Since there has been vigorous discussion about ET systems and I don't doubt at all they can do the job, I thought someone who can attest to flat plate systems doing the job in Melbourne and Tas would be of interest. So far I don't know of any, so if there are any out there please let us know. I'm thinking of a subjective assessment only that greater than 70% of hot water is provided.
Flat Plate hot water.. do they deliver in Melbourne and Tas?
(28 posts) (9 voices)-
Morbo
Memberwhats difference in cost? I.e. if tube costs way more than flat plate, go flat plate. Our summer gas bill is $3 per quarter and $50 for the rotten pipework.
In winter its maybe 20 vs 100, no idea, why utility fees are higher than, too. Maintenance is zilch all across the year.
So maybe flat plate will cost $10 more in consumption over the year.
Last Melbourne winter was cloudy for 6 months and then within 3 weeks the SHW went from 20° to 70° (some cloudy period inbetween) and thats how it is since 4 months now. Some more sun in winter it would be at 40°. For 2 people. 225L 20 tubes.
Cannot comment to TAS but. I think tubes would be even more on an advance and 30 don't cost that much more than 20. The plumber is the bulk of the cost, and it will be same installation for both systems (even if he claims its different, connections to the panel and to the tank are identical, unless the tank is on your roof)Posted Sunday 24 Feb 2013 @ 4:32:34 am from IP # -
dbindoff
MemberAs I understand you Morbo, you have 20 tubes and 2 people and perhaps your shw is contributing 60% or so total energy.
What I am really interested in is whether there are any flat plate installations in these regions which give greater than 70% of total energy. I simply want to see how many can attest to flat plate 'doing the energy job' - because I have zero confidence in them myself. I am not asking about costing here, since if I don't think they can provide greater than 70% total energy I would not bother costing or assessing particular suitability for a specific site.Posted Sunday 24 Feb 2013 @ 5:44:18 am from IP # -
Morbo
Memberhard to say, you could oversize them but then have to shade them in summer. Or put them really steep. (if we ever going to build our own, it will have a roof to suit). But no matter what you do, in cloudy conditions not much going on. In summer nice to have because it saturates, with clouds it cools down. In winter not so nice. Never had 1 week or so sun every day so I could see if it gets to more than 45°.
Maybe chase up someone from sustainable housing day, remember one guy who put his panels 60° or so, but he has 4 people but not 40 tubes, would need boosting either way.
Also, winter has more cooking, and the heater is on, so no idea how much the hot water part is. But our hot water consumption is not that much, 2 showers, dishes once. And in summer I put some in the washing machine, some I used for weeding (straight of the PRV at 70+°, your oxalis is down in seconds, but the grass is unaffected).Did you get a claim that flat plates would contribute more than 70%?
Posted Sunday 24 Feb 2013 @ 6:50:00 am from IP # -
dbindoff
MemberI just found a previous thread about flat plate solar hw in Melbourne, as far as I can tell only Optiplex attested to getting a good job from flat plates.
http://www.ata.org.au/forums/topic/1647So that is count one for flat plate so far.
In the same thread franks was using a flate plate as a preheater I believe - not really what I was looking for.
If there are any other 'lurkers' out there from Melbourne or Tas, please add your count if your flat plates are working to the 70% or more standard.
@Morbo - 70% is a simple reference point since the competing technology is heat pump hot water with a COP of around 3.
Posted Sunday 24 Feb 2013 @ 10:55:44 pm from IP # -
franks
Memberelectric 250lt storage tank (location Melbourne 2 adults) 2 1x2mtr flat plane collectors mounted facing north 40` elevation, using solar powered pump to pump water up to collectors..as a DIY retrofit..total cost $600..dont need electric boosting between november and march..winter 40-50% solar fraction.
Posted Sunday 24 Feb 2013 @ 11:55:48 pm from IP # -
dbindoff
MemberThanks franks, I think I'll count that as another success for flat plate in Melbourne and a very cost-effective one!
So that's 2 flat plate success stories for Melbourne and Tas. (both in Melbourne) My confidence in flat plates is rising somewhat from a low base.
Posted Monday 25 Feb 2013 @ 12:54:45 am from IP # -
franks
MemberFlat plate collectors are not in fashion nowdays, much cheaper than evacuated tube..for a DIY with low cost is the way to go
Its horses for courses..ET collectors are more efficient than flat maybe 20% in a real world test.I think the real reason is ET are more popular..easy to install less OH&S issue due to less weight ?
manifold 10-20kg, evac tube2kg, frame bits 2-4kgs ??
Posted Monday 25 Feb 2013 @ 2:33:02 am from IP # -
TonyT
MemberAgreed Franks
For solar thermal to deliver a reasonable % return on the capital $ invested it needs to be Do It Yourself.
The cost of the tubes for ET has been decreasing.
The DIY installation of ET is simpler than DIY installation of Flat Plate.More info
http://www.ata.org.au/forums/topic/6783/page/3#post-38707Posted Monday 25 Feb 2013 @ 11:04:09 pm from IP # -
Harry Stottle
MemberTonyT said:
Agreed FranksFor solar thermal to deliver a reasonable % return on the capital $ invested it needs to be Do It Yourself.
The cost of the tubes for ET has been decreasing.
The DIY installation of ET is simpler than DIY installation of Flat Plate.More info
http://www.ata.org.au/forums/topic/6783/page/3#post-38707You do need to be a bit careful with DIY solar.
If little Johnny gets scalded or a panel falls on his head, there'll be trouble!
(did I mention Legionella/Electrocution/Gas explosion?
Posted Tuesday 26 Feb 2013 @ 1:20:44 am from IP # -
Baldrick
Memberdbindoff said:
It appears most people in southern climes share my lack of confidence in flat plates.I don't know if I can agree with you. I have 2 FPC because I didn't have the roof space for ET. Have been looking around my area lately for Solar Thermal to see what others are doing. So far I have not found any ET, they are all FP, some must be 50 years old. New small houses will have one collector as a boost for Instantaneous Gas HWS. While others will have 3 FPC for HW and Hydronic heating as well.
If I can get my Data Logger working, I will continuously monitor my system so that everybody is sunny/cold/dry/hot/overcast/wet Melbourne can see how well they work.
Posted Tuesday 26 Feb 2013 @ 1:47:06 am from IP # -
Harry Stottle
Memberdbindoff said:
So far we have only 2 people attesting to the efficacy of flat plates, both in Melbourne, none so far in Tas.It appears most people in southern climes share my lack of confidence in flat plates.
Well now......that's certainly a bold assumption!!!!!
Posted Tuesday 26 Feb 2013 @ 2:49:18 am from IP # -
dbindoff
MemberYeah,.. I know, I'm trying to elicit someone from Tas to stand up and tell me they have a successful flat plate installation - as I said previously, I don't know of a single one and (somewhat irrelevantly) I do know of failures.
On the other hand , all the ET installations I know of in Tas are successful.(also irrelevant)
Posted Tuesday 26 Feb 2013 @ 3:39:02 am from IP # -
TonyT
Memberdbindoff
What is the $ cost, including installation, of a typical solar thermal Hot Water System ?
Is $4,000 a reasonable figure ?
What % annual return is needed on this investment for it to be "successful" ?
A return of 10% ($400/year) would pay for the system in 10 years.
Do many households spend more than $400 per year to heat water using off-peak electricity ?
.
What size of installed solar electric PV system would $4,000 buy ?
A 1.5kW PV system will deliver about 2,000kWh/year of electricity.
If the electricity from the PV system replaces day-rate electricity costing 30cent/kWh the return for 2,000kWh is $600/year
Posted Tuesday 26 Feb 2013 @ 4:30:01 am from IP # -
Harry Stottle
MemberTonyT said:
dbindoffDo many households spend more than $400 per year to heat water using off-peak electricity ?
Probably not! Off peak electricity is still a bargain.
Nice thing about it is that you can set it to 60 Deg and it doesn't need any woozy tempering valve to ensure lukewarm water!Talking about warm and fuzzy.............
Posted Tuesday 26 Feb 2013 @ 4:54:54 am from IP # -
Baldrick
MemberWhile the power companies keep pushing off-peak, its use is not increasing like peak power. In Victoria off-peak Storage HW is declining. The best value for money systems are instantaneous gas. You are not spending money on heating water you may not use.
Solar Boosted instantaneous system will reduce gas bill. Does it have a good ROI, I don't know.
Just like with PV as Solar Thermal becomes common place, prices will reduce. If you can install Hydronic Heating as well, you will get big saving.
Posted Tuesday 26 Feb 2013 @ 5:26:30 am from IP # -
dbindoff
MemberTonyT, the definition I used in this thread for 'successful' flat plate installation was (subjectively) ' replace 70% of previous energy used in an electric storage heater'.
So this is putting myself in the shoes of a prospective purchaser of a new hot water system, having had a storage electric which is typical in Tas and no natural gas (again most common in Tas, though some is available nowadays) .
The three obvious contenders are solar thermal Evacuated tube, flat plate and heat pump . I wanted to know if a prospective purchaser could virtually rule out flat plate in Tas, simply on the basis that it does not work to the required threshold standard of greater than 70% energy replaced . When I investigated the purchase of ET some years ago, I concluded for myself this was the case based on the scant information available and previous long-term personal bias i.e I knew from hearsay that flat plates worked OK in Perth and Sydney and north of Sydney but 'probably' would not work so well in Melbourne and Tas.
As I recall also, the price of flat plate systems when installed by plumber and electrician was not much different to evacuated tubes - hence I chose ET. For my situation heat pump was not suitable (and similar cost also)
Now that I have ET installed some years I know it works greater than 90% from my baseline, from personal experience.
This thread is simply exploring whether my personal bias against flat plate installs in Tas is unfounded or not. I am quite happy to be disabused. (I also think there is Buckley's chance of anyone doing a decent objective comparative study)Cost considerations and return on investment is a further issue;
energy saved over previous baseline is approx 10kwh /day (year average)
hydroheat tariff is approx 17c/kwh (I had off-peak many years ago, but moved to the continuous hydroheat, only slightly more expensive but more convenient)
hence savings on previous baseline use is 10*365*.17= $620.50, more or less
$4000 is probably about right for unsubsidised collector and installation (not sure if that would include the tank or not)
I have not kept up to date with prices (and I have never seen flat plate collectors at $300 as franks used)So the npv of cash flows over 15 years expected life of an electric storage heater will be far greater than for the ET solar system, I have not done the calculation to determine payback. I expect /hope the ET system to last far longer than the tank, so longer term again it is a far better and 'successful' financial proposition I think.
In my case, as you are aware, minimizing CO2 emissions ranks as importantly as cost and on this measure the ET system is also 'successful', as far as I can tell, better than any alternatives including natural gas instantaneous.
Edit: OK I had 2 quotes of $3500 and $4000 for 1.6kw pv just the other day. expected yield 2200kwh and with Tas tariff of 1:1 at 27cents 2200*.27 =$594.00, so on current situation not much difference again. (though FIT may change with govt.) Anyway that is not an answer to my hot water in particular, since I could fit an ET system where it counted and heat pump is not suitable. Also I intend to install more PV independent of my need for hot water.
Posted Tuesday 26 Feb 2013 @ 5:40:00 am from IP # -
Harry Stottle
MemberI have heard the opinion that off peak electricity is not such a good thing.
It ensures that there is an ever present base-load which ensures coal fired generators will keep running and might even be used to justify building new ones.
True/false who knows?
It's hard to tell these days.
Will we ever stop burning coal/gas/oil and exporting it to make money?
I am inclined to doubt it.Such is life
Posted Tuesday 26 Feb 2013 @ 5:41:23 am from IP # -
TonyT
MemberBaldrick said:
If you can install Hydronic Heating as well, you will get big saving.
.
Winter is when (hydronic) heating is needed.
In winter most solar thermal hot water systems use their booster heater to supply additional heat.
Summer is when solar thermal systems collect excess heat.
The summer excess of heat cannot be sold or stored.
Posted Tuesday 26 Feb 2013 @ 5:45:45 am from IP # -
Baldrick
MemberHarry Stottle said:
I have heard the opinion that off peak electricity is not such a good thing.Off-peak is disappearing and the generators are not happy. Looks at the 11PM bump over the last few years.
http://www.wattclarity.com.au/wordpress/wp-content/uploads/2011/07/20110723avedemandbyTOD.png
I understand that the big drops have occurred in QLD & NSW (heat pumps?) with smaller drops in the other states. They may try and reduce prices but that won't help.
Posted Tuesday 26 Feb 2013 @ 7:26:52 am from IP # -
Baldrick
MemberTonyT said:
Summer is when solar thermal systems collect excess heat.
The summer excess of heat cannot be sold or stored.All true, but I live in Melbourne where you can get hail stones on Christmas day. Winter & Summer are all to confusing for us.
Posted Wednesday 27 Feb 2013 @ 2:01:32 am from IP # -
Compton
MemberMy comments are not really valid as I have never been able to monitor the use to the stage of solid figures. I put in flat plate solar 30 years ago, coper tubes with aluminium plate painted plain old flat black about5 sq metres of collector, facing almost due north at 30 degrees. 120 litre thermosyphon tank in a uninsulated box on a tower on the roof. Boost is electric on a manual switch, in winter I have a homemade loop in the stove which doesnt provide much heat( you can always tell when it starts up by the water noises so wont atart on low fire only if its roaring and thats not often).
So with no wood fire in winter maybe 50% of the hot water requirement for family of 5, but usually we find if all showers are evening, then boost is required only a few hours per week, and electric booster only heats 20 litres then thermostst switches off, so runs only a couple of times per week in winter.
As on other posts I am planning a new house Hills outside melbourne, and I cant make up my mind about solar Flat plate for HWS and Hydronics in slab or insulated slab slurry but the flat plate is still excellent in my mind. The 5 sq metres never boils in summer, but if I put a modern FP with 10 sq metres + I expect to use surplus heat in the pool which is also the fire backup supply.
I was in China recently at a conference and the main tube manufacturer in Shandong said that the best tubes loose vac after 6 years, less if the tubes are stressed. So I am concerned about whether this is true, or jsut speaking about substandard tubes I havent been able to find out. Flat plate after 30 years I think its great, but I dont have relaible data.Posted Monday 1 Apr 2013 @ 9:42:56 am from IP # -
peter69_56
MemberWell I have ET and am very happy with it. 3 in the house and mid winter about 45 degrees. I have a work colleague who has flat plate and he hates his system and is going to the expense of adding ET. We live in Gippsland/Hallam area. Although this is not a scientific result, clearly he is sufficiently unhappy to not believe in his system. We compare results regularly and clearly he is getting significantly less energy from his system. Our systems have both been running for about 2 years
Posted Friday 5 Apr 2013 @ 10:50:38 pm from IP # -
Baldrick
MemberI live in the Melbourne burbs and have a 2 FP system with 315Ltr tank and gas boost (Installed in Feb). Was planning for ET but it was impossible to install sufficient number a tubes in the area available.
From the 28th of March the weather was overcast for 7 days in a row. While I did get some Solar boost it wasn't keeping up with usage. By the 31th the gas boost was starting to cut in and by the 3rd it was being used most of the time.
The gas boost cuts in if the water coming from the tank drops below 60oC. I could have switched it off and I would still have had water for a shower, but that wouldn't kill the bugs, so I leave it on.
Only time will tell.
Posted Saturday 6 Apr 2013 @ 1:16:44 am from IP # -
proftournesol
MemberWe have a Solarhart Blackchrome flatplate system installed in Melbourne. During winter it provides lukewarm water at best so we use it s a pre-heater for an instant gas heater. There were no evacuated tube systems when we installed it so a more modern flat plate system may be more efficient.
Posted Sunday 7 Apr 2013 @ 11:02:37 am from IP #
