Taking the plunge Daiken Altherma HT

TiredGeek · 2 September 2011 at 5:09PM

No buffer tank, direct to the rads, TRV's upstairs only, downstairs fully open, flow back from the rads to the ASHP is ~25L/min upstairs open or closed. There is a low loss header in the circuit to ensure constant flow through the ASHP. (Mitsi spec flow be 18+ L/min)
The buffer tank debate is a long one. Mitsubishi and 50% of people on "professional" forums say they don't need one, the other 50% say they do. Installation companies I have asked are the same, 50/50.
As I don't have 1/ space & 2/ the money for a tank and anti-freeze, there isn't going to be one in my place. I don't see how one would help anyway as I already have good flow through the units.

The Mitsubishi units are (supposed to be) smart, they wind up or down depending on load. The 14kw units can operate from 5kw - 14kw depending on the demand and ambient temperatures. In theory then mine should be 10 - 28kw, which nicely brackets the 16-17kw estimated load.
It may be that there's something peculiar about my house, far north, river valley, old stone building. I know the humidity outside is unusually high year round (for the UK), and I think this is one of the problems that is leading to my icing issues.... who knows

Pace: running costs are hovering in the area of £8-12 / 16 hours. Against the £1/hr of oil that looks pretty similar, considering the difference in outlay for the two systems, approx £10k, £4 saving per day over oil will take 6.8 years to break even. The "50-75% cheaper than oil" promise isn't quiet there

LOL
BTW, how do you calculate that £1/hour figure. Not doubting you, I'd like to know the formula so I can use it again.

lovesgshp · 2 September 2011 at 5:49PM

TiredGeek wrote: »

No buffer tank, direct to the rads, TRV's upstairs only, downstairs fully open, flow back from the rads to the ASHP is ~25L/min upstairs open or closed. There is a low loss header in the circuit to ensure constant flow through the ASHP. (Mitsi spec flow be 18+ L/min)
The buffer tank debate is a long one. Mitsubishi and 50% of people on "professional" forums say they don't need one, the other 50% say they do. Installation companies I have asked are the same, 50/50.
As I don't have 1/ space & 2/ the money for a tank and anti-freeze, there isn't going to be one in my place. I don't see how one would help anyway as I already have good flow through the units.

The Mitsubishi units are (supposed to be) smart, they wind up or down depending on load. The 14kw units can operate from 5kw - 14kw depending on the demand and ambient temperatures. In theory then mine should be 10 - 28kw, which nicely brackets the 16-17kw estimated load.
It may be that there's something peculiar about my house, far north, river valley, old stone building. I know the humidity outside is unusually high year round (for the UK), and I think this is one of the problems that is leading to my icing issues.... who knows

Pace: running costs are hovering in the area of £8-12 / 16 hours. Against the £1/hr of oil that looks pretty similar, considering the difference in outlay for the two systems, approx £10k, £4 saving per day over oil will take 6.8 years to break even. The "50-75% cheaper than oil" promise isn't quiet there LOL
BTW, how do you calculate that £1/hour figure. Not doubting you, I'd like to know the formula so I can use it again.

We quoted a couple of weeks ago, for a 180 sq mtr house, with low insulation, rads. Similar to yours with thick walls etc. This was a 17kw Optima unit with 13.5 kw electric cassette (250w power increments) and 500ltr water tank.
With the buffer tank idea on another installation, we have 2 floors running on their own thermostats, 1 x 19C and the upper 17C. These are UFH systems though.

TiredGeek · 2 September 2011 at 6:27PM

You don't work in Scotland as well do you?

I could do with someone who knows what they're doing..... LOL

Yes I know you're in Italy

paceinternet · 2 September 2011 at 6:33PM

BTW, how do you calculate that £1/hour figure. Not doubting you, I'd like to know the formula so I can use it again.

16kw / 10.4 kw/litre / 0.85% efficiency * 55p/litre

On your 16 hours running time, that would cost you £16 on oil, but if you are at £8 for electricity for the ASHPs, you are saving £8 / day * say 180 days which could be saving £1440 / year.

TiredGeek · 2 September 2011 at 6:51PM

Put like that it doesn't look too bad actually

I think were closer to the £12 mark than the £8 on a regular basis but then the 16kw is only an estimate so it could actually be 17kw which makes it look better

albyota · 2 September 2011 at 10:04PM

Hi TiredGeek, I was hoping you 'd got that lot sorted by now, I remember in one of my earlier posts, suggesting that the system was not plumbed correctly from what I'd read on here and on the Refrigeration com forum, I was hoping you got the installers back to sort out the plumbing, if the hot water cylinder coil is as you say only .7M2 then you should contact Mitsubishi, get it swapped and get the installers taken off the AEI register, keep us informed of progress please, you should not have to go through winter with that.

Good luck

maelstrom · 28 December 2011 at 10:28PM

Hi there, thought I'd post a quick update:
After a dramatic few weeks -the original installer went bust and I ended without any heating and back to square one- the Daiken Altherma HT has been installed for a couple of weeks. So far I cannot complain, apart from a couple of niggles. Compared to bottled LPG it's magic!!

[Deleted User] · 29 December 2011 at 10:24AM

maelstrom wrote: »

Hi there, thought I'd post a quick update:
After a dramatic few weeks -the original installer went bust and I ended without any heating and back to square one- the Daiken Altherma HT has been installed for a couple of weeks. So far I cannot complain, apart from a couple of niggles. Compared to bottled LPG it's magic!!

Great to hear

I'm lovin mine too

Tis a great feeling to bin LPG

mario2013 · 20 March 2012 at 4:19PM

Cardew wrote: »

If someone is fortunate enough to get a system that performs as promised - then good luck to them; although they have no way of verifying the performance.

Hi I am new to this forum but have read the posts on ASHP for some time now and find the discussions very interesting and alot of the points valid, there are obviously alot of people out there with bad experiences and i am sure even more with good experiences who you dont hear about as they are happy. We specify alot of Mitsubishi products and have contacts there and this thread got
me wondering if anyone was aware of the independent monitoring programme that Mitsubishi have been running for nearly 4 years now, there is alot of talk about not being able to substantiate performance and of fixed point CoPs (which are fairly meaningless), you need to look at CoPs with an element of time included (SCoP) in order to get a true idea of how a system is performing in the real world.

The Mitsubishi Ecodan monitoring facility does this and I believe they have about 70 houses throughout the UK showing live data and in total have over 30 years worth of data, may be worth a look, they have 2 versions, a recently launched public version and the engineering version where all the data is taken from (i believe they will be adding all sites to the public version in due course).

The EST report released to public is only a snippet of the full version and I agree it paints a bad picture for ASHP on the face of it, however there are some positive messages hidden in there also as well as which units performed the best.

Search on google for ecodan dashboard (cannot post links as a new user so cant send the link for the full M2M dashboard with all 70 sites)