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solar power

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Re: solar power
Post by thinkstoomuch   » Mon May 02, 2016 10:54 am

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Start at Battery University.

http://batteryuniversity.com/

After you understand the batteries that are currently available. Then maybe we can talk intelligently.

4,500 PSIG is nothing to joke about. Splitting is an explosion just a cold one.

Really could go on but not worth it until you read up on it.

By the way did anybody wonder why I want a technology that is efficient at converting thermal differentials to energy. This is one of them.

T2M

Lord Skimper wrote:...snip...
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A: “No. That’s just the price. ...
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Re: solar power
Post by Lord Skimper   » Wed May 04, 2016 6:39 am

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4200-4600 psi cylinders were designed to split not explode, be scary but not explosively deadly, in a car accident. In a home system the cylinder would be underground.
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Re: solar power
Post by Imaginos1892   » Wed May 04, 2016 8:02 pm

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If you cram 150 cubic meters of air into a 500 liter tank at 300 bar, it would represent a bit over 12 KWh of stored energy. That's about the minimum for a residential solar/storage system intended to get through a few cloudy days at a time.

If Something Bad happens to the air tank, all that air will want to expand back to 150 cubic meters very very fast, and the absolute last thing you want to do is try to confine it. That's the volume of a small house, and that's the size crater it will make in your yard. You didn't put it under the house, did you?

By the way, compressing the air to 300 bar will heat it up to almost 2,000 C - what's that tank made out of, again? If you let the air cool off before using it, all the energy that went into heating it was wasted.
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Re: solar power
Post by HB of CJ   » Wed May 04, 2016 8:27 pm

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It is my understanding that fire fighting service self contained breathing apparatus has safely used 4500 psi for quite sometime?

The aforementioned high pressure fiberglass, carbon fiber and aluminum bottles seem to hold up quite well under fire conditions.

In 1980 we used 2200 psi common underwater scuba tanks to power many air driven screw drivers in the building construction trades.

The high pressure contents of the tanks required procedures in the refilling procedures. No big deal but very important for safety.
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Re: solar power
Post by thinkstoomuch   » Thu May 05, 2016 4:04 am

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Do some looking around for a Mark 32 Torpedo Launching System. Mechanism for launching I think it was 5 pounds (mass) of atmosphere. Watch how far the torpedo goes in some of those pictures. Not at 300 bar! Much less.

For HB the steel bottles are fairly safe. Except of course the fitting to the bottle prior to the regulator and air hose attachment. Bet that bottle was securely attached to something out of the way. The more modern materials are lighter and probably fairly safe. No idea on the pressures.

Also the reason a 15 pound CO2 bottle from when I was in the Navy was considered very dangerous. Always keep a hold on it. Otherwise it turns into a pretty good reaction engine. Even with 35 pounds of steel wrapped around it.

Even a low pressure air line(<150 psi) is fairly dangerous if it is cut and starts whipping around.

Everything is safe until it isn't. ;)

Be safe,
T2M

PS just finished another read through of the RCN series. What was the bosun's preferred weapon? A length of HP tubing. :D
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Q: “How can something be worth more than it costs? Isn’t everything ‘worth’ what it costs?”
A: “No. That’s just the price. ...
Christopher Anvil from Top Line in "War Games"
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Re: solar power
Post by Relax   » Mon May 09, 2016 11:56 pm

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T2M et al: If you want to cut your AC/Heat bill(includes hot water) by 2/3 or more, install a solar collector. Uses evacuated tubes filled with R314a fluid. We use 6 square meters on roof roughly(48 degrees North). We also use geothermal as heat source.

This gives 150-180F water for hot water in the home as well as dropping your heating cooling bills drastically. Also heat via dual burning chamber wood stove for garage.

PVA panels are horribly inefficient compared to solar heat collecting for heating. Solar heat collecting is roughly ~70% efficient whereas PVA panels are ~17% at best which then degrades over time which no ones bothers to mention as the silicone oxidizes.

If the price of thermalpiles drops, or there is a breakthrough, then PVA panels will disappear. IE collect the hot fluid, and then use the delta temperature differential between that and the air inside your home, water heater, incoming water to the home, or ground. Would be roughly 50% efficient collecting the sun or greater depending only on how many thermalpiles one stacked up.

PS. Most modern Hydraulics operate at 4000-5000 PSIG or greater. Logging operations keep a helicopter on standby with a water bucket attached to put out hydraulic fluid fires when said hydraulic lines inevitably bursts drenching the machine and surroundings in hot oil. Said hot oil inevitably gets in contact with the exhaust system setting the whole shebang on fire even though most modern machines have a steel plate(s) dividing the two sections on the engine compartment. Hydraulic pump etc / exhaust system. Watching the 4000psig oil go shooting out into a giant mist 40 feet is quite sweet... :twisted:
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Re: solar power
Post by DDHv   » Tue May 10, 2016 8:27 am

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thinkstoomuch wrote:
snip

Everything is safe until it isn't. ;)

Be safe,
T2M
snip



Ain't that the truth :!:

This is why there are fuses and similar equivalents for any well designed system using highly available energy. It is also why my primary heat storage is seasonal heat storage using the dirt under the house. It is low availability, but lower cost. DIY, so I may not live to see it finished, but the seven year 14 degF rise in dirt temperature so far has cut the heat bill, even if it isn't enough to be comfortable. The solar room on the south pays off best in the spring when temperatures are low and solar hours are long.

BTW, there are some systems using little or no storage designed to provide power when the sun is shining.

For light, some poor countries in warm areas are putting large pop bottles half way through a roof or outside wall, filled with liquid. Neat and simple
:!:
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Re: solar power
Post by DDHv   » Tue May 10, 2016 8:48 am

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Imaginos1892 wrote:If you cram 150 cubic meters of air into a 500 liter tank at 300 bar, it would represent a bit over 12 KWh of stored energy. That's about the minimum for a residential solar/storage system intended to get through a few cloudy days at a time.

If Something Bad happens to the air tank, all that air will want to expand back to 150 cubic meters very very fast, and the absolute last thing you want to do is try to confine it. That's the volume of a small house, and that's the size crater it will make in your yard. You didn't put it under the house, did you?

By the way, compressing the air to 300 bar will heat it up to almost 2,000 C - what's that tank made out of, again? If you let the air cool off before using it, all the energy that went into heating it was wasted.
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There are near isothermal methods of compression. They are more expensive, of course. Efficiency is higher, but still low unless you spend a lot. MDI is using one.

For cavern CAES, you could design the down pipe with density increased by much liquid, having one return pipe for the liquid and one for the air. Enough liquid would absorb most of the heat, producing near isothermal compression.

One reason for using cryogenic energy storage is that there is only a little pressure problem, the primary storage is low pressure. The energy comes from pumping small amounts of liquid to high pressure and then absorbing energy from the surroundings. This part needs to have good protection.

On the hot end, there are phase change materials with temperatures over 1,200 deg F.

All of these add to the capital expense. I wonder why they are mostly currently limited to experimental setups :?: ;)

You could get energy storage using 500 liters of liquid nitrogen to be pressurized to 300 bar, then absorbing energy from, perhaps, a high temperature solar heated primary source. It might be fun to run the numbers on this
:!:
Douglas Hvistendahl
Retired technical nerd

Dumb mistakes are very irritating.
Smart mistakes go on forever
Unless you test your assumptions!
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Re: solar power
Post by thinkstoomuch   » Tue May 10, 2016 11:24 am

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Relax wrote:T2M et al: If you want to cut your AC/Heat bill(includes hot water) by 2/3 or more, install a solar collector. Uses evacuated tubes filled with R314a fluid. We use 6 square meters on roof roughly(48 degrees North). We also use geothermal as heat source.

...snip to save scroll wheels I mostly agree with it all (well except the difference between compressed liquids and compressed gases and the results of failures.)...


This was actually addressed up in the water heater question topic.

Problem being:

A) Solar hot water heaters (and there parts) are horribly expensive (more than 20 years worth of the current total electric bill in an all electric house).

B) Require modification to the house (drilling holes in a concrete house's walls is not my current skill sets). Then again putting 20-80 holes in a roof isn't either but it is closer.

C) I really don't trust tanks emotionally. Last thing I want when I come home after being away for a few months is a water damaged floor. Or worse.

Though I am tossing ideas around in my head on cheap way to do the solar water thing and feed in to the newly installed instant electric water heater. Which already seems to be making a dent in the electric bill.

Did I mention I thing too much. :)

Have a good week,
T2M
-----------------------
Q: “How can something be worth more than it costs? Isn’t everything ‘worth’ what it costs?”
A: “No. That’s just the price. ...
Christopher Anvil from Top Line in "War Games"
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Re: solar power
Post by Relax   » Tue May 10, 2016 3:26 pm

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You are correct if you are trying to buy it in the USA. Of course just buy it from Israel and it is cheap. In Israel every single home is forced to install solar heating for hot water at minimum. Obtaining the components is cheap.

Yes, if you are unwilling to do the work yourself it is expensive. If do yourself it is very cheap. All you need is copper pipe, aluminum sheeting, and black paint and glass. Oh yea, a tiny water pump you can buy for $80. All you have to do is use your preexisting hot water tank, though, in reality one needs a secondary 100 gallon stainless steel tank which will never rupture.

And NO, there will be ZERO, NADA, Zilch holes through your roof. If some dumb ass contractor wants to put such a hole through, get a different contractor who is not a stupid chit.

PS. Get a stainless steel hot water tank unlike the moronic steel ones with a glass or plastic lining that WILL fail. 100% of the time.
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