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Solar Immersion geyser controller

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Easy sum : R3k is for the geyser, or R15k for the panels, and you still have to buy a geyser. :rolleyes:  I really still don't see how anyone can make the case that water heating by PV is better than direct solar heating. It doesn't add up. 

Hi DB9

It is no contest. A solar geyser will heat water more efficiently than PV.

I will use my situation as an example. We have gas geysers. I use excess energy to heat a standard electrical geyser which preheats the water. On most the water does not need further heating. If however I decide to use that energy in the workshop I can. Why do I have excess energy? I need to cater for some days where we do the washing and ironing and generally use a lot of power. Will I spend my next 3k on a geyser? Probably not. Another R8k  would give me 750W of panels and give me maximum power for a larger part of the day. A friend who owns a game farm has about 50 evacuated tubes in his shed from solar geysers that he has had to abandon. I would consider a retrofit system using his tubes but I am loathed to spend money on a system that can only heat water.

A heat pump is even more attractive but most seem to have a start spike and since I use a relay to switch the geyser on/off a resistive load makes sense. The R3k solar geysers I have seen might give you a hot shower but definitely not a hot bath and if you need to have a glycol system the expensive is even greater.

36 minutes ago, DeepBass9 said:

Easy sum : R3k is for the geyser, or R15k for the panels, and you still have to buy a geyser. :rolleyes:  I really still don't see how anyone can make the case that water heating by PV is better than direct solar heating. It doesn't add up. 

Easy a solar water geyser cannot run my aircon(insert other appliance here) but PV panels can do both

19 minutes ago, Chris Hobson said:

If however I decide to use that energy in the workshop I can.

 

9 minutes ago, viper_za said:

Easy a solar water geyser cannot run my aircon(insert other appliance here) but PV panels can do both

Exactly, you pay three times more for the flexibility :-)

What if I don't need the flexibility? That's sort of my point. When it comes to hot water and a tumble dryer, I don't need it. I know X amount is required every day. No need to make it flexible.

8 minutes ago, TinkerBoy said:

 

Let me post the video again. Obviously this is why we like the heat-pump more than the tubes. Tubes can only make hot water . And can only make it when the sun is out. PV panels can make hot water via element or heat-pump and do other things as Viper stated any time of the day, not just when the sun is out (via batteries or gird tied storage).

Thus PV is a lot more flexible than just tubes. If you don't have PV then yes tubes will save you money, but if you have a big enouph PV system you dont need tubes. If I bought more panels with the R26K I paid for the tubes I would have sooo much extra power per day to run the aircons without using any Eskom and have hot water.

 

 

Nice demo.

 

Do you notice a difference in heatpump performance in winter and summer? Alot less ambient heat for the pump on highveld winters morning.

I am thinking we have an advantage here along the coast... the temperature remains above 10 the whole year through. It does not get as hot, but it never goes to 0!

1 minute ago, TinkerBoy said:

No Richard not really. You have to hit about -10 end below before the heat-pump wont produce hot water from the ambient. In SA we are very lucky to not drop down to those temperatures so we have very nice hot water any time of year any time of day.

Intresting.. and any sign of a change in efficiency? Not sure how you would see that, maybe energy consumption if you measure it

  • 1 year later...
On ‎2016‎/‎10‎/‎19 at 4:37 PM, cvzyl said:

BTW, Richard Viljoen here on the forum will be importing these units. Think he plans on keeping stock. Will save you the cursing associated with importing anything through our shit fabulous Post Office.

hi there is your Richard guy still importing these and how much are they

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