Muhammad Ali

Impact of Low ΔT on a Network with Multiple Production Sites

- The largest district cooling plant in the world – The Pearl

- The largest district cooling required in one development in the world – Lusail City

In Qatar

Lusail City

•Lusail City is the largest single development to be undertaken in Qatar, located about 15 km north of the city center of Doha.•19 districts • Area of 38 km2 including 28 km2 of waterfront

•Mix of entertainment, residential and commercial projects covering:

- 200,000 residents

- 170,000 workforce

- 80,000 visitors.• The master plan sub-divided into a

total of 4,929 plots.

• Light Rail Transit, Rail and Metro connections.

•More than 22 Hotels

Lusail City

District Cooling

Pneumatic Waste Collection

Gas Network

DCP Wadi

DCP West

DCP North

DCP Marina

Cooling plant

• Four main plants : Marina , Wadi , West and North.

• Total Market > 500,000 TR

Lusail City – District Cooling

•Total length of district cooling network in Lusail 168 Km•Total length of wet utility tunnel in Marina district = 13 Km•Total length of dry utility tunnel in Marina district = 13 Km

Lusail City – District Cooling

Marina DC plant - Initial capacity 33,000 TR - Final capacity 92,000 TR ( TES 16,000 TR )- Phased development- Awarded to EPC contractor in 2014 and to be completed

in 2015.- Construction work on going

Wadi DC plant- Initial capacity 14,250 TR as modular construction- Final capacity 74,400 TR ( TES 14,400TR )- Phased development- Awarded to EPC contractor in 2014.- Construction work will start soon

Marina and Wadi Plants

Marina DC Plant

Marina DC Plant

Marina DC Plant

Marina DC Plant

Design Supervision & PM

O&MBilling &

Customer Services

Marafeq’ s Role As Utility Provider

Securing Chilled Water Supply and Return

Temperatures

Low Δ T; Why?

Improper Calculations of Cooling Load

Non-Phased Development

ETS Controls and

Instruments

HVAC Cooling Coil

HVAC Control Valves

Improper Set Point or

Control Logic

Plant-A Plant-B Plant-C Plant-D100

300

500

700

900

1100

1300

1500

1700

1900

Effect of T on Hydraulic ProfileΔ

Design ΔT Design ΔT-1 Design ΔT-2 Design ΔT-3 Design ΔT-4

MED

IAN

PRE

SSU

RE

87 7.5 7

98 8.5

8

109 9.5

9

12.5

1111.5

11

16.5

14.5

15.5 14

Plant-A Plant-B Plant-C Plant-D100

300

500

700

900

1100

1300

1500

1700

1900

Effect of T on Hydraulic ProfileΔ

Design ΔT Design ΔT-1 Design ΔT-2 Design ΔT-3 Design ΔT-4

MED

IAN

PRE

SSU

RE

16.5

14.5

15.5 14

Plant-A Plant-B Plant-C Plant-D0

10

20

30

40

50

60

70

80

100100

100100

129

124127

125

174

168171

164

252

239

246

232

405

371

387

357

Effect on Annual Pumping Energy9 8 7 6 5

45678910 0

50

100

150

200

250

300

350

400

450

100

Effect on Overall Pumping Energy

Design ΔT-1 Design ΔT-2 Design ΔT-4

125

170

245

385

Design ΔT Design ΔT-3

Approximately 4 times

IS THERE A SOLUTION

• Variable speed pumps• Two industrial grade PDT• PICV- one for each PHE• Two-way control valve for AHU & FCU• TAB of tertiary side by specialized third party• PHE as per AHRI-400 with zero tolerance• PDT: Pressure Differential Transmitter• PICV: Pressure Independent Control Valve• PHE: Plate Heat Exchanger• AHU & FCU: Air Handling Unit and Fan Coil Unit• TAB: Testing, Adjusting and Balancing• AHRI: The Air-Conditioning, Heating, and Refrigeration Institute

Marafeq Requirements

• 2-way control by-pass around the pump• Keep extra space on frame for capacity

expansion• Two PHE of 50% each. Higher availability• PICV for AHU

Marafeq Recommendations

PRODUCTIONDISTRIBUTION

CONSUMPTION

Common ProblemsProblems Design O&M

Control valve for AHU/FCUImproperly piped coilImproper set point or control logicImproper coil selectionNo control valve interlockETS Controls and Instruments

Quality Control and Compliance with Particular Requirements

Three stage review of ETS1- Design StageDesign conformance applicationP&ID and layouts (ETS)Equipment schedule and schematic (tertiary side)- for information2- Material ReviewPICV, PHE, PLC3- Construction InspectionsInstallation, flushing, T&C

+

.

.

..

. ENGAGE AND DEVELOP THE

WHOLE

Thank you

Muhammad AliPhone: 00974 55293436Email: muhammad.ali@Marafeq.com.qa

Resources1. Marafeq Design Guidelines for the Connection of

ETS (s) to the District Cooling System2. District Cooling Best Practice Guide, 1st Edition,

International District Energy Association