"Loop" in chilled water distribution piping system

[Stephen]

We are designing a new district cooling plant and the question has come up regarding the benefits of "looping" the chilled water distribution piping.  We have included a loop in some of our district cooling plants and in others we have not.  I'm curious if anyone has evaluated the benefits of looping the chilled water distribution.  The primary benefit we have identified is the ability to utilize valves to isolate various sections of the pipe and thus contain the impact of a potential pipe break/leak.  It would seem there are other hydronic benefits, but I have not found any research to support the benefits.

Has anyone else faced this decision?  Thanks for your feedback!

Stephen Koontz

[Edward T. Borer Jr.]

Our system includes a few loops.

It seems to make troubleshooting a bit harder, but hydraulics will be a little more energy efficient. It can be a long time between someone accidentally closing a valve and the problem being discovered.

The more valves and loops you add, the more instrumentation should be included.

 

Ted Borer, PE, CEM, LEED AP

Princeton University

Energy Plant Manager

MacMillan Building, Elm Drive

Princeton, NJ 08543-2158

Ph:(609) 258-3966

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Home: (609) 466-3322

etb...@princeton.edu

 

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[Coolsol...@aol.com]

Stephen,

 

A CHW "loop" has advantages over a traditional "spine and branches" layout (although the loop will often have a higher first cost).  As you noted, the loop provides the flexibility to isolate areas of the network, without cutting off access to other users.  In addition, the loop can often avoid bottlenecks in piping capacity and/or allow larger loads to be served with smaller bore piping.  Of course, a detailed hydraulic analysis will quantify the differences.  Locating satellite CHW plants and/or remote Thermal Energy Storage (TES) along the network can also have a positive impact on addressing all the above issues, whether the network is a loop or a spine.

 

John S. Andrepont, President

The Cool Solutions Company

5007 Lincoln Avenue, Suite 201

Lisle, IL 60532

tel: 630-353-9690

fax: 630-353-9691

e-mail: CoolSol...@aol.com

[Issa Qandeel]

Stephen,

Other than the benefits of isolation (which is real important when failures start occurring with time), the one important benefit is the flexibility the looping provides to add unplanned developments to the network in the future. With adequate isolation measures you can always tap into the existing network (using the isolation valves) rather than having to go through hot-tapping or freezing.

 

Issa Qandeel  VP-Development  Development  P.O. Box 24979  Doha, Qatar  Direct: +974 4496 0542  Fax: +974 4496 0599