In-slab UFH layout and suitable ASHP?

[JohnMo]

1 hour ago, garrymartin said:

I've read this correctly, that's a 175mm slab with two sets of mesh reinforcement

We're at 200mm concrete below the insulation with 2x rebar, then I put 100mm fibre reinforced over the insulation. Plus there are reinforced strip foundations under that.  But we are a sand hill side.

[saveasteading]

I hate waste.

50mm of concrete and a layer of mesh is costing you about £20 /m2, maybe more when all is considered, and then margins.

 

I don't see any harm in asking your SE if it can be reduced because it will cost you whatever .... £5k?

 

A good SE welcomes feedback.

[zzPaulzz]

I finally found a local Heat Geek to take a look at my requirements.  His feedback was: maybe use a 5kW ASHP to avoid being capped for DHW on colder days; use a design temp of -3º external and 21º internal; use a spiral pattern to avoid pressure losses caused by excessive bends.  Apart from the last one, you guys called it first  I'm now waiting for him to quote for me for the design and install. Feeling much more confident.  Thanks!

[saveasteading]

@zzPaulzz it could be that your se has simply taken the thickness off a drawing by others. It happens a lot in linear design, with no feedback in the design chain.

Then it reaches the contractor who costs it, and client who maybe questions it, but usually accepts it.

[G and J]

15 minutes ago, saveasteading said:

@zzPaulzz it could be that your se has simply taken the thickness off a drawing by others. It happens a lot in linear design, with no feedback in the design chain.

Then it reaches the contractor who costs it, and client who maybe questions it, but usually accepts it.

We could easily have fallen into that rut.

 

However, I think I’m the other extreme.  I'm too willing to stop, retrace, refine, improve, etc.   That spills over into knob polishing very easily.   But as a founder member of Obsessives Anonymous….

 

(@zzPaulzz - please can I see the alternative spiral pattern when you have it.)

[zzPaulzz]

3 minutes ago, G and J said:

We could easily have fallen into that rut.

 

However, I think I’m the other extreme.  I'm too willing to stop, retrace, refine, improve, etc.   That spills over into knob polishing very easily.   But as a founder member of Obsessives Anonymous….

 

(@zzPaulzz - please can I see the alternative spiral pattern when you have it.)

I'm with you @G and J - I think I've driven my architect mad with all my revisions. I'm sure they'll have PTSD by the end of this process. 

Will share what he comes up with, though I hope he meant 'counterflow spiral'. 

[saveasteading]

4 hours ago, G and J said:

I'm too willing to stop, retrace, refine, improve, etc.

 

4 hours ago, zzPaulzz said:

I think I've driven my architect mad with all my revisions.

It's good for them to learn about building from real people. 

[Nickfromwales]

4 hours ago, G and J said:

please can I see the alternative spiral pattern when you have it

Reverse / inverted / snail, all called different things by different folk, just where the pipe isn't serpentine; eg it's not just simple up / down / up / down runs with 180^o loops at each end. This is easy to implement when pipes are at 150-200mm oc, but at 100mm it's nigh-on impossible to do anything other than inverted.

 

 

 

[marshian]

19 hours ago, Nickfromwales said:

Reverse / inverted / snail, all called different things by different folk, just where the pipe isn't serpentine; eg it's not just simple up / down / up / down runs with 180^o loops at each end. This is easy to implement when pipes are at 150-200mm oc, but at 100mm it's nigh-on impossible to do anything other than inverted.

 

 

 

 

That just makes my eyes go weird!!!!

[Nickfromwales]

19 minutes ago, marshian said:

 

That just makes my eyes go weird!!!!

Makes your fecking knees hurt!!!!!