Solar questions

Snyper564

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Hey guys, I am in the process of considering going solar. I think I would likely go grid tied. Before I go into too much detail there is something I just wanted to check. We use about R1500 worth of electricity a month. We have two geysers (150l). I see retrofitting these with tubes is about R15-R20K each.

Would it be a better idea instead of doing this just adding to the PV panels? R30k worth of panels? which is the better option? Ill pose more queries over time but I think this is the starting point.
 

R13...

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Your geyser makes up more than half of that 1500. I'm sure you can get a 300l solar water geyser for less than 30/40k.
 

Sinbad

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Always reduce your usage as much as you can before trying to go PV.

Solar geysers will save you a considerable amount. PV efficiency is very low compared to vacuum tubes for water heating.
 

Snyper564

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Always reduce your usage as much as you can before trying to go PV.

Solar geysers will save you a considerable amount. PV efficiency is very low compared to vacuum tubes for water heating.
Ah I see, this is what I was thinking. but wanted confirmation.

I was essentially thinking PV for house (excluding oven/stove) and tubes for geysers. This sound about right?
 

Sinbad

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Ah I see, this is what I was thinking. but wanted confirmation.

I was essentially thinking PV for house (excluding oven/stove) and tubes for geysers. This sound about right?
Pretty much. Be sure also to convert all your lights to LED as well.
 

Snyper564

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Pretty much. Be sure also to convert all your lights to LED as well.
Most are already but will bear that in mind, any recommended places in Pretoria area for installations etc?

On the tubes, am I correct in saying frost is an issue and you can get "frost resistant" ones?
 

swakop_toe

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Vacuumtubes tend to boil the water, which is not desired.
You'll have to restrict them, manually , with shadecloth or similar.

You best alternative is solar heating setup, one that circulates the heated water through the geysers.

Else, heatpump/exchangers is also an option.
 

signates

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Vacuumtubes tend to boil the water, which is not desired.
You'll have to restrict them, manually , with shadecloth or similar.

You best alternative is solar heating setup, one that circulates the heated water through the geysers.

Else, heatpump/exchangers is also an option.
Vacuum tubes has a circulation pump that circulates the water to the geyser. Unless you are referring to the vacuum tubes directly attached the geyser on a complete roof mounted unit.

You can retrofit vacuum tubes to an existing geyser where only the tubes and collector is on the roof which then circulates the water to the geyser in the roof.
 

Snyper564

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Vacuum tubes has a circulation pump that circulates the water to the geyser. Unless you are referring to the vacuum tubes directly attached the geyser on a complete roof mounted unit.

You can retrofit vacuum tubes to an existing geyser where only the tubes and collector is on the roof which then circulates the water to the geyser in the roof.
Just to confirm can I use the tubes + circulation pump on existing geyser?
 

signates

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Just to confirm can I use the tubes + circulation pump on existing geyser?
Yes. My existing geyser was retrofitted with the evacuated tubes and collector and then a Geyserwise to control the setup.
 

swakop_toe

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Vacuum tubes has a circulation pump that circulates the water to the geyser. Unless you are referring to the vacuum tubes directly attached the geyser on a complete roof mounted unit.

You can retrofit vacuum tubes to an existing geyser where only the tubes and collector is on the roof which then circulates the water to the geyser in the roof.
Yes, the directly attached tubes setup.
But even the circulation setup I have heard is prone to boil.
It is because the vacuum tubes was developed for northern hemisphere applications, our southern hemisphere conditions sun time is "too much".
 

Snyper564

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Yes. My existing geyser was retrofitted with the evacuated tubes and collector and then a Geyserwise to control the setup.
Great, just to confirm then that the "power" only kicks in when the tubes hot water isnt sufficient?
 

signates

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Evacuated tubes and collector on my roof. Geyser is still in the attic. 20200722_113045.jpg
 

signates

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Great, just to confirm then that the "power" only kicks in when the tubes hot water isnt sufficient?
Yes. You can set the temperature differential on the Geyserwise. Mine is set as below.

If temp in collector is 7° higher than the temp in the geyser, the circulation pump starts up and then stops when the differential is 2°.
 

signates

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It also has frost protection so if the collector temp is 0° it will pump water from the geyser and heat it up to 4° and then switch off. This v can also be set higher.
 

swakop_toe

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@signates, very interesting.
I am pleasantly surprised at the improvements the these systems.
I had three installations on my Karoo farm and they were forever in need of attention.
Either a tubes cracked because it boiled dry, causing scale buildup too.

How long have you had yours?
What make model and model do you have?
 

signates

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@signates, very interesting.
I am pleasantly surprised at the improvements the these systems.
I had three installations on my Karoo farm and they were forever in need of attention.
Either a tubes cracked because it boiled dry, causing scale buildup too.

How long have you had yours?
What make model and model do you have?
Can't remember the make. Had it installed at another home in 2008. When i moved and rented out the home, I had it moved to my current home. That was in 2015. So it's been going now for 12 years. It think I need to replace the collector soon.
 

Currantly

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Hi everyone,

I'm looking for suggestions for someone, suitable qualified, to service my thermosyphon solar geyser. It was last serviced in 2016, but I've just left it the last couple of years due to the water restrictions we had/have. I live in the northern suburbs of Cape Town.

Thank you in advance.
 

adielk

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May 21, 2009
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Most are already but will bear that in mind, any recommended places in Pretoria area for installations etc?

On the tubes, am I correct in saying frost is an issue and you can get "frost resistant" ones?
Contact Jaco from go solar electrical for installations


He regularly does installations in Garsfontein Pretoria.
 
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