Heatgeek and flow temperature YouTube

JulianC · 2022-02-11T21:43:19Z

This is an excellent video that explains why lower flow temperature is the way to go. Balancing heat loss to heat input. I read Chemical Physics at Uni and I hadn’t thought about it like this. Good. But how does this relate to electric spend? Having a SCOP of 5+ is fabulous, but if you are spending more on electricity, then it’s of no benefit - except for the heat geeks 😊 So appreciate thoughts. I still plan to run my ASHP on Nest control for a year until April when I will switch to weather compensation for a year to compare.

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Air Source Heat Pumps (ASHPs)

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JulianC

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Topic starter 14/03/2023 6:26 pm

@heat-pump-newbie Hi HPN. We purchased the Gold level service. It was £264 per year for ten years. This includes an annual service by Daikin and all parts and labour if something fails. So a bit of an insurance plan because if a pcb fails, that’s £1000 just for the part.
At the time of my first service last April, the Daikin engineer said id purchased the unnecessary higher spec and Silver would have been fine 🫤. But when I came to change it in December, before the next payment was due, all the prices had gone up and Silver was more than I was paying for Gold. I stayed put. 😊

I’ve found Daikin central fairly easy to deal with. They do what they say. Others have had mixed results. Perhaps it is down to the quality of the engineer who turns up. Which would be true of any HP company.
You need to have the system serviced each year. Most products come with warranty. Never sure if this is parts and labour

Daikin Altherma 3H HT 12kWh ASHP with Mixergy h/w cylinder; 4kW solar PV with Solic 200 electric diverter; Honda e and new Hyundai Ioniq 5 N electric vehicles with Myenergi Zappi mk1 charger

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Marzipan71

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17/03/2023 12:24 pm

Hi @julianc we've been running our Daikin 16kw HT ASHP for three seasons now - 21, 22, and part way through 23. The kWh consumption for just heating (not inc. DHW) are shown below. For 21, the heat pump was shiny and new and I was cluelessly running it like a gas boiler with set LWT and controlled by smart thermostats, pressing boost when we felt cold (I know...); 22 I fiddled around with the settings to try to reduce consumption but still running like a gas boiler with smart thermostats. With the energy crisis this past winter, it would have been unaffordable to run the heat pump without the patient help from @derek-m who guided me through migrating from smart thermostats and into the wonderful world of weather compensation. I realise this isn't the exact use case you're talking about but the numbers may be of interest (current month figures are projected). I could apply a trendline and label it 'level of ignorance' in my case 😀

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JulianC

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Topic starter 17/03/2023 12:58 pm

@marzipan71 thanks Maz. That’s a dramatic reduction. Top job. What size is your home? I was in a different position. I use just over 4100kWh in year one. This using Nest control. In year two I moved to weather compensation. So far I’ve used about 4000kWh with another month to go. I think this year was colder. So I’m happy with the weather compensation approach. My home is 204m2.
My electric use includes hot water.
So my system was better set up than yours initially I would suggest. And we’ve ended up in a similar place.

Daikin Altherma 3H HT 12kWh ASHP with Mixergy h/w cylinder; 4kW solar PV with Solic 200 electric diverter; Honda e and new Hyundai Ioniq 5 N electric vehicles with Myenergi Zappi mk1 charger

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Marzipan71

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17/03/2023 1:23 pm

Hi @julianc house is 240m2 internal floor area, 300m2 footprint. We have 6.6kWp solar which produces ca. 8Mwh annually and we use 80-85% of the solar in the winter months (we're in Italy, so solar is a no-brainer) going mostly towards the ASHP. We use the ASHP for DHW as well but I stripped out the DHW consumption from the figures in my last post - if I include them, our total calendar year 2021 heating + DHW grid consumption was ca. 14k kwh; 22 was 8k kwh, and for 23 I've modelled around 6k kwh (inc Oct-Dec of this next winter). Yes your system definitely sounds like it was set up better than ours for sure - I didn't get any handover from our installers at all and was completely ignorant of how ASHP's work. Luckily energy was still cheap in 2021. The help from this forum has really been invaluable, particularly in understanding zoning, weather comp, and the like. Our next improvement is probably going to be solar thermal which is the recommended set up for our Daikin ASHP and the thermal store and should help vastly reduce the DHW grid consumption and make the ASHP heating more efficient also. Interesting thread, thanks!

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