[Surferdude]

We've been promising ourselves this for ages so I finally got around to doing some sums and projections, then some research.
Because our HWS is 11 years old and in a worst case scenario we could fork out for a large solar power system and have the HWS sh*t itself in a year or two, we decided it made more sense to go with a solar HWS and reduce the number of PV panels in line with the reduced demand for power.

So we've installed a 300L Rheem HWS system and 12 x 190w Suntech PV panels, coupled with a German SMA 2.5Kw inverter.

All done now and working (except it's raining cats and dogs ATM  ).

I've calculated a ROI of approaching 20% (best case).

Anyone else utilising solar power?

[Phil №❶]

Yes, we did that 12 months ago.

We had a gravity feed off peak electric in the roof, working fine and very hot too. We put 310l Edwards solar on the roof machine and it's great, in summer. Naturally, it has off peak electric heating as well, BUT, I believe the element is sickle shaped and does not heat all the water. It assumes that every day you will have some solar as well, but this is not the case where we live. It is possible, with visitors, washing machine & my long showers to use all the hot water in winter. I think the element can be turned 180 deg to heat more water, but I can't be bothered doing anything about it.

Solar panels, we put an entry level 1.5KW system in on the same day as the HWS. This too is good, but remember that the solar panels loose efficiency in hot conditions and being black, they heat up rapidly. They run at about 80% on a good day so our 1.5 is more like 1.2. On a cold cloudy day, when the sun is shining they will jump to about 1.6, till they start getting hot. We receive the maximum rebate offered in SA @ 52c / nett KWh and even our little system has made a difference to our bill.

Surferdude I'd be interested to know how you arrived at your ROI. Here are some of the factors to be considered & it all got too hard for me to bother with. I'm not a patient person.

The panels - Lifespan of approx 20 years, depending on type, some have declining outputs over that time period (Monocrystaline I think). Polycrystalline dont decay, but have lower output / sq metre.

The money - If it is your savings, then what investment return would you have received over the 20 years & how would you have invested the money to determine this return.

Our little system has generated 2286 KWh, some of which we have consumed, but the total @ 52c = $1188.72

Looking forward to long sunny days this season.

[Surferdude]

^^
I worked on about 90% efficiency.
Your comment about them losing more efficiency when they get too hot (hot, sunny days) has me a bit perplexed. My understanding was PV panels needed both heat and light to get close to maximum efficiency (about 90% - although some claim more). I'll need to ask my son about that tomorrow. He's an electrical engineer, still working in power generation/ distribution and he started his career working for Pacific Solar while still at uni in Sydney then spent a couple of years with them after graduation.

I cheated a bit on my ROI in that I only worked it over about the first five years. Did some calculations based on expected output of the PV plus the virtual elimination of our hot water bill ((more on that in a minute). The expected reduction in our power bill then calculated as a percentage of our outlay gives me an ROI of about 18%.
So an investment of $10,500 would have to return me better than 20% somewhere to improve on putting the money into solar power. Our rebate is 55c in Qld - from Energex anyway.
Suntech panels give a sliding scale guarantee over 25 years as follows.
95% > 5 years
90% > 12 years
85% > 18 years
80% > 25 years
So, as we are both 63 years old ATM, don't figure we'll be in this house to worry about it after that.
Most other panels give 90% for 10 years then 80% for the next 15.
An analysis of our power bil showed nearly half of it could be attributed to hot water - obviously the system was not very efficient. The Rheem Hiline system has a booster which will heat enough water for a couple of showers from nothing in a bit over half an hour. I am leaving that switched off at present. Even with 3 straight overcast days with some rain we haven't had any hot water issues. It's summer of course but asking a couple of other people with similar systems suggests that only for a few weeks in winter we MAY have to turn it on. The HWS booster and our reverse cycle A/C are connected to Tarrif 33 which guarantees power at least 18 hours a day (which  only the electric HWS was connected to before) - in fact in our area it rarely goes off so even when they are in use, the cost will be low, especially when compared with the 55c buy back cost.
Also, the HWS installer was different to the PV installer and he reckoned with what we were doing PV wise we'd get money back. If that happens it'll be a bonus; I haven't allowed for it in my ROI calculations.
It's been a bonus having Cameron to check back with, although I did all the research myself so I could understand what was happening. When he worked at Pacific Solar, the engineer he worked alongside was a Chinese called Dr Zhengrong Shi who, when the Australian and NSW governments, in their infinite wisdom pulled funding for the research, bought the rights to the patents off UNSW, went home to China and was granted Chinese government backing. His Suntech panels are one of the most used in the world and he still collaborates with UNSW on R&D. Just after moving back to Qld a little over 3 years ago, Cam was offered a job with thier Australian operation in Sydney but had commited to someone else up here. Incidentally, the Qld gov't took the unusual step of issuing a statement a while back when there were issues raised about Chinese panels, to say that Suntech was the only Chinese panel they could recommend at that stage.

BTW, we never use hot water in our washing machine or dishwasher.
Now, if I can just stop my wife using the drier.

[Phil №❶]

Our dishwasher heats the water if it's not hot enough, at full price, so we use a short cycle & hot fill because the water was either heated free from the sun or at least off peak tariff from AGL. Can your dishwasher wash in cold water only?, You must use a longer cycle to achieve good cleaning. 

[Dazzler]

We look into solar from time to time .. I only checked again recently when they advertised a 1.5 KW system installed for $1691 ... I knew there would be add-ons (sure enough $200 for travelling and $200 for installing on a double story)

He said to get anything back from the government (only 20c rebate in Tassie ... ) we needed to have a Smart meter (which we don't have or want) ... He said without that probably save about $100 per quarter off our $600-$700 bill.. so it would take about 5 years to pay for itself..

Now the tech at work says inverters only have about a 5 year life span and aren't cheap so need to factor that into the equation too maybe (Be interested to hear your son's feedback on that Trev)

Taking everything into account including the adverse effect to the appearance of our home, we decided against it ...

My Brother in Kingscliff is actually generating more power than he can use but the money he is getting back will take a few years to offset the cost of his very large setup.

[Phil №❶]

dazz

I think my inverter is warranted longer than that, I'll have to find the paperwork. When I did my sums, the % of the price paid by the govt in rebates suggested to me that only an entry level 1.5 was warranted. If you want to generate heaps of power, then the additional cost is 100% yours and the way the rebates work, it's a bad deal.

The top rebate ever offered in SA was 52c / KWh. As a total of 20 MW was achieved nationally, the rebates have fallen. Due to your southern latitude at your rates, I don't think any combination would be viable.

Another trick the utility companies are using is that all solar installations are a contract between the original owner only. If you move, your existing contract is cancelled and the new owner must enter into a new contract at the going rate of rebates, which are and will continue to decline. Also, we have been warned that electricity prices will rise and at any rate of rebate, it will be impossible to actually generate revenue from solar. 

[Surferdude]

Our dishwasher heats the water if it's not hot enough, at full price, so we use a short cycle & hot fill because the water was either heated free from the sun or at least off peak tariff from AGL. Can your dishwasher wash in cold water only?, You must use a longer cycle to achieve good cleaning. 

Sorry. To clarify. Both are hooked up to cold water only. We've only ever washed in cold water in the washing machine.
The dishwasher heats it's own water. I surf with a plumber who recently confirmed for me what I was told years ago - that it is more economical to let the dishwasher do that than use the HWS.  I don't know why exactly.  Also, we normally only use the 60 degree setting on the dishwasher which only lasts about 30 minutes. The other cycles run for an hour or more and on the recommendation of our friendly local electrician who also is an appliance repairer, once every couple of weeks we use one of the longer cycles to clear any gunk buildup in the system.

[Phil №❶]

Mine is set to hot water fill at all times. I'd check out that logic with your son because that doesn't sound right to me. If your HWS heats at tariff 33 that has to be cheaper than daytime electricity. The amount of energy required would be the same IMO. I even make sure that the dishwasher runs at night so it doesn't rob any of our solar contribution, as we make a dollar or two from solar at present. 

[Surferdude]

Dazz and 84+, our inverter has a 10 year warranty and is expected to last well beyond that.
As usual with these sorts of things when there's big demand the cheapies turn out in droves. There's been quite a bit about some of the questionable stuff in both inverters and panels, so you do need to be careful.
IIRC, the inverters which are causing problems aren't German made like the SMA we have.
But, time will tell.

Also, on the power buyback scheme, as I said, Energex is paying 55c but again (IIRC), the gazetted rebate is about 44 c in Qld. And that's the law until about 2024 or something. Energex can drop the 55c but they can only go as low as 44c.If you are interested, this is the best thing to read.
http://www.google.com.au/url?sa=t&rct=j&q=clean%20energy%20council%20solar&source=web&cd=7&ved=0CJ4BEBYwBg&url=http%3A%2F%2Fwww.cleanenergycouncil.org.au%2Fdms%2Fcec%2Fresource-centre%2FSolar-PV-consumer-guide%2FSolar%2520PV%2520Consumer%2520Guide%2520Vol15%25208%2520November%25202011.pdf%3Futm_campaign%3Dconsumerguide&ei=16j1TvPJIsqUiQeDt6G5AQ&usg=AFQjCNHy3nZZScA_MSije9J0p4PlFJdj5Q&cad=rja

[Surferdude]

Mine is set to hot water fill at all times. I'd check out that logic with your son because that doesn't sound right to me. If your HWS heats at tariff 33 that has to be cheaper than daytime electricity. The amount of energy required would be the same IMO. I even make sure that the dishwasher runs at night so it doesn't rob any of our solar contribution, as we make a dollar or two from solar at present. 

Nah. It's not an issue of power useage, although we also run ours at night for the same reason.
Both a plumber and an electrician who work in our current house, plus one in Sydney and one in Brisbane before we moved down there, have all said it's better for the dishwasher to heat it's own water.
When we bought this house the diswasher was hooked up to the hot water line and I asked around becaus eit seemed so unusual. All the advice I said suggeste dgoing back to cold water fill and heat its own. So we did.

[Phil №❶]

On that point, we'll have to differ. 

[Dazzler]

Thanks for the info Trev and Phil either way i don't think the figures add up in Tassie (Not so much the quality and amount of Sun as other factors like the rebate amount)

[Surferdude]

Thanks for the info Trev and Phil either way i don't think the figures add up in Tassie (Not so much the quality and amount of Sun as other factors like the rebate amount)

Yeah the rebate down there is pretty ordinary but as Phil says, probably not very efficient anyway so maybe that's why the government isn't hyping it up.

[Phil №❶]

The rebate deals are different in each state and are latitude dependant.  Tassie has hydro, which is about as green as you can get too. 

[Surferdude]

The rebate deals are different in each state and are latitude dependant.  Tassie has hydro, which is about as green as you can get too. 

I notice they've slashed the feed in tariffs for SA for new connections, too.

[Phil №❶]

That's why we got in b4 that happened. 

[rustynutz]

My hot water is heated off peak and that cost me a whopping $36 last quarter...

Me thinks I'll give solar panels a miss....

[Dazzler]

We have 2 x hot water systems (one at each end of the house) but they are reasonably efficient...

[Surferdude]

On that point, we'll have to differ. 

OK. I have a better idea of what I'm talking about now.
Talked to Cameron and after much discussion (and calculations) considering things like the temperature loss from the HWS to the dishwasher so still some external heating required and the effect on availability of hot water for other purposes like showers if we use some for the dishwasher, we agreed it would be marginally better to use the  hot water connection rather than cold water. However, as the cycle we use most only uses 9 litres or water, it seems the benefit would be minimal ( but definite).
Looking for reasons why plumbers and electricians have told us to use the cold water connection I resorted to (horrors  ) reading the manual..................... And I quote. "The dishwasher may be fed with either hot (max 60deg) or cold water. However a hot water supply is not always efficient as it shortens the washing programs a lot. Therefore we recommend connection to a cold water supply".
The current one is a Westinghouse but previously we've had a couple of Dishlex (which are the same company these days).
We use the shortest program because we hand wash anything really dirty or fatty so if we used a longer wash cycle for more cleaning efficiency on washing we'd offset the benefit by using considerably more water (up to 16 litres).
A a result of all that we'll stay connected to the cold water for a while until we guage where we are at with "actual" benefits in power savings.
Thanks for making me look more closely at this as I now have a better understanding of the pros and cons.

[Phil №❶]

My family have a habit of putting the dishes in the sink rather than load the washer, so in the end I do it. We do have a long run from our solar HWS to the kitchen unfortunately, so after I've loaded the machine, I run the hot water into the sink and clean any residue from the sink that may collect. Leaves it nice and fresh overnight etc. Even then, the DW heats the incoming water for about a minute to reach it's required temp. 

[Surferdude]

Ha. My family puts the dishes in the dishwasher. But before I turn it on I always have to re-arrange things.
We have a long run to our sink to. It's a largish house all ground level and the sink is in the island bench pretty much in the geographic centre of the house. We have a couple of plastic bottles we run the water into to get hot then use that on pot plants or the garden. Or, refilling the 2 litre water jug after dinner to go back into the fridge more than does it. Takes about 1 - 1.5 L to get some temp in it. The guys installing the sloar HWS warned me it could take longer because of where they had to route the copper pipe, but in fact the difference is minimal.

From what I understand reading the DW manual, the washing cycle starts and keeps running until the water reached operation temp. That's the only way I can see the cycle would be lengthened as they say. But i will seek clarification next time we have our local sparkie in for something.

[Phil №❶]

Glad to see the water isn't wasted. Cheers

[eye30]

Looked into having solar panels on the roof, south facing roof, but just as I was about to get them the government decided to cut the tariff by 50% on the electricity sold back to the power company.

Decided against storage of produced electricity due to cost and nowhere to put the storage facility.

Decided against it as the pay back period doubled.

[Phil №❶]

Bad luck eye30, It's sad to think that there are people prepared to invest in our future generation's welfare by greening the planet, only to be thwarted by govt decisions. Any CO2 saved is a bonus for us all. 

[Surferdude]

Panels have been in operation for a week at Noon today.
A couple of quick calculations based on the kw/hrs generated since the start would indicate a total wipeout of our Peak Power bill plus about $130 rebate per quarter. Which is pretty much in line with the calculations we did before commiting to the installation.
Our hot water should be eliminated by the Solar HWS so, all looking good.
I appreciate this time of year is the peak period for energy generation, but offsetting that has been two days of solid rain in the seven, plus another day or so of heavy overcast conditions.
There will also be some offset of the saving on "Off Peak" because we've added the aircon to this tariff, along with the HWS booster which we'll only turn on in the middle part of winter.

[Phil №❶]

Are you reimbursed for Gross KWh or Nett. We only get Nett in SA. 

[Surferdude]

Are you reimbursed for Gross KWh or Nett. We only get Nett in SA. 

Yeah. It's Nett in NSW too. They changed it when the new Government came in.

We get Gross. 

[Dazzler]

True Value Solar (different from True Solar apprarently) had a January special of $1692 fully installed for a 1.5 KW system. I did my sums and thought even with  a $200 loading for double storey house that was a tempting price to save maybe $100 on each quarterly bill...

I went on their live chat line which ended up being a joke.. about 30 minutes of please wiat will be with you shortly etc.. I gave up trying to get through on the phone. I ended up with a reference # and some guy was supposed to ring me back but he only tried once when I was at work (nearly a week ago)

Anyway, I went on goggle to look up their number again and decided to look at their reviews .. Wow do they get a caning on Whirlpool.. Glad I read that before I went any further 

http://forums.whirlpool.net.au/archive/1456932

With our limited 20c buyback a well installed system with 20+ years warranty on the panels and 10 years on the inverter for under $2000 would have been very tempting.

Unfortunately, a couple of quotes from local crowds (I have another couple pending) at $3,800 and $4,700 don't tempt me a bit 

[Dazzler]

Update: I've been offered a 1.5 KW sytem + 2 KW inverter for $2500 and am negotiating to make it a 1.9 KW system with 2 KW inverter for $3000 (A crowd called Ultra Greensun) The electrician is apparently coming this week for a look.

I would Ideally like German made SMA Inverter and German Panels but that would be twice the price from other quotes I am looking at.. Not paying $5,500 or $6000 

We have double glazed windows everywhere and use 99% low voltage light Globes 7w - 14w maximum. Using energy saver master/slave powerboards with our two main entertainment set ups and recently in my office too (so taking this pretty seriously)

Apparently, and I've been told this by a couple of different sources, our temperate climate means the efficiency loss due to the latitude is somewhat offset by the low number of days where the panels are heated past their optimum efficiency temperature (if you get my drift)

[Surferdude]

Update: I've been offered a 1.5 KW sytem + 2 KW inverter for $2500 and am negotiating to make it a 1.9 KW system with 2 KW inverter for $3000 (A crowd called Ultra Greensun) The electrician is apparently coming this week for a look.

I would Ideally like German made SMA Inverter and German Panels but that would be twice the price from other quotes I am looking at.. Not paying $5,500 or $6000 

We have double glazed windows everywhere and use 99% low voltage light Globes 7w - 14w maximum. Using energy saver master/slave powerboards with our two main entertainment set ups and recently in my office too (so taking this pretty seriously)

Apparently, and I've been told this by a couple of different sources, our temperate climate means the efficiency loss due to the latitude is somewhat offset by the low number of days where the panels are heated past their optimum efficiency temperature (if you get my drift)

That last paragraph is interesting Dazz. Someone else on here alluded to that and whilst it's true in part, The two biggest generating days we've had since our system went in were 30 degree plus days. So I'm guessing whilst they lose some efficency, they're still generating more than enough out put.
I can't remember if you have electric, gas or solar hot water, but if you have electric, check your bill and see how much it is costing you. I've been talking to a few people and they are all surprised at what the HWS is costing them. Changing to solar HW is the single most effective upgrade you can make towards reducing your power bills (if you have gas, ignore all this).