Solar electricity production

**drivesafe** · 1st September 2008, 10:32 AM

Hi folks, I’m interested in electricity production, made from solar voltaic, wind and thermal, both solar thermal and geothermal and I’m also interested in producing reasonable amounts of purified water for domestic use, so to start the section off, any discussions and project ideas for any of the above is welcome.

**muddymech** · 1st September 2008, 11:07 AM

great idea for a forum, i like to follow developments of this sort of thing and when i can asfford it start buying into alternate energy.
pity the gov pulled the plug on the rebates as i nearly got solar hot water heating this year, i reckon thats the biggest quickest and cheapest option to start with.
i was considering the heat transfers pipes as i can not get my head round a heat pump being efficent when the pump has a 2000w motor and a heater eleemnt is not far off that.
one idea for heating hot water that i have not seen for long time is to run it though wood chipping or i guess a compost plenty of hear there.
ian

**JDNSW** · 1st September 2008, 11:25 AM

For what it is worth, my home has been running on solar power for the past fourteen years, together with solar hot water.

Consequently I have an ongoing interest in the subject.

John

**isuzurover** · 1st September 2008, 11:34 AM

Originally Posted by JDNSW

For what it is worth, my home has been running on solar power for the past fourteen years, together with solar hot water.

Consequently I have an ongoing interest in the subject.

John

Care to elaborate on your system John? I recall you aren't connected to the grid.

Btw - related to our previous discussion about hydrogen... AFAIK - hydrogen produced from algae would be regarded as a fuel by your definition, rather than an energy storage system.

On that note - diesel and other fuels derived from algae photo-bio-reactors may start to appear soon. There are groups claiming to have the costs down to US$120/barrel for pbr-derived oil. Several mining conpanies are seriously interested apparently.

**jik22** · 1st September 2008, 12:12 PM

Originally Posted by JDNSW

For what it is worth, my home has been running on solar power for the past fourteen years, together with solar hot water.

Consequently I have an ongoing interest in the subject.

John

I'd be interested in a write up of your solar hot water system? I've been thinking about this more and more, and am keen to get some real info to see how close to the marketing hype from the companies selling the stuff the reality really is!

**drivesafe** · 1st September 2008, 12:52 PM

Originally Posted by JDNSW

For what it is worth, my home has been running on solar power for the past fourteen years, together with solar hot water.

Well don’t be bashful, tell us all about it.

This is exactly why I asked Inc for this section to be started.

**drivesafe** · 1st September 2008, 12:53 PM

Originally Posted by muddymech

one idea for heating hot water that i have not seen for long time is to run it though wood chipping or i guess a compost plenty of hear there.
ian

Never heard of it before, got any more info on it?

**muddymech** · 1st September 2008, 02:08 PM

sorry no, i remember watching it as a kid on a programme caller "tomorrows world" from what i remember it was a simple case of running a pipe though decomposing wood chippings, then out came hot water.

guess it would have to be a run of pipe work to allow it to heat the water before use, not sure what temperatues came out, but might be enough to give the main water heater an easier time, especally in winter.

**dobbo** · 1st September 2008, 02:33 PM

Originally Posted by muddymech

sorry no, i remember watching it as a kid on a programme caller "tomorrows world" from what i remember it was a simple case of running a pipe though decomposing wood chippings, then out came hot water.

guess it would have to be a run of pipe work to allow it to heat the water before use, not sure what temperatues came out, but might be enough to give the main water heater an easier time, especally in winter.

Thats similar to the way the earth ships store their heat. Interesting, just imagine, a busted pipe would result in making your cup of tea in black water

**JDNSW** · 1st September 2008, 04:01 PM

Originally Posted by drivesafe

Well don’t be bashful, tell us all about it.

This is exactly why I asked Inc for this section to be started.

When we started building the house in 1994 we investigated the relative costs of getting the power on and getting a stand alone power system. In the end, the costs came out around the same, so we went with the stand alone system.

While living in a caravan and building the house, we used a 12v 300VA Sine Wave inverter, with a pair of 12 v batteries and three 60w panels. This was supplemented by a 2.5kva petrol generator. This system was also used in the house as an additional supply, with the batteries replaced by a set of 400AH cells, and an extra panel added.

The house power system is in fact two identical systems, for redundancy - either can run the house at a pinch, but generally the load is shared, with the two major loads, refrigerator and freezer, being one on each.

Each system is based on a 24v bank of 760 AH cells, charged by a tracker with eight 75w panels via a BP controller or a 40A charger. Each system has a Selectronics 2kva (6kva for 30 seconds) sine wave inverter.

The battery chargers were originally powered by the 2.5kva petrol generator, later replaced by a 6.5kva petrol generator, and now usually by a 5kva Lister diesel generator.

A fairly recent addition has been a 200w nominal wind generator on one system. I intend to get another of these.

Problems:- Two of the 60w panels have failed (out of warranty), one apparently due to lightning, the other apparently a manufacturing fault. One 75 w panel was replaced under warranty.

One Selectronics inverter failed spectacularly shortly after installation ( I suspect a loose nut or something in it initiated a short) and was repaired/replaced under warranty.

Both tracker electronics modules have failed - and the manufacturer is defunct, and parts are unavailable; and they removed all the ID information from the ICs, and no circuits are available.

Two of the big cells were replaced under warranty, and another eleven have failed in recent years - fortunately, I managed to get hold of a part life set of twelve. But with the batteries fourteen years old, and an expected life of about ten years, I am looking at having to get at least twelve new cells in the reasonably near future!

Apart from the problems mentioned, the electronics have given no trouble. Routine problems are frequently due to bad intercell connections, or more recently, failing cells.

Apart from the power system, hot water is provided by a pair of solar collectors on the verandah roof. These have a frost valve to prevent freezing rather than operating a closed loop. They feed into a gravity tank in the roof, which is boosted by the kitchen wood fired stove, which also provides hot water for the floor heating system. This has proved to be totally successful, just that you have to light up the fire to get hot water during overcast, even if the weather is warm.

This what you were looking for?

John

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