Tech Spam thread - because 1/4" BSP gets 5 hand spans to the jiggawatt

[h4nd]

12 hours ago, ThePog said:

It is to make an air battery, basically use the excess solar I generate to pump air into a large tank. Heat shouldn't be too much of an issue as I wouldnt think it would be fast.

But a slow high pressure pump is key, I am just not sure what that is.

Why air? for shits and LoLs, or for cheap storage / direct mechanical?

I see you're looking for 0.6 * 24 is about 14kWh, so $pendy conventional  battery.

You got a handy hill? Pumped mini-hydro?

Also, there's some cheap big electrical battery tech I've been considering playing with.

[fletch]

15 hours ago, ThePog said:

 air into a large tank.

Large tank will be large, and heavy for that pressure.

Bit of weight and energy to carry around a couple of G's on the back

[ThePog]

5 hours ago, h4nd said:

Why air? for shits and LoLs, or for cheap storage / direct mechanical?

I see you're looking for 0.6 * 24 is about 14kWh, so $pendy conventional  battery.

You got a handy hill? Pumped mini-hydro?

Also, there's some cheap big electrical battery tech I've been considering playing with.

I watch too many youtube vids for off gridding.

But I have a certain amount of power capacity on a sunny day that goes to waste. My battery is fully charged by 9.30 or so and all that lovely power goes nowhere.

And sometimes I need extra charge on a cloudy day.

So I have devised many schemes for capturing that power to use on the cloudy days, and this 'seems' like a relatively simple one.

I have also thought about pumped hydro but the infrastructure requirements are a bit too hard out where I am.

I have thought about winching a heavy weight up then letting it fall down and spin a genny, but my P=mgh or whatever it was told me it would need to be a very big weight lifted up really high.

I have thought about a sand battery heated by an element, with a stirling cycle engine sitting on it.

There is no wind in Nelson and in particular in the valley where I live.

So now I have the scheme of several old gas bottles pumped up to less than they are rated for, spinning some sort of air motor/generator as needed.

I also am looking for an old multifuel Lister genset, so all my waste oil can get used up.

Any othe suggestions are happily considered, particularly how to store my excess solar (and yes I know more batteries, but that is no fun).

 

6 hours ago, NickJ said:

Mean, keen to see how you get on, my brain is poisoned with having worked with commercial high pressure systems and knowing how complicated they need to be.

 

I am hoping for a fairly simple solution, but that is probably the eternally optimistic dickhead I am.

 

2 hours ago, fletch said:

Large tank will be large, and heavy for that pressure.

Bit of weight and energy to carry around a couple of G's on the back

This will be static, its backup for my wee cabins solar setup....

[ajg193]

Air is stupidly inefficient, it's effectively a heat engine with a temperature difference of less than 20 degrees. You will be storing a hell of a lot of explosion potential for hardly any return.

You'd be better off heating water, or pumped hydro

[NickJ]

Yeah, but who cares if its inefficient when the input power was free?

Any extractable energy stored is a bonus 

[h4nd]

34 minutes ago, ThePog said:

(and yes I know more batteries, but that is no fun).

https://news.vanderbilt.edu/2016/11/02/making-high-performance-batteries-from-junkyard-scraps/

[ThePog]

14 minutes ago, NickJ said:

Yeah, but who cares if its inefficient when the input power was free?

Any extractable energy stored is a bonus 

This.

Hot water is no use to me in my cabin, and extracting useful work from even 100deg water is mechanically intense.

Steam is a different story but not suited to slow, intermittent power input.

I am keen on pumped hydro but while I have a good fall on the land my cabin is at the top of my property, this makes the power cabling back to the cabin very lossy.

I might be able to convince my neighbor that another 25k litre tank up in his paddock above me is a good thing.

[ThePog]

3 minutes ago, h4nd said:

https://news.vanderbilt.edu/2016/11/02/making-high-performance-batteries-from-junkyard-scraps/

I actually know a man who just replaced a shitload of his batteries in his solar setup, even at 70% soc I could stack up enough of them to be sweet....

[h4nd]

17 minutes ago, ThePog said:

this makes the power cabling back to the cabin very lossy

Nah, just yoink up the volts a bit. 48V is extra low voltage, but will still need enough copper for 20A/kW, which is a bit beefy, but if there's a way to run 230V / 600DC in ditch, you could use doorbell wire

[h4nd]

If if any maniac suggested a pair of microwave transformers, FFS use them well isolated and put ELCBs around them

[ThePog]

8 minutes ago, h4nd said:

Nah, just yoink up the volts a bit. 48V is extra low voltage, but will still need enough copper for 20A/kW, which is a bit beefy, but if there's a way to run 230V / 600DC in ditch, you could use doorbell wire

Yea so I am thinking about replacing my inverter and charge controller (due to that noisy power stuff we discussed) with a solar inverter unit of much higher quality, and the ones I have been looking at have a 230v input for plugging in to shore power or a genset. So I guess running 230v hydro isnt out of the question....?

The most convenient arrangement for this would put the hydro something like 150m away from the cabin.

Fuck now I have to work out how much head and capacity I need.

[ThePog]

Im not sure hydro is the way. I found an online calculator for micro hydro and it seems that to make 800w for an hour with a 10m head I would need 54000 litres...

[h4nd]

If you look into the datasheets, some PSU ( and possibly/probably some chargers) are OK with 320V DC in (peak mains V) and some up to 600V in (hey have internal boosters to 600V anyways).

So that's only 1.3A per kW. have to be careful with the switching breakers and and fusing tho - DC is a bit harder to break (including quenching arcs)

[h4nd]

^^ need more head

[h4nd]

OK - scrap iron and brass batteries then?

Or if you're feeling frisky, just electrolyse water and put the H2 in a big rubbish bag

[ThePog]

3 minutes ago, h4nd said:

OK - scrap iron and brass batteries then?

Looks like it, unfortunately I just dont have that much elevation. I do have another two panels so can potentially generate 1.5kW to fill up scrap batteries.

[NickJ]

Go dig up the system from Somes island?

https://www.hylink.nz/

[Doug Hill]

The answer is so obvious 

Grow lights pointed at the PV panels. Big Leccy hates this one trick

[tortron]

1 hour ago, h4nd said:

OK - scrap iron and brass batteries then?

Or if you're feeling frisky, just electrolyse water and put the H2 in a big rubbish bag

 

[ThePog]

46 minutes ago, NickJ said:

Go dig up the system from Somes island?

https://www.hylink.nz/

Electrolysing hydrogen sounds like a good time