Efficiency in LEDs and lower costs for Solar Panels?

What would be up-to-date product examples for a high efficiency LED and a cost-effective solar panel? Thanks.

Reply to
Davej
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Does such beasts really exist ?

Reply to
upsidedown

You can buy them from Solyndra. To get a discount use the keyword "obamacon". ...Jim Thompson

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| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

Any solar panel can be cost effective if you get someone else to pay for it. Subsidies are your friend. Just beware of long-term power buyback programs that may vanish at any time. There have been examples of regional subsidies/rebates that vanished leaving customers shackled to EXPENSIVE systems they couldn't afford.

Reply to
mike

Make the check out to the "Democratic National Committee".

Reply to
krw

The blue spectral peak also inhibits the production of melatonin, thus, such lights should be avoided prior to going to sleep.

Reply to
upsidedown

onal

In my locale (ZA) it's beginning to be cost-effective to install PV panels even without getting someone else to pay for it - that is, if your electricity consumption is more than a few hundred kWh per month, which many households seem to manage. We have no power buyback scheme (big coal and big nuclear dominates our energy discourse) for residential users either. There are some factors in play here that might not apply in, say, Seattle. Good insolation, rapidly rising city tariffs, a national grid that's running at close to capacity with more coming online only over the next several years.

Water-heating panels have been cost-effective at the no-brainer level for a long time now, at least when compared to electric heating (which is still the most usual here - gah!), but unless you run a heat engine off it, it won't be lighting any LEDs.

Reply to
Bernd Jendrissek

Water heating panels have proven to be infuriating because of leaks, corrosion, appearance, installation costs, performance, temperature regulation, taste, and such. Virtually all of the local ones were torn out decades ago despite them being given out more or less free by a community college.

To date, not one net kilowatt hour of electricity has ever been produced by any pv panel. Breakeven will not happen until something like ten years AFTER the panel prices drop under twenty five cents per peak watt. Present true consumer pricing misses by a factor of THIRTEEN.

To date, pv panels are not in any manner renewable nor sustainable. They are simply gasoline destroying net energy sinks.

There are outrageous scams, of course, to steal federal funds that only marginally involve pv panels. All based on treating a subsidy as an asset, rather than a 3:1 to 5:1 hidden liability of true costs.

Much more at <

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Many thanks,

Don Lancaster                          voice phone: (928)428-4073
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Reply to
Don Lancaster

Rubbish "more or less free" ones might be. The Japanese seemed to be able to do thermal solar hot water correctly more than two decades ago.

That isn't true. You are just repeating an urban legend (unless that is you are counting the energy costs of all the refined semiconductors ever produced against the PV panels). Or as I suspect deliberately conflating their unfavopurable price with energy yield ratio.

The *energy* payback on a typical PV array 20 year lifetime is around 4x in the UK and 7x at more sensible latitudes for using solar power. The cost of the kit is far too extravagant but the net energy payback is real enough. See for example Richard & Watts 2007 as summarised by physicist David MacKay in Without the Hot Air.

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Non focussing concentrators can get you another factor of 2-3 without much extra cost but that is about as good as it gets.

The prices are outrageous but there is a small net energy gain from deploying them provided that they operate for at least 5 years. .

Not true. They may not be remotely cost effective unless you are off grid, or have insanely generous government backed feed-in tariffs (like in Germany) but they do provide some meagre energy payback after the first 5 years or so of operation.

I'd be happier if they were cheaper but I don't think that conventional refined semiconductors will ever be cheap enough for this purpose.

We have to wait for sunlight photostable screen printable organic LED type technology to make this technology really viable.

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Regards,
Martin Brown
Reply to
Martin Brown

Hi Don, Are you just counting the 'raw' energy used in making all the pieces involved. Or are you also including the 'cost of borrowing money', in that calculation?

George H.

one: (928)428-4073

Reply to
George Herold

Equate retail dimes to kilowatt hours just as the utilities do, and the numbers all fall in place.

If the panel generates two cents of electricity per day and true full burdened costs amortize to three cents per day, it is a net energy sink.

If the panel generates two cents of electricity per day and amortizes two cents (minus obscene subsidies, of course) it is only a "paint it green" and "feel good" transfer payment. Of gasoline in disguise.

With reasonable assumptions, a dime per kilowatt hour translates to fifty cents per peak panel watt. The "dollar per watt" holy grail is based on total system cost, not raw panel cost which only usually accounts for half the total. Since breakeven makes no economic sense, another 2:1 factor is needed to make pv viable for renewability and sustainability. Thus a quarter per peak panel watt.

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I reasonably expect the twenty five cent per peak watt to be achieved in a year or two. But certainly not with conventional silicon. And certainly not for consumer scale systems.

When it does, of course, the energy breakeven date will be pushed far into the future by all the new dollars being thrown at the technology. I'd estimate another eight years for the first actual pv net kilowatt hour being generated.

Much more at <

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Many thanks,

Don Lancaster                          voice phone: (928)428-4073
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Reply to
Don Lancaster

Hi Don,

That's interesting - as a casual observer over the years this is the first time I have seen you say this. That is, that you do expect solar PV power to be economically viable in such a near-term timescale. (Sorry if I missed this before).

Do you think we would be so close without any subsidies stimulating the industry?

I actually find that quite encouraging.

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John Devereux
Reply to
John Devereux

Thatcher, Arizona should be an absolutely optimal place for a solar hot water heater.

Number presently installed ---> approximately zero.

Number trashed out ---> approximately all.

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Many thanks,

Don Lancaster                          voice phone: (928)428-4073
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Reply to
Don Lancaster

Which subsidy do you prefer...?

The OLD CALIFORNIA model in which virtually all of the paybacks went into boiler shop scams that set pv back by many decades.

The NEW CALIFORNIA model in which it may take FIFTY THREE YEARS of total pv net new energy production to pay the debt. (analysis at <

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The TORONTO model in which they hand pushed and coasted their nonworking hydrogen bus into a major media event. Where, of course, it was lavishly praised for its silent operation.

The ARIZONA model in which you were given a free SUV for installation of a unconnected one gallon tank.

The DETROIT model where their bus demos are trucking hydrogen in from Pittsburgh.

The MIDWEST model where a monumental energy sink was cleverly disguised as a twelve billion dollar vote buying scam.

The SOUTH CAROLINA model where they added a five ton evaporative cooler to get their 3 ton but nonworking solar adsorption cooler to look good.

The BRAZIL model that nearly bankrupted the entire country over monumental ethanol stupidity.

The SOLYNDRA model that was obviously a blatant political payoff.

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The subsidies, of course, have been a ludicrous joke that do ridiculously and insanely more harm than good.

That is before you accept the reality that a dollar subsidy is not at all an asset, but a liability whose true cost is likely to exceed $3 to $5 per dollar of face value.

Please see <

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Many thanks,

Don Lancaster                          voice phone: (928)428-4073
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Reply to
Don Lancaster

A few decades ago, when I was working in the Middle East, they used white (not black) plastic containers for heating water for the shower. The only problem was that you had to take the shower in the evening (not the next morning).

These days, the tubular vacuum collectors are quite effective even above 60 N between spring and autumn. At these latitudes, any solar based system is useless between October and March.

Reply to
upsidedown

A solar water heater SHOULD be useful, and cheap, but...

First, you need to have a larger than normal storage tank because what you have is ALL you have.

Next, you need to have a circulating pump, because you can't just plumb your water line into the panels. The panels need their own closed system, that must contain antifreeze, anti-corrosives and other additives. Must also be able to compensate for pressure changes as the system heats and cools.

It takes electrical power to run that pump.

You still need a backup water heater for long cloudy spells.

By the time all this gets factored in, a gas water heater makes a lot more sense!

Charlie

Reply to
Charlie E.

33S with maybe 200 sunny-ish days is just fine then.

Most solar water heating systems around here have electric backup for the cloudy/rainy days.

If you're lucky or just willing to do the extra effort, you put your tank above the panel. Thermal siphon.

Not a problem in my city, but may be elsewhere. Direct heating (no heat exchange with a closed system of working fluid) works just fine. Here. Maybe not where you are.

Hot water plumbing has this anyway.

Depends. Gas can be expensive and sporadically unavailable (ever since everyone mass-converted to gas cookers in 2008 when our national grid ran out of oomph). Either way, there seems to be a powerful incentive at work around here to install solar water heating panels - not gas, and not electric-only heating. The only other system gaining traction is to install a heat pump, but I don't know enough about prices etc. to comment on those.

Reply to
Bernd Jendrissek

Natural gas only makes sense if it is available at your house.

Dan

Reply to
dcaster

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