×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Chilled water coils
2

Chilled water coils

Chilled water coils

(OP)
We know that it is usual practice to pipe chilled water to coils counter flow in respect to airflow.  Another words the coldest water on the leaving air side of the coil.  

Question, is there any documentation that dictates whether the supply and return should be high or low on the coil?

RE: Chilled water coils

Generally air trapped inside, if allowed to go in the direction of water flow, will reduce the formation of vapor lock. As a natural phenomenon air always flows up, so return line should be high.

Regards,

RE: Chilled water coils

The most common practice is to arrange the piping to the coil such the the water flow is counterflow to the air.  This gives the best performance since the LMTD is higher in counterflow.  

It is also good practice to have vent and drain connections at the high and low points on the coil to provide to getting rid of trapped air.  These connections also allow for hydrotesting and draining of the coil at the factory.  In any closed-loop system, there should be a surge tank at the high point in the system to allow for venting, too.

RE: Chilled water coils

In addition to the any entrapped or dissolved air moving up to be pushed out of the water coil, the water is also warming up, and will tend to rise. The air is cooling, and will tend to fall. The chilled water would go in the bottom, and out the top, the air will go in the top, and out the bottom. If you've got something that's tending to happen naturally anyway, and you can arrange things such that it helps you, why fight it? Use it.

RE: Chilled water coils

quark/TBP: dead on. Use engineering sense per those two posts and documentation isn't required.

RE: Chilled water coils

Counterflow is very important for heat transfer. You will not be able to attain design leaving conditions if flow is not arranged counterflow.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources