4-port or 2 x 3-port mixer?

[le-cerveau]

Whilst I deliberate over the tank design:

In my 1 tank design I have included a 4 port mixer from the TS :

The Lower part of the TS being around 40^oC the top being 60-80^oC (load dependant), however my UFH only requires around 23^oC, so the plan was to take it out of the store at around 30^oC and let the manifolds do the rest.  However a 4-port valve with actuator will mix some from the top some from the middle and some from the bottom (I think) to achieve the desired output utilising a valve like this:

This means that I am utilising high grade (expensive) heat when I don’t need to.

Would it be better to use 2 x 3-port mixers as follows:

The first mixer isolating the top (hot) part of the tank unless there is a drop in the lower part that needs boosting, then the second mixer doing the final blend with the bottom/return leg.

Would this be more efficient?

Also I could use thermos actuators (no electricity).

Potentially I could do away with the TMV’s on the manifolds if I put the second mixer to the desired temperature, but that is for another day.

Thoughts please.

Edited June 3, 2016 by le-cerveau
Pictures included

[Nickfromwales]

Does the dotted line denote the 'deemed' midway point or is it a tank in tank design you've looked at for this example ?

Going to look at your tank thread again to try and join the dots, but this is a very curved ball here as the first needs to be ascertained in order to arrive at this thread, does it not?

[le-cerveau]

Nick,

The dotted line is a stratifying plate, the example is an AKVATERM tank, it is not a tank in tank one, a Thermal Store.

Yes the 1/2 tank question is relevant, however the base question is relevant about 4 port vs 3 port mixers.