Ashp, ufh and fancoils. Help!

[lizzieuk1]

So, I'm going round in circles trying to sort this out. It is seriously stressing my nerves! 

 

Plan was to have an ashp with ufh on gf then use fancoils on ff&sf so we can have top up heating & some Cooling if needed in warm summers.  Sounds simple but, No!

I'm still not sure we will need any extra heating upstairs (ICF build, aiming for very good air tightness etc etc) but too unsure to not put any in and would also like the option to cool if needed. 

 

The installer we've been working with is very comfortable with ashp and ufh, he is keen on the Panasonic aquarea as is a registered Panasonic supplier and thinks they will fit our scenario well.

Fair enough, I know they are more expensive than some but also reputed to be a good ashp and, Panasonic do make multi room fancoils which would go well with our design for ff&sf. 

 

However, he seems to be struggling to get a design solution for the fancoil units. I'm not sure why! 

His latest email has said that, having spoken to Oceanair (i contacted them to see if they could help and pointed him to them to see if he could get a design sorted as Panasonic werent being very helpful!) the response he's had is that they're not ideal for heat/cool as require a much larger power input for cooling, I've not got the detail on why yet but will once I speak to him.

 

Surely that's what fancoils do well??

Or, maybe its the ashp supply to them for cooling that's the issue as we have a heat loss of around 4kw for heating requirement 🤔

 

Can anyone please help me find someone who can offer a solution? I'm going round in circles here!

None of the options are cheap but if we're spending large amounts we want a really good system that does everything we need! 

 

Maybe we should get a separate A2A system for ff&sf to run aircon but seems nuts if we can use the ashp.

🤯😩

 

 

[SteamyTea]

Have you had room by room heat loss calculations done yet. That is the key part.

The reason that you may need a bigger cooling load is because of outside air temperatures.

In winter, most of the time, you will need a temperature difference of about 12°C (8°C outside, 20°C inside).

Summer it may be 15°C delta (30°C outside, 20°C inside, or lower the n bedrooms). You then have to add on the solar gain, which when the sun is lower in the sky, can still be 600W/m² through the windows.

 

It is possible to set up a UFH/FC system to run as one zone, with just the airflow through the fancoil units being modulated, though this may get noisy in the bedrooms.

 

The heat loss calculation is the important thing to get to grips with first, that will tell you what is needed.

[JohnMo]

Others will be along soon and tell you I don't know what I'm talking about. But having had UFH cooling for a few years plus a fan coil. I do have some actual experience.

 

I would look for simple install, fan coils will compensate for over sizing by varying it's fan speed down (good, less drafts, less noise etc). 

 

So size fan coils for heating and then actually install one size bigger ones to allow for cooling. Then operate the system as a single zone on a single flow temp in cooling (16-17 degs) and WC for heating. 

 

This may not be perfect, but will give you a comfortable house year round and good performance (CoP and EER).

[SimonD]

4 hours ago, lizzieuk1 said:

His latest email has said that, having spoken to Oceanair (i contacted them to see if they could help and pointed him to them to see if he could get a design sorted as Panasonic werent being very helpful!) the response he's had is that they're not ideal for heat/cool as require a much larger power input for cooling, I've not got the detail on why yet but will once I speak to him.

 

Surely that's what fancoils do well??

Or, maybe its the ashp supply to them for cooling that's the issue as we have a heat loss of around 4kw for heating requirement 🤔

 

Is it that Panasonic are not being helpful for him or for you? So far my experience of Panasonic tech (I'm a Panasonic pro installer too) has been very good, and when I needed an extra push for some assistance, my rep was amazing and followed through on all promises. So I'm a bit surprised to hear this. 

The problem is that we really need to know more details about the design issues and what they're referring to as much more power, which will depend on the design parameters too. 

[lizzieuk1]

17 hours ago, SteamyTea said:

Have you had room by room heat loss calculations done yet. That is the key part.

The reason that you may need a bigger cooling load is because of outside air temperatures.

In winter, most of the time, you will need a temperature difference of about 12°C (8°C outside, 20°C inside).

Summer it may be 15°C delta (30°C outside, 20°C inside, or lower the n bedrooms). You then have to add on the solar gain, which when the sun is lower in the sky, can still be 600W/m² through the windows.

 

It is possible to set up a UFH/FC system to run as one zone, with just the airflow through the fancoil units being modulated, though this may get noisy in the bedrooms.

 

The heat loss calculation is the important thing to get to grips with first, that will tell you what is needed.

I've only done the whole house calcs via Jeremy's spreadsheet.  

I will set to work with a room by room calc and see how the rooms compare.

Our part O was fine so no issues with overheating but, we'd like the option to cool anyway. 

[lizzieuk1]

17 hours ago, JohnMo said:

Others will be along soon and tell you I don't know what I'm talking about. But having had UFH cooling for a few years plus a fan coil. I do have some actual experience.

 

I would look for simple install, fan coils will compensate for over sizing by varying it's fan speed down (good, less drafts, less noise etc). 

 

So size fan coils for heating and then actually install one size bigger ones to allow for cooling. Then operate the system as a single zone on a single flow temp in cooling (16-17 degs) and WC for heating. 

 

This may not be perfect, but will give you a comfortable house year round and good performance (CoP and EER).

This sounds sensible, thanks JohnMo. The ashp will be set up for wc and we're going with a single zone for ufh in the gf. Not sure about the ff/sf though, the Aquarea allows 2 zones so we could keep the bedrooms a little cooler I guess, not sure it's needed though 🤷‍♀️

[Nickfromwales]

3 minutes ago, lizzieuk1 said:

I've only done the whole house calcs via Jeremy's spreadsheet.  

I will set to work with a room by room calc and see how the rooms compare.

Our part O was fine so no issues with overheating but, we'd like the option to cool anyway. 

Room by room is a bit pointless, imo, as the house will just do all it can to equalise the temps throughout.

 

Add MVHR in to the mix and it becomes even less important.

[lizzieuk1]

14 hours ago, SimonD said:

 

Is it that Panasonic are not being helpful for him or for you? So far my experience of Panasonic tech (I'm a Panasonic pro installer too) has been very good, and when I needed an extra push for some assistance, my rep was amazing and followed through on all promises. So I'm a bit surprised to hear this. 

The problem is that we really need to know more details about the design issues and what they're referring to as much more power, which will depend on the design parameters too. 

Thanks Simon. I've not had any contact with Panasonic, I've left that up to the person who doing the install - he seems to be struggling with a fan coil system design,  initially it was a spec for the ducting but now seems the more complex issue of whole design for pressure drops etc if we went for a multi room fancoil. 

I think we've almost ditched that option now as seems far too complex to sort out so, looking to do individual fcu in each room instead, obv more pipework needed but I guess it's swings and roundabouts compared to the multiroom option.

[SteamyTea]

1 minute ago, Nickfromwales said:

Room by room is a bit pointless, imo, as the house will just do all it can to equalise the temps throughout.

Eh

How does one size the thermal emitters without knowing what they need to cope with.

May as well go back to an open fire on an outside wall if RbR is of no relevance.

[lizzieuk1]

2 minutes ago, Nickfromwales said:

Room by room is a bit pointless, imo, as the house will just do all it can to equalise the temps throughout.

 

Add MVHR in to the mix and it becomes even less important.

It's a valid point Nick, I suppose there could be some short term variation room by room and, perhaps more so floor by floor with insulation between floors having an effect, but I guess overall the temps will balance fairly quickly with flow round the house via the mvhr anyway.

[SimonD]

7 hours ago, lizzieuk1 said:

I've only done the whole house calcs via Jeremy's spreadsheet.  

I will set to work with a room by room calc and see how the rooms compare.

 

Hang on, serious alarm bells going on here. What has your installer done? The installer cannot complete a proper system design without a full heat loss calculation. Whatever anyone else tries to tell you, you absolutely need a proper room-by-room heat loss calculation to inform your system design. To plug my own tool again - you, or your installer can produce a proper one to current standards for free at openheatloss.com

 

7 hours ago, Nickfromwales said:

Room by room is a bit pointless, imo, as the house will just do all it can to equalise the temps throughout.

 

Add MVHR in to the mix and it becomes even less important.

 

Not at all Nick, rooms will by their very nature have varied heat load requirements due to lots of things like exposed area, perimeter length/area ratio in floors, size and shape and they all need sizing according to their individual needs, otherwise you'll take a hit on system efficiency and comfort, even if you design for 21C across the whole house. 

[SBMS]

Hi lizzie

 

ive just gone through this process with Panasonic and our installer. I wanted the setup you are aiming for - UFH as zone 1 and fancoils upstairs on zone two. Everything I have read on the system points me to it being well designed and totally capable for what I want. The weak link was indeed Panasonic uk design. Eventually I got the contact details of the design team themselves and liaised directly with them. I don’t think many people in the uk use the two zone setup so it took a while to get the design so we all understood it. The benefit is that they produce the full hydraulic and electrical design (not that straightforward) AND then warranty it. So if anything is incorrect Panasonic pick up the tab. Your installer just follows it. 

the rep was useless and just tried to sell

me aircon.

 

The best thing to do is strongly suggest that the design team follow Panasonics own reference diagram which you can find in their main manual. Can forward if you need. 
 

The Panasonic control unit is fairly smart and supports multi zone by way of controlling a mechanical blending valve and water temperature sensor. In cooling mode this is what protects your UFH from running too cold. Return water is blended to mix up to a limiting temperature (say 16 degrees). Fancoils can run at 7 or 8 degrees which is what the buffer will be chilled to. You can even do the reverse in winter and have your zones on different temps if you want the fancoils running a bit hotter ( probably not necessary). All my pipework was lagged. In theory it should be as good as aircon. 
 

PM me if you want the email For the guy I spoke to at Panasonic. It’s a very capable well designed system though and only one I came across that natively controlled multiple zones, had the fcus from same manufacturer etc. and the tcap range is very impressive in the way it can maintain a constant output irrespective of environment temperature. 

[SBMS]

Panasonic will also do a heat loss calculation as part of their design so they can size the correct unit 

[lizzieuk1]

2 hours ago, SimonD said:

 

Hang on, serious alarm bells going on here. What has your installer done? The installer cannot complete a proper system design without a full heat loss calculation. Whatever anyone else tries to tell you, you absolutely need a proper room-by-room heat loss calculation to inform your system design. To plug my own tool again - you, or your installer can produce a proper one to current standards for free at openheatloss.com

 

 

Not at all Nick, rooms will by their very nature have varied heat load requirements due to lots of things like exposed area, perimeter length/area ratio in floors, size and shape and they all need sizing according to their individual needs, otherwise you'll take a hit on system efficiency and comfort, even if you design for 21C across the whole house. 

No need to panic! They are definitely going to do room by room calcs, all mcs certified.  We're just at the initial design phase so once everything is firmed up on that will proceed to final design with full calcs. 

I was reading about your program and it looks really good - once I get time I will have a go with it for our design and give any feedback I can.