Lets expand this a little; I am considering if it worth putting in double the number of 45m UFH loops then a standard design with 90m loops.
Each additional loop cost about £25 as the total required pipe length is the same. Having shorter loops reduces the pump power required for any given flow rate.
So you would have two 45 m loops in parallel instead of one long 90 m loop (i.e. two 45m loops in series?
Let’s think about this. What needs to be kept fixed here is the total heating power, which is given by \dot m \Delta T. Your total flow rate is the same in both scenarios. In parallel mode, each loop gets half the total flow rate, and each loop is half as long. So the \Delta T of each of the individual loops will be the same as the big loop. At the same time, with half the flow rate and half the head loss due to length, each loop will require 1/4 of the long loop pump power, i.e. 1/2 power in total. That makes sense, you essentially doubled the available pipe crossection.
At 25£/loop it seems like a no-brainer from a financial standpoint. You basically only need a bigger UFH manifold, right?
It makes sense completely independent of what the optimum flow rate is, as you would have lower power requirements for every flow rate.
I cannot see any downsides to it besides a slightly increased system complexity. There might also be some practical issues with how the loops are being laid, but I have no experience there.
Thanks that was my thinking. (Cost would be more for each addation port if using activators to zone all loops.)
Is there a minimal required presure lose for the water pump in any make of heatpump?
I also don’t understand why most people design for a single manifold when I can use 3 to get easier pipe layout. With each manifold connected back in 32mm PERT-AL-PERT to the common point. (Total Heatlose under 10kw.) Having many manifolds add little cost when they don’t have pumps and mixers.
Hm, I really doubt it. The heat pumps also work to heat DHW, and the DHW coils are significantly shorter and hence have lower pressure drop.
Thanks, so a minimal dt is not required.