I was wondering whether Hep2O is good for the flow at return pipes to UFH manifolds?

 

Originally I had a NuHeat design (feeds section below), but then swapped to WUNDA who didn't give a pipe spec for the manifold Flow an Return pipes. The design was also tweaked to be 3 manifolds. NuHeat said 35mm Copper for the higher flow pipes and 28mm Copper for the lower flow ones.

 

The highest flow rate in the design is 22.8 L/min in 35mm Copper. That makes for a flow velocity of 0.46m/s in the 35mm Copper pipe (32.6mm ID). The largest Hep2O pipe is 28mm OD and the flow velocity would be 0.94m/s (22.7mm ID).

 

NuHeat had a branched design though and I'm sure @Nickfromwales will advise 1-to-1 layout from the source (I'm learning). Then I'd only have a highest flow rate of 10.5L/min = 0.18 kg/s --> 0.45m/s pipe velocity.

 

At what sort of flow velocity do I have to worry about a pipe getting noisy? The house we are currently in has noisy heating pipes, so I definitely want to avoid that.

 

[Power check: f=22.8 L/min, dT=5C --> Q=0.38kg/s * 4.2kJ/kgK * 5K = 8kW. 11.2kW ASHP so may want a bit more flow or dT=7C]

Wunda did give a flow for their manifold designs and the highest was 20.3ltrs which I presume is 20.3 L/min, so about double NuHeat and back to the around 0.9m/s pipe velocity. but I think that's over based on the power check, unless we only heat downstairs.

 

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Always prefered plastic. If only because copper transmits heat much better then plastic! 

This paper has some interesting data on pipe flow noise.