My previous topic disappeared, so I’ve created a new one. I’m looking into getting a heat pump water heater. I’d like to control it through my Victron system with a 15 kWh Pylontech battery. I understand this can be done using a flow in Node-RED. I’ve also read that you can control this and other things using the integrated Shelly. But is Wi-Fi also an option? I received a reply from Christophe H, but I can’t respond to it.
In addition, I’d like to consider an electric central-heating system that would also need to work with a flow. Is all of this possible, and what would be a good setup?
As far as I know, all of that is possible. I don’t use Node-RED myself, but Home Assistant sends a signal to the smart grid contact on our Bosch heat pump when there is a PV surplus and the batteries are full.
A charging point will be added here as soon as possible too; I’m waiting for Victron’s new EVCS 2.
If I’m not mistaken, you’ll also be able to use EEBus alongside a smart grid contact on the Victron GX systems; I’ve read that EEBus support is on the way.
We just finished a 3 year testing of several heat pumps with solar, Portugal, Spain, Mozambique and Angola.
Non of them reached the savings which were predicted.
The highest gain of 3 we have seen at 10-11 degrees C outside temperature, below 7 and above 14 degrees C the gain is 1-1, so no gain.
All these investments are now spread from 10 to even 15 years and the verdict is that some of these pumps do not even get to that, so, if the government is not giving special conditions when buying, its not worth to use these.
The other tests we did as well were simple boilers with a 2 till 6Kw coil making use of the frequency when the batteries are full, just like the Ohmpilot or MyPv, all these installs returned their investments within a year, that’s a massive difference.
Also, simple off the shelf products can be used (not Ohmpilot or MyPv) what cuts investment for the controls only by half and so local elecs can easily mount it themselves and owners do understand how it works.
One of such install runs since 2016, no maintenance and no repairs done ever.
One thing, the correct amount of overcapacity PVs need to be calculated to be most efficient of course.
Yes, indeed, below 7 and above 14 degrees C outside its not worth it, it behaves then as an air conditioner.
Also, it can only do an optimum delta of 11 degrees Kelvin only between outside and inside temperature, you want it more than that, heating or cooling it behaves 1:1, so no gain.
It’s tested for 3 years by 55 HVAC engineers we have in our tech group in these countries in normal homes, high rise buildings, government buildings, hospitals, etc.
Delta is given in Kelvin, so outside to inside temperature difference has gain of 3 till 11 degrees Kelvin, if you want to cool the house or heat it, we see no difference, it does that optimum with an outside temperature from 7-14 degrees C.
So, if it is 7 degrees C outside, then you can gain a factor 3 till about 18 degrees inside when you heat the place.
If it is 14 degrees outside you can heat the place till 25 degrees C with the gain of 3.
If it is outside 40 degrees C and you want to cool the place, you can cool it down to 29 degrees C, the gain is then very close to 1 and it just behaves as an air conditioner, and if you want to cool more than 11 degrees Kelvin, then it goes below gain 1 and even might consume more than a real air conditioner.
All that above, also counts for heating or cooling water in a closed circuit.
What does your rambling (sadly, a genuine trend in what was once a good community) have to do with the OP’s question?!
And it’s quite obvious that you have no idea how a heat pump works, or an air-conditioning system, which is ultimately “just” a heat pump too. Based on years of operating several LL and LW heat pumps, I can confirm that they work wonderfully across all relevant temperature ranges.
Do your homework first. By writing without a clue or any understanding of the subject, you’re only making potential heat-pump buyers feel uncertain…
I don’t understand how you arrived at this. I’ve had a self-installed NIBE S2125-12 running for almost a year now, and I’ve fitted it with a Kamstrup heat meter directly on the output, as well as a separate meter in the hot-water cylinder circuit (300 litres). The heat pump itself has an ABB kWh meter. The measured efficiency is above 400% for central heating and just under 300% for the hot-water cylinder. On top of that, last winter was far from ideal, with a lot of snow resulting in many defrost cycles.
The results above were measured during 3 years and are the average results from more than 40 installs, these measurements are clear and were partially discussed with the engineering order of Portugal.
Please leave ideological thinking out of it for now and look at the data first.
There are always effects that perhaps nobody has considered and that can really ruin your day (e.g. wind farms slowing down near-surface wind fields, resulting weather changes leading to increased soil drying or a lowering of the groundwater table in the long term).
