Zehnder Q350 + ComfoPost CW12

[Nick Laslett]

14 hours ago, Dan F said:

@Nick Laslett I wouldn't do it again, instead I'd put fan coils in.   Compost for the whole house, or just the first floor?  What about easterly/westerly windows, any shading/overheads?

Thank you for advice. This is for the whole house. Only 2 small windows on the east, one small window on the south. 
 

My original design was to use the original version of the ComfoClime, the new model is too tall.  But I wasn’t aware of the ComfoPost at the time, this looks like a cheaper more effective way to add some cooling. 
 

So the choice is to do nothing or have the ComfoPost. I think I will plumb it through the UFH manifold as @PeterW suggested in this post. Based on this summer, the cooling demand did not seem to be too great, but hard too tell with so little data. 
 

 

[markharro]

hi no i ditched the comfopost idea in the end as didnt think it was going to be worthwhile

[Dan F]

On 17/11/2023 at 20:06, Dan F said:

@Nick Laslett I wouldn't do it again, instead I'd put fan coils in.   Compost for the whole house, or just the first floor?  What about easterly/westerly windows, any shading/overheads?

 

Did you see this post?  That summarizes all my findings I think..

 

[Great_scot_selfbuild]

@BartW Thanks for creating this thread - having read it now, I think I’ve saved myself a lot of work being led down the comfopost path by some M&E suppliers.

 

I’m becoming less trusting of the technical competence of some of the companies I’ve reached out to and am finding myself doing so much double-checking and calculations myself, I’m very interested in how you’ve gone about designing the UFH / ASHP / DHW system. I’ll be starting my search for tutorials and advice on how to go about this, but would welcome any advice you can offer?

[BartW]

Hi,

I used some basic calculators online like heat punk and rounded up.

 

UFH is fairly straightforward. You just lay pipes at 100 - 150 - 200 increments, and it is almost guaranteed to work. I know it sounds very ignorant, but it is that easy, knowing that you will never run the UFh at its full potential (if fraction of it).

 

ASHP is sized up, and I used 7kW AroThermPlus with the sleek looking all in one UniTower. 

 

Forget Comfo post.

[Nickfromwales]

41 minutes ago, BartW said:

Forget Comfo post.

Easily dismissed, but I accept the caution here.

 

If your MVHR is sucking in cold air over the winter, and you bought a half-decent MVHR unit, then the 1kw pulse-heater will be going most of the time. This uses direct electricity on demand.

 

If the ASHP is providing space heating regardless, then why would you not use that (very cost-effective) source of heat energy to off-set the cold incoming air temp?

[Nickfromwales]

For completeness, I wouldn't go for the Comfopost as it's a basic item in a very pretty box. Simple and effective options are out there, for far less money.

[JohnMo]

MVHR cooling is pretty ineffective due to limited flow rates. Heating is limited to about 10W/m², based on passivhaus air flow rates. Anymore more heat causes any dust particles to burn. To that with an ASHP isn't cost effective due to por CoP. So in real terms post heating with ASHP and MVHR flow rates isn't really likely to achieve 10W/m² either.

 

Best option keep your money in your pocket. We get -9 here, I haven't got any heaters in the MVHR, it's doesn't seem to suffer. Heating WC (weather compensation) curve is just set to compensate or those against WC your CH thermostat compensates automatically.

[Great_scot_selfbuild]

23 hours ago, BartW said:

UFH is fairly straightforward. You just lay pipes at 100 - 150 - 200 increments, and it is almost guaranteed to work. I know it sounds very ignorant, but it is that easy, knowing that you will never run the UFh at its full potential (if fraction of it).

Any recommended tools / method for the UFH layout/circuit designs?

[JohnMo]

9 hours ago, Great_scot_selfbuild said:

Any recommended tools / method for the UFH layout/circuit designs?

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