(a) Daikin vs Atlantic (and Mitsubishi), (b) integrated hot water vs hot-water with its own heat pump

[Garald]

[Another chapter in the house saga!]

 

So, two separate installers visited, agreed to take on the job and sent us quotes! Exciting.

 

Company A works exclusively with Atlantic (due to some exclusivity contract, presumably). 5.0/5.0 rating in Google, with 44 reviews (but many must come from their experience with AC).

Company B works with whatever it wants. 4.5/5.0 rating in Google, 12 reviews.

 

They agree not only to install the external unit in the courtyard (I've got a signed agreement from the coop) but also to give the green light to the use of the heat-pump to do pre-heating and pre-cooling in the PIV (Hydro' R system). They seem mildly interested, in fact, since their experience with other cooling uses (fan-coil units?) has been disappointing, apparently.

 

Company A is sending us what looks like a reasonable quote (ca. 15k EUR including taxes) for providing and installing an Atlantic Alféa Extensa DUO A.I. 10 R32 (actual power: 9kW). Its SCOP 35C/55 C is 4,53 / 3,33. 

Its external unit produces 62dB - bit higher than I was aiming for. (Most companies insist on overdimensioning, presumably to avoid liability. Heat loss according to our worksheet is only 5,3kW, but try to convince installers with their own software of that.)

 

Company B offered to match the first company's quote (but didn't really; it offers an older, less effective, noisier Atlantic model for just 500 eur less). However, the installer said he preferred a different possibility.  He said that (a) Daikin, Mitsubishi and Panasonic were high-range, and Atlantic only mid-range; (b) Panasonic was too focused on performance without improving noise levels - not great for my case - and Mitsubishi was hard to order and find parts for in France; Daikin, he said, is a world leader; it would be wise to spend a bit more on a Daikin; (c) since I do have a small garage and no intention of having a car, it would make more sense to have a hot-water tank with its own heat-pump ("thermodynamique") in the garage, feeding off the ambient heat in the garage. The internal unit of the main heat pump could go in the garage or in the cabinet of sorts we'd reserved for it (I pointed out having a machine in a place where the heat it inevitably produced would contribute to heating the place might be a good idea; besides, the garage will be my bike shed and storage space, so I can't take infinite space from it). He pointed out that an advantage of having the hot-water tank be separate is that the main heat-pump fan in the courtyard would not bother the neighbors during the summer, when their windows are open. (I'd still want to run it to provide a bit of cooling; I wonder whether it modulates nicely?)

 

As you can see, there are really two different issues here.

 

a. Daikin vs Atlantic (vs Mitsubishi)

 

Do people agree with the general "Daikin is better than Atlantic" vibe? There are threads online supporting this, but they are from 2015 and before. The technical specifications of the Atlantic Alféa Extensa DUO A.I. 10 R32 unit seem to match very closely those of Daikin or Mitsubishi products. In fact, the Daikin 11kW device Company B proposes would produce 64dB, and those additional 2dB give me pause (they could put me above the regulation limits - and I had told the nice people at the coop I would get either Saunier-Duval (60dB) or something equivalent; 4dB is already a clearly perceptible difference). So, on the key parameter, courtyard noise, Atlantic seems to have an edge. 

 

(Is produced sound pressure what I should be looking at? All companies also give optimistic estimates of how loud the heat pump will be at 5m; it always seems to be 40dB.)

 

b. Integrated hot-water unit or independent water heater with its own heat-pump

 

Company B proposes: 

CHAUFFE-EAU THERMODYNAMIQUE THALEOS - PERFORMER 2 - 200L      (for ca. 2k EUR)

- Capacity : 200l
- COP at 7°C : 2,78 
- RENDEMENT ENERGETIQUE Eta wh : 116 %

 

Now, Atlantic itself produces "thermodynamic" water heaters (which, if I understand correctly, have their own tiny heat pump somewhere inside)

https://www.atlantic-comfort.com/Water-Heaters/Heat-pump-water-heaters/Explorer

 

It seems to be a very similar product (200L, COP at 7C of 2,8 (that's probably as cold as the garage will ever get; it will have a solid wooden door), etc.). For comparison, the heat-pump has a domestic-hot-water COP of 3,1 (at what outside temperature, I do not know).

 

It will produce a non-trivial amount of noise (the technical documentation says 53dB both for Thaleos and for Atlantic, and Thaleos specifies it was measured 2m away - this sounds  about as noisy as the external unit) - we would have to insulate the ceiling of the garage very well (it's just under my library/dining room/music room).

It would also inevitably cool the garage, just not very much (neither product absorbs more than 700W from ambient air).

 

My summary:

- it is something that would be interesting mainly to minimize sonic annoyance to the neighbors in summer, at the possible cost of causing year-round sonic disturbances for me.

- since its heat pump is at a much smaller scale than the main heat pump, this wouldn't create some cold-vortex effect in the garage that I'd have to worry about.

 

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An old drawing of my architect's, showing what things would more or less look like if I got a separate hot-water heater and installed the PAC internal unit in the garage as well (ignore the garage door drawing - we are getting a solid wooden door).

 

What is your take and your verdict?

 

 

 

 

 

 

 

 

 

 

 

 

[Garald]

(I'm still trying to figure out what the "thermodynamic" water heater would be feeding off. We will have PIV, so it wouldn't be feeding off the PIV. Ambient temperature in the garage - well, there's no reason to have a warm garage, but wouldn't the garage eventually become so cold that the water heater would become inefficient, unless it is drawing heat from the rest of the house - which it will do, but really slowly (since we are insulating, obviously) so that the garage would become colder until the temperature difference with the house is large enough that it is sucking heat from the house rapidly enough? In the end, the architect's original drawing made more sense, in that there would have been a flow of air from the outside, and so the garage would never have got colder than the outside world.

 

700W is not so little: it's like a fairly large negative radiator. I wonder why anybody would ever have one of these devices running in a heated room.

 

Also, is the installer's legit about noises in summer legit? You'd think the heat-pump would then be extremely efficient, and, being a contemporary heat pump, would modulate down far enough that it would be very quiet. Or am I too much of an optimist?)

[Garald]

Another self-comment:

 

Why aren't there arrangements where the hot-water heater takes hot water produced by the main, central-heating heat-pump during the winter, and heats water using heat extracted from the ambient temperature (outside or, even better, inside) during the summer? 

[Iceverge]

The stand alone water heater with an inbuilt heat pump makes sense where you have heat to spare, like a freely fueled wood burning stove or summer time. 

 

They're harder to justify if you use them in winter because as you've noted they steal heat from inside the property. Unless this heat is being replaced cheaply like with another heat pump they'll be inefficient to run. 

 

If you had switchable ducting they could be used to cool the inside of the house in summer like you note. I've not seen it done however. 

 

My mate who installs heat pumps reckons Daikin and Hitachi are the berries by the way. 

[Garald]

1 hour ago, Iceverge said:

They're harder to justify if you use them in winter because as you've noted they steal heat from inside the property. Unless this heat is being replaced cheaply like with another heat pump they'll be inefficient to run. 

 

Well, of course I'll have another heat pump running, but it makes much more sense to let it produce DHW directly! 

 

1 hour ago, Iceverge said:

 

If you had switchable ducting they could be used to cool the inside of the house in summer like you note. I've not seen it done however. 

 

Right. Somebody ought to get clever about it and market it.

 

1 hour ago, Iceverge said:

 

My mate who installs heat pumps reckons Daikin and Hitachi are the berries by the way. 

 

Not poison berries I hope? Is Atlantic known in the UK at all? (It's a French company.) Hitachi Yutaki seem to have a good quality/price ratio, but the external unit is too noisy for my purpose (67dB for the 8kW model - similar to Panasonic, also a good brand that is unfortunately not a silence leader).

Edited January 31, 2023 by Garald

[Garald]

What I am getting is that, if V₀ is the outside temperature and V₁ is the inside temperature, and V₀ + c (V₁-V₀) is what the temperature of the garage would be without the fancy water heater, then, once you install the water heater, a proportion c of the heat extracted by the fancy water heater from the garage is being sucked from the house. 

 

That is: if it would be 10 C in the garage when it's 0 C outside and 20 C indoors, then half of the heat "gained" by the water heater is being stolen from the house;

if it would be 15 C in the garage when it's 0 C outside and 20 C indoors, then three-fourths is being stolen from the house;

if it would be 5 C in the garage when it's 0 C outside and 20 C, then only one-fourth would be stolen from the house - but then it will certainly be colder than 5 C in the garage once you install the fancy water heater, meaning it will most likely stop working in fancy mode, and it will just become an old-fashioned electric water heater.

 

Yes, I'm using the letter V for temperature because I drew an electric diagram :). 

[Garald]

(This is a fun physics test - I think I'll use it to help me decide between installers.)

[saveasteading]

11 hours ago, Garald said:

wouldn't the garage eventually become so cold that the water heater would become inefficient, 

Not "eventually" but very quickly. The air flow is high and the garage would very soon become cold (or hot) from chucking out the waste warm, (or cold), air.  It would soon be very inefficient. 

 

The installers should know this and i would be concerned if they suggested or agreed to do this.

[Garald]

21 minutes ago, saveasteading said:

The installers should know this and i would be concerned if they suggested or agreed to do this.

 

Right, exactly. In defense of the second installer (who suggested this), the current garage door is a conventional metal garage door with holes in it, and he saw that; however, I explained that it would be replaced by a solid wooden door.

I wish the first installer could at least agree that we are right, instead of offering "we will do it for 1000 eur more"!

 

 

23 minutes ago, saveasteading said:

Not "eventually" but very quickly.

 

I meant "eventually" in the sense of "let us assume we have reached a stable state..." (i.e., I was being agnostic as to whether it would take a second or a day).

[RichardL]

@Garald Did you come to a conclusion re the integrated cylinder heat pump efficiency vs the space heating A2W heat pump?
Given the same air input (outside air)

If the efficiency is equivalent - separating the processes has some merit.

Edited February 5, 2023 by RichardL

[Garald]

The specifications of the Atlantic Calypso (the better water-heater he is now proposing, ducted to outside air) are not bad, but a bit below those of the main Mitsubishi heat-pump used as a water heater.

 

Atlantic Calypso:

COP at 7 C = 3.18

When it's -5C or less outside, it stops heat-pumping and becomes purely a classic electric water-heater. (As I said, it's a good product; most water heaters of this sort stop heat-pumping well above -5C - I read somewhere that 5C is more typical.) It can of course do plenty of "classic" (resistance) water heating above that temperature - it never pumps more than 650W, and can produce up to 1800W by resistance. 

 

Mitsubishi:

COP at 7C (for DHW, not heating - I take the difference is the temperature required): 3.41

The technical information claims the Mitsubishi works even when it's -28C outside (note: it's never even close to that cold in Paris!), though of course I imagine the COP is terrible then.

Still, it still does a great deal of its heat production by heat-pumping at -7C (for heating the house, and presumably also for producing DHW). 

 

2 hours ago, RichardL said:

If the efficiency is equivalent - separating the processes has some merit.

 

I get his argument for the summer - not annoying their neighbors on those few days when it's quite hot and they may have their windows open. (My thought: one could even install a switch in the ducting so as to take input from somewhere inside the house during the summer, so as to cool it, no?) What would be the arguments for separating the processes during the winter be? Are they strong enough to justify the somewhat lower efficiency?

 

(I was also worried about the noise produced by the boiler - but if it really produces 50 dB(A) and no more (and it's not some sort of measurement taken 1 meter away or what have you) then it's something we should be able to deal with when we insulate the garage's ceiling. We've added a solid brick wall to the side wall separating us from the GP next door - hopefully that will be enough to protect him.)

[SteamyTea]

There was a craze I  the UK for 'thermodynamic' heat pumps about 12 years ago.

They seemed to be just modified fridges.

Have you got a picture of the ones you are looking at?

[RichardL]

Re Possible advantages to split space heating from hot water:

I have'nt done the in depth maths on this - just thinking out loud.
 

1. Install phasing - no need to rip out (or upgrade later due to failure) an entire system - just smaller focused components.
 

2. Hot water siting - no longer constrained for the boiler hot feed to heat the tank since the pump is built in. (or Air source trunking lines)

3. Reliability? - questionable since its more components but are they simpler and focused on their core use?  
Perhaps more robustness of system overall since hopefully nothing fails at the same time?

4. Cooling output - if you can get at it - I'd love to route this to my conservatory in the summer for a 'free' byproduct cool air stream, or even the other way might be more efficient - to draw the air from the conservatory -  Current MO is the conservatory to house door left open in the spring/autumn for free heat during the day - low tech - manual - but works.

 

Hopefully too there is some saving by not forcing the space heating heat-pump to produce 50? ish degree water for the hot water tank every day & it can focus on cooler water for heating -or- if A2A there is no warm/hot water anyway.

 

Plainly makes a difference re retro fit vs. new build in terms of flexibility to plan component location.

[Garald]

6 minutes ago, RichardL said:

1. Install phasing - no need to rip out (or upgrade later due to failure) an entire system - just smaller focused components.
 

 

Please educate me. What do you mean by "phasing" here?

 

6 minutes ago, RichardL said:

2. Hot water siting - no longer constrained for the boiler hot feed to heat the tank since the pump is built in. (or Air source trunking lines)

 

Again, not sure what "siting" means here.

 

6 minutes ago, RichardL said:

3. Reliability? - questionable since its more components but are they simpler and focused on their core use?  
Perhaps more robustness of system overall since hopefully nothing fails at the same time?
 

 

Right.

 

6 minutes ago, RichardL said:

4. Cooling output - if you can get at it - I'd love to route this to my conservatory in the summer for a 'free' byproduct cool air stream, or even the other way might be more efficient - to draw the air from the conservatory -  Current MO is the conservatory to house door left open in the spring/autumn for free heat during the day - low tech - manual - but works.

 

Yes, I'll get it - through the Aquarea Hydro'R system (which hopefully is compatible with non-Panasonic reversible heat-pumps, though who knows - maybe there's an odd bit of plumbing to be done). It's a modest 1kW, though. (Water goes around the PIV - hot water during winter, cold water during summer.) For comparison, the water heater can extract up to 650W from ambient air. Of course I don't want it to do that during most of the year, but wouldn't it be nice during the summer? Now, doing it in the garage - or the ground floor in general, though perhaps it would make some sense in the downstairs bedroom/studio - doesn't make much sense, but, if we could do it in the attic... but it's too late for that.

 

6 minutes ago, RichardL said:

Hopefully too there is some saving by not forcing the space heating heat-pump to produce 50? ish degree water for the hot water tank every day & it can focus on cooler water for heating -or- if A2A there is no warm/hot water anyway.

 

Plainly makes a difference re retro fit vs. new build in terms of flexibility to plan component location.

 

Right, this is a retrofit - which is running very late. If we had known everything from the start, we might have decided to try out the arrangement sketched above in the attic. That's also what we could do in the future (5-10 years) if I ever have money again and decide to raise the roof.

[RichardL]

Phasing - if on a retrofit - removing the main boiler which does space heating and hot water.
Not having to replace it all in one go - Phase 1 might be for space heating,  Phase II the hot water including removing the old boiler?

Siting/location - not be constrained where the hot water feed from the boiler is because the combined system just needs electric.
If the hot water tank only needs power and a cold feed it has more options - closer to the bathroom than the boiler for example - a loft space - a cupboard in the end of the bathroom.
 

[Garald]

9 hours ago, RichardL said:

Siting/location - not be constrained where the hot water feed from the boiler is because the combined system just needs electric.
If the hot water tank only needs power and a cold feed it has more options - closer to the bathroom than the boiler for example - a loft space - a cupboard in the end of the bathroom.
 

 

Right. Is it possible to have the heat-pump in the ground-floor and the water heater (with its own heat-pump, and ducting that enabled it to feed off both outside air and inside air, at will) in the attic? My naive take is that, in the summer, we could just let it feed on ambient air and thus cool the attic, which I would expect to get hot (by convection; we also have skylights, but they have outside shades, so they should be OK). Of course that may be too major a change by this stage.