Gas vs. Solar geyser

[stefmeister]

That is a big ask ... but the most recent system I did (like last month) using Victron Inverter, charge controller etc. 6kW peak PV array, 12kWh Lithium batteries totaled about R250k all in. That is a very decent system that can do all sorts of wonderful things with a robust 5kW inverter that can handle motor startup in-rush currents.

 

Yeah, R250k is not going to fly.

I'd be happy if I can expand on a solar PV geyser kit with an inverter and backup battery to run the tv/modem during loadshedding. Not being entirely off grid.  If I have to spend that much money just to live a normal life, I'd rather just pack up and leave altogether. 

[Shebeen]

Can you suggest a PV/heatpump system that can also supply some power during load shedding to run a few led downlighters, TV and modem? 

Looking to install such a kit in the next month or two.

if it's just for load shedding then you don't need solar.

 

if you just want wifi, then this is the easiest no hassle solution

https://www.arionpower.co.za/wibox

 

the more you add to it, the more it costs.

if you can handle a big trolley in your house, then this is a good option, as it can actually take a solar panel input

http://smartpowersystems.co.za/

[kosmonooit]

You can get  a 10kWh Lead Acid solution with a decent robust 5kW inverter for under R40k that's good for standby power, load shedding.

[stefmeister]

if it's just for load shedding then you don't need solar.

 

if you just want wifi, then this is the easiest no hassle solution

https://www.arionpower.co.za/wibox

 

the more you add to it, the more it costs.

if you can handle a big trolley in your house, then this is a good option, as it can actually take a solar panel input

http://smartpowersystems.co.za/

 

New house needs to have a solar geyser installed for regulatory compliance, so if one can expand on that system it would be a plus instead of having to have an additional setup that takes up space and/or extra costs.

[PhilipV]

New house needs to have a solar geyser installed for regulatory compliance, so if one can expand on that system it would be a plus instead of having to have an additional setup that takes up space and/or extra costs.

If I understand correctly the solar geyser and solar panels are two different systems.

Solar geyser pumps water through a panel with a lot of tubes on the roof, the heat from the sun warms the water and warm water is stored in a reservoir (geyser) that has a backup element for when it can't harvest enough energy from the sun.

 

If you want electricity you'll put a seperate solar panel(s) on the roof, and thus will need a seperate reservoir (ie battery) to store the harvested energy.

 

The solar geyser isn't fed electricity from a solar panel, that would be inefficient.

[stefmeister]

If I understand correctly the solar geyser and solar panels are two different systems.

Solar geyser pumps water through a panel with a lot of tubes on the roof, the heat from the sun warms the water and warm water is stored in a reservoir (geyser) that has a backup element for when it can't harvest enough energy from the sun.

 

If you want electricity you'll put a seperate solar panel(s) on the roof, and thus will need a seperate reservoir (ie battery) to store the harvested energy.

 

The solar geyser isn't fed electricity from a solar panel, that would be inefficient.

 

Newer systems use PV panels, not the old evacuated tubes - which is a high pressure system that also wastes water etc. IIRC

https://www.sustainable.co.za/geyserwise-pv-solar-water-heating-kit-for-150l-geyser.html

Edited July 15, 2020 by stefmeister

[PhilipV]

Newer systems use PV panels, not the old evacuated tubes - which is a high pressure system that also wastes water etc. IIRC

https://www.sustainable.co.za/geyserwise-pv-solar-water-heating-kit-for-150l-geyser.html

I learn something new every day. Thanks.

[Shebeen]

Newer systems use PV panels, not the old evacuated tubes - which is a high pressure system that also wastes water etc. IIRC

https://www.sustainable.co.za/geyserwise-pv-solar-water-heating-kit-for-150l-geyser.html

i have no experience of this directly, but in theory that is an incredibly crap option. "newer" systems, is hardly better.

 

a solar thermal (it, how water form the sun) is about 80-90% efficient.

a solar pv system converts photons to electricity, which is then used to heat. about 15% efficient, best case.

 

i understand you are saving on the geyser, but any recently installed geyser is solar compatible.

if you want pv solar panels for hot water, get a heat pump rather

[kosmonooit]

Newer solar water panels look like PV panels but they are not, they heat water in some way or another that get circulated to a geyser storage tank that may or may not have a heating element in it.

 

As said the most efficient way of using electrical energy to heat water is a heat pump, but it also means a bit of capital out lay.

 

Or at least that's how I have figured it out.