I have had my solar hot water system installed ( by ZEN Albury)for approx 4 mths (315/30 SS) and has worked very well over summer, going to lock out at 70 oC on numerous occasions. It has been installed on a western roof at 25 degrees at there recomendation. They said that it would work OK. I wanted it facing north on a frame but I think they took the easy option and just put it on the house roof facing west as the north roof was to far away and had solar elec panels on it. The hot water panels don't even get any sun until 9 am. I had to repair a small leak on the plumbing myself and had problems with the positioning of the non return valve on initial fittment. Since the cooler weather I have found that the tank temperature and the roof temp have been very similar during night hours. I turned the hot water booster on (elec)and found that the temp in the manifold on the roof also increased from what it was at sunset even though there had been no more pump activities.
I feel that the water is siphoning through the roof manifold, cooling down then returning to the bottom of the hot water service thus cooling the whole system down. I feel that an electric solenoid placed in the water line to the roof manifold, activated by the pump cycle would eliminate the cool down cycle. Has anyone else had any problems like the loss of heat over night.
Aprius Solar Hot Water System Heat Loss
(15 posts) (7 voices)-
malt
MemberPosted Sunday 15 May 2011 @ 12:37:24 pm from IP # -
hamish05
MemberI don't have any of your heat loss problems, I just never get enough heat unless I electrically boost that is.
However back to your issue, you should be able to track temp changes in the lines simply by hand holding the pipes, that's if there is a flow. Of course there should not be any flow if the pump is not running, and there should be a NRV in the line upstream of the pump. Have you had the NRV checked?
I can confirm that overnight my "collector temp" is always a lot lower than my "bottom of tank temp", which usually is around cold water temp, unless elect boost is occurring.
Posted Monday 16 May 2011 @ 7:02:32 am from IP # -
burtons40
MemberI've had my Apricus system for a few years now and not had your problem. I'd get onto the installers. You either haven't got a one way valve in the line or it isn't working properly. This would stop the hot water from the tank flowing up to the tubes on the roof and cooling down at night.
You could well be right about them being slack with not wanting to install it on the north. Although there are all sorts of regulations about distances between the solar PV or hot water and edge of roof etc. There is also the issue of heat loss from long pipe runs. These guys aren't always very good at explaining their reasoning for putting things where they put them.
Posted Monday 16 May 2011 @ 9:19:21 am from IP # -
burtons40
Memberhamish 05: I don't have any of your heat loss problems, I just never get enough heat unless I electrically boost that is.
Why is this? How far south are you? Which way does the unit point? Do you have the recommended number of tubes to the size of the storage tank?
I live in far south NSW. Our tubes point due north and the tank and panels are the right size. I turn off the booster for many months of the year. Our only issues have been some cavitation in the pump when it gets too hot in summer and a lightening strike on the roof took out the control panel. (As well as our inverter on the solar PV.)
Posted Monday 16 May 2011 @ 9:23:15 am from IP # -
hamish05
MemberHamish is in Melb. 22T x 250L on the ground tank. Second floor, Nth facing at approx 36 deg tilt, no shading. Retired couple, minimal / normal water usage.
I have had the Apricus Rep visit twice, lots of support from the Co that I purchased it from, numerous parts replaced without any improved performance. The system defies the experts, who seem to agree it is underperforming. I now have twice a day readings since early Feb. to support my claims.
I am now electrically boosting every night. In summer I have to electrical boost after 1 cloudy day. I used 1800 kWh boosting last year!
My "top of tank" temp has not been above 55deg in months. The tank usually operates in the 40s. In summer occasionally it gets to 60deg, never ever has it got anywhere near "top out" temp.
I continue to hear about systems like yours, those with an interest tell me mine should operate similarly. However at the moment I have a very expensive EHW system which is Solar boosted!!!
I think the collector is inefficient for some reason, or it needs a few more tubes.
I am open to any suggestion/s.
Posted Tuesday 17 May 2011 @ 8:19:00 am from IP # -
cnheu
Member@malt, I am of the opinion as well (agreeing with others) that there must be something wrong with the NRV, especially since you've already mentioned that there was someting wrong with it initially. There is no reason why it would thermosiphon otherwise. Please give us a call: 1300 277 428 or call your installer, since it seem's like one of their issues.
@hamish05, I've tried continuing our conversation in the other forum, sorry I'm a little slow to reply. The only reason why your tubes would read 60C in summer is:
1) faulty sensor - maybe it is actually greater than 60C - especially if you only had to electrically boost on cloudy days in summer (not unreasonable), nor is electrical boost in winter everyday... like i said, it's not entirely out of the norm...
2)faulty pump/controller or NRV - perhaps it is a case of a fault NRV, that might explain why the heat which is being generated is prematurely being passed down to the tank, so you never see the temperature go past 60. Another question I have (now that I've realised your in Vic) is do you have a Solastat relay? (a way to control the element from your Solastat controller)?
3) cracked evacuated tubes/cracked manifold - this is for obv reasons, if there are physical cracks, then that would be why they are leaking heat out.Other than the above reasons I can't see why our evacuated tubes would be underperforming. Our systems, whilst highly efficient are simple. They use solar radiation to heat water, and because they are evacuated glass tubes surrounding a copper tube, there is VERY LITTLE convectional heat loss (air gap).
Posted Wednesday 18 May 2011 @ 12:17:24 am from IP # -
hamish05
MemberThanks for your interest cnheu, I don't personally access my roof for safety reasons. However others have to inspect the collector to ensure that its plumbing is correct.
Whilst I thought (in my innocence) that my system performance was as good as I could expect i.e.. 1800kWh heating last year, it's the experts that queried it (system performance) and suggested that it was seriously underperforming.
At the end of the day I am just about resigned to the fact that maybe I have not chosen the best performing system for my area.
Maybe, I will have to look at another type of SHW system, and put this experience down as one to learn from.
I have substantially reduced my hot water heating costs from what I had previously, so I am receiving some Solar benefit. It just seems that everyone else talks in temperatures that I can only dream about!!
Posted Wednesday 18 May 2011 @ 12:44:40 am from IP # -
cnheu
MemberHi Hamish, that's a real shame that you believe this. I would not suggest you go onto your roof, definately some serious OHS issues there for me if I did!
To be honest, it sounds as though your system is working quite fine. When you say hot water heating costs being reduced how much? 20%? 30%? 60%? Especially since you've mentioned that the system only needs boosting on cloudy days in summer (expected) and almost everyday in winter (also, generally expected)
I'm currently thinking (only through intuition) that something is causing the heat to flow downwards into your tank (not cracked components), and that whilst the roof is always reading a "low temperature" all of that heat is still going back into your tank, but probably not in an optimal way!
Posted Wednesday 18 May 2011 @ 1:32:51 am from IP # -
hamish05
Member50% reduction on my previous HWS which was a 400L Rheem. As I have said that was certainly pleasing.
The $ savings I achieved then are now seriously compromised as I have installed Solar PV, which for me now has a much higher electricity cost for heating. I am also using power to run the system and pump all day that could be exported at 62c/kWh
I am in the process of now fitting a time clock to ensure heating takes place mainly on OP tariff.
On the surface, it would seem (in that nobody can detect a system fault), the claims made as to the system efficiency are somewhat exaggerated, for Melb metro at least.
Could I need 30 tubes on the roof? That maybe is less expensive than replacing the whole system with another which will perform better in my area.
Do you supply a 22 tube collector with a 250L tank in NSW and QLD? If so, it would seem obvious to me, that a larger collector would be needed this far south.
Maybe I am being to simplistic, I don't design or sell them.
I do have a Solastat relay, why do you ask?
Posted Wednesday 18 May 2011 @ 2:09:20 am from IP # -
Enzo
MemberHamish05, This may be a little late to help, but try asking Apricus about the so called fauly batch of tubes that are out there. My system (30tube x 250ltr tank) was seriously underperforming. After about 3 yrs of frustrating trouble shooting (which still continues), I was advised of a faulty batch of tubes. I have had them subsequently replaced under warantee, with instant improvement in solar gain. This has been a great improvement, however it took a long time for the problem to be diagnosed, and this was only one in a long list of problems I've had (and continue to have) with this system.
I too regret the purchase of this system.
Cheers.Posted Saturday 14 Apr 2012 @ 11:19:05 am from IP # -
peter69_56
Memberhamish I am in Gippsland, I have a 340l vitreous enamal with 4x6 tube parabolic mirror panels (24 tubes) (originally 3 which was 18 tubes) they are equivelant to 30 Apricus style tubes due to the mirror backing. With this setup in summer on 3 sunny days I peak out at 85C and have to cover one set of panels in Jan-Feb. I originally had 18 tubes (equiv to 22 Apricus style) and I think if you wanted a trouble free and not wanting to get on the roof to cover for a month or so this would be about the correct size for this area. I elected to go for 24 tubes (30 Apricus style) as I wanted better heating in winter and knew the issues I would have in summer but am happy.
With the original 18 tubes (22 Apricus) it needed some boost in winter and on cloudy days and more than I really wanted. I have Rennai solar 20 instant gas boost. However my gas bill to date has only been about $30-40 for 2 months when running gas boost (normally $100 summer, and $300 winter). In summer I have Gas boost HW, central heating pilot light and stove top so pretty good cost for all that and I am very satisfied. Anyway my system works well and that might be a basis for you to compare against to see if your system works properly.
There are 3 adults in the house and we use no hot water for laundry or dishwasher, we shower daily in the morning. panels are angled at about 25 degrees facing NE
I see on my system the solar panel supply and return are taken off the lower part of the tank, about 300mm supply and 380mm return so no non return needed and thus no recirculation at night.
I have trended my daily tank temp for the last 8 months if you want that data to compare.
If you want any more info to help you in fault finding just ask.
Posted Sunday 15 Apr 2012 @ 1:03:35 am from IP # -
hamish05
MemberHi Enzo. Yes it has been awhile since our last post on this thread.
During the last 12 months I believe I have been able to get my SHW system working efficiently. It has come at a cost, but now having it working effectively is pleasing.
My retailer and Apricus have been helpful with solutions, but for the life of me I cannot understand how anyone would ever achieve a satisfactory performance from their SHW unit unless they were very mechanically minded and able to reason problems/solutions.
I wasn’t aware of the bad batch of ETs, however I did know they changed the design slightly which was supposed to give added performance.
There is a trail of posts here over the last 12 months which cover most of what has happened during that time.
Posted Sunday 15 Apr 2012 @ 9:43:48 am from IP # -
hamish05
MemberG’day peter. I read your regular posts here and elsewhere and I am aware of your SHW situation.
Thanks for your kind offer, but frankly there is little to compare because of our different equipment, locations and household circumstances.
I am extremely happy with the help and support I have had from both my retailer and Apricus, and will continue to liaise with them going forward, if and when I need assistance.
For now my SHW unit is working satisfactorily, and saving me heaps of electricity consumption.
Edit, since Nov01 I have boosted 19 times. Approx $14.50 cost. Thats -60% on prev year.
Posted Sunday 15 Apr 2012 @ 9:57:21 am from IP # -
hamish05
MemberAn incident here with my SHW yesterday demonstrates the need to be vigilant.
When recording the night-time temps, I noticed that the roof temp reading was showing (SSd) alarm instead of a temp.
On investigation I found, that a bird had pecked thru the lead to the ET temperature sensor up close to the manifold.
Just another hiccup! Fortunately it was easily fixed this time.
Posted Wednesday 18 Apr 2012 @ 12:07:13 pm from IP # -
Rob123
MemberHi there from reading every ones responds to the Apricus issuse around 3 month ago they did have a number of faulty heat pipes apricuse did fix the problem however most people don't know if there system is working or not.
One thing is for sure they do have alot of issues with there system but at least they try to fix them.Posted Wednesday 25 Apr 2012 @ 5:48:19 am from IP #