Electric or Gas Boosted Solar Evacuated Hot Water System « Alternative Technology Assn Forums

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Electric or Gas Boosted Solar Evacuated Hot Water System

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Started 2 years ago by RogerCrawford
Latest reply from Roo

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RogerCrawford
Member

Thanks to Munter for giving me the Suntrap site to view their Solar HW Systems http://www.suntrap.net.au/index-02.html

I have now reviewed three suppliers, Hills, Epricus and Suntrap. All systems basically use the same tubes, manifolds, gas boosters etc etc

It appears Suntrap offers the best deal in Sydney. I like the fact also that Suntrap publishes their system prices up front, see http://www.suntrap.net.au/index-02.html

I was keen to install a gas boosted system, however, given the glowing feedback and apparent lack of need to boost or infrequently boost these systems and the fact gas boosted are much more expensive, why would one go to the added expense of having a gas boosted system? Supply of gas for me is not an issue as I already use it for heating and cooking.

I would appreciate the thoughts of others here.

What is the benefit of going to gas boosted system with evacuated tube technology?
Why not just stay with electric boost given it will be required infrequently-based on user reports on this forum?
Do you feel it is possible to add too many evacuated tube panels to a system, ie, if I am using a suntrap system, 315 litre tank is there any point to using three panels instead of two?

Cheers, Roger

Posted Friday 29 May 2009 @ 7:23:21 am from IP #
Sunshine
Member

Roger,

It is possible to have too many tubes I suppose, as then in summer you will more than likely have over production of hot water, and you may loose some water from the pressure relief valve in the tank etc.

We connected our dishwasher to hot water to help address this issue to help increase the hot water usage particularly in summer.

I suppose it biols down to how many people in the house, amount of hot water usage in the household, and to some degree position of the collectors on the roof.

A gas boosted system costs another $800 over an electric boosted system, and as that was the only appliance in the house using gas, I wanted to get away from paying $160 per year in paying gas line rental just in case I might need it.

I would recommend getting a system slightly larger than what the installer recommends, and go electric boost, and that should be ok.
Been 8 months since install, and still haven't used boost, even after a week of rain and overcast conditions in Brisbane.

Posted Friday 29 May 2009 @ 7:57:23 am from IP #
Solgen
Member

As another user of a Hills 315l system I cannot fault them. My Sydney experiences are not quite as good as Sunshine, in the 6 months we have had it installed I have only turned on the booster 4 times for a total of 37 kWh. Two of those occasions were when we had visitors with 4 or 5 adults in the house rather than the normal 2.
I support Sunshine, it would be hard to justify the expense of a gas booster for the small amount of time you would need it.
I don't know how gas boost operates and whether it is a simple matter to only turn it on as required or must it be on all the time. If it is on continuously, you will find that you have installed solar boosted gas hot water system unless you are very careful about when you use your hot water!
With electric boost it is a simple matter to control the boost using the hot water service circuit breaker in the switchboard.

Posted Sunday 31 May 2009 @ 4:52:34 am from IP #
Roo
Member
Hi Solgen –

I cannot recommend Suntrap.

Our experience is that of poor design, solar collectors being delivered by men who could not speak English; they asked me where to put them and the collectors were installed in the wrong place. The phone calls are taken by people in Dural with cultivated Australian accents which tends to throw you off the track of the business owner, who is also the importer from China, and who does the design and quotes.

The solar collectors were laid flat on the roof and we had to pay extra to have them installed at an angle to the sun. This is important so as to harvest winter sun, and sun throughout the day, not just midday in Summer, and to minimise the chance of boiling in the tubes in the middle of hot Summer days.

Three of the tubes leaked in the first month.

The installation required many call-outs to remedy problems including:-
1. Mounting at an angle to the sun (although it is only tilted at 36 degrees and not angled at the recommended angle of latitude plus 10 to 15 degrees being 44 degrees to 50 degrees facing North for Sydney) – the greater the angle the better the performance in Winter and mornings and afternoons, and the better the protection from overheating in Summer.
2. Moving to the most logical and convenient place with minimum run of pipes.
3. replacing leaking collector tubes.
4. A pressure release valve was installed only after the collectors developed a leak.
5. The temperature sensors which controlled the pump were not connected to the cold 'water in' and 'hot water out' which meant that much of the summer hot water was not harvested and stored in the storage tank. The pump (to pump the hot water from the evacuated tubes to the storage tank) was often inactive in the middle of hot cloudless Summer days in spite of there not being much hot water in the storage tank and there being extremely hot water in the solar collectors.
6. The exchange of hardware fittings to meet specifications of suppliers (I had to contact suppliers of each component to get their review of poor performance of the total system and all were generous with their time and knowledge but it was at considerable cost to me in anxiety and time).
7. The original gas booster did not work and had to be replaced, at significant extra cost for the hardware, on advice from the manufacturer who sent out a technician and who was an excellent source of help in redesigning the system so it finally worked.
8. The original quote simply trapped us in a financial deal which did not reflect the final price, and required a lot of time and effort on our part to have the solutions to the problems identified and fixed with a total of 6 modifications over 15 weeks for them to be fixed with additional costs.
They were not reviewed by Choice when they recently did a review of solar hot water installation and you will find a most annoyed customer at:-

http://www.suntrapped.com

(note spelling of suntrapped not suntrap)

review of suntrap, how good is Suntrap?, problems with Suntrap, recommend Suntrap
Posted Sunday 17 Jan 2010 @ 11:11:35 pm from IP #

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