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Solar Power From Home Curtains
kaliann writes "With the push for more sustainable energy, easy DIY kits for alternative energy sources are likely to become quite popular in the coming years. We may see some big improvements in our ability to 'green up' if these photovoltaic curtains become widely available."
Actually, RMIT (a tertiary institution here in Australia) recently announced that one of their new buildings will be solar-powered thanks to the glass on the buildings. From the article: blah blah blah "with an outer skin of 16,000 sand blasted glass cells, some of which will be photovoltaic solar power collectors to help shade and power the building."
The panels turn transparent when they come in contact with water, so it's mainly for when it's raining (I suppose there are other, far less peaceful circumstances in which water can hit them). Otherwise they're translucent.
Actually I think they will save more power with the curtains open than closed.
I'm shooting from the hip here but looking at the picture I expect there's a serious flaw here. The Curtains look black so they are absorbing a lot of light energy. We know they are highly inefficient. So they mainly heat your house.
SO in summer time you will pay more in cooling costs than you gain in electricity. Either that or be warmer. Logically you want the drapes outside where they would be amiently cooled.
Now if you draw the blinds and thus it gets darker and you need to turn on a light well. So much for any gains.
Finally most houses are designed to have their windows shaded more or have an oblique incidence in summer time. Thus during the time of maximum sun, and warmth you get the least electricity.
In winter time when the solar flux is less and there will be fewer hours of daylight the direction of incidence will be better. But chances are you'd like the light.
The drapes have no thermal mass so they act like the worst kind of traum wall where they heat up and cool down quickly. No thermal damping.
Seems like archecturally this is a bad idea from the get go regardless of how the solar fabric technology improves. Maybe in northern canada or something it makes sense.
Some drink at the fountain of knowledge. Others just gargle.
While this is true for batteries, I do not believe that batteries will power the future electric cars. Do a wikipedia search for Supercapacitors to see what is on the horizon. They are not yet perfect but MIT has demonstrated capacitors that offer 1/4 of the storage capacity of Li-Ion batteries.
There are many advantages to using capacitors in place of batteries - mainly due the the greatly reduced internal resistance. First, the charge time is reduced to under 10min. Second, when used in a hybrid vehicle, one does not encounter the loss associated with "charging" the batteries so regenerated power can actually be reused. Thirdly, they will not go bad like batteries. They are typically rated for ~10000 charge cycles. There are also many other reasons why these new capacitors are desirable - just read the wikipedia link.
Nasch already took care of some of your illogical arguments... but you've made other assumptions that are just plain wrong or at best outdated.
20% efficiency on a solar panel is not uncommon. In fact, you can buy 28% efficient solar panels (as long as you don't live in the US *grumble*). Over their lifetime, of course that rate is going to fall, but it will still remain a bit above 20%.
Given time, that efficiency is only going to improve. Both of these factors right there shoot your 600M^2 theory to shit.
Using you and your family as an example, your average 1.4KW usage could be dramatically reduced without impacting your quality of life in an appreciable manner. I know this is so because I've done it myself. It takes some will power and awareness of what power you are actually using, but it can be done fairly painlessly. You can start by replacing your incandescent bulbs with CFL or better yet with LEDs. One of the largest single power draw in a home is from all the light bulbs. Reducing that can cut your monthly average quite a bit.
You need to turn off stuff you aren't using. Putting things into standby is not turning them off... in fact, many appliances and electronic gadgets don't even HAVE an off switch, they go into standby. So that means you have to unplug them. That's a pain in the ass. However, a simple solution to this is to plug everything you use for a particular activity into a power strip... when you're done, turn the power strip off. This overcomes the leeching power used by wall-warts, as well as gadgets and electronics that go into standby mode. Yes, you may have to wait a few seconds longer for something to power up, but it's not a huge deal.
Another big energy saver is to replace your windows. If you have contractor grade windows in your house, you are leaking energy like a sieve. Replacing your windows with high quality double or triple paned, krypton filled windows with insulated frames will save you a TON of money and energy for cooling and heating.
Do you have an ancient refrigerator? If so, it's probably drawing 2 to 3 times the amount of energy a modern refrigerator uses (or more if it's REALLY old). Might be worth it to replace it.
Do you leave your computer on at night? Turn it off, or at least put it in standby. My system, at idle, draws about 600w, when it's in standby it drops to about 30w. That's a HUGE savings on a month or yearly basis. If you're on Slashdot, chances are you've got multiple computers - I think you see where that's going. If you're using an old computer as a Linux router or something we are all fond of doing - stop. Old computers are incredible power hogs. A cheap wireless router that you can load new firmware onto will suck a fraction of the power, produce a fraction of the heat and noise. It's nice to think you're recycling your computers, but it's costing you more than they are worth in power per year, for sure.
There's lots of things you can do to reduce your power consumption. You can take your 1.4kw to 800kw fairly easily I suspect. That almost halves your 600M^2, coupled with the fact that you can buy efficient PV panels, now you only need about 200M^2. The average house has that much roof space that's likely suitable.
Even if you don't, as long as you are offsetting some of your power needs, it goes a long way to helping bring about a more energy efficient future.
Is it going to be uncomfortable? Probably a bit, but not cripplingly so, and once the "new" way sets in, it will seem silly that we didn't do it a long time ago.
Study some heat transfer principles. Depending on their reflectivity, these curtains may cause the roof to absorb MORE heat than the roofing does.
Ideally, solar installations for home use will not transfer heat directly into the house. A curtain laying directly on the roofing surface will absorb some light and create some electricity. However, light and heat that is not reflected will absorb and the greater part will transfer through to the house a large amount of heat. A smaller portion will radiate from the house.
Solar panels are typicaly elevated above the house. The air gap allows the panels to be cooled by airflow.
The actual news here is that they can create solar fabric. I'm sure they can design a roofing system that will use the material to generate electricity while the system maintains an air and water seal and reflectivity of the largest part of the sun's energy.
TANSTAAFL GIGO Acronyms to live by!
People don't even do it when it's a trivially easy task that they perform regularily anyway.
Take modern light-sources as opposed to incandescent ones. A typical bulb migth live for 2000 hours, cost $1, and consume 60W. A modern replacement (that screws directly into the same socket) migth live for 8000 hours, cost $10 and consume 15W.
At current electricity-prices it SHOULD be a complete no-brainer.
$1/2 + 1000 * 0.06 * $0.15 = $9 (for each 1000 hours of light)
$10/8 + 1000 * 0.015 * $0.15 = $3.50 (for each 1000 hours of light)
It's one third the price, basically.
It's also more environmentally friendly (ok, so you DO need to return the used bulbs responsibly), creates less extra heat in the summer, and thus reduces your AC-bill somewhat.
And it literally costs you NO time at all. When the old bulb burns out you need to put in a new one ANYWAY. And putting in a modern one instead of an old-fashioned one is a similar task, one ain't harder than the other.
Nevertheless, hundreds of millions of old-fashioned bulbs burn in USA today. It's sad, really.