Fan Coil Units for use with a (cooling) ASHP

[NCXo82ike]

I'm early on looking into this cooling. Planning to cool UFH at ~15 and fancoils at 7-8, so running at 2 temperatures.

 

It looks like the Daikin Altherma 3 all-in-one can do bizone heating at different temperatures- so presumably could do bizone cooling too? This would avoid the need for a buffer.

Edited January 9 by NCXo82ike

[JohnMo]

55 minutes ago, NCXo82ike said:

I'm early on looking into this cooling. Planning to cool UFH at ~15 and fancoils at 7-8, so running at 2 temperatures.

 

It looks like the Daikin Altherma 3 all-in-one can do bizone heating at different temperatures- so presumably could do bizone cooling too? This would avoid the need for a buffer.

Fan coils may drive a buffer as they only hold a litre of water. Plus depending on which fan coil they may have a set or adjustable fan start thermostat, so as you heat pump cycles so will the fan coil fan on and off. So steady flow temps may be an advantage.

[Originaltwist]

Before you go spending a lot of time and effort could I point out my recent experience with a mini-split. I had assumed that the cooling effect would be like the heating but just the opposite way round. Not so, when heating the effect is very localised but when cooling the cold air sinks down and spills across the floors. So one little mini-split is cooling the whole of our ground floor.

[Norbert]

Given that the price of these FCUs are very similar to A2A heat pumps, why not have these instead? It may well be a simpler install.

[Duncan62]

Here we are approaching Summer again!

 

Please critique my thoughts on the install for a passive class house for cooling in the (increasingly?) hot summers.

• 4 upstairs bed rooms to be served
• 5kw heating/cooling air source heat pump (unsure of brand, suggestions?)
• Single larger FCU, 4 ducts, 1 output duct to each room
• Intake from upstairs hall

 

FCU: INNOVA Ducto Multi SLC+ 1000 - 7.2 kW

7kW is large, but the only option with 4 outputs, one for each bedroom

£1600 one unit, compares to £500 per unit if I had one in each room?

(plus, on the wall units are less attractive than big unit hidden in cupboard)

Manual: https://www.innovaenergie.com/site/assets/files/2792/n421040a_manuale_installazione_ducto_multi_en.pdf

Tech Spec: https://www.innovaenergie.com/site/assets/files/2792/scheda-tecnica-slc_multi_2022_-_en.pdf

 

Control: INNOVA EEA649II Smart Touch Wall Control Panel - Black

One per room. controls the fan speed.

FCU has one fan per output duct.

 

Ducting: Foam Ducting Ubbink 160mm

About £25/m.

Looking at plain plastic rigid pipe + insulating sleeve £20/m, so not worth the hassle?

 

Postage: Possibility of sending to Italian friends, unboxing and man in van service to bring to uk?

 

Heat Pump: How do I get the controls for the FCU to ask the HP to start making cold water to circulate?

 

 

well done all, a great amount of info in this thread.

Edited May 22 by Duncan62

[JohnMo]

7 minutes ago, Duncan62 said:

FCU: INNOVA Ducto Multi SLC+ 1000 - 7.2 kW

7kW

The link is in Italy, so subject to a chunk of import duty also, so make sure you factor that in, so no nasty surprises.

[JohnMo]

11 minutes ago, Duncan62 said:

Heat Pump: How do I get the controls for the FCU to ask the HP to start making cold water to circulate?

Simplistic you could just use a  normal thermostat that can switch to cooling. I like Computherm Q20RF. And let it say when you cool/heat and when you don't.

[Duncan62]

6 minutes ago, JohnMo said:

Simplistic you could just use a  normal thermostat that can switch to cooling. I like Computherm Q20RF. And let it say when you cool/heat and when you don't.

 

Instead of the room thermostats, or in parallel, as a "master" on/off so to speak

[JohnMo]

16 minutes ago, Duncan62 said:

 

Instead of the room thermostats, or in parallel, as a "master" on/off so to speak

Let the room thermostat say when you want cooling overall, it gives permission to start the heat pump but let the fan coil controller when actually cooling do the room temperature control.  The fan coil will have a thermistor measuring water flow temperature and the fans will not start if the water in the heat exchanger is too warm. So when you don't want cooling set the thermostat to say 26, when you want cooling set it to 20. Then on a cool wet day like today, the cooling stays off.

[Dave Jones]

9 hours ago, Duncan62 said:

 

 

Heat Pump: How do I get the controls for the FCU to ask the HP to start making cold water to circulate?

 

 

 

 

It's the other way round.

 

We have this exact setup working at the moment with 7 fancoils and UFH coil.

 

We have the ASHP setup (we use Home Assistant to automate everything) to provide cooling 2c above the current dewpoint running 24x7. Dont need it for DHW as eddi and solar more than takes care of that. 

 

The fancoils (panansonic) can individually be turned on and off. Thy are just dumb radiuators at the end of the day all your controlling is a fan.

 

Commissioning the Zehnder unit the weekend which has the intake cooling/heating battery also in the ASHP loop so will see how that assists as well.

 

 

[NCXo82ike]

21 minutes ago, Dave Jones said:

 

It's the other way round.

 

We have this exact setup working at the moment with 7 fancoils and UFH coil.

 

We have the ASHP setup (we use Home Assistant to automate everything) to provide cooling 2c above the current dewpoint running 24x7. Dont need it for DHW as eddi and solar more than takes care of that. 

 

The fancoils (panansonic) can individually be turned on and off. Thy are just dumb radiuators at the end of the day all your controlling is a fan.

 

Commissioning the Zehnder unit the weekend which has the intake cooling/heating battery also in the ASHP loop so will see how that assists as well.

 

 

Amazing. This is the essentially setup I want to go for. Loads of questions!

 

How much cooling performance do you get? How much additional cooling do you expect from the MVHR?

 

Any buffer in that system, or is there enough volume already?

 

What kind of flow temps are you typically running at with the dewpoint offset?

I wonder how much cooler you could run water to the fancoils (using insulated/vapour barrier pipe) if it weren't for the UFH, and the difference in cooling performance?

I believe the Panasonic ASHP can do two sides at different temperatures, so wondered about having loop A with a dewpoint offset for the UFH and then loop B at 7 degrees for the fancoils and MVHR 

[Duncan62]

1 hour ago, Dave Jones said:

 

It's the other way round.

 

We have this exact setup working at the moment with 7 fancoils and UFH coil.

 

We have the ASHP setup (we use Home Assistant to automate everything) to provide cooling 2c above the current dewpoint running 24x7. Dont need it for DHW as eddi and solar more than takes care of that. 

 

Interesting. So the fan coils run off a higher temp (~16) than they could (say ~7) and just run all the time.

 

Higher temp = better COP too. Probably offset the fact you run it all the time?

[JohnMo]

5 minutes ago, Duncan62 said:

COP too.

In cooling it's referred to as EER. But a 20 degree day flow at 7 it's about 5.1 while at 12 it's about 6.7. Quite a big jump.

[Dave Jones]

3 hours ago, NCXo82ike said:

Amazing. This is the essentially setup I want to go for. Loads of questions!

 

How much cooling performance do you get? How much additional cooling do you expect from the MVHR?

 

Any buffer in that system, or is there enough volume already?

 

What kind of flow temps are you typically running at with the dewpoint offset?

I wonder how much cooler you could run water to the fancoils (using insulated/vapour barrier pipe) if it weren't for the UFH, and the difference in cooling performance?

I believe the Panasonic ASHP can do two sides at different temperatures, so wondered about having loop A with a dewpoint offset for the UFH and then loop B at 7 degrees for the fancoils and MVHR 

 

Buffers kill efficiecny so no to that, have a LOT of ufh like 1.5km as its 100mm spaced which they tell me is more than enough so buffer not needed.

 

Just cooling the slab makes a massive difference downstairs, basically any solar accumulation is negated. We have big bifolds which catch the sun all day, the  floor would be very warm without it.

 

Here is home assistant app, it pulls the date direct from the aquaera heat pump.

 

The fancoils are not aircon by any means but cost virtually nothing to run as its only spinning a tiny fan through a plate heat exchanger. I left them on 24x7 with 16c flow and the bedrooms were very comfortable.

 

MVHR we commissioning tomorrow, not expecting anything from the heat battery really but anything helps right. More for winter use.

 

 

[NCXo82ike]

16 minutes ago, Dave Jones said:

 

Buffers kill efficiecny so no to that, have a LOT of ufh like 1.5km as its 100mm spaced which they tell me is more than enough so buffer not needed.

 

Just cooling the slab makes a massive difference downstairs, basically any solar accumulation is negated. We have big bifolds which catch the sun all day, the  floor would be very warm without it.

 

Here is home assistant app, it pulls the date direct from the aquaera heat pump.

 

The fancoils are not aircon by any means but cost virtually nothing to run as its only spinning a tiny fan through a plate heat exchanger. I left them on 24x7 with 16c flow and the bedrooms were very comfortable.

 

MVHR we commissioning tomorrow, not expecting anything from the heat battery really but anything helps right. More for winter use.

 

 

Thanks Dave, this is fantastic to see and very interesting.

 

What period is that cooling accumulated consumption over?

Or do you have a measure for how much heat you've been able to extract over a day? And could you share your approx. floor space?

Do you have data for your dew point in the summer? I presume when it's hotter, with incoming air being cooled as it passes through the MVHR, you'll have a high relative humidity and a higher dew point, so the flow temp to the underfloor heating will have to be substantially higher than the 13.3+2 celsius dew point offset above?

 

[garrymartin]

What FCUs are you using @Dave Jones? How have you installed them?

[joth]

14 hours ago, Duncan62 said:

FCU: INNOVA Ducto Multi SLC+ 1000 - 7.2 kW

7kW is large, but the only option with 4 outputs, one for each bedroom

 

 

Another alternative is a (large) FCU with custom 4-port manifold.  I've useed https://www.ductstore.co.uk/acatalog/4_Spigot_Plenum_Box.html a few times to make up bespoke plenum box.

You then need electric dampers on each outlet duct, and some logic to control the (single) shared fan speed plus the 4 dampers.

OR just run the whole lot together and do so manual balancing (e.g. using manual adjustable room outlet dampers) to get the whole lot running and a relatively balanced level, which would be the simplest overall control (single hot&cold room stat somewhere fairly central)

 

Note 7kW is probably not too large, as that'll rated at a fairly cold flow temp transmitting to fairly warm air (8C vs 25?).  For ASHP running closer to target room temp (e.g. 16C vs 22?) then delta-T is smaller so a larger heat exchanger and higher throughput fan will help compensate.

 

 

I used insulated flexible ducting: https://www.ventilationland.co.uk/en_GB/isodec-thermally-insulated-ventilation-hose/1142/ perhaps quicker to install but not as neat end result as your proposal.

 

 

[Dave Jones]

2 hours ago, garrymartin said:

What FCUs are you using @Dave Jones? How have you installed them?

 

these are what we are using 

 

https://www.bpcventilation.com/panasonic-fan-coil-unit

 

[Dave Jones]

2 hours ago, NCXo82ike said:

Thanks Dave, this is fantastic to see and very interesting.

 

What period is that cooling accumulated consumption over?

Or do you have a measure for how much heat you've been able to extract over a day? And could you share your approx. floor space?

Do you have data for your dew point in the summer? I presume when it's hotter, with incoming air being cooled as it passes through the MVHR, you'll have a high relative humidity and a higher dew point, so the flow temp to the underfloor heating will have to be substantially higher than the 13.3+2 celsius dew point offset above?

 

 

we have 220m2 slab, this is new build so no historical data!

[puntloos]

FWIW the above, smushing together pieces of tech from different makers together feels somewhat risky. Might work, might be a huge headache, and 'aircon' is a pretty proven and commodity tech nowadays so I would certainly explore getting an off-the-shelf solution. 

 

Also worth noting that for (my, mitsu M32 based) solution, the FCUs have a little more say in what to do, in particular they measure the input air temp and humidity and will scale the cooling based on that. 

[eniacs]

2 hours ago, Dave Jones said:

 

these are what we are using 

 

https://www.bpcventilation.com/panasonic-fan-coil-unit

 

 

Those are Innova units. Same as what i have but rebadged to panasonic. Lovely units, im very happy with mine.

[LA3222]

7 hours ago, joth said:

 

Another alternative is a (large) FCU with custom 4-port manifold.  I've useed https://www.ductstore.co.uk/acatalog/4_Spigot_Plenum_Box.html a few times to make up bespoke plenum box.

You then need electric dampers on each outlet duct, and some logic to control the (single) shared fan speed plus the 4 dampers.

OR just run the whole lot together and do so manual balancing (e.g. using manual adjustable room outlet dampers) to get the whole lot running and a relatively balanced level, which would be the simplest overall control (single hot&cold room stat somewhere fairly central)

 

Note 7kW is probably not too large, as that'll rated at a fairly cold flow temp transmitting to fairly warm air (8C vs 25?).  For ASHP running closer to target room temp (e.g. 16C vs 22?) then delta-T is smaller so a larger heat exchanger and higher throughput fan will help compensate.

 

 

I used insulated flexible ducting: https://www.ventilationland.co.uk/en_GB/isodec-thermally-insulated-ventilation-hose/1142/ perhaps quicker to install but not as neat end result as your proposal.

 

 

This looks exactly what I need, it will be interesting to see how you get on. I haven't the time to tackle this issue yet, hopefully by next summer!

[JoeBano]

I’ve managed to get hold some myson I-vector’s. Going to swap the out radiators upstairs for them. Don’t know what route I should go insulated pipe or get a dew point sensor for my heat pump. I really only wanted to use cooling when’s is 25c+, the sensor would be the cheapest and easiest route