HONG KONG: Packaged chilled water plant rooms supplied by Armstrong Fluid Technology are contributing to impressive energy efficiency at a major new Digital Realty data centre facility in south east Asia.

The plant rooms are said to incorporate latest generation chilled water control technology which optimises PUE, ensuring excellence in environmental performance. As the plant rooms were off-site manufactured and tested at Armstrong’s factory, they also reduced installation times for the project, and will ensure maximum system integrity and reliability throughout their lifetimes.

When Digital Realty, a leading global supplier of data centre solutions, embarked on a joint venture with Century Link to construct the HKG10 facility, it was decided that off-site manufacture of fully-integrated chilled water plant rooms with variable-primary distribution would meet key priorities of the project.

Armstrong Fluid Technology, an approved supplier for Digital Realty in the UK, was chosen to deliver the plant rooms on the second phase of the development.

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The chilled water systems supplied employ Hartman LOOP, described as a digital relational control technology that is capable of treating the entire system ‘holistically’, rather than as individual sub-systems.

Armstrong says that chiller plants traditionally use technology based on independent control loops with PID feedback control, but maintains that this analogue approach is insufficiently flexible to deliver the sorts of energy efficiencies demanded for energy-intensive sites such as data centres.

By contrast, it argues that the Hartman LOOP control incorporated in the Armstrong chilled water-plant rooms has the ability to calculate and determine the best power relationship between key system components. This, the company maintains, achieves optimal power relationships across each system, with equipment loading in one device traded off to pick up more load on another, thereby achieving the same net “tonnage” for a lower kW input.

It replaces conventional, inefficient capacity-based sequencing whereby devices are run at full speeds before the next one is sequenced on or off to match varying demand. Instead, components are sequenced to operate at their peak efficiency during part-load operation, along their natural curves. This may result in a greater number of devices being operated at lower speeds to take advantage of the affinity laws. When fans and pumps are slowed at lower loads, greater air and water volumes pass over larger surface areas per unit of energy expended. This improves part load approach temperatures and provides the opportunity to operate on the lower areas of the curve for higher chiller efficiency. This improves overall energy efficiency significantly.

The chilled water plant rooms were assembled, integrated and tested off-site, at Armstrong’s purpose designed factory in Halesowen.