solar geyser choice

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mayurh

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hi everyone

looking at getting a solar geyser
currently using a kwikot 150LITRE

which brands of solar geysers are best?
i've heard of some solar geyers having problems during winter when it was very cold?

hope someone can help me decide which is the best system for me

thanks
mayur
 
There are several options available when choosing a solar geyser namely:

Collector Type:

Flat panel or evacuated tube. The flat panels are probably the most aesthetically pleasing however they do not perform as well as evacuated tube systems. I have a flat panel system running next to an evacuated tube system outside my office right now. With zero consumption on both systems the flat panel is currently (8h40) at 43° and the evacuated tube system is at 73°. I consider the use of a flat panel to be a "solar assisted" geyser system and an evacuated tube system to be a true solar geyser in that the majority of your water needs will be catered for by the power of the sun.

System Design:

You can choose between split or close coupled systems. In a split system you will only have the collector on the roof and the tank will be inside your ceiling like with a normal geyser. The water/glycol will be circulated through the panel by using a low wattage pump powered by a small PV panel. This design looses a lot of efficiency by having to force the water to circulate and losing heat through the piping. A close coupled system means that the collector and the tank both sit on the roof as one integrated system. This is more efficient as the heated water is stored directly at the point of creation.

Circulation type:

Most solar geysers work on the principle that as a fluid heats it becomes less dense and causes it to rise naturally. This is called the thermosyphon effect. You can choose between an indirect or direct system. With a direct system the usable water will be drained from the tank directly and this will be the same water that circulates through the collector. Direct systems are not suitable for any area which gets frost in winter as they are prone to being damaged if the water in the collector should freeze. Most people purchase an indirect system as there is less liklihood of damage through freezing. An indirect system uses a heat exchanger to transfer the heated fliud from the collector to the usable water. We use a copper coil heat exchanger in our systems - and do not need to use any kind of antifreeze/glycol - only water to heat your water.

Materials:

Your solar geyser will be on the roof 24/7 and exposed to whatever nature can throw at it, therefore it makes sense to purchase a product manufactured from materials which will last under the harsh african conditions. Cheaper products on the market will use mild steel powder coated tanks - our products are made entirly from corrosion resistant stainless steel.

Certification and warrantees:

There are hundreds of products available at the moment. At the very least one should purchase a system which qualifies for rebates from Eskom. These systems have undergone testing by the SABS and this should provide a little peace of mind. I would recommend that you purchase a product which holds the SABS Mark of Approval - this goes a step beyond the SABS Tested products and means that the factory itself has been audited by the SABS to ensure that the necessary quality standards are in place. It is relatively easy to produce a "perfect" product for testing at SABS - which allows for Eskom rebates - but to consistantly produce such quality is where the SABS Mark adds significant value.

A good place to start looking would be on Eskom's website at www.eskomdsm.co.za

Systems do struggle a bit more to perform in winter, so any installation is optimised to offer the best winter performance possible. In winter the ambient water temperature drops lower meaning the system must work harder, also people tend to use more water and at a higher temperature in winter, also the limited amount of sunlight and cooler ambient air temperature means systems must work even harder. This means that you should purchase a system which includes some kind of electrical back up for the winter months.

In July I had a client call me to complain that he had to switch his element on for the first time and for the previous 9 months he had used no electricity for water heating - but it all depends on how much water you use and if your system is sized correctly for your use. Because the re-heat time for a solar is a lot longer than an electrical geyser you will need to store the equivalent of 24hrs water usage. We work on 50L/person per day as a rule of thumb.

Hope this helps ......
 
JJCOOL said:
In July I had a client call me to complain that he had to switch his element on for the first time and for the previous 9 months he had used no electricity for water heating -
Click to expand...

LOL - some people are never satisfied! :D Not paying a cent to heat up water for 9 months is a serious bargain!
 
You have various choices... The 150lt Kwiksol systems is a firm favourite. There are other Imported German makes too which are even better offering a 10 year guaranty.
. In that range your choices are as follows. Kwiksol 150lt - 5yr guarantee, Conenergy 180lt - 10yr guarantee. That is what I will recommend .Then there is hundreds of cheaper alternatives.
 
Quick question to the boffins here please! :o

I just got a quote for a 200l, 20 evacuated tube system and a quote for a 250l, 2 x 2 square meter flat panel system. The 250l system is about R100 per month more (I'm taking out financing for the system)

For 4 adults that bath/shower mostly in the morning, which one would be more suitable? The 250l will obviously have more water but it might not get as hot as the 200l? So then, also, the 250l should have better heat retention overnight?

We currently use a normal 200l system that copes ok, though the thermostat is set quite high (about 70 degrees)
 
Paulr said:
Quick question to the boffins here please! :o

I just got a quote for a 200l, 20 evacuated tube system and a quote for a 250l, 2 x 2 square meter flat panel system. The 250l system is about R100 per month more (I'm taking out financing for the system)

For 4 adults that bath/shower mostly in the morning, which one would be more suitable? The 250l will obviously have more water but it might not get as hot as the 200l? So then, also, the 250l should have better heat retention overnight?

We currently use a normal 200l system that copes ok, though the thermostat is set quite high (about 70 degrees)
Click to expand...

This is where sizing of solar is critical - your existing 200L system is not coping well with the demand (hence your thermostat set at 70°).

Although I do not know which particular systems you are considering, you will need at least a 250L system for 4 adults (allowing a bit extra for kitchen use too).

In fact a 300L system or 2 x smaller systems would probably be the best for you - this way you cater for the bulk of your water needs through sun power not electrically. I suspect that even the 250L system will use its backup element more than usual in your case.
 
Best Brand

mayurh said:
hi everyone

looking at getting a solar geyser
currently using a kwikot 150LITRE

which brands of solar geysers are best?
i've heard of some solar geyers having problems during winter when it was very cold?

hope someone can help me decide which is the best system for me

thanks
mayur
Click to expand...

Hi there

The key is to choose a solar geyser that will keep the water contained in it hot for as long as possible. This means you need to keep the heat in, by ensuring the system is well insulated. It would also be better in this instance not to have the water moving through the system and potentially be exposed to a cooler temperature when there is no sun. So it would also then be better to get an indirect system. Indirect systems don't circulate water but rather a solution that can be warmed and then circulated and heat up the water.

My company (Bonitcom Energy) is a registered ESKOM supplier and we sell a brand called Chromagen:Afrilanga. Their website is www.Afrilanga.com if you want more information.
If you're interested in a quote or want more information on our solar system, please send me a mail: [email protected] or call me on 087 820 7001
 
Great post there by JJCOOL.

For me it would come down to cost versus savings.
If the R5k system saves you R100/m it would pay itself off in 50 months or just over 4 years. (flat panel)
If the R25k system saves you R250/m it would pay itself off in 100 months or around 8 years. (evacuated tube)

Also remember that you need to change your lifestyle somewhat to suite.
 
Thanks everyone
will look into all this information
 
Some more questions two years later.

Based on the excellent and helpful advise from JJCOOL I've done some further investigation. My traditional geyser broke and I need to replace it.

One technical issue: JJCOOL states 'evacuated tube' is more effective than 'panels'. I see very few offerings of evacuated tube unfortunately. Inquiring about this with various providers they tell me the evacuated tube systems overheat and brake in Pretoria. They just become too hot. Is this true?

A system that came highly recommended because of the superior build quality was the Schueco SWH 300. Unfortunately Eskom apparently canceled the R 7,159 rebate on this system. Apart from the price this will probably mean that parts will be difficult to get in the future.

I seem to be left with two serious options: 1. Kwiksol 250-i x2 (250 Litres, Flat Plate,
Thermosiphon, Indirect, Two panels) and 2. MICROSOLAR M60VTHE (264 Litres,
Vacuum Tubes, Thermosiphon, Indirect, 3.5 Litre heat exchanger, 264 Litre thermal capacity).

The Kwiksol system can be fitted so that the water reservoir will be inside my roof and the panels (obviously) outside, which is what I prefer. I have a quotation that will work out to R 18,740 (including installation and VAT, deducted the R 6,496 Eskom rebate).

The microsolar will work out to R 14,761 (including installation and VAT, deducted the R 6,496 Eskom rebate). Possibly a better saving on electricity, but looks really ugly and according to some might overheat.

Any other options I'm missing? Any experience with these systems?

Thanks!
 
It seems to me that the solar geyser system prices escalated since the Eskom subsidy was increased, offsetting the saving. Is my observation correct?
 
dits said:
Based on the excellent and helpful advise from JJCOOL I've done some further investigation. My traditional geyser broke and I need to replace it.

One technical issue: JJCOOL states 'evacuated tube' is more effective than 'panels'. I see very few offerings of evacuated tube unfortunately. Inquiring about this with various providers they tell me the evacuated tube systems overheat and brake in Pretoria. They just become too hot. Is this true?

A system that came highly recommended because of the superior build quality was the Schueco SWH 300. Unfortunately Eskom apparently canceled the R 7,159 rebate on this system. Apart from the price this will probably mean that parts will be difficult to get in the future.

I seem to be left with two serious options: 1. Kwiksol 250-i x2 (250 Litres, Flat Plate,
Thermosiphon, Indirect, Two panels) and 2. MICROSOLAR M60VTHE (264 Litres,
Vacuum Tubes, Thermosiphon, Indirect, 3.5 Litre heat exchanger, 264 Litre thermal capacity).

The Kwiksol system can be fitted so that the water reservoir will be inside my roof and the panels (obviously) outside, which is what I prefer. I have a quotation that will work out to R 18,740 (including installation and VAT, deducted the R 6,496 Eskom rebate).

The microsolar will work out to R 14,761 (including installation and VAT, deducted the R 6,496 Eskom rebate). Possibly a better saving on electricity, but looks really ugly and according to some might overheat.

Any other options I'm missing? Any experience with these systems?

Thanks!
Click to expand...

Hey Dits

It is a common misconception that evauated tubes will break on heating. This is what competitors with flat panel systems normally say. The truth is that evacuated tubes have been designed to be exposed to the sun and to heat water to a higher temp than possible with a flat panel. Evacuated tubes are made from borosilicate glass (trade name Pyrex - the same like you use in your oven) which is designed to operate at temperatures even above 200°C and can withstand the temperature fluctations.

In my experience tubes once properly installed do not break by overheating. Of the 1500+ sytems we currently have in the marketplace (effectively over 30000 tubes) I have only seen 2 tubes broken through natural causes.

The choice of system is up to you, Kwiksol systems look neater but are less efficient:

We have both these systems on test here at our office, current readings at 09h12 are:

Kwiksol 150L Indirect split pumped system: 46°C
Microsolar 264L Close Coupled: 76°C

No load being placed on either system and no electric elements connected.

Good luck.
 
My 250l flat panel system was installed on Friday and, after a bit of a fight with the company I bought from, the geyser wise was installed yesterday (it was in the quote from the start - on Friday they only installed a normal "dumb" timer).

Today, after a hot sunny day, I see 70 degrees on the geyser wise. It's been at that temperature ever since we got home (around 16:30) The thermostat is only set to 65 degrees and the element hasn't been on since 7am this morning, so this is all solar heat baby!! :twisted: :D
 
Paulr said:
My 250l flat panel system was installed on Friday and, after a bit of a fight with the company I bought from, the geyser wise was installed yesterday (it was in the quote from the start - on Friday they only installed a normal "dumb" timer).

Today, after a hot sunny day, I see 70 degrees on the geyser wise. It's been at that temperature ever since we got home (around 16:30) The thermostat is only set to 65 degrees and the element hasn't been on since 7am this morning, so this is all solar heat baby!! :twisted: :D
Click to expand...

may i ask where you got your system from please?and how much did you pay?
 
I bought a Solartech 200L system, indirect and have the geyser and panels on the roof. I also turned my geyser off mid Sept. and will turn it back on roughly end of May. Water in summer is enough for a bath for 2 kids, a shower for 2 adult at night and the next morning.
 
mayurh said:
may i ask where you got your system from please?and how much did you pay?
Click to expand...

Bought my system from Teljoy Solar. They are not the cheapest around but I went with them because the financing is quite easy and they already take the rebate amount off the purchase price, so I don't have to worry about the rebate. And at least Teljoy as a company has been around for a very long time.

Pricing is on their website. I got the 250l flat panel indirect system.
 
I have a 250L hybrid kwikhot. It does save about R500 p/m. In cloudy weather it is just about useless but then we have 90% sunshine through the year. Have it set to top up heat in the mornings. Once going Solar not going back. I am also looking at replacing other energy circuits
 
I purchased a hybrid high/low pressure evacuated tube system, doesn't qualify for a subsidy from Eskom but works like a bomb.

It is basically a 300ltr low pressure unit with a coiled copper pipe running through it under high pressure, cold water travelling through the copper coil heats up due to heat exchange with the water in the geyser. You get high pressure hot water at slightly higher cost than low pressure geyser prices. I found a picture of one that makes it a bit easier to understand the water flow.

I have had it installed for two years and it survived some really bad hailstorms last year totally unscathed. I have it running with a timer that switches power to the geyser at 15:00, it has the thermostat set at 70c. My power consumption is logged on the internet so I can check usage. The element in the geyser does not switch on for 9 months of the year. I opted for a large unit so as to be able to run for an extended overcast period without any problems.

micoecoppercoil-heat-exchanger400.jpg
micoecoppercoil-heat-exchanger400.jpg

Advantages:
Cost - way cheaper than a high pressure geyser system (Was 11,2k for a 200Ltr system installed ex vat)
Reliability - Having an pressurized geyser will hopefully result in a more reliable geyser as it is basically a large insulated bath

Disadvantages
Hot water flow - temperature seems to be reduced the more taps you have on, not a major issue
Boiling water in geyser - Low hot water usage can result in the water in the geyser boiling which spills hot water out an overflow

I purchased my one from Apollo Technology but am pretty sure that they are quite widely available if you know what to ask for.

http://www.apollotechnology.co.za/
 
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