salahzantout

07-02-2014, 06:12 PM

Hey colleagues

Ive been using ashrae for sizing up liquid lines, passed on a R404a system and got confused about something... lets say we use the middle column of the table which is 2k/m... for a 133kw capacity line and about 91m long distance...

now we have 133kw capacity, for a rough estimation 125m (90*1.5) and a change in saturation 2k/m...

applying the saturation temp formula delta T would give us a large number assuming that we chose the 35mm OD copper tube which corresponds to 169 kw.

the delta T would give about 162 K which is an unbelievable number

it should be a maximum of 1K or so to be acceptable ! but this number ! 162 K that a tragedy !

note that when using R22 it would be 0.02k/m instead of 2k/m

i really would like to get some help about that !

The reference is ashrae refrigeration 2006 or 2010 SI edition

Ive been using ashrae for sizing up liquid lines, passed on a R404a system and got confused about something... lets say we use the middle column of the table which is 2k/m... for a 133kw capacity line and about 91m long distance...

now we have 133kw capacity, for a rough estimation 125m (90*1.5) and a change in saturation 2k/m...

applying the saturation temp formula delta T would give us a large number assuming that we chose the 35mm OD copper tube which corresponds to 169 kw.

the delta T would give about 162 K which is an unbelievable number

it should be a maximum of 1K or so to be acceptable ! but this number ! 162 K that a tragedy !

note that when using R22 it would be 0.02k/m instead of 2k/m

i really would like to get some help about that !

The reference is ashrae refrigeration 2006 or 2010 SI edition