Solar hot water?

[Laava]

Thinking about putting in a new system but would like feedback from anyone who has one.
Esp if they have had it from new and all pros and cons etc. I have done some research but would like owner feedback.
TIA.

[BMWST?]

Thinking about putting in a new system but would like feedback from anyone who has one.
Esp if they have had it from new and all pros and cons etc. I have done some research but would like owner feedback.
TIA.


this is what i have found out ..I dont have a system but have doen a bit of research into whats available
vacumn tubes systems are more efficient,but are more expensive.Flat panels are cheaper but less efficent than vacumn tubes.Best effidiency is witth active systems ,ie pumps,not just relying on thermal siphoning.Some say that vacumn tubes systems are best reserved where larger volumes or higher temperature temps are needed.
Good luck i find it very difficult to find someone who talks any sense.One fella told me the payback was 12 years which i thought rather strange when the system warranty for the panels was only 10 years.He was very flustered when i pointed out this anomoly.

[pzkpfw]

It was great in Fiji.

[shafty]

Hi Laava, do a thread search cos I have seen an extensive thread covering this topic and "going off the grid" on here somewhere - would look for you but rushing out the door to work, good luck

[Laava]

Hi Laava, do a thread search cos I have seen an extensive thread covering this topic and "going off the grid" on here somewhere - would look for you but rushing out the door to work, good luck

Thanks guys, i did a search but found nothing initially. Fiji sounds great but hard to get through customs.
Hoping to get info from someone who has fitted and run one for a few years. I know the initial outlay is quite a bit but the drop in the power bill is the bit I am interested in.

[p.dath]

I have often thought about solar hot water versus solar power, and always seem to come to the conclusion you would be better off getting solar power (staying on grid, no batteries).

The problem I have with solar hot water is once your water is hot any additional solar energy harnessed is wasted. With solar power the electricity generated can still be used to power your hot water cylinder, but once that is heated the excess power can continue to be used to power other devices in your home, reducing your power bill.


There is also a global glut of electric solar panels ...

[Banditbandit]

We had solar heating for the water on our small farm in Hawke's Bay. It was the type that had an electricity option, with an on/off swith coupled to a thermometer reader in the kitchen so we could see what the water temperature was, and switch on the electricity if it needed it. It was also hooked up to our wood stove through a wetback, so we had three ways to heat the water - electricity as optional. During winter we ran it on the power at night so there was hot water in the morning - but I'm talking winter in the snow country here.

It's hard to know if there was a drop in electricity bills. My wife said yes there was, but I'm not convinced. Part of the problem was that when we installed it electricity prices were rising quite frequently. It's hard to know whether our power use was less than previously - I suspect it probably was, but the rise in electricity prices meant it didn't look like we saved much per month.

I would not say, on that basis, that it is not worth it. I might not put one in if I still lived in the high country - it's certainly an option here, as we have some of the highest sunshine hours in the country ...

[Erelyes]

Hi Laava, do a thread search cos I have seen an extensive thread covering this topic and "going off the grid" on here somewhere - would look for you but rushing out the door to work, good luck

http://www.kiwibiker.co.nz/forums/showthread.php/152937-Has-anyone-got-solar-panels-on-their-roof ?

[mansell]

A few years ago I lived in a house with an old (15-20 years) passive solar water heating system backed up by the thermostatically controlled electricity system. At the time there were 4 adults and two kids living there and there was always sufficient hot water. I am sure it severely reduced our power bill but as the system was installed well before I moved in there was nothing to compare it with, except the odd conversation with other people living in the area. Logically it must save money as a large chunk of ant power bill goes on hot water. The big concern was the water in the header tannk sometimes reached boiling point, however a simple thermostat controlled valve would probably remedy this. We have discussed this as a option for the house I currently own and will probably install a system once the rest of the renovations are complete.

[Edbear]

Don't have it myself, but if you want to know all the systems and combinations available including custom made to suit your own needs, call these guys and ask for Rudy. www.europlumbing.co.nz

[Road kill]

Thanks guys, i did a search but found nothing initially. Fiji sounds great but hard to get through customs.
Hoping to get info from someone who has fitted and run one for a few years. I know the initial outlay is quite a bit but the drop in the power bill is the bit I am interested in.

If you want to save money then turn your Hot water cylinder off for 12 hours a day.

We've been saving around $80 per power bill since we started doing this at the beginning of last winter.

[pete-blen]

A vacumn tube system lets you boil the water at lower temps :gob:

i use to work for Dom salt we had what was basicly a crude desalination plant
It would boil water at 42*C under 4 hegs of vacumn..
basicly the reverse of your bike/cars cooling system.... Put it under pressure
& yer raise the boiling point...
so the vacumn tube would have to work better on colder days/winter...
a home system won't pull anything like 4 hegs..but even half a heg will
lower the boiling point...

[pzkpfw]

A vacumn tube system lets you boil the water at lower temps :gob:

i use to work for Dom salt we had what was basicly a crude desalination plant
It would boil water at 42*C under 4 hegs of vacumn..
basicly the reverse of your bike/cars cooling system.... Put it under pressure
& yer raise the boiling point...
so the vacumn tube would have to work better on colder days/winter...
a home system won't pull anything like 4 hegs..but even half a heg will
lower the boiling point...

That might change the boiling point, and be useful for desalination, but isn't changing the heat content of the water; so not useful for making a nice hot shower.

e.g. http://en.wikipedia.org/wiki/High_altitude_cooking

[Laava]

http://www.kiwibiker.co.nz/forums/showthread.php/152937-Has-anyone-got-solar-panels-on-their-roof ?

Thanks mate. I will look into but more concerned with dedicated hot water systems at this stage.

[mashman]

Thanks mate. I will look into but more concerned with dedicated hot water systems at this stage.

Peraps yood like a windymill tae supplement yer soley?

[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.