Foo - So what's more efficient?

Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.




View Full Version : So what's more efficient?


RubenX
02-13-09, 05:45 AM
You are given 2000k square feet and have to choose one of these:

A) Cover the area with solar panels and produce electricity. Consider cost & efficiency of solar panels, inverter and any other necessary pieces.

B) With parts from home depot, construct a gigantic DIY solar water heater to make steam and run a steam turbine to make electricity. Again, consider cost of parts & possible efficiency of the rig.

I have no idea what the answer is, I just wanna see people argumenting and stuff.


mickey85
02-13-09, 05:50 AM
If it was my house, I'd put in solar panels, and augment with geothermal heat. Voila - you have electricity, you have heat, and you're good to go.

IMO, a DIY solar water heater is very inferior when talking about water heat - geothermal is relatively constant and doesn't rely on the fickle whims (yes, I used that term) of the atmosphere.

Then again, if you were to use radiant water cooling in the summer, that would be a plus...install radiators on the roof, run pipes through the walls and through a concrete floor, and it'd radiantly cool off your house. Better than air conditioning.

Metzinger
02-13-09, 06:06 AM
With parts from home depot, construct a gigantic DIY solar water heater to make steam and run a steam turbine to make electricity.

Is your roof hot enough to boil water?
Global warming must be worse than I thought.

Solar water heaters are used for water and space heating, not electricity generation. But if you can use the heat, they're more productive, per sq ft, than photovoltaics.


RubenX
02-13-09, 06:07 AM
I would go with the panels too, cleaner and more elegant. But the hidden red neck in me kinda wants the solar water heater + steam turbine to beat the solar panels. A very redneckish rig with copper pipes running on parabolic mirrors, feeding a home made tesla turbine, attached to an old automobile alternator...

RubenX
02-13-09, 06:12 AM
Is your roof hot enough to boil water?
Global warming must be worse than I thought.

Solar water heaters are used for water and space heating, not electricity generation. But if you can use the heat, they're more productive, per sq ft, than photovoltaics.

Yes, you CAN make steam with a DIY solar water heater. One of these (http://www.youtube.com/watch?v=kXXOwfZA2Rk) will do, bigger tho...

Very efficient to heat the water but... when using the steam to run the turbine, a lot of the heat energy will dissipate...

But then again, what's the efficiency on solar panels? not a whole lot... it would be an interesting experiment.

jsharr
02-13-09, 06:14 AM
I would check with my local government and homeowners association to see what they allow before I did anything.

Once I knew my options, I would begin to gather information.

RubenX
02-13-09, 06:52 AM
I would check with my local government and homeowners association to see what they allow before I did anything.

Once I knew my options, I would begin to gather information.

u have one of those? dude, I feel bad 4 u ...

Metzinger
02-13-09, 07:00 AM
Yes, you CAN make steam with a DIY solar water heater. ... it would be an interesting experiment.

I'll amend my earlier statement.
It is possible to boil water using solar.
You cannot build a DIY steam turbine power plant.
This project is far beyond the expertise of the Home Depot plumbing aisle guy.

But, then again, you could ask him.

RubenX
02-13-09, 07:14 AM
I'll amend my earlier statement.
It is possible to boil water using solar.
You cannot build a DIY steam turbine power plant.
This project is far beyond the expertise of the Home Depot plumbing aisle guy.

But, then again, you could ask him.

yes you can :D (http://www.youtube.com/watch?v=UR9xWq6J-gA)

WJ13US
02-13-09, 07:27 AM
I would first find out where the area is. If it's say on Mars or the moon then I doubt I'd find a Home Depot near by and water would be hard to come by.

RubenX
02-13-09, 07:31 AM
I would first find out where the area is. If it's say on Mars or the moon then I doubt I'd find a Home Depot near by and water would be hard to come by.

Not a problem (http://www.youtube.com/watch?v=nVYU8NJOtWw), you can order the stuff via fedex

jsharr
02-13-09, 07:39 AM
u have one of those? dude, I feel bad 4 u ...

No, I do not have one of those, but many places do. We do have a neighborhood association that helps with crime watch ( I am a block co captain), has house numbers painted on curbs, puts on holiday events and publishes a neighborhood phone book. Dues are $10 year and membership is voluntary.

RubenX
02-13-09, 07:43 AM
Remember I'm not talking for real... just for the sake of science knowledge and sacred speculation :D

pacificaslim
02-13-09, 08:56 AM
Well, hypothetically speaking, if this 2000 ft2 was in a city, I'd just turn it into a parking lot and pocket the $5k or so a month in income. That'd feed a lot of starving children.

trsidn
02-13-09, 09:28 AM
argumenting?

JoelS
02-13-09, 09:44 AM
A small nuclear reactor and sell the electricity back to the grid. I saw a paper about these a month or two back. They're designed to power small neighborhoods and are pretty cheap to run. But they cost about 25 million to install.

I found the article: http://www.guardian.co.uk/environment/2008/nov/09/miniature-nuclear-reactors-los-alamos

Michigander
02-13-09, 10:07 AM
Why not do everything you can afford and fit? It wouldn't exactly be hard to have solar panels underneath a couple small windmills, with some geothermal stuff maybe crammed in there too.

x136
02-13-09, 09:53 PM
You could fit a ****-ton of solar panels onto two million square feet of roof. It'd probably cost approximately seven ****-tons of money, though.

AEO
02-13-09, 10:39 PM
just the panels. For the same area you can use, the more efficient one would be the one with less moving parts.

but your steam turbine is going to be 3D and not just 2D in terms of space consumption.
So, if you make your boiler tall enough, I think it would win over the solar panels alone.

I wonder if the aussies have started their work on these things.
http://www.wentworth.nsw.gov.au/solartower/

RubenX
02-14-09, 01:40 AM
I did some digging. Current efficiency record for solar panels is at 42.8% (according to the wiki (http://en.wikipedia.org/wiki/Solar_cell#Records)) while heat engine methods top a 31.25$ (info here (http://www.sandia.gov/news/resources/releases/2008/solargrid.html)). No info about the cost per watt tho...

cwathne
02-14-09, 02:30 AM
Given the lack of sun here in Seattle, I would do something like this...
http://www.windaction.org/images/663.jpg

WJ13US
02-14-09, 07:48 AM
Grow corn and make ethanol?

cyclokitty
02-14-09, 09:20 AM
I'd build a massive indoor cat jungle gym then invite all the kitty cats in the neighbourhood to come play over at my house.

surfrider
02-14-09, 10:31 AM
Here in sunny Southern California, a 'hybrid' system would be the way to go.

1. Install solar panels to make electricity, plus batteries to store the extra 'juice'.

2. Install solar water heater panels to heat water up to whatever temp you can get it. Use electric power to further heat the water up to a usable temp for washing, etc.

3. Might also run the hot water through the house for passive space heating in winter.

jasonsstover
02-14-09, 03:36 PM
800 Sq Ft solar hot water, for radiant floor heating and the remaining 1200 Sq Ft for Solar Panels.

ModoVincere
02-14-09, 03:59 PM
A lot is going to depend on where you live. Angle of the sun, daylight hours, ground temps, etc.