Solar hot water?

[wynw]

inlaws have got one just up the road but it has been more hassle than its worth. I will try and get the brand and get back to you.

[Laava]

Peraps yood like a windymill tae supplement yer soley?

Gunna burn me some bumpkins! Yee haa!

[Laava]

inlaws have got one just up the road but it has been more hassle than its worth. I will try and get the brand and get back to you.

Thanks Wynn, very few people have them it seems? I only know one person who has one, it was working well at install but not sure now how it is going.

[JimO]

i was on a job the other day there was a plumber fitting a solar system, he says that for the cost he wouldnt be doing it on his own house, better to fit a instant hot water gas system and get rid of the cylinder, only heat what you use

[Winston001]

You should check out the other thread. I've clipped a couple of thoughts:

Solar electricity is quite another can of worms and so far as I know you need deep cycle batteries (expensive) to store the electrons before they can be used or sent back into the grid.


The most simple step is solar hot water panels. They work. Nevertheless you need a plumber who knows what he is doing and I don't think they work with high pressure water systems - you need a heat exchanger.

Solar electric panels are very low efficiency - about 5%. However the technology is improving and I think Sanyo have new panels in the 15-17% range. Just be aware that solar panel efficiencies are vastly below water/oil/gas/coal generated electricity.

A mate of mine in Cromwell is totally off the grid and has experimented with various solar and wind generation options. He imported a windmill from the USA about 10 years ago. It certainly worked but the wind wasn't reliable - and Cromwell is known as a windy place.

Recently he sold it. The main problem was low frequency noise day and night which penetrated the house and became a constant annoyance.

He now relies on a bank of solar panels which swing to follow the sun plus a generator backup.

[Laava]

Thanks again guys, I have heard from a plumber saying they are not worth it as well. But I am more interested in keeping the running cost down than anything else. Not going to be doing solar electric as the power we will use will be small amounts anyway excepting hot water which may end up being califont LPG. But that is not so cheap to run either, given the escalating prices.

[BMWST?]

Thats a good point tho cos once the system is installed your hot water can be free,and the cost of water heating any other way will continue to go up

sent from the tag

[Laava]

Thats a good point tho cos once the system is installed your hot water can be free,and the cost of water heating any other way will continue to go up

sent from the tag

Exactly why I am wanting to hear from owners, rather than salesmen or installers.

[Edbear]

Exactly why I am wanting to hear from owners, rather than salesmen or installers.

You will get a variety of responses, as many installations have been very inefficient and some have simply not been working at all.

My link to www.europlumbing.co.nz is to a guy who specialises in solar energy systems having designed and built them for larger commercial applications including schools. He has been horrified at some systems he has been called in to fix!

They have a very simple and inexpensive retro fit system that is almost as efficient as a full new installation
for solar hot water. But solar electric is, as has been pointed out, still in the early stages of panel efficiency.

If you want independent specialist advice, you can't do better. He actually advised me against it as we are on mains gas for water, cooking and heating. However he is up to date with the latest systems and devised an ideal solution for our house that would include heating every room independently to taste and reduce our gas bill for water heating as well, doing away with the gas cylinder entirely, but not using a califont.

[sootie]

Exactly why I am wanting to hear from owners, rather than salesmen or installers.

I have a PV based system which now provides most of the hot water for this household over a full year. (Only two adults in residence)
I think it will provide all our hot water for the first 3 days of this week provided the sun keeps shining. (Auckland)
Over the winter months it has probably provided about 20% of our water heating and nothing else. The mains power supply to our main hot water cylinder was switched off for some weeks last summer (which was a pretty sunny one). Some solar energy was wasted at that time as I had no way to properly utilize surplus output power. (I am now working on this part.)

The principle is good, but my solution has been very labour intensive. If I were doing this from scratch again I would:
- again go all PV because it is now cheap to buy & easy/cheap to install yourself.
- again use a good second hand preheat hot water cylinder to do all the solar heating & feed the main house cylinder. (some plumbing here)
- investigate a better way of efficiently coupling electrical energy from the panels to the hot water cylinder (this is the hard bit).

I do believe that commercial inverters must be available which would perfom this power match, probably to a 48V or similar replacement element in the cylinder (these are available).
If you know of anything available at reasonable cost, I would be interested to know about it.

Yes, it does require about 5 times the roof area in PV panels to give as much energy from electrical heating as you can get from direct thermal.
The installation (plumbing) costs of thermal are now however enormous! Anyway, what else do you want your roof for?

There is another point which Californians sometimes notice. I live in a house which used to get too hot for several weeks in the summer. With a good portion of the living area roof now double skinned with an air gap this house is a lot more comfortable in January/February. It does not make much difference in winter because the sun is lower. House then heats through the windows (if we are lucky!). Little winter heating would come via the roof anyway even if it were fully exposed.

Well, there is my 2 penneth worth .... Cheers

[Laava]

Thanks Sootie, that is exactly the kind of feedback I am looking for. I may PM you later in the piece to pick your brains a bit.