also known as golf cart batteries). Because I bought 12 for our friends and 2 more for us they came down in price from $249 to $139 each. All of them fit onto a smaller pallet.

The inverter is from the States.
The problem in your country and Canada is the killer duty charges.

We're going to install the set up in a couple of weeks. I'll be sure to take pictures.:)
This system is a bare bones set up. Like having a generator. Basically plug in or plug it in to your house. I think for most this is the way to go.

About DC appliances. Aki and I have two systems. Both are 12 volt. We have a few lights running, our music centre and water pumps on our smaller 85 watt panel 12 volt system. They are close to the batteries. The second system, 300 watts of panel, runs our small house and our shop through a 110/120 volt inverter. I could pick both these systems up, load them in my truck and set them up anywhere (in a day or two).
The system we are installing is 24 volt because of some of the distances, it's a farm. It has all got to do with wire loss. Copper is expensive. Inverters are getting more efficient.
A boat could be wired 12 volts, even a cabin but a house could be 24 even 48volts.

Scott
 

rik_uk3

Banned
Jun 10, 2006
13,320
20
66
south wales
What a great thread, I'm enjoying reading it. I dread to think how many panels you would need to power the typical house and all its appliances though without drastically cutting back on the amount of kit you run at anyone time:eek:

I'm going to have a walk around the house tonight and estimate how much power we are using.
 

horsevad

Tenderfoot
Oct 22, 2009
92
0
Denmark
Regarding solar power....

Just thought I would add a couple of calcultations which might be usefull for planning solar power configurations.

The amount of solar radiation output from the sun is nearly constant, but the distance between Sun and Earth changes with several million kilometers through the year.

On average we receive 1369 watts pr square metre, but this is a calculated value for a 1 metre square at 149,596,000 km distance from the centre of the sun. A small amount of radiation is absorbed by the atmosphere of the earth, but this number is rather small and difficult to calcultate exactly. Furthermore the radiation varies as the distance between the sun and earth changes, but this number is also pretty small.

Further, the radiation from the sun normally hits the earths surface at an angle, thereby enlarging the area on which a solar ray of 1 square metre would hit. This affects the amount of received energy by a large amount.

Therefore we have to calculate the amount of radiation which is practically reaching the surface of the Earth, and which can be converted into photovoltaic energy by the solar panel.

To do this calculation we need to know the angle between the sun and the horison. Where I live this is about 57 degrees in the summer and some 10 degrees in the winther.

The area which a one square metre solar ray would cover can be calculated by the formula a= 1/sin(h), where "h" is the suns angle above the horizon.

To convert this to a usable number (given in watts pr square metre) one would divide the solar constant by the area reduction calculated above.

An example for the summer:

Solar constant is 1369 watts pr square metre,
Suns height over the horizon measured in degrees (elevation) is 57,5 degrees

1369 / ( 1 / sin 57,5) = 1154,6 watts pr square metre


Similar example for the winther:

Solar constant is 1369 watts pr square metre,
Suns height over the horizon measured in degrees (elevation) is 10 degrees

1369 / ( 1 / sin 10) = 237,7 watts pr square metre

These numbers give a realistic approximation to how much solar radiation reaches the solar panels.

However, the solar panels cannot convert the energy totally efficient, instead the efficiency for good solar panels is about 20%.

This means that - in the wintertime - a one square metre solar panel might produce 47,5 watts at my location.

In the summertime it would produce 230 watts at my location.


Further one need to calculate the amount of hours that we receive usefull sunlight pr day. For the winter - at my location - this is about 5 hours a day.

This means that the one square metre solar panel would produce 5 hours of 47,5 watts, equalling 237,5 watt-hours or 0,237 kilowatt-hours. To put into perspective, this amount of power would be enough to power a small laptop for about three hours, but not for running any larger household appliances for any amount of time. It would not even be enough to supply the needed power for the circulation pump in the wood-burning central heating system.


For the summertime the numbers are all different. We would get more than 12 hours of usefull sunlight - meaning 230 watts * 12 hours = 2760 watt-hours or 2,760 kilowatt-hours. This is a respectable amount of power.


So, the conclusion for this rather long-winded (and probably terribly boring) ramble is that one need to calculate the solar power system before commiting to any purchase. For the lower lattiudes solar power is terrific - for the higher lattitudes it is seldom a viable power generating scheme for the wintertime.


Btw, english is not my native language (I am from Denmark) - so please excuse me if I have made some terrible grammatical blunder!

//Kim Horsevad
 

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