Since my last post, I have come up with SS braided teflon tubing crimped on SS fittings, that should do the job (not cheap). This will allow me to adjust between summer, equinox and winter. If I had a fixed system I would lean towards winter as Gandini states.
Apricus Or Hills Evacuated Tube Solar HW System?
(341 posts) (92 voices)-
olfella
MemberThanks Gandini & Ted583
That's dead right Gandini, the angle is the flat on the roof angle & I'll be watching closely the see how we go this winter. I'd given that some thought before, but the 'exspurt' who surveyed the job said I'd find it unnecessary.
If it does prove necessary I'll make an adjustment to the angle, after I find out how it goes. The performance at the moment, despite the heavy use it currently gets, is more than adequate.
It may be I'll end up increasing the angle to reduce over performance in summer, once there is only two of us in the house normally. If that is the case, I'll probably make it the permanent winter solstice angle.Ted, the SS flexi is interesting. My relative is getting a ET SHW unit on her WNW facing roof. The magnetic north facing roof is already taken up by a solar PV system. That means her ET system (30/315 for 2people) is actually facing only 12deg north of west. The company putting it in have told her "no worries", but I have my doubts about that in winter. To make it worse, the house has a 38deg roof angle. Better for the PV, but it means the sun will be even later taking effect than if it had been a shallower angle. It may well end up having to have the frame cranked up on the southern side, to a more northerly orientation. It will be on the house's rear roof, so the athestics won't matter too much. Flexible connection might be just the go to do that if the time comes.
Posted Thursday 11 Feb 2010 @ 1:11:31 pm from IP # -
Gandini
MemberMicko, if you’re still out there ...
In a post on page 2 (December 2009), you said “I am actively investigating methods of managing the temperature buildup and expansion of water without having to dump that 1.5% of water each day. The obvious solution is an expansion tank, but finding a suitable one that can work at 850kPa and is potable water rated and cost effective may be a challenge.”
Have you found a suitable tank yet? I don’t know the industry at all but I would be surprised if there isn’t a suitable tank available from somewhere.
An alternative to trying to reduce pressure would be reduce temperature but you did not favour use of a heat dissipater saying on page 2 “This adds about 300 AUD of cost to the system plus the complexity of needing a 3-way valve. Also means the pump would be running all day to try and keep the system cool - so is not a good solution for AUS. We use this in the US if they have a closed loop system using propylene glycol which can't handle more than 160oC, so the system needs to be kept cooler.”
If running all day is “not a good solution for AUS”, why would it be a good or at least acceptable solution for closed loop systems in the USA?
I doubt that the pump would need to run all day if the dissipater is sized appropriately. Even if it did, I thought the pump was not very power hungry so running it for much of the day –– which it would need to do in winter –– should not cost too much.
I’d be prepared to pay an extra $300 for peace of mind about reducing water loss and thermal stresses in the system. In our case, it would extend the payback period by a year or two -- at current electricity prices.
Also, in regard to having a third sensor to measure the the temperature at the top of the tank, I haven’t seen anything about using the top-of-tank temperature to control the pump or whatever so would it just be “interesting information”?
Posted Friday 12 Feb 2010 @ 12:16:30 pm from IP # -
ted583
MemberOlfella, I get the feeling, when we see the newspaper inches taken up by fly-by-night insulation installers, there are some plumbers who might try to convince you a panel on a SOUTH facing roof is ok! Anything between +-10° N is good. 12°N of W and 38°roof (52° altitude) will reduce the efficiency of the system. It comes down to a compromise between what you can afford to install (DIY or tradesman(or woman)) and what is best. I built my frame and sourced the flexible couplings. I don't have my tubes yet, just running ss tank and booster. (near Sydney)
Posted Friday 12 Feb 2010 @ 2:36:53 pm from IP # -
gully
MemberFlexible couplings are a great idea, but what about insulation for them? Unless you follow through with that you may negate any benefits to adjusting the angle. As far as I can see, there's no way to do this with insulated copper.
RE: Losing water, I would think setting it up on the right angle is one of the best things to do. You should only lose water when it gets 'too hot' (ie. hot summer days). Other thing you can do is add a cold water expansion valve, which dumps cold water instead of hot water (slightly better!). Other thought is to program your washing machine / dishwasher to come on at 2-4pm to actually use that hot water instead.
I'm not sure if i'm correct in suggesting this, but what about changing the pressure reducing valve from 500 kpa to lower (350 kpa)? This may be good for the life of the tank also, as it lowers the pressure within it. Anything coping with higher pressures is stressed more.
Posted Thursday 18 Feb 2010 @ 2:51:48 am from IP # -
fifonik
MemberFinally, 2 days ago the Solar HWS was installed at our home (Apricus 315/30 electro/SS tank). I'm very happy about its effectiveness: after 2 days without sun the water is hot (I'm in Brisbane. The heater was switched off). However, right now I've started to worry about full sunny days, when it will be very hot.
In installation instruction (from this thread) I saw the pictures where the system has 2 sensors. Also, the 2 sensors' systems were discussed in this thread. However, my system has 3 sensors: one on the roof and 2 in the tank. Is this new model?
I'm very happy about the on-roof unit design. It's very simple and should be very secure.
However, the tank and all stuff around don't look very good. Too many hot tubes and too many wires are there. It's a good idea to supply something like box for covering all this stuff. We have dogs so now I have to build some fence around the system.
I'm a bit not happy about the installation itself: the system installed not too accurate (I mean the tubes is not too pretty, I could do better, but I don't have a plumber licence), the sensors connected in very strange way (they are just inserted into big holes and should be fixed there with cooper wires aside) and the insulation on the tubes is not too thick imho (by manual it should be 15mm or thicker, in my case it is 10mm only). I don't know is it OK or not.
Posted Thursday 18 Feb 2010 @ 9:05:46 am from IP # -
fifonik
MemberI've got 4 quotes (2 for Hills Solar and 2 for Apricus). The prices were a bit the similar. The lowest one was $3860 (Hills Solar) and the highest one was $4350 (Apricus). I've chose the quote with HWS $4100 (Apricus). I've chose this company because I'm going to buy PV system as well and this company offers good price for this system and additional discount as well.
All these prices for 315/30/SS/electro systems in Brisbane with installation and after all rebates (RECs and Govt).
Posted Friday 19 Feb 2010 @ 4:01:59 am from IP # -
Short answer - yes. However you will need a copy of suppliers official ORDER to prove you ordered a system before the cut off date. A quote will not suffice.
Also, Canberra must *receive* your fed govt rebate application before the cut off date of 20 MArch 2010 (A Saturday) - so realistically, you'll need to post a few days earlier - I'd go for a registered mail ,with receiver to sign.Application must inclide tank serial number, so system must be delivered and installed before you can lodge application.
Following taken from Govt website : http://www.environment.gov.au/energyefficiency/solarhotwater/
Applicants who ordered or made partial payment for their solar or heat pump hot water systems but had not had their system installed prior to 20 February 2010, must include written evidence of their order with their rebate application. A receipt for a deposit or a copy of their supplier’s order form is required. A quote is not sufficient evidence of an order.
In all cases final decisions regarding rebate eligibility will be made by the Government.Posted Wednesday 3 Mar 2010 @ 8:22:34 pm from IP # -
questionman
MemberI have read the dept of environment website announcement about the Feb. 19 cutoff for the old rebate of $1600 and the transitional arrangements but it is still not clear how it will apply in my case.
I have paid an initial deposit for a SHWS on February 19, 2010 but if installation is done on or after March 20, 2010 ,and thus my rebate application form cannot be submitted until after March 20 ( because the system has to be installed first before the installer can fill up and sign the Fed. rebate application form) - in this case, can I still qualify for the $1600 rebate?
In short , my purchase date is Feb. 19, 2010 but installation date will be on/after March 20, 2010 , and since installer has to install system before he can sign my Federal rebate application form - my submission of application form can only be done after March 20, 2010. Will I get the $1600 Fed. rebate or $1000 rebate?
Is it a requirement that the system has to be installed first before the installer can fill up and sign section 3 and 4 of the Fed. rebate application form?
Posted Friday 12 Mar 2010 @ 6:49:14 pm from IP # -
eslideit
MemberHi
A question for those with SHW systems in Melbourne. Mine is an Apricus 30 tube with 315lt SS tank.
Over the past few days, where it's been mostly cloudy, rainy and generally getting cooler here, the electric boost has been firing up a lot more than before. The energy usage has ranged from 4 to 8 kWh a day over the last 5 days. before that the average was below 1kWh a day since installation in mid November 20009.I just wanted to compare my experience with others to see if this jump about right for the conditions we've been having.
ThanksPosted Monday 12 Apr 2010 @ 5:54:03 am from IP # -
eslideit
MemberSorry, I better clarify. The average has been between 0.5kWh and 1kWh, but many days it doesn't kick in at all.
It's just that after a couple of cloud/rain days it would usually kick in with 1kWh to 3kWh of usage.
But now I'm finding that it's kicking in a lot and using way more energy than before. I just wanted to confirm the magnitude of the increase with those in the same conditions i.e 4 to 8kWh a day.
Posted Wednesday 14 Apr 2010 @ 4:14:33 am from IP # -
newairly
Membereslideit,
What is the control system which decides when to use the electric boost? It sounds as if you have more than a simple thermostat. Is the heater at the bottom of the tank or middle? Is it connected to off peak and if so what rate?
PhilPosted Thursday 15 Apr 2010 @ 10:42:15 pm from IP # -
Benny
Membereslideit. I don't have a system and am not in Melbourne but can give you a theoretical answer that 4-8kWh sounds a reasonable (but big!!) amount of power being used.
The heat capacity of water is 4.2kJ/C/kg. This means that it takes 4200 J of energy to heat 1kg (or 1l) of water by 1 degC.
1kWh is 1kJ per s for 3600 secs which is 3.6MJ of energy.
So 1kWh would heat 1l of water by 3600/4.2 = 857 degC.
Or if it was 100l, by 8.6 degC.
Or in your case with 315l, by about 3degC.
So 4-8kWh could heat your whole tank by 12-24 degC and sounds a reasonable figure.
This would be a much higher temp increase if the booster is mounted part way up the tank and so only heats (say) half the 315l.
How much is actually used obviously depends on the starting temp and the set temp on the thermostat.I wouldn't be surprised if your thermostat is set above 65degC as there have been many comments on this forum about legislation requiring every tank to be heated to 65C every day - to stop legionaires apparently - after all the cases of legionaires that we get from having showers in warm water )-;
It could well be that you don't even need the booster - can you turn it off manually? Others have said the manual switch on the switch board isn't being installed any more to force this daily 65C boost.
Can you read what the temp is at the end of each day to decide if it needs boosting ? Ours is still turned off even though winter has started here in Perth and some days the water only gets up to 45C (20yr old flate plate system) but thats fine for having a shower and we boil the kettle to wash dishes. However I'm sure you won't hear from me again as I'm bound to die soon from legionaires.
Posted Friday 16 Apr 2010 @ 1:52:26 am from IP # -
squash
MemberTo put it in perspective my old HWS was using between 8-10kwh a day. eslideit you new system should only boost when necessary and even then the element is in the middle of the tank and therefore should not heat all 315l. IMO 4-8kwh a day seems high to me. The worst I have seen my booster do is around 2kwh one night, that was after 2 solid days of rain.
Maybe someone from Apricus can comment?
Posted Friday 16 Apr 2010 @ 2:57:05 am from IP # -
dymonite69
MemberAccording to BOM, solar insolation for the following cities in April:
Perth 15.6 MJ/m2
Melbourne 11.9
Lake Macquarie 15.0Ground temp (proportional to water inlet temp)
Perth 11.8
Melbourne 9.7
Lake Macquarie 11.1So you would expect Melbourne boosting requirements 60% higher than Perth.
Posted Saturday 17 Apr 2010 @ 5:14:42 am from IP # -
eslideit
MemberThanks for replying guys.
My SHW system a SolaStat controller where, as I understand it, is programmed to only boost when the tank temp (as per top sensor – but it also has a bottom of tank (inlet) and roof sensors) falls below 50 and the pump has not run for 4 hours.
It looks for the tank hitting 60 degrees once every 72 hours, for at least 1 hour.
The element is connected to the off-peak power.
Looks like the tank only has an element at the bottom.Over the past few days we’ve had more sunshine, and the usage has dropped off to between 1 and 3 kWh.
Posted Monday 19 Apr 2010 @ 2:55:28 am from IP # -
micko
MemberJust wanted to add a few comments to the discussion about how much boosting will be required. The boosting operation will depend on how the system is setup. If off-peak then it will only come on during that operation period, if on a timer then during that set time. If set on continuous (unlikely) then it will work to always maintain the target thermostat temperature.
If we use the off-peak example, then what will happen is the power supply will come on to the element and if below the thermostatic setting of 60-65oC it will turn on the element. The element will normally turn off at a temperature about 10oC above the ON temp, so 70-75oC. If the tank temperature was only 50oC, then a 20oC temp rise may result before the element turns off. If that is a mid element with 200L of water above the element then the amount of energy used would be:
70oC - 50oC = 20oC temp rise x 200L = 4000kcal / 860 = 4.65kWh
A 3.6kW element would therefore run for 1h 20mins.
This is NOT considering the possibility that there is 100L of 70oC water sitting in the top of the tank, which would half the heating time. Stratification is a beautiful thing!Now that it is April, the amount of solar radiation your solar collector will be exposed do is about 30% less than the peak of summer. In Melbourne this will be about 5.71kWh/m2/day in Jan vs 4.27kWh/m2/day in April.
For this data for your area you can go to http://eosweb.larc.nasa.gov/cgi-bin/sse/grid.cgi get free username and password access then enter your lat and lon to get solar data. Choose the Parameters for Tilted Solar Panels > Radiation on equator pointed tilted surfaces.
The data will provide a table like this: http://dl.dropbox.com/u/103200/Misc/Melbourne-NASA-Solar-data.pngChoose the tilt angle closest to your installation angle to get the most accurate data. This data is per m2 of area, not total for the collector. A 30tube collector for example has a aperture area of ~2.8m2, and daily conversion of this available light should average around 70%.... so for example 5.71 x 0.7 x 2.8 = 11.2kWh of energy per collector per day. This is a very rough calculation, as it is considering total day output which is dependant on the angle of the sun, ambient temperature and of course the water temp... but provides a general idea.
If you are using 300L of water (9l/min x 33min of showering) per day at around 45oC with cold water temp of 15oC in the summer and around 10oC in the winter then the energy usage for hot water will be about:
Summer 300 x 30oC temp rise = 9000kcal / 860 = 10.46kWh of energy, plus tank heat loss of about 2kWh/day = about 12.5kWh of energy per day... a 30tube collector comes close to providing this each day in the summer hence virtually no boosting needed.
Winter 300 x 35oC temp rise = 10500 / 860 = 12.2 plus tank heat loss of about 2.5kWh/day = 14.7kWh/day.
Solar will provide about half that of summer output, so a 30tube collector will provide about 5-6kWh of energy. So you will still need about 8-9kWh from electricity.So in summary for a family using 300L of showering temp water per day you can expect the following electricity usage on AVERAGE:
Summer: 0-2kWh/day
Spring/Autumn 4-5kWh/day
Winter 8-9kWh/dayHope that helps.
Posted Wednesday 21 Apr 2010 @ 2:09:46 am from IP # -
Boiling
MemberWhat is actually meant to happen in Top Out mode?
I have a new 30 tube Apricus system that has been installed in Canberra for a week, it is 20 days from Winter and it is working so well that we have already discovered "Top Out" mode and "SSD" mode.
However once the controller reaches Top Out it gets a little strange.
If you have it set to view the roof temperature, you can watch the temperature steadily climb as the system stagnates.
However if you leave it in Tank or Inlet view (2 sensor system) it periodically runs the pump for a second or two, which is enough to keep the top from reaching SSD mode, and presumably dissipates most of the heat in the pipe work. It is also a bit erratic. While the pump flicks on for that moment the display flicks from 80 deg down to 75 or 76 for that moment. Then when the pump switches off again it is back to the stable topped out tank temperature of 80 to 81 deg. (my Top out is set to 80 on a stainless tank)
I was hoping someone might let me know if this was normal behaviour?
I was also wondering if anyone has cured the SSD problem by fitting an air bleed valve? It is quite disturbing (and amazing) to see the roof temperature gauge up at 154 deg C as it comes out of SSD mode. For a while I was wondering what error code 154 was until I realised that it was the temperature being displayed.
Posted Monday 10 May 2010 @ 10:49:01 am from IP #
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