Hot Water recirculation system

[Rookie self builder]

Hi, anyone out there able to give me some advise on the above?
My heating engineer has fitted my pellet boiler and thermal store, and I am now left with the task of connecting it to my self installed UFH system and my DHW system.

The renovation project has 3 areas requiring DHW all at opposite ends of a 20m long barn. Therefore I had envisaged running three separate circuits from a manifold in the boiler room to ensure sufficient flow rate etc.. However, the heating engineer has recommended that I fit a DHW recirculation pump given the length of the pipe runs to save water and that it will be efficient and comfortable in the long term due to limited heat loss in the pipes which will be heavily insulated.

I have studied some system diagrams for the aforementioned principal but cannot see how this will work with separate flows from a single distributor/manifold using a single circulating pump.....am I being stupid? Is there a way to do it? I don't really want to have a 'ring' circuit if I can help it as I think that this will require an even larger diameter feed pipe to cover all three areas with sufficient flow.
Help please!

Cheers

 

[endecotp]

I guess that with a single pump, the challenge is getting suitably balanced flow rates to each of the three areas. Presumably you could fit valves in each of the return pipes and adjust them until the flow rates are acceptable. Would that work in practice? Maybe your heating engineer has more practical experience with this than some random bloke on the Internet!