Another trick I pulled, the kitchen is at one end of the house … with our daughter’s shower.
So for “the kitchen” I installed a 50l geyser on Eskom 24/7 for a kitchen with no hot water gets ME in “hot water”.
Because washing dishes cools the main geysers quite a bit with the water flowing +15m to the kitchen, that got me some “words” in the beginning when wifey had to wait for a shower or kitchen hot water, because she had to first press the Red Button to heat the main geyser.
Just a shame that my daughter, when she lived here, now guests, must now be careful how long she/they shower …
Here is the 50l geyser heating between 00:00 and 8am:
A permanent solution might be a bit problematic in the winter, but I presume that your aircon would be able to operate more efficiently in the summer if you put the radiator next to the heat pump’s heat exchanger?
To sort that we had the aerolite pink stuff removed and had them blow in that new insulation stuff they use on ceilings. Something like 30cm think. Sorted the heat loss and kept the house really cool in summer.
The Victron solution becomes too expensive due to all the extras needed… GX, MPPT, Carlo Gavazzi etc etc. I like the simplicity of an all-in-one. I was looking at GoodWe, then Sunsynk now Solis. Won’t my insurance cover a inverter that dies anyways? I think the technology is becoming so commodified that truly bad inverters like the early Infinisolars are not too common anyway.
Insurance does not cover wear and tear or inferior equipment. Also check with your insurer what they do cover, and the limits, and if you need to specify it, or if it is part of the Building Insurance.
Victron is not that expensive … especially with their 5 year warranty and lots of local backup and repair centers.
Batteries on the other hand, THAT is THE biggest cost if one breaks it down into parts.
If you are not worried about Eskom and grid tying, @Paul has an Easysolar 3kva for sale. Start there, sell it later when you have real data after 1 year. Has a GX and MPPT built in.
@karischoonbee , do talk to @JacoDeJongh for a competite quote. I’ve had numerous friends ask me about this, only to find that the suppliers they buy from (eg, one guy was buying from Miro, which is primarily an IT/networking supplier) have quite a high markup. The difference was more than 20%.
I have large loft areas with a double volume space in between. I’m putting in 50mm isopine up against the purlins with 100mm isotherm on top. I’m hoping I won’t need an aircon in the loft, the ventilation is good at least.
The Solis also have 5yr warranty, which can even be extended to 10. Will have to see what it’s worth but a comparable Easysolar 5k is double the price, and can’t run without battery.
You are more than welcome to give me a call, my details is on the forum. I can try and type my reasons, but it will take me an hour or more and currently I don’t even have time to sleep. Victron is more expensive, but truly with reasons.
It takes 1.16Wh to heat one liter of water by 1°C. So it is fairly easy to calculate the amount of energy required to heat, say, 150 liters of water to a certain temperature.
We also know that on average, the sun bestows around 1000W per square meter onto the surface of the earth. Sometimes slightly more, often a little less.
So you can quite easily, by measuring the temperature of the water before and after, work out how efficient a SWH is. I am told that it is at least 60% efficient, which means 60% of the heat ends up in the water, the rest ends up elsewhere (probably reflected back or otherwise lost back into the atmosphere).
The same exercise can be done with a PV module. Throw in 1000W/m^2, also known as STC (standard test conditions), and measure what you get out. Theoretically 25% or more can be achieved. In a factory/manufacturing environment, it’s hard to even crack 20%. Again, the rest goes back into the atmosphere or into the structure, either as reflected light or as heat.
From that point on, if you skip the inverter and push that energy directly into a resistive heater (you will need SOME kind of impedance matching, probably an MPPT), then the last step is 100% efficient (a resistive element sitting INSIDE the water? The heat has just one place to go ).
Install a 200L (rather then 153L) Vertical Electric geyser and dump excess Solar PV. If there is enough roof space, extra PV panels are much cheaper than Heatpumps and Solar Thermal options.
@plonkster I think people care more about Rands saved over the lifetime of the system than about the efficiency per square meter… unless that is the constraining parameter.
Apologies for the diversion but this isn’t anything new on these forums.
Granted that the solar energy is more efficiently captured with EV tubes etc.per area of these collectors vs PV panel area. However this is only an issue when you don’t have enough roof space (which I understand isn’t usually a problem)
So the comparison is to do with the cost of each system that produces the same result.
I went SWH since 2011 and have never had a problem with it.
2yrs ago I installed a gas geyser as an alternative to eskom as backup. This combo works extremely well, I have hot water all year round and only use 2 x 19kg gas bottles (R1020.00) a year for heating water / house (winter) and cooking.
using a PV panel to run an electrical geyser to heat water when you can use the same sun to heat water more efficiently is just a waste of PV capacity. I’d rather have that capacity to run my pool pump or an aircon.
I have approached this slightly differently. I have all three options.
A SWH in series with a standard geyser (2kw element). The sun preheats the water in the SWH and then the 2kw element (inverter connected) tops up the water if need. I have the electric element on a SONOFF switch which comes on, and stays on, while the SOC is above 95%.
I also have a gas geyser if needed for the “bad” days.
Thanks guys, not really interested in the turf wars. I love Victron and wish my budget suited it but for me the Solis or the Sunsynk is just unbeatable value. I’m technically minded and don’t mind installing new firmwares and looking to solve problems online. I’m also going to do a self-install. If I was off-grid and my inverter was a critical piece of equipment I would look towards Victron or SMA.
Right. You care about rands/year, not power/m^2. Reminds me of something similar my farmer dad always say: You care about the long term money per hectare, not profit per animal.
But still, a good SWH needs only last a quarter of the lifetime of a PV module to still break even. 30/4 ~= 7 years. And they do last that long, and longer… Even the cheaper ones with the fibreglass tank will easily crack that number.
Also, there is ROI. Things pay back the money the cost. A SWH does that way sooner than PV modules. Of course, one has to ask “compared to what?”, so even this isn’t an absolute argument.
Finally, at least in Cape Town we also have limits on how much PV we are allowed. Heating at least some of your water with something else means you aren’t wasting your precious PV-allowance on hot water
With all of that said: Do I have a SWH on my own house? No. I went with an option that I KNOW costs more money in the long run, but it has a more levelised cost summer vs winter: A heat pump. So most of all, I advise doing what makes the most sense to you
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