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Victaulic partners Tabreed’s growth

Rami Mahmoud, Middle East regional manager for US-based pipe joining specialist Victaulic, discusses how the company’s joining systems have helped the rapid development of district cooling systems in the Middle East.

01 August 2006

As one of the fastest growing cities on the globe, Dubai is at the forefront of the pioneering work of district cooling outsourcing.

With the dramatic increase in large-scale industrial applications and the rising height of buildings in the city, dedicated district cooling systems are proving more and more popular.
This demand has seen the emergence and growth of regional district cooling giants such as National Central Cooling Company’s (Tabreed), which is currently looking at the dramatic expansion of its district cooling systems throughout the UAE and the Middle East.
A key feature of Tabreed success in the Middle East as a leading supplier of district cooling systems has been the partnerships and alliances it has entered into with well-established engineering companies and suppliers from Western countries.
The US-based Victaulic has been playing the role of a significant partner of Tabreed through providing the company a range of products that include: pipe couplings, fittings, valves and accessories, strainers and suction diffusers for a majority of the Tabreed’s cooling facilities.
With sales and distribution offices in Dublin in Ireland, Victaulic started working with Tabreed in 2002 on its Abu Dhabi projects that include the Abu Dhabi Industrial City as well as new projects with QatarCool, a Tabreed sister company in Qatar. The use of Victaulic couplings and fittings varies from one job to another, but in general, 600 mm couplings are used for plant piping and 800 mm for buried piping.
As has been proven time and again, the benefits of using Victaulic non-weld couplings are not only to be found in their ease and speed of installation, but also in the subsequent maintenance benefits. With a union at every joint, and only two bolts holding together even the large-diameter couplings, downtime for maintenance is kept to a minimum.
Tabreed has used the couplings not only to improve maintenance and installation speed, but also to eliminate vibration throughout the pipe system. Victaulic flexible and rigid couplings demonstrate impressive vibration isolation and attenuation characteristics over all pipe diameters, and the use of flexible joints accommodates misalignments and reduced stress at pump or equipment connections.

How it works
In its eight-year history, Tabreed has established around 20 major district cooling plants supplying chilled water from a cooling plant to multiple residential, industrial and commercial buildings for air-conditioning purposes. These facilities are mainly located in the UAE, although the company has operations across the Middle East.
One such facility is located in Abu Dhabi, where present capacity is around 10,000 tons of refrigeration (TR) – which is expected to rise to 15,000 TR in the near future – services water to Zayed Sport City and nearby government and private buildings over a seven-km radius. The plant currently houses eight chillers, each rated at 1,875-TR capacity. The chiller units employ 134fa Freon refrigerant, while the cooling operation is also backed by extensive water tower facilities.
Chilled water leaves the plant at around 40 deg F, gaining only around 2 to 3 deg F en route to the customer, and returning to the plant at around 53 deg F via a separate pipeline. The pipes, which are typically installed 1.2 m deep, range in diameter from 8 to 44 inches, with operating pressures ranging from 7 to 12 bar.
The pipes are insulated with polyurethane foam and buried in the sand, which is another highly effective insulating material. Installation engineers avoid areas with a water table, which impacts thermal insulation, as well as aggressive soil, which can cause corrosion of the pipes.
The pumping systems at Tabreed Abu Dhabi plant feature both primary fixed speed pumps (FSP) and secondary variable speed pumps (VSP). The FSP is used to boost the flow of water into the chiller, while the VSP pumps the water into the network.
“We have different systems in different plants. For example, we can also have VSP in the primary and secondary circuit, or we can have only primary VSP without the secondary. It depends on the size of the plants and capacity and other issues,” points out Yahya Abu-Hijleh, mechanical engineer with Tabreed.

Demand
Chilled water has become a big business across the UAE and increasingly the Middle East. Typically, around 70 per cent of energy use in residential, services buildings and leisure facilities in the Middle East region is for cooling applications. A district cooling system can, however, reduce this figure to just 40 per cent. In addition, chillers usually require 2 kW of energy per tonne of refrigeration whilst district-cooling plants can supply at just 0.2 kW/tonne.
Last year, Tabreed signed its largest cooling services contract for a 30-year, Dh3 billion ($816.77 million) agreement with the Dubai Municipality. The company also recently signed a 20-year contract with Union Water and Electricity Company (PJSC) to provide cooling services to the Fujairah water and power plant, which will be Tabreed's first in the UAE to utilise seawater, which will regulate the temperature of the 656 MW capacity power plant and the 100 million gallons per day water plant.
It is estimated that there is currently up to $100 billion on-going or planned building and infrastructure projects in Dubai, most of which are on a suitably large scale to support the feasibility of a dedicated district cooling plant.
District cooling looks to be seen as an ongoing solution for chilled water facilities for residential, commercial and leisure projects as well as being increasingly used for air conditioning applications in industrial areas. With the immense potential for dedicated district cooling plants only now beginning to evolve, there is great scope for their expansion throughout the UAE and Middle East.