Refrigerant piping concept

[MilosBog]

Hi all,
I would like to talk about concept of refrigerant piping..Lets talk about VRV/F. We have, for instance one compressor(condensing unit) and multiple evaporators. Now, when you would use the the headers and when T joints? And what is an advantage and what is a disadvantage? I have talked with guys from Daikin and they told me that they are avoiding Headers but without any explanation....

p.s. Can somebody delete the same post in refrigerant books..i wasn't looking so i have posted it there

[nike123]

T joints are not used in VRF piping.
You have either headers or Y joint.
What should be used depend on capacity index of connected indoor unit.
Best is use of design software which every VRF manufacture provide, or read carefully design manual of selected equipment.

[MilosBog]

Yap, i have called it T joints but they are Y...we call them here T joints.Last time when support from one of thos VRV/F companies has done the drawings for us, there where no traps on the piplines, nothing, they have sold an products and that is it...So i am not confident at the technical support of some companies....That is the reason that i am asking, is it better to use a header or Y joints..advantages and disadvantages..

[nike123]

That is the reason that i am asking, is it better to use a header or Y joints..advantages and disadvantages..

I don't see any advantage or disadvantage on any part if they are installed properly!

[nike123]

Last time when support from one of thos VRV/F companies has done the drawings for us, there where no traps on the piplines, nothing, they have sold an products and that is it...So i am not confident at the technical support of some companies....

What traps you are referencing? In VRF piping there is no traps. VRF piping is done in such manner that speed of refrigerant is enough to ensure proper oil return and there is also oil return program which is executed in regular intervals to ensure oil return.

Only traps required is these:

[MilosBog]

Yap, we had a similar case and no traps where recommended back than..Also thay have selected indoor units for a DT of inlet and outlet air of 21(they have calculated with real capacity of indoor units, not with sensible capacity) so the system was really undersized..Still don't believe them.

Do you have a formula how to calculate the header dimension? For a refrigerant application...

[MilosBog]

Oh, god..when make a post after the work, i always make some stupid mistakes...I meant that they have clculated with the total capacity of the indoor units, so it was undersized for a covering of a sensible heat...