Max heating loop / branch length

[RFw3Duwrd7Yu]

I'm optimising the heating loop a bit on our home as part of a larger renovation and wondering if I'm hitting any design limits on my system, or if this could be considered optimal. This will all be fed by a Nibe F2040-16 (16kw) air source heat pump.

The feed/return loop runs as a U shape (22mm in a mix of speedfit and copper) across ground floor and then back the other direction across the first floor, for a total of 20.5m. Feed / return on the loop is connected to 13 radiators total using 15mm speedfit. Most branches feed either 1-2 radiators in a single room or run via 22mm => 15mm manifolds with individual 15mm pipe runs off the manifold to each rad. The longest branch is about 5m.

The longest 15mm pipe run (5m) is at about 15m into the overall 22mm pipe run, but I could branch this off earlier in the loop with a bit more work. Should I try to optimise this a bit further by shortening any of the branches?

 

[ScottishGasMan]

It needs calculated. Properly. I'd be surprised if the 22mm was even big enough given the number of rads on the system, although they could be 13 tiny rads with a massively over specced heat pump.

 

[ScottishGasMan]

FYI even 28mm pipe will be pushing it on a 16kw heat pump if that's the actual heating load. 35mm would be more appropriate