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Posted on December 29, 2013

Replacing equipment to use treated sewage effluent (TSE) in place of fresh water in ‘District Cooling’ plants can not only help recover the cost of equipment within three years, but also save millions of riyals to the service providers as a result of significant fall in the variable costs of cooling plants, said a senior official of Kahramaa. District Cooling (DC) is an innovative and energy efficient refrigeration system which delivers chilled water via an underground insulated pipeline to offices and factories needing cooling. 

It is a very cost effective and environment-friendly system which uses 30 to 40 percent less energy than conventional refrigeration system, resulting heavy reduction in CO2 emissions.  Since it works on water-intensive technology, it suffers with some limitations in water-starved countries. Faced with the challenge of saving water and making the technology more cost effective, Qatar’s Permanent Water Resources Committee (PWRC) has recommended using only TSE in all existing and upcoming DC projects, replacing fresh water, which in turn will reduce the running costs of plants significantly.

“The replacement of fresh water with TSE can help recover the cost of equipment within three years, and after that operators can enjoy up to 80 percent savings over all the remaining years of a plant,” Ibrahim Mohammed Al Sada (pictured), Manager District Cooling Services Department at Kahramaa, which is responsible for the regulation of DC market, told The Peninsula. Al Sada said: “Using TSE in DC systems has huge benefits in terms of monetary, CO2 emissions and environmental protection. It saves a lot of water and electricity. Given the wide ranging benefits, the UAE has already started replacing fresh water with TSE.”

He noted that Qatar promotes only electricity driven DC system, because natural gas powered cooling system emits relatively more CO2 and needs about 40 percent more water. DC system is in a very advanced stage in Qatar, and according to Al Sada, it is one of the very few countries in the world to have a regulatory body to monitor DC market to practice highest standards. “We have sent over 50 letters to different DC plants to install only approved equipment, use TSE by replacing fresh water, which is allowed to use only as a back-up option,” he added.

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Qatar has set an estimated target to reduce about 3.5 million tonnes of CO2 emissions by 2022. It has already reduced over 500,000 tonnes of CO2 so far, by introducing DC system in the country. Qatar Cool and Marafeq Qatar, two major suppliers of DC service in the country, have assured to use only TSE in their upcoming projects to comply with the latest guidelines. 

Asked if there is any replacement deadline for the existing plants, Al Sada said: “Yes the deadline ends by this December, but some of the plants have expressed their limitations with regard to TSE use, with whom we are cooperating.  “But they have to convince us by showing a clear replacement plan with official letters from Public Works Authority (Ashghal), which updates clients about the availability of TSE.

Qatar Cool, which was incorporated in 2003, has installed many projects in Qatar, including the world’s largest district cooling plant at The Pearl, which has a 130,000 tonne cooling capacity. The company’s two plants in West Bay, with a combined cooling capacity of 67,000 tonnes of refrigeration, are serving to nearly 50 percent of existing towers. Qatar Cool is looking forward to install its third plant in West Bay, according to Al Sada.

Marafeq’s DC system in the upcoming Lusail City, once fully operational, will be one of the biggest plants in the world with a cooling capacity of 374,000 tonne refrigeration. In addition to Lusial and some 2022 Fifa World Cup projects, Hamad International Airport, Barwa Commercial Avenue, Qatar Foundation, Katara Cultural Village and Hamad Hospital are some of the other major projects which will have DC systems.

source: The Peninsula