Hydraulic split or not?

[Benpointer]

Looking for some more advice please guys.  

 

I am looking at a 7kW Panasonic Aquarea L series but finding their literature less than clear.  https://www.aircon.panasonic.eu/MT_en/model/kit-wc07l3e5-wh-sdc0509l3e5-wh-wdg07le5-kit-wc07l6e5-wh-sdc0509l6e5-wh-wdg07le5/

 

These units seem to be 'hydraulic split'.  Presumably that means the refrigerant (R290 - aka butane?) passes through the wall and the part of the heat pump that releases heat sits inside the house (a plant room in our case).  Does that mean noisy machinery inside the house?   Is having R290 inside a timber house a great idea?

 

Also what is Bi-bloc versus, presumably Mono-bloc?

 

Sorry for the dumb questions - I seem to be having a bit of a Mental-bloc.

 

Thanks for any help.

 

 

[JohnMo]

5 minutes ago, Benpointer said:

hydraulic split

No hydraulically split is water split. You have an external monobloc (with some parts such as pump moved inside) that only works with the internal unit.

 

I would do a proper monobloc (everything outside) and third party cylinder. 

 

Have you sized heat demand at 7kW? I have a 6kW and it's twice the size I need.

 

 

[sharpener]

21 minutes ago, Benpointer said:

These units seem to be 'hydraulic split'.  Presumably that means the refrigerant (R290 - aka butane?) passes through the wall and the part of the heat pump that releases heat sits inside the house (a plant room in our case).  Does that mean noisy machinery inside the house?   Is having R290 inside a timber house a great idea?

 

R290 is propane but the quantity is relatively small (960g) so even if it is inside the house (not clear from a quick read) the danger will be much less than an unlimited supply of natural gas. The compressor will be in the outdoor unit either way so not a problem.

[G and J]

1 hour ago, Benpointer said:

Also what is Bi-bloc versus, presumably Mono-bloc?

Bi bloc is a unit that sits inside the house.  It connects via a refrigerant circuit to the compressor which sits outside.  The two units make up the heat pump. (A split unit I think it’s referred to as). 
 

Put both units in your garden on the same concrete plinth and you have the equivalent of a monobloc. 
 

Split units are good at handling larger distances from the house to the heat pump. But they cost more partly I believe as you need an fgas installer. 
 

Are you looking at siting your heat pump a long way away from the house?

[Iceverge]

Long distances = split unit. 

 

Everything else = mono block. 

 

 

Tbh Even with a long distance I would be tempted use a monoblock and extra and well insulated pipes. They're just so much simpler to replace and far less chance of chasing down a gas leak. 

[JohnMo]

8 hours ago, G and J said:

Bi bloc is a unit that sits inside the house.  It connects via a refrigerant circuit to the compressor which sits outside.  The two units make up the heat pump. (A split unit I think it’s referred to as

Not quite correct. A bi bloc is water split, not refrigerant split. A split unit is refrigerant split.

 

This is the internal unit. It has water connections to outdoor unit - not refrigerant. It contains water filter, water pump, expansion vessel and the control system for the whole unit.

 

[Benpointer]

10 hours ago, JohnMo said:

No hydraulically split is water split. You have an external monobloc (with some parts such as pump moved inside) that only works with the internal unit.

 

I would do a proper monobloc (everything outside) and third party cylinder. 

 

Have you sized heat demand at 7kW? I have a 6kW and it's twice the size I need.

 

 

Thanks, I've sized the heat demand using Heatpunk at 5.3kW so a 5kW is not technically quite big enough.  

 

But you've got me thinking:  You sized at 6kW and it's twice what you need... so this sizing business is not necessarily that accurate.  I might be sizing too high, I might be sizing too low.  How would I know? 

 

Overall, I'd prepare to pay for a bigger pump and  some over-capacity than risk having a cold house during the next 'Beast from the East'. I am told by the guy that's going to do my MCS certification that these Panasonic units modulate down efficiently.

[Benpointer]

1 hour ago, JohnMo said:

Not quite correct. A bi bloc is water split, not refrigerant split. A split unit is refrigerant split.

 

This is the internal unit. It has water connections to outdoor unit - not refrigerant. It contains water filter, water pump, expansion vessel and the control system for the whole unit.

 

Are those diagrams the Aquarea L series or just illustrative of similar ASHPs?

Edited Thursday at 08:19 by Benpointer
Typo

[Nick Laslett]

@Benpointer, my understanding with the new ‘K’ and ‘L’ ranges is Panasonic doesn’t have a simple monobloc option anymore. You would need the ‘J’ range for the traditional monobloc installation. With the ‘K’ & ‘L’ ranges they come in a kit with an additional indoor component.

[G and J]

1 hour ago, JohnMo said:

Not quite correct. A bi bloc is water split, not refrigerant split. A split unit is refrigerant split.

 

This is the internal unit. It has water connections to outdoor unit - not refrigerant. It contains water filter, water pump, expansion vessel and the control system for the whole unit.

 

I didn’t realise that some spilt units connected hydraulically.  I’ve been looking at the Panasonic Aquarea split units and they connect by refrigerant.   Every day is a school day.  

[sharpener]

1 hour ago, JohnMo said:

This is the internal unit. It has water connections to outdoor unit - not refrigerant. It contains water filter, water pump, expansion vessel and the control system for the whole unit.

 

Don't know about Panasonic specifically, but in general it would seem you pay a lot for the convenience of having these components packaged in a glossy white unit to sit alongside your kitchen cupboards like a boiler.

[JohnMo]

13 minutes ago, G and J said:

Panasonic Aquarea

The L series are a bi bloc, so  hydraulic (water) split. As per last post.

 

2 minutes ago, sharpener said:

 

Don't know about Panasonic specifically, but in general it would seem you pay a lot for the convenience of having these components packaged in a glossy white unit to sit alongside your kitchen cupboards like a boiler.

While deleting storage space. Don't know you would want anything inside when it happily sits outside. I would just choose a simple monobloc every day. We have our heat pump a good distance from the house and it doesn't seem to suffer much by it.

[JohnMo]

46 minutes ago, Benpointer said:

Are those diagrams the Aquarea L series or just illustrative of similar ASHPs?

From the installer manual for the Panasonic L series.

[JohnMo]

49 minutes ago, Benpointer said:

But you've got me thinking:  You sized at 6kW and it's twice what you need... so this sizing business is not necessarily that accurate.  I might be sizing too high, I might be sizing too low.  How would I know?

I didn't size at 6kW I bought it because it was super cheap and really only for cooling (now does everything). It does the job with all UFH, no buffer or volumiser needed to stop short cycling. Can batch charge on cheap rate, really well. But doing WC it would get a better CoP is it could modulate down further but it's ok. Its way more important to try to find the minimum modulation kW at 7 degs rather than ultimate max kW.

 

The new mitsubishi 8kW (only that model), is really two heat pumps in one case. There is a fixed speed 2kW and an inverter driven 6kW heat pump in series. So will output a constant range between 2kW and 8kW. These seems to tick quite a few good boxes. Good modulation for WC, plenty of power for DHW and plenty of power for using cheap rate electric. Not sure if it ticks the cooling box?

 

On the Panasonic front I would be more tempted to go J series (proper monobloc as @Nick Laslett says) they are cheaper, have good control algorithm, modulate well, very quiet. Think it's @Nickfromwales go to heat pump.