Which Solar hot water system?

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Which Solar hot water system?

Postby 737 pilot » Sun Jul 04, 2010 1:56 pm

My Son has a 1.5Kw solar system going on the roof in about a month.

However, he wants to chuck the old electric HWS and go solar hot water. (He should get rebates of $1,000 from JuliaGillard and $600 from AnnaBligh.)
For What Its Worth, we have a 15 year old Edwards roof top system which has been great- only maintenance/repairs needed in 15 years are two booster elements, and one thermal expansion/overheat valve. I have had standard electric systems worse than that. I installed low flow showers as soon as we put the solar HWS on the roof- this is essential with a large family and would be a bloody good idea in any event - (we had four kids).

Some questions please:
What sort of Solar Hot water do you have?
How old?
What did it cost, preferably before rebates/incentives?
Are you happy with it's performance?
Are you happy with it's reliability?

Any and all information much appreciated.
Cya
Dave
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Re: Which Solar hot water system?

Postby Tracker » Sun Jul 04, 2010 4:56 pm

.
737 pilot wrote:My Son has a 1.5Kw solar system going on the roof in about a month......, we have a 15 year old Edwards roof top system which has been great-


You might like to check on the rebates... I THINK that rebates only apply when you are replacing a "Resistive Heating" HWS with a SOLAR or a Heat-Pump.

Perhaps the installer will be happy to tell fibs for you, but the normal process involves YOU taking the completed paperwork to MediCare and having it processed..

737 pilot wrote:My Son has a 1.5Kw solar system going on the roof in about a month.

This would make me think that it is all signed and near delivered..

I have a Heat-Pump HWS, but if I were looking at SOLAR - then I am pretty sure that I would be picking the Glass-Tube systems, of whichever brand as they are likely much of a muchness..
I was taken with the [url]skysolar.com.au[/url] system, but suspect that others might not like it.
The reason why I would be looking at the Tube system is that the weakest link in the system is the tank.
I hear reports suggesting tanks are only lasting 7 years average (excluding stainless and other special long life (expensive) systems) ..
The less that you have on the roof, the likely cheaper the maintenance.
It is becoming more and more difficult to get people to go onto roofs because of OH&S.. etc.

Others might have better ideas on cost... BUT do be careful re the rebates.. Check the 'rules'
( and naturally he did not get the Insulation done under that Gizzard Grant ...)

I could imagine installers not caring as they get paid first and then you claim and if it aint right, you get rejected.... BUT the installer has the money..

I know people who installed an OLD resistive HWS.. :( ., just so they could honestly say, the SOLAR replaced an electric system..
.
.
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Re: Which Solar hot water system?

Postby karlajensen » Sun Jul 04, 2010 9:08 pm

315L solar tank ~$1400
evacuated tubes and controller $1400
Solar tempering valve $150
Instant gas booster $1000
installation $1500
all up $5500 give or take
bargain will do 80%+ hot water depending on what state you live in.

I did evacuated tubes in Melbourne as a retrofit myself, all out $1600.
I have since moved and have an edwards unit, its performance on less than perfect
days is leagues behind the evacuated tubes.
In fact the only problem I had with the tubes was what to do with the massive amount of hot
water I had in SUmmer -i did have a small 225L tank which was part of the problem
but a $1400 fix hence happy enough to boil some water, it was all rainwater anyway.

Electric hot water uses about 10KW/day which is HEAPS the 1.5kw will make 5.5kw day
do the math, cheaper to heat water by sun direct not via KWHRS
8E + 8W + 8Nth Garage CMS2000-1 with ~4500W in 3 strings of 8.
Fronius Galvo 3.0 inverter with ~6.6kW panels
12x ZNShine + 12x 180W Solarfuns both NW + ZNShine 12x190 facing SE.
Edwards Solar Hot water


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Re: Which Solar hot water system?

Postby 737 pilot » Sun Jul 04, 2010 11:02 pm

Sorry,
just to clarify:
I have 3kw of solar plus an Edwards solar HWS which has been on the roof for 15 and a half years.

My son (in a different house) is fitting 1.5kw of solar very soon and wants to replace his electric HWS with solar hot water. There has been no insulation rebate claimed so he should get the federal and state rebates ($1000 plus $600)
He's looking for feedback on "who has what" solar HWS, and cost, how happy you are with the system etc.

Thanks again
Dave
Xantrex 2.8Kw inverter.
3.6kw of panels.
Mad keen on improving energy efficiency of the whole system and house.
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Re: Which Solar hot water system?

Postby Gordon-Loomberah » Sun Jul 04, 2010 11:08 pm

737 pilot wrote:What sort of Solar Hot water do you have?

RunOnSun 30 evacuated tube, 250l SS tank, no gas or electric booster connected

How old?

I installed it last winter

What did it cost, preferably before rebates/incentives?

Cost me about $2600 including $250 freight, no rebates

Are you happy with it's performance?

Very, it gets us (2 adults) through most periods of cloudy weather, although the showers arent as hot as I would like after a few days of very little sun. In almost a year that its been installed there have only been 3 or 4 days where I decided not to have a shower as the water wasn't as hot as I would like.

Are you happy with it's reliability?

Very. The only modification I plan is to make an automated cover that covers up ~half the area of the tubes in periods of long sunny days, to prevent loss of (rain) water released by the pressure/termperature relief valve.
http://gunagulla.com Loomberah weather and astronomy including live solar radiation intensity and UV + Gunagulla aquaponics, organic eggs and cherries
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Re: Which Solar hot water system?

Postby gully » Sun Jul 04, 2010 11:20 pm

Gordon: What was involved in installing the unit(s) / how long did it take? Can I ask why no booster was installed?
------ --- - -- -- - -
Network/Retailer: SP Ausnet / Red Energy (EM 1200 smart meter)
PV: 10 x 175w Suntech (1.75kW) panels and SMA SB1700 Inverter
SHW: AAE Solar Gas Storage 250L 30 tube
Tank: 10,000L Tankmasta w/ Rainbank 2 into laundry/toilet
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Re: Which Solar hot water system?

Postby Gordon-Loomberah » Sun Jul 04, 2010 11:41 pm

Its mounted on an embankment behind the house, I have posted a pic somewhere in the EM forums, maybe in my Intro thread.
EDIT, here is the pic, right click to "view image", the SHW is on the right side, the rest is the hydronics system.
Image

It took a few days total to install, but I had to wait for the concrete that holds the legs to set properly before loading it. Actual time spent on it was a bit over a day I think, although I didnt keep any records of the time taken - mostly just me doing it.

I deliberately bought a unit with no booster in it. I'm planning on building a heat exchager to add some heat from the solar hydonics/slow combustion wetback stove house heating system, for those times when a bit more heat is required. The heat exchanger will incorporate 25kg of wax as a phase change material, to store/release most of its heat around 56C, and also act as a heat storage buffer.
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Re: Which Solar hot water system?

Postby karlajensen » Mon Jul 05, 2010 12:11 am

NICE one! ;)
8E + 8W + 8Nth Garage CMS2000-1 with ~4500W in 3 strings of 8.
Fronius Galvo 3.0 inverter with ~6.6kW panels
12x ZNShine + 12x 180W Solarfuns both NW + ZNShine 12x190 facing SE.
Edwards Solar Hot water


Luck Favours the well prepared.
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Re: Which Solar hot water system?

Postby gpigeon » Sun Feb 18, 2018 6:17 am

Gordon-Loomberah wrote:Very. The only modification I plan is to make an automated cover that covers up ~half the area of the tubes in periods of long sunny days, to prevent loss of (rain) water released by the pressure/termperature relief valve.


Gordon.....how is the "Runonsun" unit going after all these years?
Did you ever fit the "automated cover" for the hot days?
If so, I would be interested to see your ideas. I am currently in the middle of the same project.
I understand there could be a problem with corrosion at the joint between the copper insert (for the tube) and the SS tank. Have you heard of any issues with this?
thanks.
Bill.
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Re: Which Solar hot water system?

Postby australsolarier » Sun Feb 18, 2018 8:47 am

copper and stainless steel do not have any corrosive action needing to be concerned about. it is a common thing to do in plumbing. neither have i heard anything about it. i suppose if you plan to keep the system for 10'000 years and send it to mars you might think about corrosion. also common is copper and brass joints in plumbing.
however if you want to worry about corrosion, galvanised steel and copper can have a problem, IF the copper pipe is before the galvanised pipe. naturally i have not tested that, but heard of that.
so, don't worry about it.

as for covering up the heat pipes. this also is a non issue. it looks great on paper and in the planning phase. in practice however, it has a lot of problems. it is mechanical and can fail. there is a problem with wind. and it is costly.

the best i can suggest is a diversion. if you are worried about the 140 degrees or so in the "collector". in the commercial house system the pump just gets turned of when the water turns to 80 degrees in the tank.

the way i have built my 100 evacuated heat pipe house heating system:
when the tank reaches 82 degrees the circulation water is diverted through an outside tank. this cools the water before it gets heated up in the sun collector again. most hot water controllers have that feature built in.
stagnation ( turning off the circulation pump) is not a problem if you just use water circulating. the water in the collector just vaporises. when antifreeze is used in the circulation it has to be planned a bit better, as the antifreeze boiling creates havoc with the inside of the pipes.

another way to cool the tank is having a radiator outside for diversion.

i followed fora where people built large systems for house heating. not one of them built something covering the solar panels. but many were thinking about it.
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