I’m an air source installer in the Alps and I’m looking to move away from Daikin largely based on what I’ve learned here from @KnightPhoenix and @matt-drummer (big thanks guys)! Also Anthony Dyer on YouTube has a great series with similar Daikin results.
My view is that I can install underfloor heating at 50mm pipe spacing (profix panels, imported) in the right project and the flow temperatures will be as low as possible. I can’t make the design outside temperature any warmer (-18 in Chamonix) despite the last few winters not seeing this, so lowering the flow temperature is my only way.
As it’s often not very cold, heat pumps will be operating in the middle of the temperature ranges, so if I design for a 30 or 35 degree flow then the majority of the time it’ll only need to be in the 20’s. I therefore need to fit units that will do this in a stable and efficient manner.
I watched @glyn.hudson’s video on the Samsung getting unstable below about 34 degrees.
Daikin struggles below 30 (and it’s all on the backup below 25 as the compressor stops!)
Nick Irlam on the Heatpumps UK group suggested Stiebel Eltron and the initial discussions with their local rep and some of the documents and training confirm that they are a good match. They are all however monoblock, and one of the things I like about Daikin is the range of mono/split(hydro/refrig.) units. Stiebel aren’t cheap for sure.
I’ve been trying to get some contacts locally with Vaillant, and struggling, which doesn’t bode well for having manufacturers support (which I need as an installer). I’ll continue to look…
Based on the monitoring here and this great community learning, what other brands should I be looking at?
What is your average outdoor design temperature, I know you mentioned -18 being possible but not for the last few years. If you have the option of hybrid or cascade system with a smaller heat pump designed and sized for the “warmer” winters and a gas boiler or a secondary heat pump designed for when it gets really cold for that boost.
It will all depend on the heat loss of the property and the temperature swing in the areas you are installing (going from +16 to -18 on a single unit efficiency would prove challenging for quite a few units).
Designing for low flow temperature will help a lot with efficiency but again it depends on how much heat is needed in the building at the lower end of that heatloss.
Thanks Zak, great observation on the fact that we’re asking alot of the technology here. It’s a little different in France. I’m audited (by our MCS equivalent) on the use of -18 as a design outside temperature so that’s what I have to use. I’m however allowed to include the backup electrical heater, so typically I make a chart like this:
To show how the heat pump fits the building.
In this case an “8kW” heat pump is good down to about -12 and then a little help is needed, and this is deemed as ok due to the low frequency of those days, and the cost of a non-electrical alternative. Our electricity is also much cheaper than the UK.
Most properties here don’t have town (mains) gas so hybrid isn’t a thing.
You’re spot on with the warmer temperature question. We typically put more insulation in houses thank a typicak UK house so the balance point can be a little below +16, so the cycle risk at the warmer heating temps is between +7 and say +14. There was a discussion on the Heat Geek forum about what outdoor temperature to use in calculations and the answer was +7, so I ensure enough system volume to get below 3 starts per hour at 7 degrees, but I’d go on the safe side of that as a bigger volumiser on the return isn’t a bad thing, and Dakin don’t exactly publish minmum outputs!
Awesome, it’s great to hear that you’re installing HPs in the alps! I’ve got a lot of happy memories climbing around Chamonix.
What sort of SCOP performance are you getting from HPs in that sort of environment? Do you design for 100% heat load from the ASHP? Or do you have electric booster heaters to toup the heat output during the coldest days?
Do you prefer split units to avoid having to deal with having water outside, which removes the need for glycol or antifreeze valves.
This issue has now been solved, I just needed to update the firmware to allow the circulation pump to be able to PWM modulate. It now runs nicely at lower flow temperatures. This has resulted in the COP increasing from 4.2 last year to 4.5 this year. However, Samsung WC controls are not the best, Vaillant or Viessmann are much better in that regard. But for the price of the unit I’m very happy with my Samsung, it’s just not quite as easy to set up and adjust as other units.
I believe Vaillant have a good range of split units.
Local manufacturer support is important, so it’s worth investigating which is the best in your area. I agree that moving away from Daikin is probably a good move.
@glyn.hudson I thought you’d be interested, having seen your videos on the channel!
I’ve not got any monitoring yet on any of my installations. Reason being that I’ve not had the right project yet to showcase my abilities at designing a really efficient system. Mainly retrofit units with existing underfloor heating where there is no client desire to make the pipe spacing tighter or do a screed to increase the output. I’ve only really started installing in the last year or so having changed career to spend more time at home as my professional engineering career had me all over the place. As yet I’ve not come across a radiator as that’s not much of a feature in an alpine chalet… So unlike the UK, where you’d normally change a few rads to design the system well, my hands have been a bit tied. UFH at 150mm in foam panels isn’t bad, but I’m pushing my next few clients to 100mm (or 50mm) in screed which is significantly more output (or lower flow). For the right project I’d swallow the monitoring kit cost to get one on the board. With the Daikin “limit” of around 30 degrees that’s why I’m keen for a different brand.
My own home is on gas, but I have 50mm pipe spacing, so I’m excited for a Heat Pump when the time comes!
That said I’ve been working hard on @Raomin’s ESPAltherma earlier in the year, the Daikin data transfer system, and I re-coded that with some help on here to cut out the need for an instance of Home Assistant, so it can send directly to HTTP in openenergymonitor. I’ve a client who’s keen to have one, so I’ll post on how that works. I didn’t install the heat pump (which has undersized pipework!) or the UFH so it’s not going to show off my skills!
You can see on the chart above I design for as much as I can from the heat pump, but accept some backup use, else I’d be oversizing the unit every time and giving modulation issues in the less cold times.
I prefer splits for the freezing risk reason (and have the French F-Gas), but one of my installations next month has pre-existing underground hydraulic pipes that I’ll resuse from the old heat pumps. I’ve done a mono, but that was to save as much space as possible. The daikin mono’s are a bit of performance compromise. If I can find a Vaillant supplier and support then that’s my best hope I think. I’ve seen one on a chalet round the corner, so they do exist!
I’m glad the PWM update sorted your Samsung, would be great if Daikin could do the same! How low can you flow now?
We struggle for Viessman support locally too, they only have 2 technicians for the whole region and don’t make it easy to contact them, so I’ve seen a few locally run into problems.
I’ve only got radiators, so I can only go down to about 31C, any lower than this and the radiators are not able to dissipate the minimum heat output of the heat pump so it would cycle.
I was recently involved in installed the same Samsung 5kW for a friend of mine with UFH in a thick screed, he’s got much more emitter area to be able to dissipate heat at lower flow temperatures, he can run down to about 24-25C without the HP cycling:
