Double fintube piping

Jamie306A

Hello all,

 I’m installing a slantfin commercial double-stack,18’ long at home. I typically install new-build, engineer designed hydronic systems.  My supplier sales rep was incredibly helpful with my reno design for home. His suggestion was to pipe the top and bottom elements as a reverse-return, rather than in series. Now that I’m ready to install, I’m thinking supply the top and return the bottom would provide better heat transfer and save some work. My thoughts:

reverse-return = half the length is counterflow to the air; half is parallel

 series = all counterflow (typically recommended for heat exchangers)

Any thoughts or documentation?

EBEBRATT-Ed

You will get more heat if you supply each row in parallel rather than in series because your average water temp will stay higher.

Is it worth it? Depends

Figure out your water flow and temperature drop through each section and see what is better.

Example using run of the mill baseboard:

18' of baseboard x 550 BTUs/foot (yours may differ) @190 supply water say 4 gpm=9,900btus

Water temp drop 4.95 deg so 190-185.05

So piped in parallel temp drop is about 5 deg
in series about 10 degrees

At 1 gpm piped in parallel temperature drop is 20 degrees
in series 40 degrees

So it makes a big difference you need to know your flow and water temp

If you have enough flow series or parallel doesn't matter

Keep in mind with stacked radiation you don't get double the btus of a single element because a double stack reduces the air flow

Jamie306A

The heat run is dedicated to this baseboard. The flow rate is adjustable and it’s adequately sized no matter which way I pipe it. I’m just a theory/ numbers kinda guy; shooting for my 20*dT. 

EBEBRATT-Ed

@Jamie306A

Then I would pipe it in series your probably somewhere around 2 gpm

Rich_49

Piping it in parallel will give highest output . If you pipe with one supply and return Top supply and bottom return will output better than bottom s , top r . You can see it here from a different manufacturer , but physics is physics . https://smithsep.com/wp-content/uploads/Heating-Edge-2-Literature-2.pdf

EBEBRATT-Ed

Yes but with only and 18' run on it's own zone the difference is insignificant