Solar powered motorhome question.

[Sunking]

nternal the only way you are going to get electric heat in an RV is to park it at an RV park and plug into the grid.

Lights are no problem using solar in an RV. Refrigeration is going to be a challenge but possible and will need a generator as backup. For heat and cooking you are going to need LPG.

[rbtrrer]

4-6-8k$ should get >adequat system but still may have to suplament with generater/grid charge based on amount of sun.


*caveats abound!!!

[nternal]

You can read the MIT and other university web sites for this kind of stuff as well.

When the product goes commercial and is actually used in other than an extremely controlled environment for a selected audience it means something - this is PR chatter probably looking for suckers for more funding. The fact they list a Cleantechnica article for PR says a lot about the company and none of it good - I firmly believe they post articles for pay.

Ok... how about "cold fusion"!

[russ]

You can read the MIT and other university web sites for this kind of stuff as well.

When the product goes commercial and is actually used in other than an extremely controlled environment for a selected audience it means something - this is PR chatter probably looking for suckers for more funding. The fact they list a Cleantechnica article for PR says a lot about the company and none of it good - I firmly believe they post articles for pay.

[Mike90250]

... BTW, does anyone have any thoughts on the recently developed full spectrum solar panels that are 70% efficient and, in theory, cheaply manufactured?

Vaporware and/or scam - they don't exist

[nternal]

1) The claims made by the company are a bit magic - if you check up on both flat plate and evacuated tube type exchangers their overall efficiency is quite similar -
a) In a cold or cloudy situation the evacuated tube type are generally better
b) Evacuated tube type can produce hotter water but less volume
c) In a mild sunny climate the flat plate type win hands down

2) Their chatter about converting 92% of incidental UV is of no meaning - except to impress newbies

3) Solar for infloor radiant? I have looked at that before and have come away totally unimpressed - takes storage and many panels.

They must be having fun trying to sell their product in the land of cheap electricity - even with the rather inflated claims.

The site is dedicated to the fuzzy headed green lot that love such inane chatter.

Well it did sound a little too good to be true.

[nternal]

You might be talking about Off Grid Solar in Florida (I believe that is the correct name)? That has been well documented to be nothing more than a scam from what I have read.

Nope, here's a very recent article: http://www.photonics.com/Article.aspx?AID=50200
and... one of the companies that I believe is currently developing the concept : http://www.sj-solar.com/

[russ]

Electrical heating looks like it's a no go but this vacuum tube "heat pump" idea looks promising. Would this work on a motor home do you think? Check it out:http://www.solarheatingcanada.com/

1) The claims made by the company are a bit magic - if you check up on both flat plate and evacuated tube type exchangers their overall efficiency is quite similar -
a) In a cold or cloudy situation the evacuated tube type are generally better
b) Evacuated tube type can produce hotter water but less volume
c) In a mild sunny climate the flat plate type win hands down

2) Their chatter about converting 92% of incidental UV is of no meaning - except to impress newbies

3) Solar for infloor radiant? I have looked at that before and have come away totally unimpressed - takes storage and many panels.

They must be having fun trying to sell their product in the land of cheap electricity - even with the rather inflated claims.

The site is dedicated to the fuzzy headed green lot that love such inane chatter.

[russ]

I've read about recent advances in full spectrum solar panels. Any thoughts on when these might become available?

You might be talking about Off Grid Solar in Florida (I believe that is the correct name)? That has been well documented to be nothing more than a scam from what I have read.

[nternal]

P.S.

Thanx for setting me straight Sunking.

BTW, does anyone have any thoughts on the recently developed full spectrum solar panels that are 70% efficient and, in theory, cheaply manufactured?

[nternal]

Those 40% cells are actually available. however the only one that can afford them is NASA. They are not commercially available in any kind of quantity and can run into the thousands of dollars per watt. Not something you would be putting on your RV roof.
Lighting and Refrigeration are the two things you will most likely be able to run. And refrigeration in the winter means for the most part in the out of doors or cooled by ambient. Luckily this cold part of the year with little sun is the time when there is a reduced need for refrigeration.
Heat is probably not possible unless you can come up with a wood burning boiler that would sit outside but moving it around could be an issue.
Moving around and plumbing a number of thermal collectors could be an issue too. and having enough storage to keep you through a night or a day or two of no sun would be a huge storage mass. (4-500 Gallons of water in a well insulated vessel)

Electrical heating looks like it's a no go but this vacuum tube "heat pump" idea looks promising. Would this work on a motor home do you think? Check it out:http://www.solarheatingcanada.com/

[Sunking]

1) You claim a 400wh of sun gives 200wh hours of recharge but I was under the impression that even the very best cutting edge panels are only about 40% efficiency?

You are confusing two different parameters. You are confusing panel efficiency with system efficiency. They are not related to each other.

Mike is speaking to over all efficiency of an Off-Grid Battery System which is 50%. The panels generate 400 wh to generate 200 wh of usable power.

You are speaking of panel efficiency which is only important with reference to physical size or area of the panel. Best panels on the market are about 20% and very expensive. A square meter of surface has 1000 watts of electrical energy at high noon on Equinox and Solstice. So if the panel is rated at 20%, and 1 square meter in size it will be rated at about 200 watts.

2) Also, aren't lithium ion storage cells the current state of the art?

Yes and no. The kicker is expense for top of the line A123 System batteries beiong used in production electric vehicles. A good flooded lead acid deep cycle battery will outlast a lithium, and cost about 12 to 15 cents/watt hour. A Lithium will cost upwards to around 50-cents/watt hour for a low grade Chi-Com unit and up to $1 or per watt hour for high grade LFP pouch or prismatic cells.

Lithium advantage is energy density which is mission critical for electric vehicles as their specific density runs up to about 120 wh/Kg vs 45 wh/Kg for a lead acid cell. Weight is not an issue for Solar PV systems, but critical for a EV.

[Naptown]

Mike90250, I get it that one isn't going to be able to capture much usable energy from the sun. I'm an absolute newb and confused about 2 things:
1) You claim a 400wh of sun gives 200wh hours of recharge but I was under the impression that even the very best cutting edge panels are only about 40% efficiency?
2) Also, aren't lithium ion storage cells the current state of the art?

I guess I would need a massive set of panels to do what I'm proposing or maybe... Could this technology be used on an RV:http://www.solarheatingcanada.com/

Those 40% cells are actually available. however the only one that can afford them is NASA. They are not commercially available in any kind of quantity and can run into the thousands of dollars per watt. Not something you would be putting on your RV roof.
Lighting and Refrigeration are the two things you will most likely be able to run. And refrigeration in the winter means for the most part in the out of doors or cooled by ambient. Luckily this cold part of the year with little sun is the time when there is a reduced need for refrigeration.
Heat is probably not possible unless you can come up with a wood burning boiler that would sit outside but moving it around could be an issue.
Moving around and plumbing a number of thermal collectors could be an issue too. and having enough storage to keep you through a night or a day or two of no sun would be a huge storage mass. (4-500 Gallons of water in a well insulated vessel)

[nternal]

Are full spectrum panels available yet?

I've read about recent advances in full spectrum solar panels. Any thoughts on when these might become available?

[nternal]

Panel efficiency?

Mike90250, I get it that one isn't going to be able to capture much usable energy from the sun. I'm an absolute newb and confused about 2 things:
1) You claim a 400wh of sun gives 200wh hours of recharge but I was under the impression that even the very best cutting edge panels are only about 40% efficiency?
2) Also, aren't lithium ion storage cells the current state of the art?

I guess I would need a massive set of panels to do what I'm proposing or maybe... Could this technology be used on an RV:http://www.solarheatingcanada.com/