The North Shore District Cooling project is being developed by Tabreed, the world’s largest district cooling company, while Atkins is the lead consultant and construction supervisor.

District cooling involves supplying cooling as a utility service, similar to electricity and water. Instead of using local cooling systems in each building, one central source is used to generate chilled water for an entire district. This water is then distributed for cooling via a network of pipelines.

This centralised cooling method has environmental and economic benefits for both the customer and cooling supplier, and is becoming increasingly popular in hot climates where air-conditioning dominates energy usage.

The North Shore project, which is the first of its kind in Bahrain, involves the production and distribution of 23,000 tonnes of chilled water via 14 km of pipes and several energy transfer stations.

When complete, this system will supply cooling to the Bahrain World Trade Centre and other developments south of the King Faisal Highway, significantly reducing the cost of providing air-conditioning to offices, residential buildings and shopping malls.

Microtunnelling has been a major feature of this four-year project. Atkins Site Operations Manager Ian Cordingley said “We struggled to install large diameter insulated steel pipes through relatively confined streets. Two very busy highways had to be crossed four times and we used Herrenknecht AVN machines to do the work, this ensuring no disruption whatsoever to the traffic above.”

In late May construction was completed on two 86 m microtunnels beneath the King Faisal Highway, which were bored at a rate of approximately 6 m per day. The parallel 900 mm insulated carbon steel pipes were installed more than 10 m below ground, without impacting on the traffic above. These pipes will transport district cooling water from the Diplomatic Area chiller plant to Bahrain Financial Harbour, Reef Island, and other developments in the area.

Mr Cordingley said “It is not easy to drill through 86 m of earth with such little disturbance to the surroundings. The team did a fantastic job in ensuring we deliver a chilled water network that will make the cooling of developments in Manama more economical and help in reducing Bahrain’s carbon footprint.”

Meanwhile, the longest drive was for the chiller plant cooling water outfall, which measured 154 m in length and had an outside diameter of 1,956 mm.

Atkins is extremely satisfied with the decision to use Herrenknecht equipment. “In each case the alignment was near perfect, so using the AVN machines was a good choice,” said Mr Cordingley.

“Further work in the centre of Manama is scheduled and it would be good to use the same type of machinery, but as yet no firm decisions have been taken.”

The Diplomatic Area chiller plant is also nearing completion, and work on the North Side District Cooling project will be concluded later this year.