Large Chilled Water Network Design

Hi

I am an Australian engineer working in the Middle East designing some particularly large district cooling networks.

My experiences have been somewhat restricted to smaller systems within Australia and I am looking to tap into the expertise of this forum to educate myself on the best design practices for large systems.

One of the critical factors obviously in the pipework sizing is the tradeoff between pipe diameter, velocity and system head losses. We are looking at designing our network with a maximum pressure loss of 100Pa/m and allowing the velocity to go as high as 2.5-3m/s on the main ring of the system.

The branch take offs are being designed at a lower pressure drop than the ring main to ensure we can get adequate flow into the branch lines.

Anybody have any comments or suggestions regarding these design parameters?

Further to this we have selected our piping material to be of steel only as we view any risks associated with a rupture as catastrophic. We understanding that GRP has been used previously on this type of application but we are hesitant. Does anybody have an agreeing or disagreeing opinion to these comments or justifications for using GRP? I understand that the significant benefit is resistance to corrosion.

These projects we have here in the Middle East are somewhat beyond the scope of your average building chilled water project, any that I have experience with anyhow, and it is extremely important that I consider all phenomena which may occur.

Are there any rules of thumb, or good design papers, or the like, which are applicable to thrust block, anchors or expansion loop design, and the best locations within a network to use these components, which may assist in our preliminary designs. At present we are very much relying on the stress analyst to provide advice.

Other problems such as water hammer I understand are also important considerations, cause if it is missed now it can be very troublesome further down the road, as with any project.

Does anybody have any suggestions regarding those considerations in the design of a large cooling water network which MUST be factored in to the network design at an early stage to ensure at the end of the day the system runs efficiently and trouble free.

To give you an understanding of our design, it involves approx 80km of network piping flow and return lines to a number of plants on the site.

Thank you in advance for all suggestions and I eagerly await some responses.

Thanks and kind regards

Ken Eppleston
Mechanical Consulting Engineer
Middle East & Australia Received on Wed Dec 14 05:00:00 2005