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Which is the most efficient Hot Water Storage Tank

PostPosted: Thu Apr 28, 2011 12:41 pm
by mick_queensland
Hi All,

I have been hunting around for information on energy efficiency of household hot water storage tanks. There seems to be very little information around. Does anyone have any good info or links?

I am going to install Solar Hot Water soon and I am going to use one of the Aussie made Stainless Steel tanks. I just wonder if there is something better for a reasonable price.

Cheers n Beers
Mick

Re: Which is the most efficient Hot Water Storage Tank

PostPosted: Thu Apr 28, 2011 12:55 pm
by Gordon-Loomberah
Energy Matters have a number of different systems available, have you checked: http://www.energymatters.com.au/solar-hot-water-c-162.html

Re: Which is the most efficient Hot Water Storage Tank

PostPosted: Fri Apr 29, 2011 3:26 am
by mick_queensland
Hi,

thanks Gordon, yes, I have looked through hot water systems on EM site before, actually about 12 months ago, and I have been looking at systems for that long now. EM has a lot of systems to look at but what I am interested in right now is how good each of the storage tanks in all the systems works. In my opinion the storage tank is really the heart of the system, if you have cloudy days and a great tank you will be ok, if your tank leaks heat like a sieve then you will be out of hot water pretty quickly.

So, I want to know how good the tank insulation is. There is so little info about that.

cheers
mick

Re: Which is the most efficient Hot Water Storage Tank

PostPosted: Sun May 01, 2011 11:37 am
by Sandivee
Do you have mains gas available? If so, I'd consider just using an instant gas booster.

Re: Which is the most efficient Hot Water Storage Tank

PostPosted: Sat May 21, 2011 11:42 pm
by mick_queensland
Hi guys,

interesting..... you can hear the tumbleweeds rolling through this thread. It is as I have found elsewhere, there just isn't any decent info on storage tank efficiency. Well, at least no info that anyone wants us to know about. I am getting a real sense that manufacturers are hiding the data from us. I didn find a list of hot water tanks and Standing Heat Loss but it was not a complete list.

I have found a bit of info though. http://www.energyrating.gov.au/ewh2.html This shows us two things. 1/ Our government has put no pressure on suppliers to improve their products (compare 1999 and 2005 ratings for any tank larger than 80lt) and 2/ Solar hot water systems are exempt from a minimum heat loss standard under the current rules. (4th paragraph down)
I guess thats why none of the manufacturers give a toss about Standing Heat Loss.

I am still going to use an aussie made stainless storage tank for my new hot water system, I was just hoping to see how it would perform against other makes and models.

My suburb does not have gas piped in. I do use bottled gas for cooking as that is the second most efficient method second only to induction heating. I am not going to change that and its a different topic.
Also, whether or not I have gas or electricity has no bearing on a list of thermal losses for hot water storage tanks.

Cheers all, Mick

Re: Which is the most efficient Hot Water Storage Tank

PostPosted: Sun May 22, 2011 11:18 am
by Gordon-Loomberah
mick_queensland wrote: I do use bottled gas for cooking as that is the second most efficient method second only to induction heating. I am not going to change that and its a different topic.


Indeed it is a different topic, and that topic is here: energy-efficiency/topic2540.html
;)

Re: Which is the most efficient Hot Water Storage Tank

PostPosted: Sun May 22, 2011 8:53 pm
by karlajensen
300l tank can (and mostly do) loose 2kW per day

they are all similar and I'm not sure that SS is any better than enamelled.

The best kind are those from Ebay that cost almost nothing are electric and can be easily converted into DIY solar hot water.

If you dont have the skills for this then a six star condensing instant gas unit is awesome.

if you dont have town gas then a solarhart/ edwards is the best (most reliable). as there are no moving parts as there are in a split system

Re: Which is the most efficient Hot Water Storage Tank

PostPosted: Mon May 23, 2011 4:23 pm
by mick_queensland
Hi All,

thanks Gordon, nicely pointed out.

Hi Karla (I hope that right or is it Karl)

Yes, I have been thinking about moving parts in the system lately. I keep swaying between the tank on the roof and the tank on the ground. Do you have any recommendation on the ebay tanks? Do you need to increase the insulation on those tanks?
I noticed that there are some really cheap SHW systems available on ebay, these however are typically not mains pressure. That actually may be a good thing. But we are straying a little off topic with that.

I am having trouble making up my mind now... Oh dear... :?

Cheers, Mick

Re: Which is the most efficient Hot Water Storage Tank

PostPosted: Mon May 23, 2011 4:45 pm
by Alex Morrow
Karl mentioned the Edwards. I have one of those on the roof; when I asked the installer about insulation between the tank and the plastic/poly/whatever cover, I got a blank look. Apparently there is no interest in putting insulation in the cavity (I don't even know how big the cavity is, since I've never removed the cover); we have tank water, so whatever went in there would need to be inert and stable.

The only time I'm not happy about the water temperature is on winter mornings, when it isn't really as hot as I would like for doing dishes. I don't turn the booster on, except (a) on very overcast days with low temperatures, and/or (b) on winter afternoons.

I still think that more insulation around the tank might improve the winter morning situation, but I haven't followed up on it.

Alex

Re: Which is the most efficient Hot Water Storage Tank

PostPosted: Mon May 23, 2011 5:51 pm
by Gordon-Loomberah
Alex Morrow wrote:... we have tank water, so whatever went in there would need to be inert and stable.


or completely sealed so nothing leaks out and rain cant contact it. Also need to keep the sun off it, as UV breaks down a lot of non-metallic substances over time.

I still think that more insulation around the tank might improve the winter morning situation, but I haven't followed up on it.


It certainly will help, its a case of more is better, it depends on how huge you want to go with it ;)