Australian Politics Forum - Thermal Solar for the home?

Jed Stuart

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Thermal Solar for the home?
Jan 6^th, 2014 at 2:12pm

This might be a silly idea, but how about modifying a solar hot water system to generate steam and connect to a steam engine to produce electricity.

Something like have the solar hot water system operating normally and add another device above it that would be designed for the higher pressure of boiling water and steam. The water would already be hot so would not take much more solar heating to boil it. If 4-5 amps could be produced that might be enough to make it worthwhile constructing.

This device would have to be designed by a expert or could be dangerous. Has anyone tried such a thing I am wondering?

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gizmo_2655

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Re: Thermal Solar for the home?
Reply #1 - Jan 6^th, 2014 at 2:29pm

Jed Stuart wrote on Jan 6^th, 2014 at 2:12pm:

This might be a silly idea, but how about modifying a solar hot water system to generate steam and connect to a steam engine to produce electricity.

Something like have the solar hot water system operating normally and add another device above it that would be designed for the higher pressure of boiling water and steam. The water would already be hot so would not take much more solar heating to boil it. If 4-5 amps could be produced that might be enough to make it worthwhile constructing.

This device would have to be designed by a expert or could be dangerous. Has anyone tried such a thing I am wondering?

Not really allowed for most of Australia, with some exceptions.

Being off the grid isn't permitted, unless you are very remote (or the power company thinks it's too hard to install and maintain the power lines.)

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It's similar to a strawman fallacy"
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Doctor Jolly

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Re: Thermal Solar for the home?
Reply #2 - Jan 6^th, 2014 at 3:00pm

Jed Stuart wrote on Jan 6^th, 2014 at 2:12pm:

This might be a silly idea, but how about modifying a solar hot water system to generate steam and connect to a steam engine to produce electricity.

Something like have the solar hot water system operating normally and add another device above it that would be designed for the higher pressure of boiling water and steam. The water would already be hot so would not take much more solar heating to boil it. If 4-5 amps could be produced that might be enough to make it worthwhile constructing.

This device would have to be designed by a expert or could be dangerous. Has anyone tried such a thing I am wondering?

The trouble is you need some "machine" to convert steam into power. A steam engine and a generator. This makes it expensive and need maintenance.

Solar PV with a Battery bank is the prefered small scale system because it has no real maintenance requirements at all.

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gizmo_2655

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Re: Thermal Solar for the home?
Reply #3 - Jan 7^th, 2014 at 1:42am

Doctor Jolly wrote on Jan 6^th, 2014 at 3:00pm:

Jed Stuart wrote on Jan 6^th, 2014 at 2:12pm:

This might be a silly idea, but how about modifying a solar hot water system to generate steam and connect to a steam engine to produce electricity.

Something like have the solar hot water system operating normally and add another device above it that would be designed for the higher pressure of boiling water and steam. The water would already be hot so would not take much more solar heating to boil it. If 4-5 amps could be produced that might be enough to make it worthwhile constructing.

This device would have to be designed by a expert or could be dangerous. Has anyone tried such a thing I am wondering?

The trouble is you need some "machine" to convert steam into power. A steam engine and a generator. This makes it expensive and need maintenance.

Solar PV with a Battery bank is the prefered small scale system because it has no real maintenance requirements at all.

Depending on the type of batteries, yes.

The other problem with the steam/generator is that to produce enough pressure to turn a generator to any decent current (even allowing for low wattage appliances) would take high temperatures and extremely high pressure, you'd be just asking for DIY incompetent to scald himself (or worse, his kids) to death.

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"I just get sick of people who place a label on someone else with their own definition.

It's similar to a strawman fallacy"
Bobbythebat

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Sir Spot of Borg Gold Member Offline WE ARE BORG Posts: 26594 Australia	Re: Thermal Solar for the home? Reply #4 - Jan 7^th, 2014 at 5:55am My next house is going to be just solar power. Bugger these electricity companies. SOB
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Re: Thermal Solar for the home?
Reply #5 - Jan 7^th, 2014 at 7:36am

Sir Spot of Borg wrote on Jan 7^th, 2014 at 5:55am:

My next house is going to be just solar power. Bugger these electricity companies.

SOB

It won't be too long before solar PV plus storage passes parity with mains electricity. State governments, centralised generators and distributors are waking up to the threats to their business models.

Go for it, but be prepared for your State government to try and charge you for not being on the grid.

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Sir Spot of Borg

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Re: Thermal Solar for the home?
Reply #6 - Jan 7^th, 2014 at 7:39am

# wrote on Jan 7^th, 2014 at 7:36am:

Sir Spot of Borg wrote on Jan 7^th, 2014 at 5:55am:

My next house is going to be just solar power. Bugger these electricity companies.

SOB

It won't be too long before solar PV plus storage passes parity with mains electricity. State governments, centralised generators and distributors are waking up to the threats to their business models.

Go for it, but be prepared for your State government to try and charge you for not being on the grid.

Yeah bit like how they charge you for not being in the phone book . . . .

SOB

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miketrees Gold Member Offline Australian Politics Posts: 6492 Gender:	Re: Thermal Solar for the home? Reply #7 - Jan 7^th, 2014 at 7:51am When we get better battery technology (and we will) it is going to cause some big problems for utility companies and poor people. If you are too poor to go off grid, you will be stuck with a very expensive grid. Its a very good reason for governments to be getting out of the power business now.
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Doctor Jolly Gold Member Offline Australian Politics Posts: 3808	Re: Thermal Solar for the home? Reply #8 - Jan 7^th, 2014 at 8:02am Yeah, these new salt water flow batteries, offer the potential for cheap storage of power.
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Re: Thermal Solar for the home?
Reply #9 - Jan 7^th, 2014 at 8:02am

miketrees wrote on Jan 7^th, 2014 at 7:51am:

When we get better battery technology (and we will) it is going to cause some big problems for utility companies and poor people.
If you are too poor to go off grid, you will be stuck with a very expensive grid.

Its a very good reason for governments to be getting out of the power business now.

Or not. The assets are commercially worthless. Their only value now is social.

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Jed Stuart

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Re: Thermal Solar for the home?
Reply #10 - Jan 8^th, 2014 at 9:31am

On or off the grid is a separate question. Solar thermal could be on the grid in the same way as PVs.

DIYs can hurt themselves setting up PVs especially around batteries. It would obviously need an expert design and installation. Just the right pressure release safety valve etc.

PVs seems really good, but what happens when China India and all the rest of the billions of people start getting heaps of them? Are there the resources for that I wonder. Solar thermal whether mega or domestic is made from more readily available materials.

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Doctor Jolly

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Re: Thermal Solar for the home?
Reply #11 - Jan 8^th, 2014 at 9:42am

Jed Stuart wrote on Jan 8^th, 2014 at 9:31am:

On or off the grid is a separate question. Solar thermal could be on the grid in the same way as PVs.

DIYs can hurt themselves setting up PVs especially around batteries. It would obviously need an expert design and installation. Just the right pressure release safety valve etc.

PVs seems really good, but what happens when China India and all the rest of the billions of people start getting heaps of them? Are there the resources for that I wonder. Solar thermal whether mega or domestic is made from more readily available materials.

Current PV pannels are mostly made of silicon (ie sand) so no real problems with supply. The cost obstacle is the process to make them.

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Re: Thermal Solar for the home?
Reply #12 - Jan 9^th, 2014 at 9:24am

Jed Stuart wrote on Jan 8^th, 2014 at 9:31am:

On or off the grid is a separate question. Solar thermal could be on the grid in the same way as PVs.

With the state of the art as it stands, PV is more cost-effective. Thermal, gives more scope for the hobbyist or home handyman, but is that an advantage? Consider the temperatures and voltages involved.

Jed Stuart wrote on Jan 8^th, 2014 at 9:31am:

DIYs can hurt themselves setting up PVs especially around batteries. It would obviously need an expert design and installation. Just the right pressure release safety valve etc.

Good reasons why DIY is a bad idea for any such system. Too much to go wrong and kill someone or burn the house down.

Jed Stuart wrote on Jan 8^th, 2014 at 9:31am:

PVs seems really good, but what happens when China India and all the rest of the billions of people start getting heaps of them? Are there the resources for that I wonder. Solar thermal whether mega or domestic is made from more readily available materials.

What are the pros and cons of the alternatives? It's called risk management.

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Jed Stuart

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Re: Thermal Solar for the home?
Reply #13 - Jan 15^th, 2014 at 1:49pm

[/quote]

Current PV pannels are mostly made of silicon (ie sand) so no real problems with supply. The cost obstacle is the process to make them.
[/quote]

According to Wikipedia which seems pretty good on PVs

"Materials presently used for photovoltaics include monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, and copper indium gallium selenide/sulphide "

Does the planet have endless resources of these things I have never even heard of? Solar thermal systems seem to be mainly made of steel.

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Jed Stuart

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Re: Thermal Solar for the home?
Reply #14 - Jan 15^th, 2014 at 2:03pm

Doctor Jolly wrote on Jan 6^th, 2014 at 3:00pm:

[quote author=Jed_S link=1388981538/0#0 date=1388981538]
The trouble is you need some "machine" to convert steam into power. A steam engine and a generator. This makes it expensive and need maintenance.

Solar PV with a Battery bank is the prefered small scale system because it has no real maintenance requirements at all.

Having had a look around at other systems, solar Stirling thermal seems to be a better option than steam. There have been some big systems created but dismantled because PVs are less expensive, but will that change? It seems a fantastically simple engine but probably also more expensive to produce for a small scale solar thermal parabolic dish thing. That should be able to be made safe as far as fire risk goes.

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