green power solar is

[octave]

Nobody seems to want to look at using solar to heats salts to store heat for producing off peak steam for turbines. It has been done I think in Spain and also germany, but obviously we don't get enough sun in Australia for us to do it here.

 

South Australia planning to build the world’s largest thermal solar plant

 

 

[Old Koreelah]

...My home built system worked, but was not efficient...

Neither is mine, Yenn, so I went larger and used glass from public phone boxes to double-glaze it. Almost vandal-proof so never hurt by hail.

 

... Solahart was efficient, but their service and knowledge of their system was deplorable...

Perhaps their service reps were either poorly trained or not supporters of solar. I suspect the same is true of some Beasley installers; I was asked to advise on one which performed very poorly and found a couple of small-diameter 90 bends in the circuit which would have choked off the thermosyphon flow.

 

...Nobody seems to want to look at using solar to heats salts to store heat for producing off peak steam for turbines. It has been done I think in Spain and also germany, but obviously we don't get enough sun in Australia for us to do it here.

You're on the money, Yenn! Saline pools are ridiculously simple to make and get scaldingly hot. The brine is an awesome way to store lots of heat overnight or even for a few days of overcast weather.

 

I'd love to see some serious research into converting a few of our old coal burners to this technology.

 

 

[Bruce]

The figure that matters is watts per dollar so you did good old K with your water heating. But now you need some system to stop the water going over 60 degrees

 

Batteries... I reckon you summed it up well Yenn.

 

Batteries from hobbyking cost about $1 per watt-hour, that is $1000 per kiloWatt hour.

 

A fridge in summer uses about 6kWh per day, so that would need $6000 worth of hobbyking batteries to power for a day when no other energy came in.

 

A converted chest freezer of the same size would use 2kWh per day so would be just feasible. Funny how nobody makes such a fridge huh.

 

 

[octave]

The figure that matters is watts per dollar so you did good old K with your water heating. But now you need some system to stop the water going over 60 degreesBatteries... I reckon you summed it up well Yenn.

 

Batteries from hobbyking cost about $1 per watt-hour, that is $1000 per kiloWatt hour.

 

A fridge in summer uses about 6kWh per day, so that would need $6000 worth of hobbyking batteries to power for a day when no other energy came in.

 

A converted chest freezer of the same size would use 2kWh per day so would be just feasible. Funny how nobody makes such a fridge huh.

 

We lived for 21 years in an off-grid house There are plenty of high-efficiency low voltage appliances. Our fridge was converted from a 240 volt freezer into a 12 volt fridge. It was very efficient but I can't remember exactly how much power it drew. We bought all of solar gear from the Rainbow Power Company. These days they have a range of efficient fridges. Power usage figures here (page 6) https://www.rpc.com.au/pdf/evakool_upright_manual.pdf

 

 

[Bruce]

There is a big mistake on that page 6 octave. They say " a daily power as little as 55 amps...." which is meaningless. Amps are a measure of current, not power. And power is not what you pay for, it is really energy. kWh is an energy measure.

 

I would trust your opinion about the converted chest freezer though. Strange that all the "efficient " fridges are door type, where you lose all the cold air every time you open it. I really believe that a chest type would use a third of the energy per day.

 

 

[octave]

They say " a daily power as little as 55 amps...." which is meaningless. Amps are a measure of current, not power. And power is not what you pay for, it is really energy. kWh is an energy measure.

The relevance in a stand-alone system as we had is that the batteries are rated in amp hours, our batteries were about 420 Ah. I think from memory the compressor of the fridge would draw about 5 amps (60 watts /12 volts) Our calculation then would be 5 amps X the number of hours the fridge was actually operating. This tells us how long we can run our fridge before the batteries are flat. The input from the solar panels was measured by an amp meter the and what the house was drawing was metered in Ah. Most of our appliances were rated in Ah but I think the lights we used which were quartz halogen and were 20 watts but it was more convenient for us convert that to amp hours in order to determine our draw on the battery 20watts at 12 volts = 1.6 A, if we leave it on for 10 hours this will this will reduce the power the batteries capacity by 16 Ah, I am assuming the specs on page 6 are the Ah times the number of hours the fridge would operate in 24 hours and that is relevant to battery sizing as well as charging capacity.

 

 

[kgwilson]

Just to explain electricity a little more

 

Voltage

 

Everyone talks about voltage, but what is it, exactly? It’s the electrical equivalent of

 

pressure – a 12 volt spark jumps less than 1/8 inch, but a 12,000 volt spark will jump an

 

inch or more. Voltage is pressure.

 

Guidelines:

 

• A regular D cell battery is about 1.5 volts

 

• A car battery is 12 volts

 

Current

 

Current is measured in Amperes, or Amps, and is the electrical equivalent of flow.

 

Guidelines:

 

• A 12 volt radio draws about 3 amps

 

• A starter can draw 150 Amps or more

 

Power

 

Power is measured in Watts and is simply Volts x Amps. How much current times how

 

much voltage is how much power.

 

Guidelines:

 

• A 12 volt radio drawing 3 Amps is using 12 x 3 = 36 Watts

 

• 1 Watt dissipated in free air is warm to the touch

 

• 10 Watts in free air will burn your fingers

 

Resistance

 

If Voltage is like pressure and Current is like flow, Resistance is just that -- resistance to

 

flow. Resistance is measured in Ohms and is equal to Volts / Amps (how much pressure

 

divided by how much flow). For a given voltage, the lower the resistance the more

 

current will flow. Guidelines:

 

#18 wire has a resistance of 0.0064 Ohms per foot.

 

#22 wire has a resistance of 0.0161 Ohms per foot.

 

A good connection should read less than ½ an Ohm

 

Since the voltage measured across the wire is the Resistance of the wire times the Current

 

flowing through it, you can see that you’ll lose some voltage, and lose some precious

 

power in your wiring. Take this example:

 

A 10 foot chunk of #18 is carrying 5 Amps to run our transponder. Ten feet of #18 has a

 

resistance of 0.064 Ohms, which means we’ll drop 0.064 * 5 = 0.32 volts in each wire,

 

both power and return. This means of the 12.5 volts you’re sending to the transponder,

 

the transponder only sees 11.86! Not a big deal, but when the battery gets low, it doesn’t

 

leave you a lot of margin. The voltage drop is only ¼ as much at 24 volts, and you have

 

a lot further to go, but I believe I beat that horse enough for one day.

 

To Review:

 

Power in Watts = Volts x Amps (Voltage across it times the current through it)

 

Volts = Ohms x Amps (Resistance of it times current through it)

 

 

[nomadpete]

That explains instantaneous power. Total energy is usually expressed in A/H. (for stand alone power supply systems.)

 

The modern solar regulators can monitor the Amp/Hours going into and out of a battery in order to tally the available amount of energy. This allows the consumer to see (for instance) how long the fridge will run. The better controllers will also send a control signal out to start the standby generator when state of charge falls to a predetermined level.

 

This helps battery management, so batteries should last their design life.

 

 

[Marty_d]

There is a big mistake on that page 6 octave. They say " a daily power as little as 55 amps...." which is meaningless. Amps are a measure of current, not power. And power is not what you pay for, it is really energy. kWh is an energy measure.I would trust your opinion about the converted chest freezer though. Strange that all the "efficient " fridges are door type, where you lose all the cold air every time you open it. I really believe that a chest type would use a third of the energy per day.

We have a chest freezer. It's been sitting in the shed, empty, for the last 6 years.

 

Reason is that when you fill a chest freezer you have to spend 5 minutes leaning into the thing freezing your ass off to get that bit of steak that's at the bottom (which you put in a year ago). Whereas with an upright you open the door, everything's immediately available and you're in and out in 10 seconds.

 

Not really a fan...

 

 

[Jerry_Atrick]

I saw a fridge the other day that had a door within the main door - the idea is that you put the small stuff (mainly drinks) that you access a lot and the only latent heat transfer when opening the door (regularly) will be to a small area of the fridge...

 

 

[Bruce]

My wife agrees with you guys. No way was she going to live with a converted chest freezer.

 

So the planet loses out.

 

If she was wrong, you could buy a chest fridge at harvey norman.

 

 

[octave]

My wife agrees with you guys. No way was she going to live with a converted chest freezer.So the planet loses out.

 

If she was wrong, you could buy a chest fridge at harvey norman.

I would suspect that modern fridges have become more efficient and the gains would not be worth the inconvenience. I do get amazed when I walk around an appliance shop by the size of some of the fridges. I can only speak for myself but I have no need for a fridge the size of an office block.

 

 

[Bruce]

there's not much you can do to increase the efficiency of a fridge. The one Jerry saw was a good idea though. Not having to open the door completely would really help.

 

The door seals really matter and will be best on day 1 of the life of the fridge.

 

You can't change the physics, for example freezing ice cubes would require more energy than some claims would have you think. And freezing water from the air to be later defrosted out is a terrible loss. Just think of the energy used in a kettle if you start with solid ice and later boil it all to dryness.

 

On Batteries:

 

1 amp at 12 volts for 1 hour is not trivial for a battery, but it is only .012 kWh which costs a trivial amount from the mains. We really need cheaper batteries for this green stuff to take over except in really remote places.

 

 

[octave]

there's not much you can do to increase the efficiency of a fridge.

A refrigerator cools by harnessing electricity to drive a compressor. The efficiency of the compressor has improved markedly and will probably continue to improve.

 

source: How your refrigerator has kept its cool over 40 years of efficiency improvements | ASAP Appliance Standard Awareness Project

 

[ATTACH]49676._xfImport[/ATTACH]

 

Let me just say that I do not believe there is an economic case for the average household to be totally off grid. In our case, we made the choice based on the fact that the nearest power lines were 4 KM away and the price of connection was astronomical, for a fraction of the price we installed our own system.

 

1 amp at 12 volts for 1 hour is not trivial for a battery, but it is only .012 kWh which costs a trivial amount from the mains.

Seems like a trivial amount to me. We had 405 Ah batteries, assuming we only wanted to run the batteries down to 50% we could have run one of the old quartz halogen bulbs (much more efficient lights available now) rated at 20 watts (about 1.6 Ah) for 131 hours. During this time we would, of course, have expected to be charging the batteries via solar panels. Of course in the real world, we ran many more appliances than just 1 light bulb.

 

We really need cheaper batteries for this green stuff to take over except in really remote places.

I would generally agree with that. I do not believe standalone is the way to go at this point unless you live away from the grid or you can afford the new technology and have an interest. Batteries have improved since I first installed our battery bank and they continue to improve and get cheaper but again I am not saying everyone should go off grid (I no longer live off grid)

 

[octave]

Here is a look at a modern grid connected system.

 

 

[kgwilson]

The thing about going off grid is that it is now feasible and cost effective to do so rather than pay the exorbitant amount energy companies want to put in a couple of poles and 3 wires. They then charge a ridiculous supply charge which is a large percentage of the total cost of energy. Before affordable solar, wind and small scale hydro, the only option was expensive fossil fuelled generators. Some of the tiny inexpensive hydro systems produce just enough energy to pump water from the stream that drives them up to a storage tank on a hill.

 

A farmer friend of mine & fellow pilot decided to build a new house on his property some way from the available grid supply about 4 years ago. He went 100% solar with the battery technology of the day including a backup diesel generator. His house was built with the most energy efficient appliances including 2 big freezers for home kill meat etc , LED lighting and in 4 years he has only used the generator the check that it still works. The only gas he has is for his BBQ. Total cost was less than 70% of getting connected to the grid. Factoring in battery replacement & maintenance he reckons he is still well ahead & of course new batteries are far cheaper and have greater storage capacity that what he now has. If I was in his situation I'd do the same.

 

 

[Bruce]

In my case the grid was cheaper by a long way, but being off the grid would feel a lot better. With water and sewerage, we are off the grid at the farm and its better and cheaper than being in a suburb and paying rip-off prices.

 

Alas, they get you at the farm with exorbitant council rates and you can't go off the grid with those.

 

 

[Jerry_Atrick]

I have just switched to an all renewables electricity supplier- there are 1/2 the price of my old supplier which was one of the el cheapos anyway (I am not into luxury electricity these days).

 

Bonus- they charge wholesale spit prices (they make their money on the futures)

 

Halved my bill

 

 

[Bruce]

cripes Jerry, how much is it per kWh?

 

right now in South Australia we are paying about 40 cents /kWh and it is said that this is the highest in the world, due to those greenies of course.

 

 

[Jerry_Atrick]

My old rate was either 13p/kWh or 0.13kWh - will get back to you..

 

Now it is half of one whichever is the accurate one..

 

Reminds be - the old provider owes be £380 =- better get onto them - that's 2 hours in a PA28 (161)..

 

 

[Yenn]

Octave. That report about SA is good news to me. SA must be the only state not in love with coal. Here in Qld we have a government dead keen to gt Adani coal up and running. They wanted to provide the rail and water requirements of Adani from state evenue and also relax just about any environmental controls, all to get a bit of income from the royalties. They had Rockhampton and Townsville councils going to finance a fly in fly out airport at the mine so that their residents could be workers there. Adani have come up with highly inflated employee figures. I think at one time they were saying 3000 staff but I think that it is now down to less than 1000.

 

All that for dirty coal, not even what the pollies keep calling clean coal.

 

 

[Bruce]

Sodium based batteries might just be the answer to living off the grid. It's very cheap compared to lithium.

 

Of course, if the electricity is made with coal burning, the whole system is dirty.

 

We could pay farmers to char and bury wood and straw etc, which would be the exact opposite of mining coal. BUT coal sells for about $125 a tonne, and the farmers would need at least $250 a tonne to do this.

 

So the planet has to die, at least as a home for what we foolishly call civilization.

 

The alternative could be to stop coal mining everywhere, and to stop military spending everywhere, and to use the ex-military money to char and bury until the CO2 is under control again many years from now.

 

 

[Marty_d]

I don't think the answer is creating more coal, it's to stop digging it up.

 

 

[Bruce]

It's not enough to just stop digging it up. In addition, you need to make more and bury it.

 

There are other ways to take CO2 out of the air, but charring organics is the cheapest way. Unfortunately, there is not much profit in this for the rich people, so it's not going to happen.

 

Spreading chemicals into the stratosphere would work too. I doubt that this will happen either.

 

Things will just get gradually worse, and Trump types who promise to fix things by blaming whoever will get elected .

 

 

[storchy neil]

marty there are to to many dumb ars in aust now stop digging coal NO MORE HOSPITALS NO MORE SCHOOLS NO MORE AIRFIELDS NO MORE PUBLIC SERVANTS NO MORE ROADS I AINT PAYING FOR YOUR STUPIDY NO MORE NEIL