The recent ZeroDisrupt discussions reminded me to take another look at Aira. I went through their “Get a Quote” process again, and it raised a familiar red flag: the automatic inclusion of a buffer tank on every install.

For those of you here with an Aira system, did you ever question the need for the buffer? And if so, did Aira provide any justification for including it, especially given the extra cost it adds to the overall system?

@editor hi Mars, after being let down by Octopus, I was to a little too hasty in my decision making. Aira was the next best cheapest at the time. But they were not the only one who quoted with a buffer. I wasn't aware at the time, how much the experts advise against a buffer. I did question why they only fit with a buffer. They explained that the system was specifically designed from the ground up to use the buffer. I have evidence of the system adapting the flow temperature depending on the buffer tank temperature. Not sure if others do this or if this is unique.I Have now had the system over a year and it has worked well. We saved about £400 over gas.if you believe Aira's own heat delivered and energy consumption data we had a SCOP of 4.64 over 12 months.

@editor when I was looking for a HP I went to the Fully Electric Show North and Aira were there. At this stage only a few test HP’s had been installed. However this gave me the opportunity to speak to one of their designers and I asked about the buffer tank. He said that the system has been designed to include a buffer tank which increases its SCOP. I ask how and he tried to explain that it was way the water entered and left the tank and was a variable temperature. It also had volume so when a defrost is needed this means that this water can be used rather than water from the system which would then require that water to be rapidly reheated to keep the house warm. With their buffer tank the HP could continue on a slow continuous output therefore increasing the SCOP. We managed to achieve a SCOP of just over 5 which I’m happy with. I don’t care if there is or isn’t a buffer as long as it works, obtains a good SCOP and saves me money. Having a battery will also help.

@bromide @mikeh @editor

This is interesting indeed.  It is undoubtedly the case that buffer tanks can work, the problem is that they are generally thrown in by installers unnecessarily, poorly set up and with poor or no controls and subtracting rather than adding value.

It is indeed possible that Aira, having more control, have actually 'got it right'.  If so it would be good to get some more detail, not because it will give us reason to change what we generally think about buffers, but because it might carve out an exception for Adia because of the way their install process/controls work.

When I asked during the design phase, I was told this is to do with defrost cycles. We have achieved a good SCOP so far and are very happy with the performance. We have achieved COP of 4+ for heating (as per the app) and that reflects in our lower bills when compared to prior years. Whether the SCOP can go even higher without the buffer tank, that's way beyond my technical capabilities!

Posted by: @chandykris

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When I asked during the design phase, I was told this is to do with defrost cycles. We have achieved a good SCOP so far and are very happy with the performance. We have achieved COP of 4+ for heating (as per the app) and that reflects in our lower bills when compared to prior years. Whether the SCOP can go even higher without the buffer tank, that's way beyond my technical capabilities!

Do you happen to know if it a buffer (4 port) or a volumiser (2 port).  A volumiser is sufficient for defrost cycles.

@jamespa This is a 4 port buffer tank.

Posted by: @chandykris

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@jamespa This is a 4 port buffer tank.

 

interesting.  It would be good to know how it and the pumps either side are controlled by Adia as well as what sensors it has and where.

It is undoubtedly the case that buffer tanks can work, the problem is that they are almost invariably thrown in by installers unnecessarily, poorly set up and with poor or no controls and thus subtracting rather than adding value.

It is indeed possible that Aira, having more control over the end to end process as I understand it, have actually 'got it right'.  If so it would be good to get some more detail, not because it will give us reason to change what we generally think about buffers, but because it might carve out an exception for Adia because of the way their install process/controls work.

@jamespa The mechanical engineer in me wants to attempt to answer. But after decades in finance and management consulting, unfortunately I am incapable of answering even a basic question about my own heating system! I will let more capable folks here who have the Aira system answer the question.

Maybe, time to refresh upon my Thermodynamics and Engineering Mechanics knowledge!!

I must confess that I am unconcerned by the buffer/volumiser tank, though at the time it was another item to shoehorn into the limited space we had available. 

What I do want, and not sure where to start, is to get Aira to, at least, release a API that can be used by Home Assistant, to read the ASHP operational state and consumption. At best, release a supported Home Assistant Integration. In the meantime, I am contemplating using a Shelly EM unit with CT to at least monitor the electrical consumption. There are HA integrations/HACS for Octopus, GivEnergy and I have a few Power Monitoring smart plugs for individual sockets/devices, but the consumption by the Aira system is just lumped into the "untracked consumption". 

Anyone any thoughts?

@vsmith1, you've uttered several words (Home Assistant & Shelley) that will probably summon @pirate-rich... this is his playground.

Posted by: @vsmith1

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Shelly EM unit with CT to at least monitor the electrical consumption...

 

Anyone any thoughts

My vaillant heat pump reports various parameters in an 'unofficial' interface to HA but sadly not instantaneous power consumption.   I have learned to do without and use proxies plus the info in the Vaillant app, but I do have a Shelley power monitor on my main incomer and my pv feed.  If I really needed instantaneous heat pump power I would have no hesitation in fitting another Shelly, they seem to 'just work'.

I have just one automation currently, which switches on my granny charger between midnight and 7am (my cheap hours) using a Shelley relay.  Of course the relay could do this without HA, but previously I had a more complex automation for the function linked to solar output, so I stuck with automating via HA in case I need something more complex again in future.

My ha runs on a pi, it's pretty robust needing just one forced reboot in a year of operation to keep it going, for reasons I don't know.

Overall very impressed both with HA and Shelley.