HOT|COOL NO. 1/2018 "Global District Energy Climate Awards"


By Vinod Kesavannair, Engineering Manager, Marafeq Qatar LLC

cooling load of around 500,000 tons of refrigeration (TR) or 1,760 MW, by using multiple chiller plants with a total capacity of approx. 360,000 TR. The ultimate district cooling system will serve over 800 buildings through 170 km (supply and return) underground piping from four production plants. Plants are built in phases to meet the phasing of the development and to reduce the capex spending upfront. Chilled water will be delivered at interface in buildings between the district cooling system and the customer buildings (Energy Transfer Stations or ETS). To maintain adequate cooling to the buildings, the district cooling system is designed to deliver 5°C chilled water to customer buildings. The system is also designed to operate distribution pumps to supply the necessary differential pressure at the hydraulically most remote point(s) in the distribution system. For the system to operate properly and efficiently, the buildings must be designed and operated to deliver an aggregate return water of 14°C from the ETS to the plant. As buildings come online, Marafeq Qatar will continuously monitor building performance and work with customers to solve problems that might arise related to lower delta T. To help the building owner meet design delta T and reduce his operating cost while maintaining building comfort, Marafeq Qatar guides them in basic principles needed to make a building “district cooling ready”. Marafeq Qatar’s planning made sure all four district cooling elements would work integrally so that availability, comfort, and energy performance objectives can be met.

One of the largest district cooling systems in the world when completed, Lusail City District Cooling System, being developed to the north of Doha, Qatar, will have around 500,000 TR (1,760 MW) connected load. Through many design innovations it aims to provide extremely reliable, flexible and efficient cooling service to end-users. When fully completed, the system will save around 500,000 tons of CO2 emissions compared to traditional air-cooled systems used in the region. INTRODUCTION Lusail City is being developed to the north of Doha by Qatari Diar and Lusail Real Estate Development Company (LREDC). More than 200,000 residents will live in Lusail City, with 170,000 people expected to work in the city’s different districts, and 80,000 expected to visit its entertainment, recreation and retail and hospitality facilities. Lusail City’s 19 districts will encompass not only new residential, commercial, hospitality, and retail opportunities, but a full array of community needs, complete with schools, mosques, medical facilities, sport, entertainment and shopping centers. From the beginning, the visionaries expected a utility company would provide district cooling services, and in 2009, Marafeq Qatar was officially created. Marafeq, which in Arabic means utility, was tasked with providing district cooling, gas, pneumatic waste, and traditional waste management. Of these business classes, district cooling is by far the largest in terms of capitalization and revenue. DISTRICT COOLING SYSTEM OVERVIEW The Lusail City district cooling system will be the largest district cooling system for a development, which will supply chilled water to end-users through an integrated network with a connected

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