View Full Version : Solar water heater
01-01-2007, 01:49 PM
we're just buying a house (I know we should first have the plans before making big plans).. but dies anyone know how much a solid thermosyphon solar water heater costs inclusive the installation (roundabout)??
Which brands are good, sturdy? I think in BRissie it should be enough with a solar warter heater and one won't need an electric one -isn't it?
Richard on Maui
03-01-2007, 01:21 AM
I have made a couple out of recycled parts for less than a hundred bucks. Learnt how to solder copper fittings in the process! I bet someone else will tell you which new brands are good. There are quite a few Aussie made ones I think.
You might want to have a back up heat source unless you are prepared to go lukewarm sometimes.
08-01-2007, 11:49 AM
I yet thought about this option - but as we won't live eternally in this house we have always to think about how things will sell.
I wonder why heaters are boosted here - in Greece there was a boosted system but we used the solar heater nearly all year and winters are lot colder there that in SE QLD (sunshine state)
Richard on Maui
08-01-2007, 02:01 PM
I guess there is a point where the efficiency of the system is compromised by the larger size of tank, so you are limited in how many days of hot water you have without sun.
Here in Huelo right now we have had pretty consistent cloudcover for about 4 days. The solar showers are all cold... :cry:
Of course, it has also been windy, and I bet if we had the wind generator up and its excess energy was dumping heat into a tank of water we'd laughing! And probably not using the generator to keep the solar system batteries topped off, or propane for a hot shower!
08-01-2007, 03:34 PM
I'm not shure how rules are in australia, but I think that hot water is much hotter than in Germany. My husband had to change something, surely illegally in our electric hot water system after he burnt the bottom of our little one. This should have influence on the energy you need.
In this house there is an electric boiler yet and we only have to top it with a solar system. Perhaps we don't need electrical boosing though.
I would like to get a quote but I don't know which system is reliable??
Richard on Maui
08-01-2007, 03:45 PM
Surely someone here has bought a solar hot water system recently?
10-01-2007, 08:06 AM
I tried at green plumbers now to get a quote.
10-01-2007, 01:36 PM
I know a friend that got a traditional "solarhart" type roof system installed for about $2500, in Mount Isa, so you can probably scale the install costs down a bit for Brissy.
In our new place, I'm looking at a evacuated-tube system, with a heat exchanger for our genset (there's no grid power). Seeing as when it's cloudy I'll need to run the genset, it seems to be a good sort of match. This is a pumped system with the controller/pump/tank down low somewhere.
It's from these guys :
11-01-2007, 09:41 AM
waht is genset and what is gridpower?
The price sounds reasonable (howerver it will never been paid with savings while electricity is so cheap) the price included installation isn't is?
11-01-2007, 10:02 AM
waht is genset and what is gridpower?
Grid power is the thing that isn't connected to my house. That is, I don't have 240V power supplied on site - the nearest connection to the electricity grid is about 15k's away through very mountainous national park.
So the house is mostly going to be solar-powered. Unfortunately, it's often cloudy there, so a genset (small engine + generator) is needed to keep things going during the cloudy bits. The engine is water cooled.... so there's hot water available from it when it's running, at about 90 degrees C. If you plumb the engine's cooling system through the hot water system with a heat exchanger, you can then transfer the heat from the engine into your hot water tank.
This is handy, as when it's cloudy the generator needs to be run to help the solar power system along. And seeing as the generator is running making electricity and giving off heat.... and the solar hot water isn't working when it's cloudy.... it's a good idea to tie the two together. All that heat is 'wasted' otherwise.
For the solarhart, that was a full installation quote, ripping out the old hot water system and putting the new one on the roof,etc. It really depends on how much hot water you use - our family with a small electric hot water system uses about $30 a quarter.... that's a long time to pay off $2500.
11-01-2007, 10:17 AM
The first time I really studied our electricity bill.
!.) We would save the most buying a reasonable fridge
2) We spend $ 33 in three month for hot water - this is an extra tariff with energex which is about 8.33 cents!!! (energex website)
Electricity is much to cheap, now I understand that outside lights are often burning during the day.
23-01-2007, 07:03 AM
We have a Water Heater that is not run of photovoltic cells but for most people it sound solar.
On the tank it says it is a Mains Pressure Storage Heat Pump Water Heater it is made by a company in NSW called Quantum Energy P/L phn 1800644705.
We have a panel on our roof but it is not north facing.
How it was explained to me was that it works like a fridge in reverse...instead of removing the heat from fridge to the outside this captures the heat and stores it.
Because we live in the Blue Mountains we don't have all year round sun but I can vouch that it really works. It does have a small compressor (gas or electric) which
we have in our garage I wouldn't want it too close to my bedroom.
Hope this helps
23-01-2007, 07:39 AM
If you are considering a solar system you can probably get one second-hand very cheaply. I have had 3 or 4 thrown out [I run a tip] by plumbers who said that people didnt want them on the roof and the electric booster heaters had stopped working so they were converting back to electricity.
If you are on grid power I wonder about the economics, both environmental and cost, of installing a solar hot water system. The last new electric one I purchased cost $400 and took 10 minutes to fit. If you get into your HWS and reduce the thermostat temperature from 75c to 60c you will save a lot in power anyway and wont scald anyone.
24-01-2007, 02:35 PM
My old gas hot water storage tank had a minimum temperature 'holiday' setting that I found great for the majority of the year in Qld. The one that eventually replaced it did not have this very low setting. I did a bit of research to find out why and discovered that Legionella thrives at 35-46 deg C. Minimum safe HWS temp for storage tanks is over 50 C. Drat!
Living in town, I thought that an 'on demand' gas system would be sensible, but the plumber dissuaded me as they don't work very well with single lever mixer taps, which I need because of dodgy hands :( .
Floot, I was interested to see you questioning the validity of solar systems for we townies. So, when the current one goes the way of all things, do I continue with the inefficiency of an electric (natural gas not availiable in this suburb) holding tank style system, or is there a place, on-grid for solar?
Susan's system sounds interesting, does anyone else have any experience with heat pump hot water systems?
Richard on Maui
24-01-2007, 04:22 PM
Using electricity to make heat is one of the least efficient uses of electricity. When electricity is made in a coal fired power station, there is energy lost at each of production - the coal is burned, and only a percentage of the available energy heat the water. The water turns into steam and only a percentage of that energy in the steam turns the turbine. Energy is lost in transmission of the electricity to your house...
Using gas is much more efficient... Using solar is much, much more efficient...
If you are looking at making your house more energy efficient, the first thing you do is replace or remove anything that uses electricity to make heat.
08-02-2007, 02:17 PM
Hi Permpolly I think your plumer is not right , were I lived before we all had gas and single lever mixer taps (or how you may call the stuff). Yes, there is a problem with legionella but it is much more dangerous to to run hot water at high temperatures and burning your childrens bottom. (My husband found out how to lower the temperature lower than min). I think heating too much costs quite a lot of energy. Legionella are only dangerous to people with a low immune - defence.
The idea of buing a second hand system is quite good.
15-02-2007, 01:11 PM
I've just come from the Molesworth, Tas. PDC where we built a pretty nice looking solar panel out of a discarded glass door, some old tin and some poly pipe, just to see what would happen. As soon as we finished it we had a week of cold and rain, but when the sun came out it took a few hours to heat an uninsulated 44 gallon drum of water to 33deg C.
Considering the back of the panel, the pipes and the tank were uninuslated, and that we we were working with no plans and few tools, we thought that was a pretty good result for such a southern lattitude.
I have no doubt you can build your own solar booster very cheeply, Hedwig, with only the most basic of tools and know-how, and in Brisbane, were there's plenty of sun, you'd probably find it produces all the hot water you need.
16-02-2007, 10:26 AM
Sorry to be so long in replying, I have been away from the computer for a week.
Hedwig, its not gas that is the problem, it is demand feed that is the issue, whether gas or electric. According to the plumber it will not work with single lever mixers, for some reason. Storage tank heater is fine for a mixer. This was told to me nearly a decade ago, so I will ask again, in case they now have compatible systems.
Re water temps, my elderly mother also lives here, so I have to be more careful about the water temps, both high and low. The high is easily sorted by using a single lever mixer with an adjustment disallowing too much hot to be used on its own. I had one in the shower at my last house and it was easy to set up with just a screwdriver.
I also set the volume low on the kitchen mixer at the last house(can't remember the brand at present), because most people cannot resist using water pressure to do work for them, instead of just grabbing a brush. I get irritated watching someone use three full fills of water to rinse out a mug before refilling it with tea or coffee. Without sufficient flow, they mostly get too impatient and settle for using way less water. Inconvenient for me when I need water for cooking, but some people will simply not listen.
Richard, I did note your suggestion to discard the current, operative electric storage heater ASAP, but I have a problem with junking functional objects. It will see the end of its life soon enough, judging by the state of the rest of the appliances here. I know electricity is a lousy means of producing heat, but is it better to discard a functional object, thus requiring the manufacture of a new one to replace it, or 'use it up' first?
I really do need to have easy taps as there are two arthritics living here. I have found that single lever mixers, if the handle is sufficiently long to elbow operate, have resulted in much lower water consumption, so I would prefer to use them. If it is still not possible to use an 'on demand' gas (bottled) hot water system, then I am currently leaning towards a well insulated, small gas water storage heater. Gas recovers quickly, and I've found that running the tank to cold for the next person wanting to shower is a good way of discouraging excessive use of hot water!
How much maintenance does a solar panel HW system require? I'm concerned about the cost of maintenance/repair aspect given the height of my two story roof. No one climbs ladders anymore, they all rent scaffolding due to OH&S regs. Not sure I am up to doing much 'high wire' work myself!
Alex, your experiment sounds great! Did you take any pics?
Since I find no problem in showering, including washing my hair using the volume in a camp shower, it occured to me that I could install a small holding tank for the shower. Something that could be filled with your 'allotment' for the shower, and unrefillable within a set time? I'm not sure how that could be done, but I am living in dread of my partner's pre teen arriving in June with her 20-45 min showers.
16-02-2007, 12:00 PM
I did take pics of the project, but will be unable to post them for at least a few days. Maybe someone who was there and took pics can help out?
As for retiring your unsuitable equipment, PermaPolly, don't think of it as "junking". Just put it up for re-use by someone else. There'll be someone out there looking for a hot water service like yours, just as you're looking for a more suitable one for your needs.
You can't just throw it away, because there's no such thing as "away" everything you throw goes somewhere, and all too often these days, it's the wrong place.
Hobart has a much-loved and well supported Tip Shop where "junk" is resold at very good (ultra-cheap) prices to people who think they have a use for it.
The rule is similar to compost: What was once useful, can be used again (in some other form, for some other purpose)
I have been researching solar hot water myself lately. I live in Townsville and I am flat out getting cold water out of the cold tap most days up here and reckoned it should be easy to heat my water on purpose. This system seems to be a very good idea and I plan to use a version of it at my house. My brother in law is using a 12v diaphram pump to circulate water through about 200m of 20mm poly on the ground at his house since his gas ran out and it is all he uses.
20-02-2007, 01:59 PM
unless you've got hydropower, or serious wind... and as long as you local gaseous fuel economy is viable... :)
03-03-2007, 05:39 AM
Just a thought on electric heaters and reducing the temperature.
If the hearer is an 'off-peak' system any reduction in the temperature will mean that the amount of hot water at 'bearable' temperature will be diminished. The hotter the water in the storage tank the more cold water that can be added during the peak demand period which is when most water is used.
03-03-2007, 08:30 PM
I've studies our electricity bill. this time, in the new house we've got only one meter. Our costs raised dramatically (we're not using perhaps 20 l a day for showering and water for dishwsahing). the problem: we've got only one meter. If you have got a extra meter for the hot water here in Brisbane electicity is incredible cheap - enrgex is doing their very best to prevent solar hot water.
SEcon: the heater is quite far away. That means much loss. (we will chane this) and as far as I could see - the pipes are not insuilated.
In Germany we had always gas (which was the heating for the appartement as well) and for dishwashing a small 5 ltr appliance under the kitchen sink, this is pretty economic you haven't got the loss of the transporting water.
I think we are ot that much handypersons - perhaps we're getting a quote and if it's really too expensive we will think then of constructing something ourseves.
04-03-2007, 03:51 PM
In the interest of re-cycling and saving money, go to your local Op-Shop and buy unuseable blankets (usually very cheap or even thrown out-depends who's on duty that day :) ).
Rip them into, say, 30mm wide strips and bind these around your pipes, then paint with old paints...colours don't matter.
The beauty of this system is that it is cheap, effective and if it doesn't give sufficient insulation at first then just add more binding.
07-03-2007, 11:55 AM
Take a look at this solar villiage!
http://www.tamera.org/Solar_Power_Villa ... _engl.html (http://www.tamera.org/Solar_Power_Village/SPV10_2004_engl.html)
07-03-2007, 12:26 PM
Not to knock the wind out of your sails but we have a number of solar towns in australia now. Here's a link http://www.greenhouse.gov.au/renewable/rrpgp/index.html
If you scroll down to the NT section, both Bulman and Lajamanu are on solar power that runs schools, streetlights, service stations and other shops. At a guess Bulman is probably about 500 people and Lajamanu & Hermansburg 1000 or more.
I feel that at long last the whole solar issue in Australia is set for exponential growth with serious practical developments and technology rolling out nearly on a daily basis. Sunballs, tiny inverters, microprocessors and a lot of 'smart' technology are bringing solar into peoples homes now. Check out eBay for solar torches etc and solar garden lights are now becoming a standard.
I can forsee a time when, it will be mandated, that in an average house all lights, hotwater and small appliances will be on solar circuits with grid power being used for airconditioners,washing machines, microwaves etc.
This will happen when the true environmental cost of power stations is put back on the consumer.
07-03-2007, 12:31 PM
I forgot to add.
The link you posted looks excellent and a well considered system, particularly the use of solar cookers. From what I understand of that region much of the food cooked is relatively simple fare that lends itself to solar cooking. Even the ability to boil water for free would have a huge impact on the lives of most of the world's villagers.
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