Fan Coil Units for use with a (cooling) ASHP

[joth]

58 minutes ago, joth said:

we'll set the zone 1 to a higher target temp so the fan coil should rarely come on.

Of course, I meant zone 2 (downstairs) to the higher target temp... ?

[arg]

Here's a few UK suppliers of fan coils that I've bookmarked when I came across them - I'm still not started on my build so haven't contacted any of them yet:

 

https://coolenergyshop.com/collections/radiators-fan-coils

 

https://www.biddle-air.co.uk/en/products/fan-coils/deco-fan-coil-unit

 

http://www.dunham-bush.co.uk/index.php/products/fan-coil-units/ocelot

 

First one has prices (£195+VAT) but no data of any sort; others have data but no prices....

[joth]

39 minutes ago, arg said:

Here's a few UK suppliers of fan coils that I've bookmarked when I came across them - I'm still not started on my build so haven't contacted any of them yet:

 

https://coolenergyshop.com/collections/radiators-fan-coils

 

https://www.biddle-air.co.uk/en/products/fan-coils/deco-fan-coil-unit

 

http://www.dunham-bush.co.uk/index.php/products/fan-coil-units/ocelot

 

First one has prices (£195+VAT) but no data of any sort; others have data but no prices....

 

You could also try contacting SystemAir and see if they can sell the Panasonic rebranded units direct in UK

 

https://shop.systemair.com/en/scc202plg2/p402066

Systemair Ltd

Unit 28, Gravelly Industrial Park, Birmingham, B24 8HZ, England
Tel: +44 (0) 121 322 0200
Fax: +44 (0) 121 322 0201
info@systemair.co.uk

 

[joth]

On 26/09/2020 at 11:01, joth said:

It has arrived! Although the box it arrived it was 90% destroyed, visual inspection it seems ok and mercifully the loose items in the box were still there. Next up will be an electrical and water (air??) leak test

 

 

 

 

€289.00 delivered from ShopClima, took about a month from order to on-site

 

 

 

 

Well 6 months on we finally got this working! I won't quite say commissioned yet, as we're still running the FTC6 in single zone for fan coil + ufh, but now the plumbing is all complete I can think about getting the control systems properly working. (I say plumbing is complete, there's still a broken flow sensor to replace)

Progress has been so slow with our MCS installer I actually got my main contractors plumber to help me debug the fan coil yesterday. The issue was obvious, looking at that photo above the red things in the threaded connectors are bungs. Kinda important you remove those before hooking it up, else no water ain't flowing anywhere. Would have been nice if the MIs has mentioned that!

 

Being in the loft, this is obviously the highest point in the system by quite some way, so bleeding the system has to happen here. It has manual air release vents but it'd be nice to have automatic ones (or a system fill point up there next to it) to allow single person system pressurisation. 

 

Anyway, bit of a faff but I think this is really going to pay off come summer. It's amazing how no one at all on our build has ever seen anything like it. Thanks RHI random restrictions. They're so common on the continent. Glad I read about it here. 

In a pinch a plinth heater would also have worked I think, but for cooling we'd have to DIY build a condensation tray and ensure it doesn't get into the electrics. 

Edited March 20, 2021 by joth

[Ommm]

Do you reckon the fan coil units would make sense over a separate air-to-air split unit?

 

I've been looking at an ASHP for heating, but we have a loft conversion which gets hot for about 6 months of the year.  Window gain and lack of thermal mass are issues (it's lightweight wood/plasterboard construction, and we can't really add masonry for structural reasons), but it just has a lot of external area and in summer the temperature can sit at 20+ all night so there's nowhere to drain the heat out to.  Being lightweight should hopefully mean it's quick to flush out with active cooling, and then added insulation (my current WiP) should help keep it cool, and more should reduce energy requirements.  The advantage of ASHP cooling is only a single external box, and not having a separate radiator and indoor A/C unit (space is a bit limited for both in the rooms).

 

I'd be looking at the radiator style fan coil units.  Plumbing into a separate ASHP zone would be feasible, and a condensate drain could be tapped through the loft into the existing soil stack (although I'd be worried about it freezing and backflow of sewer gases) or out of the soffit (backdrafts of cold air from outside?).  The single-panel radiators will likely need replacement for an ASHP anyway.

 

On the merit of the split unit, it's simple, ubiquitous in other countries, easy to fit, and the failure modes are well-known. I also can't work out how it plays with using the ASHP for hot water - supposing somebody has a shower and the tank needs refilling, does the ASHP cycle between pumping cold for the rooms and hot for the water? Does that kill performance? I suppose it's not a big problem when it's that hot - people might like a cold shower!  If you have an ASHP sized for heating a whole house (say 5-10kW) then would it be feasible to cool say 30m2 (obviously that rather depends on heat flux, but as a rule of thumb)?

 

But I'm also curious how well the air to water ASHP compares for cooling with an air to air A/C unit.  Is the A/C unit more efficient?

Edited April 16, 2021 by Ommm

[joth]

@Ommm you've thought through it well and not a lot for me to add! We installed it in March and it's now April (and a cold one at that) so I honestly can't say I can give any real world feedback on its cooling performance.

 

For us it was a choice between fan coil or nothing, and for the price (and apparent effort required) the fan coil was a no brainer. I'm sure a dedicated split air to air unit would outperform it and peak power, and is a better choice if you're doing an isolated retrofit and not doing ASHP already.

It's only for a few days a year, and when we have very cheap electricity from PV, so I didn't worry so much about efficiency as for the heating, but yeah I would expect the split unit to outperform it as less losses in pipework (that said, for us the pipework "losses" are in effect cooling the rest of the house so not all bad)

 

 

[ProDave]

I favour a FCU actually 2 of them one in each bedroom.  The ASHP can do cooling, it would just be some pipework, a motorised valve and an alteration to the controls.

 

If I went individual A2A AC units, it would be an extra unit outside and extra penetrations through the wall.

 

My gripe though has been why are Fan Coil Units so expensive?  They are just a heat exchanger and a fan in a pretty wall mounted box.  Not far off just the inside unit of an A2A AC unit.  So why typically does a FCU cost as much as a complete A2A AC unit?

[Nickfromwales]

On 20/03/2021 at 13:02, joth said:

Kinda important you remove those before hooking it up

A cheque for £50 and a 1st prize BH ribbon is winging its way to you in the post  

[joth]

31 minutes ago, ProDave said:

My gripe though has been why are Fan Coil Units so expensive?  They are just a heat exchanger and a fan in a pretty wall mounted box.  Not far off just the inside unit of an A2A AC unit.  So why typically does a FCU cost as much as a complete A2A AC unit?

Where can you buy a complete a/c unit for €289 inc VAT & delivery?

 

[Nickfromwales]

2 hours ago, joth said:

Where can you buy a complete a/c unit for €289 inc VAT & delivery?

 

Nowhere unless it’s pure chinesium. 
Can you post the link for that unit please? And what are the dimensions? TIA. 

[joth]

On 26/09/2020 at 20:26, joth said:

On 26/09/2020 at 20:14, tanneja said:

@joth have you got the direct link to the product to hand?

I ordered this one

https://www.shopclima.it/en/panasonic-paw-fc-d15-aquarea-compact-fan-coil-with-left-side-connection-1-5-kw.html

 

It's clearly just a systemair unit: https://shop.systemair.com/en/scc202plg2/p402066 

 (haven't worked out exactly which model number) - they didn't even bother reprinting the MI with Panasonic branding, says Systemair all over it

 

@Nickfromwales

Dimensions (LxHxD mm)	570x220x430

Edited April 17, 2021 by joth

[Nickfromwales]

Sorry. Too busy / lazy to scroll up. I’m trying to stop @pocster from going over the edge elsewhere. 
 

Appreciated. 

[willbish]

I am in the market for a fan coil unit, it must be ceiling mounted and will be installed in 300mm deep I-joist.

 

These 3 models fit the bill, 

 

Daikin FWC06BT

 

Aermec FLCI 32

 

Biddle CWC010

 

Does anyone have experience of either of these 3? 

 

Im tempted towards the Daikin but it has a condensate pump which I don't need and consider something else to go wrong 

The Aermec is Italian built and the control options seem unnecessarily complicated

Biddle is 40% dearer than the other two but I haven't shopped around.

 

 

Aermec FLCI.pdf biddle-cwc-brochure-a4-v5.pdf Daikin FWC-BT BF.PDF

[Ommm]

Having done some digging around, I find there are plenty of fan coil units on Alibaba in the $100-200 range:

https://www.alibaba.com/trade/search?IndexArea=product_en&CatId=&fsb=y&viewtype=&tab=&SearchScene=&SearchText=fan+coil+

They appear to be imported into the EU and rebranded as various local brands (found some in Greece, Bulgaria).

 

Of course the suppliers are in China so you need to pay shipping and import taxes (but shipping from Italy might not be a lot different - how much does a FCU weigh?), and the unit price for small volumes may be higher.

 

The main thing that's hard to judge is the quality. But a fan coil isn't that complicated, just a motor and some metalwork, so I wonder if it would be worth the risk?

Edited May 26, 2021 by Ommm

[MortarThePoint]

What flow temperature do people use to cool their UFH? I'd imagine wanting to use a higher temperature (to avoid condensation) than an air blower would need.

[joth]

On 22/07/2021 at 07:53, MortarThePoint said:

What flow temperature do people use to cool their UFH? I'd imagine wanting to use a higher temperature (to avoid condensation) than an air blower would need.

I'm using 15°C in the UFH and 8°C in the fancoil 

[Nickfromwales]

4 minutes ago, joth said:

I'm using 15°C in the UFH and 8°C in the fancoil 

Via a buffer to allow segregated supplies at varying temps?

[Dan F]

4 hours ago, Nickfromwales said:

Via a buffer to allow segregated supplies at varying temps?

I would assume so, how as would you do it?  That's what our setup will look like; approx 17C for UFH and 7C for Comfopost is what we had panned.

 

@joth Are these temperatures fixed in your setup or can you adjust them, based on for example the relative humidy?  I haven't got it set up just yet, but I was thinking it might be good (if not slightly unnnecesary maybe) to be able to adjust the UFH/ComfoPost temperatures based on RH and/or how much cooling is required.  You could then potentially adjust the ASHP set-point (between say 5C and 15C) based on the UFH/Comfopost temperatures and if ComfoPost is/isn't enabled.

 

Farily non-trivial, and probably won't initially commison it with this inteligence, but given the ComfoPost will be used rarely it would make sense from a COP standpoint to use a higher ASHP set-point when it's not in used.   I still need to explore exactly what the vaillant EEBUS interface does/doesn't support though, to understand how easier this would be.   The only disadvantage of this approach is that on enabling comfopost/fancoil, you'd have a delay before they are effective while the buffer is cooled to 5C.

 

 

[joth]

25 minutes ago, Dan F said:

5 hours ago, Nickfromwales said:

Via a buffer to allow segregated supplies at varying temps?

I would assume so, how as would you do it?  That's what our setup will look like; approx 17C for UFH and 7C for Comfopost is what we had panned.

 

@joth Are these temperatures fixed in your setup or can you adjust them, based on for example the relative humidy?  I

 

Yes this is ecodan with a small low loss header tank and electronic mixing valve, so I can freely run any temp on each zone down to 5°C

In retrospect I larger (100L+) buffer tank would have been worth it, as I'm using the fan coil cooling more than expected (see other thread on bedroom overheating) but it's only rated about 1kW cooling so the ashp short cycles a bit driving it alone without the UFH cooling load. Also the buffer could have been cooled during solar generation time and then discharged overnight. Maybe I'll do that another time.

 

The ecodan cloud API does allow for setting the flow temps so could do this automatically if I wanted I guess. I'm currently looking to use the API to configure heat vs cooling mode as needed. 

 

 

[Dan F]

23 minutes ago, joth said:

electronic mixing valve

 

What valves are you using and are these controlled from Ecodan wiring center or via Loxone?  Do these values take a temperature set-point or there is also a temperature sensor and the fancoild feed and an feedback loop used?

 

We have 25L buffer by the looks of it.

 

28 minutes ago, joth said:

The ecodan cloud API does allow for setting the flow temps so could do this automatically if I wanted I guess. I'm currently looking to use the API to configure heat vs cooling mode as needed.

 

That would be good, assuming it supported.  If the API allows for adjusting set-point as well you could have 4 modes:

- Cooling 5C           (UFH + fancoil)

- Cooling 15C         (UFH)

- Heating 30C         (UFH)

- Heating 40-55C   (UFH + fancoil)

 

[jack]

On 22/07/2021 at 07:53, MortarThePoint said:

What flow temperature do people use to cool their UFH? I'd imagine wanting to use a higher temperature (to avoid condensation) than an air blower would need.

 

15 degrees. Admittedly we have concrete floors, but when it's been on for a couple of days it's borderline uncomfortable spending too long walking around in bare feet. Very pleasant when you come in from the heat though!

 

I've never seen any beaded condensation at this temperature. The worst it gets is a breath of condensation on the metal UFH manifold. Nothing on the floors or other pipework.

[MortarThePoint]

This is cool, literally. If just looking to cool the floor, is it just a matter of having the right ASHP?

 

Sending 15C water through the UFH pipes feels pretty low risk from a condensation perspective. If concerned by condensation on the manifold, one can always run a separate dehumidifier nearby or perhaps just a fan blowing over their surface.

[joth]

6 hours ago, Dan F said:

What valves are you using and are these controlled from Ecodan wiring center or via Loxone?  Do these values take a temperature set-point or there is also a temperature sensor and the fancoild feed and an feedback loop used?

 

 

The mixing valve it the one the Welshman recommended on here a while back:

 

Esbe ARA662 actuator 230v 50hz 120 sec

 

https://www.wolseley.co.uk/product/esbe-ara662-actuator--230v-50hz-120-sec-(1)/

 

The Mitsubishi FTC6 controls it all, with thermistors on all the flow and return pipes plus in the uvc and buffer tank.

You just set a desired flow temp per zone and it does the right thing when the zone calls for heat. 

[puntloos]

On 23/07/2021 at 14:27, Dan F said:

 

What valves are you using and are these controlled from Ecodan wiring center or via Loxone?  Do these values take a temperature set-point or there is also a temperature sensor and the fancoild feed and an feedback loop used?

 

We have 25L buffer by the looks of it.

 

 

That would be good, assuming it supported.  If the API allows for adjusting set-point as well you could have 4 modes:

- Cooling 5C           (UFH + fancoil)

- Cooling 15C         (UFH)

- Heating 30C         (UFH)

- Heating 40-55C   (UFH + fancoil)

 

 

This sounds lovely but how would you be able to split some "15C" coolant(water?) into the UFH and 5C (coolant?) into the coils?

[dpmiller]

Series connection could do it, the return from the 5C circuit would be a bit warmer...