Sunshine
Member
peter69_56,
I agree. The people who I know here in Qld with flat plate solar all boost considerably more than mine, so I see no real world evidence that flat plate is better, rather the opposite.
I think real world performance results from friends/neighbours is more valuable than sales
talk with lots of promises.
As the flat plate systems aren't vacuum insulated their performance in winter in the colder climates can only be worse than here in the warmer parts of Oz.
Tony, I've posted the charts on a test site I'm still working on, but I'll only have it up for a little while, see
http://www.solarpoolpanels.com.au/temp-page
Uses published data for all available systems eligible for rebates at the time from http://www.resourcesmart.vic.gov.au (taken a 3 years back)
The area given in the resourcesmart data was the Aperture, for ET's I converted this to gross by multiplying by 1.6. (note this will be different for each ET brand, but I just use an average)
For Flat plates you multiple by 1.1 to get gross area.
Hope this puts an end to the debate, you can see the spread between brands is much greater than ET vs Flat plate averages.
I also plotted system cost vs price for each brand which was extremely interesting but I can't show that, as it's commercially sensitive.
One other thing of interest that was the fact that ET required a larger tank for the same solar savings, the opposite of what you would expect.
Flat plate collectors get a bad rap from all the lower efficiency talk, but as you can see they make it up and more in gross area,
anyway I have to stress that this is part theoretical, the panel efficiencies might have been tested in actual tests but the simulations to get the solar factions are done on computer.
peter69_56
Member
Mine is done real life, in comparison with others who have flat plate at work. All theirs have been fitted to new houses supplied by the builder. As i said previously they are NOT happy with their units and one is going to add evac tubes to get it to perform as expected.
I am happy with mine after bad installation work was fixed. I have hot water in Gippsland, they however do not and have luke warm water. I find that real life is the best test of all. Forget all the theoretical stuff. In any event I will still say that those who sell the products have a VESTED interest. Why would anyone bag flat panel if they have a warehouse full of them to sell, same with evac tubes. I sell nothing, I am a consumer. I dont care which one I buy as long as it works well and is cost effective. I have that with my system, I have no barrow to push.
My workmates are NOT happy with their systems and they have invested significant funds into them. They have no barrow to push and would prefer theirs to work well I am sure and would prefer to be singing their praises.
We all just want HOT water when it matters the rest is just hype and talk. Who cares about gross area, its all about cost and ensuring that the energy to heat the water comes into the tank. Nothing more than that.
peter69_56
Member
EcoOnline, how much for a flat panel setup that will give me an aperture of 4m2 ???
peter69_56
Member
franks said:
For a DIY project, flat plate collectors are much cheaper than the same thermal capacity in EV Tube collector..brand new chrome copper 200x100cm collectors are around $250 each vs $1000 for 24 ET collector.
franks
Where do you get these $250 brand new chrome copper 200x100cm collectors, what store will sell some to me? At that price I am interested in trying some. Whats the aperture on each panel so I can compare them with evac tubes for price as well as size?
peter69_56
Member
Interesting site I found as I went looking for specifications on Dux flat panels.
http://www.thesouthernhighlands.com.au/directory/building/dux-hot-water
Didnt find the actual spec info I was looking for on the Dux flat panel (aperture size etc)
peter69_56
Member
Oh well what I was saying was, if the flat panel is as cheap as stated in posts here I would be happy to buy one and try it in comparison.
As you dont sell flat panel I stand corrected with the comment about not believing sellers of products. Most of us here are consumers and just want a good product and dont care what the brand/type etc. it irks me however when people come on line and post as though they have special knowledge on products and how great they are and then one finds out that they sell the product and are just pushing it regardless of how good/bad it is.
franks
Member
Hi Peter
OEM suppliers of chrome copper flat collectors collectors..brands DUX Chromagen Conergy..all use the same 200x100cm flat collectors..there has been some surplus stock due to the removal of rebates..some have appered via the buliding surplus sellers..prices $250-400 per collector with 22mm compression fittings new unused stock
peter69_56
Member
When I had my system fitted I wanted more capacity from it. I have effectively 30 tubes (24 parabolic ones). I saw a local seller and asked if he sold tubes, he asked why and "suggested yes he did" (not I say suggested). Anyway he said he would come out to look at the system. Came out and then spent about 30 minutes telling me I need to pull down my 2 month old system and get a flat plate system from him, throw away the tank, pump tubes etc, he might be able to resell mine for some amount. I asked why I couldnt have one more bank of tubes. He said it wouldnt work. I asked why not. he said the temperature sensors will get confused (gee the one sensor in the panel will be confused if I add another set of tubes to the input end????)
He assumed I was an idiot and knew nothing about thermodynamics, thermocouples etc. I work with energy/steam/water. Anyway he went away to make up a quote for me. never came back as perhaps he worked out it would be a hard pill to swallow to try and sell me another solar HWS when I just bought one 2 months previous. They also only sell flat plate (oh what a suprise).
the words Crook, Rogue, Scammer come to mind here.
Anyway I contacted the chinese manufacturer, he put me onto a company in SA, who organised a 6 tube panel for me exactly the same as I had. It was 60% of the cost of exactly the same bank that the original supplier was going to sell me. Anyway i put it on and I am very very happy and get overheating in summer (as I expected so cover on panel then) and great performance the rest of the year. Each 6 tube bank has an aperture of 1m2
peter69_56
Member
franks said:
Hi Peter
OEM suppliers of chrome copper flat collectors collectors..brands DUX Chromagen Conergy..all use the same 200x100cm flat collectors..there has been some surplus stock due to the removal of rebates..some have appered via the buliding surplus sellers..prices $250-400 per collector with 22mm compression fittings new unused stock
Same as the ones on ebay???? item number 270950978954
franks
Member
DUX Chromagen Clenergy chrome copper collectors all the same using extruded alumunium frame with plastic back 200x100cm 22cm compression fittings..gees gone up in price looked last week were $250, looks like there is a rediscovered market!
for any tech info can email me
peter69_56
Member
Perhaps the guy who was wanting to replace the (I think) Edwards panels (per my previous post) was being ripped off just like me (above post) by a scamming retailer of the product. I would be interested to know the average cost of a flat panel (normal price) and not a reduced price because they are not selling. That would give me a good realistic comparison between ET and FP.
It seems as though if you buy a system they are all (were) on the inflated rebate price no matter which system you bought. I might just get one FP and try it on my garage for the HWS there.
Peter, yes that's what gets me too, especially with the ET guys, they make it out like ETs are so much more efficient, showing efficiency comparisons based on absorber or aperture area which give a totally misleading picture, see here
http://www.solarenergy.ch/index.php?id=111&L=6&no_cache=1
(European testing institute) download some of the efficiency plots of ET tubes and you'll know what I mean. No wonder they don't show gross area ET efficiencies, only aperture or absorber area. I've seen absorber area comparisons with ET at 90% efficiency, then you ask "what about all that sun falling in between the tubes and glass?" ... "err umm well ...we don't count that in the efficiency plot"
I'm surprised Aus manufacturer flat plate guys don't do much to counter the ET spin.
peter69_56
Member
franks said:
I think the wholsale cost is $600 for flat plate collector..who knows what the end price to a customer is ?
As I have said previously this guy who was changing to ET because he was told his 6 yr old flat plates that were leaking were going to cost him something like $1800 each. Now I choked on that as I can get 6 tube parabolic mirror ET for about $520 each so a bank of 2 of them would be about 1 flat panel thus half price. I suspect the end sellers are making a killing and overpricing their product. Much like the end seller for my ET's about $780 compared to $520. Both places were end sellers, just one was being fair and resonable.
peter69_56
Member
EcoOnline said:
Peter, yes that's what gets me too, especially with the ET guys, they make it out like ETs are so much more efficient, showing efficiency comparisons based on absorber or aperture area which give a totally misleading picture, see herehttp://www.solarenergy.ch/index.php?id=111&L=6&no_cache=1
(European testing institute) download some of the efficiency plots of ET tubes and you'll know what I mean. No wonder they don't show gross area ET efficiencies, only aperture or absorber area. I've seen absorber area comparisons with ET at 90% efficiency, then you ask "what about all that sun falling in between the tubes and glass?" ... "err umm well ...we don't count that in the efficiency plot"
I'm surprised Aus manufacturer flat plate guys don't do much to counter the ET spin.
Dont get me wrong, I am more impressed with the ET. I have seen a number of flat plate systems leaking or with discolouration which suggests something wrong, ll on relatively new systems. Also the reports back from my workmates who are not happy.
My 6 tube bank gives an average output of 620 kWh/m2 and they have a footprint of 1.15m2, aperture of 1m2
I see the flat plate banks give 472 kWh/m2 and the sample has a footprint of 2.82m2 aperture 2.596 m²
That alone suggest that ET are giving better performance, never mind the roof footprint.
TonyT
Member
EcoOnline said:
Tony, I've posted the charts on a test site I'm still working on, but I'll only have it up for a little while, see
http://www.solarpoolpanels.com.au/temp-page
Uses published data for all available systems eligible for rebates at the time from http://www.resourcesmart.vic.gov.au (taken a 3 years back)
Thanks EcoOnLine
Your first Chart shows that for a chosen number of square metres of collector the savings vary widely e.g. for a 4sqm area the savings vary from 65 to 82 units
Q1. What is the unit of "Solar Saving" on the X-axis ?
Q2. On the resource smart website, where does the data come from ?
The solid trend-line on the Chart shows that for a flat plate collector with area 2sqm the saving is 60 and with area 7sqm the saving is 92.
Q3. Can this be correct ? Surely, with 3.5 times the collector-area the saving must be more than 92/60 or about 1.5 times.
On the second to last chart, for a panel of 3.5sqm the costs for systems with different brands varies widely - from 3500 to 7500 !
yabbietol
Member
Really interesting disscussion I have 12 year old flat panels that are not leaking, but have lost their black coating. I repainted one and then sought replacement panels for my Edwards system. The repainting was difficult due to moving the thin glass and replacing it. I approached ACTUAGL as the local Edwards agent and the price per panel was $1500 plus about $300 installation per panel giving a total of $3000 for two panels plus installation of $600. A total rip off by the authoriised agent for ACT and Queanbeyan.
$600 panels would be great, but if this is the wholesale price where does a member of the public get them at $600. Also it appears the $250 panels are a furphy. It all makes a new tube system simpler and better value that replacing my flat panels, surely I should be able to go to my original supplier and get parts at a fair price instead of been ripped off.
A simple question where can I get 2 Edwards flat panels to replace mine at a reasonable price in my area?
Sunshine
Member
Ecoline,
What your flat plate stats fail to show is the amount of energy being lost due to poor insulation of the flat plate collector. The stats only show the amount of energy absorbed, and not lost back to the atmosphere due to cooler ambient temperature.
The ET are vacuum insulated whilst the flat plate is only single sheet of glass which bleeds alot of heat back to the atmosphere in cool ambient temperatures.
That's why the stats on flat plate look good, until they get used in the real world.
It's like comparing single glazed windows to dual glazed in cooler climates.
peter69_56
Member
You could buy a whole evac tube HWS including tank, pump, tubes, pipework, tempering valve for that. I priced getting a system in parts from plumbers etc and could get the system for about $3600
Some companies are so greedy and wonder why people dont buy through them and why they get bad publicity on the net
GREED
peter69_56
Member
Well given the energy figures from my tubes and the flat plate site given by Ecoline, and the heat loss stated by sunshine, it all makes sense why I am still getting good heat from my system and my workmates are getting little. The ambient temperature is dropping and has been quite cold, hence the heat loss from their systems.
Sunshine said:
Ecoline,
The stats only show the amount of energy absorbed,
They show nothing of the sort, these are not efficiency plots.
Tony, Solar Factions are quoted in percentage hence 60% and 92%, hope that explains as there is a point of diminishing returns with putting more panels up.
Anyway point is look at the spread of data, you have ET systems that are heaps better than flat plates and flat plates that are heaps better then ET.
The argument should not be framed as flat plate vs ET.
I realise that people latch onto the differences they can see, hence ET are different from flat plates, therefore its flat plate vs ET, but what are you referring to when you talk about flat plate collectors, which one????
Which surface selective coating does it use? There are huge efficiency differences, there are flat plate collectors sold today that don't even use surface selective coatings, then there are the super efficient TiNox coating flat plate collectors. Same with ET, there are U-tube or heat pipe versions that vary greatly in efficiency, the point is this ET vs flat plate argument is useless, as you're not defining what you're arguing about.
peter69_56
Member
EcoOnline said:
Same with ET, there are U-tube or heat pipe versions that vary greatly in efficiency, the point is this ET vs flat plate argument is useless, as you're not defining what you're arguing about.
Though I did that up front. Its about cost to the customer vs returns. The rest doesnt matter as its all talk. Saying I can get 2 plates at a super special price right now is fine but can the general public buy them at that rate normally. No they apparently cant.
The price of replacement flat plates per the posting above was in the order of $1500 per panel is excessive. It appears from all that I have seen and discussed to date is that this is the sort of price one buys them for. I can only talk for the parabolic mirror tubes which 24 are the same as 30 standard Apricus tubes and they sell for $520 per bank of 6 so $2400 for a set that will overcook in summer (could go with 18 at $1560). The equivelant flat plates would cost in the order of $3000 (apparently) and not give the same effect (as has been proven to me by people who have them running as we speak compared to what I have).
The proof is in the eating of the pudding, not the making of the recipe or mulling over the mix. You can go on all day about statistics and theoretical arguments, but the proof to me is the ambient temp, and amount of hot water gained compared to cost of the system. End of story.
I do agree flat plates "probably" work quite well in NT and upper Qld with high ambient temps, for Vic Tas SA ET does a much better job at it at same or apparently lower cost.
peter69_56 said:
The proof is in the eating of the pudding, not the making of the recipe or mulling over the mix. You can go on all day about statistics and theoretical arguments, but the proof to me is the ambient temp, and amount of hot water gained compared to cost of the system. End of story.
Exactly cost of system per solar saving, thats what the last chart shows and it clearly flat plates - ON AVERAGE - win out, does not matter if the ETs collect more in winter, what matters is the total savings across the year.
Also you say theoretical but all collectors attracting the (now closed) rebates, are physically tested to AS/NZS 2535.1 2007 which is an efficiency standard, they get the entire efficiency plot and the sun angle modifiers, then the data is plugged into programs that simulate the projected solar savings via Standard AS/NZS 4234:2008. The program is very sophisticated taking into consideration a number or real world factor, it was developed by Prof Graham Morrison, the Office of Renewable Energy Resources (ORER) appointed Prof. Graham Morrison from the UNSW to perform the calculations for this Australian standard. The performance of collectors and systems determine (or use to determine) the level of rebates so it has to be accurate, no cheating here.
I'll say a couple more things, from a purely solar saving vs cost perspective ON AVERAGE in my option flat plate win out from what I'm seen and tested myself (and I'm not an expert in the field) that is not to say some ET systems are better than others flat plate system.
As such it kind of gets me that what I think is the better technology (at least saving vs cost) wise - and which is mostly manufactured in Aus - is losing out to a Chinese import.
My advice to people purchasing SHW system, is to forget this flat plate vs ET hooplar, base your decision on solar saving vs system cost, but always do due diligence on system reliability.
I can't seem to find the link at http://www.resourcesmart.vic.gov.au
with all this data...
Have they taken in down now with the closing of the grants?
franks
Member
Interesting info from the resourcesmart web site, last week victorians on average would have saved 85% of energy costs having solar hot water.
Assume you have a Instant gas HWS..using 1 9Kg LPG bottle every 4 weeks..you will only need 2 bottles rather than 12 per year..saving $300 per year..not to mention the CO2 savings.
Makes a Retro eBay DIY Solar conversion aprox $1200 (250lt tank, 2 collectors + pump) pay back after 4 years.. as a pre heater for your Instant gas HWS
Sunshine
Member
I got 4 quotes when I bought my system, and the only system with flat plate collector, actually was the most expensive by around $800, and it only had a vitreous enamel tank. All system quotes were split, so the split ET systems were way cheaper.
So it was a no brainer for me to go ET system with SS tank.
I had to go for split as being an old house, there is virtually no bracing in the roof, so more cost to get the roof strengthened for a close coupled system.
