impact of low Δt on a network with multiple production sites
TRANSCRIPT
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&M
Billing &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 100
100
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
125170
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: [email protected]
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