District cooling involves providing cooling from a central plant to multiple buildings via pipes. It started in the 1930s. A case study on a residential area in Jaber Al-Ahmad City found that a district cooling system with thermal storage could provide yearly energy savings of 40% compared to conventional air cooling systems and reduce peak power usage by 50% on average. The district cooling plant would have a capacity of 41,670 tons and use 101.9 GWh of energy annually to serve over 1,600,000 square meters of buildings.

1. District Cooling
Designing for Life Power & Cost Saving
January 2011
District Cooling Power & Cost savings

2. Table of
Contents
Main
01. District Cooling
02. Case Studies
Heading
03. Animation
District Cooling Power
and Cost savings
District Cooling Power & Cost savings

3. 01
District
Cooling
District Cooling Power & Cost Savings

4. District
Cooling
Description
Involves the provision of cooling for multiple buildings
or facilities from one or more central plant via a pipe network.
History
Large District Cooling applications started in the 1930s for
the Rockefeller Center and United States Capitol Complex.
District Cooling Power & Cost savings

5. District Piping
Cooling Distribution
Pipes
DC Plant
Valve Chamber ETS
District Cooling Power & Cost savings

6. District Pipes in
Cooling Tunnel
Pipes in Tunnel with Branch-out
Pipes in Trench Pipes in Tunnel
District Cooling Power & Cost savings

7. District Valve
Cooling Chamber
District Cooling Power & Cost savings

8. Energy
District Transfer
Cooling Station
Heat Exchanger
Schematic - Energy Transfer Station with Heat Exchanger to Apartment Block
District Cooling Power & Cost savings

9. District District
Cooling Plant
Cooling Tower at Roof Level Chiller Plant at Ground Level Pumps in Basement
Vertical Arrangement
DC Plant – Verticle Arrangement District Cooling Power & Cost savings

10. District District
Cooling Plant
Kuwait University
Cooling Towers – Horizontal Arrangement District Cooling Power & Cost savings

11. District District
Cooling Plant
DC Plant– Horizontal Arrangement (Kuwait University)
District Cooling Power & Cost savings

12. District Thermal
Cooling Storage
1. Chilled Water
2. Ice
3. Eutectic Salts
Ice Storage Tank
Pre-stressed Concrete Tank Thermal Energy Storage
District Cooling Power & Cost savings

13. District District
Cooling Plant
District Cooling Plant – Architecture
District Cooling Power & Cost savings

14. 02
Case
Study
• Residential Areas
• Inner-City
District Cooling Power & Cost Savings

15. Residential Area Case Study based
on Jaber Al-Ahmad City
(Areas B & A5)
District Cooling Power & Cost savings

16. Residential
Area-
Case Design
Study Basis
Cooling Loads – Estimation Basis District Cooling Power & Cost savings

17. Case Residential
Study Areas
Number of Houses = 1836
Estimated built up area of housing = 1,560,600 m2
(95% of total Built up area)
Total Built up area including Mosques, Schools,
Clinic, Shopping centre, Bank, Office Buildings etc. = 1,645,438 m2
Chiller plant capacity = 36,790 TR
Thermal Storage = 4879.6 TR (11.7% of total)
TOTAL DISTRICT COOLING PLANT CAPACITY = 41,670 TR
District Cooling Power & Cost savings

18. Case Residential
Study Areas
Plant Arrangement
&
Chilled Water Distribution
District Cooling Power & Cost savings

19. Case Residential
Study Areas
Roof Plan
Overall Area = 136m x 40m
Foot Print = 7.66 M2/TR
District Cooling Power & Cost savings

20. Case Residential
Study Areas
Ground Floor Plan
District Cooling Power & Cost savings

21. Case Residential
Study Areas
Enlarged view
Basement Floor Plan
District Cooling Power & Cost savings

22. Case Residential
Study Areas
Enlarged View - Basement Plan District Cooling Power & Cost savings

23. Case Residential
Enlarged view
Study Areas
Site Plan - Chilled Water Distribution District Cooling Power & Cost savings

24. Case Residential
Study Areas
Site Plan Enlarged view - Chilled Water Distribution District Cooling Power & Cost savings

25. Case Residential
Study Areas
Chilled Water Network Flow Simulation District Cooling Power & Cost savings

26. Case Residential
Study Areas
Typical Cross Section of Local Road with Bldg. Connection
District Cooling Power & Cost savings

27. Case Residential
Study Areas
Chilled Water Pipe Network
• System Static Pressure - 6 bar
• Pressure difference between closest and furthest node is 24m.
District Cooling Power & Cost savings

28. Case Residential
Study Areas
Chilled Water Temperature Increase
• Calculations indicate that water temperature increase over the
longest route is 0.3 deg-C
• The calculations were based on Supply at 5.0 Deg-C, Return at
14.0 Deg-C
• Loss in thermal energy due to pipe-work distribution is
approximately 1 % overall
District Cooling Power & Cost savings

29. Case Residential
Study Area
Power & Energy
District Cooling Power & Cost savings

30. Residential
Area-
Case Cooling
Study Load
District Cooling Power & Cost savings

31. Residential
Area-
Case Cooling
Study Load
District Cooling Power & Cost savings

32. Case Residential
Study Areas
Charging Mode
Discharging Mode
Charging / Discharging Mode (TES Tank) District Cooling Power & Cost savings

33. Residential
Area-
Case Cooling
Study Load
District Cooling Efficiency
With TES = 0.86 KW/TR
Without TES = 1.00 KW/TR
Based on R-134a Refrigerant
Conventional Air Cooled Systems (excluding Indoor Units)
Efficiency = 1.6 - 1.8 KW/TR (peak load/peak cooling)
Assume Air Distribution Equipment Efficiency = 0.2 KW/TR
Based on R22 Refrigerant and
equivalent diverse electrical load
PEAK POWER SAVING = 50% (on average)
District Cooling Power & Cost savings

34. Residential
Area-
Case Cooling
Study Load
District Cooling vs. Air cooled Energy Demand
Annual DCS
Energy Demand = 101.9 GWh
Annual Air Cooled System
Energy Demand = 182.2 GWh
Yearly Energy Saving = 40% on average
when compared with conventional
Air-cooled systems (1.6-1.8 kW/TR)
District Cooling Power & Cost savings

35. Residential
Area-
Case Water
Study Demand
Peak Daily Demand
Total Demand = 7048 m3
Yearly Demand
Fresh Water Demand = 1,156,000 m3
If TSE is utilized = 1,502,800m3
Sea Water can be utilized for installations near the sea
District Cooling Power & Cost savings

36. Case Residential
Study Areas
CODE OF PRACTICE MEW/R-6 (Revised)
• Clause 8.8 District Cooling states
"District cooling shall be applied for new townships, university
campuses and similar neighborhood, in view of its proven
advantage for energy saving and peak load shaving. HVAC design
report shall include detailed feasibility study highlighting energy
savings potential and cost effectiveness over a 30 year life for plant
and equipment”
District Cooling Power & Cost savings

37. Case Residential
Study Areas
Opportunity Costs
Electicity Cost VS Fuel Cost
Electricity Unit Cost (Fills/KW-Hr)
90
80
70
60
50 Fuel Cost
40 Transmission Cost
30
20
10
0
0
0
20
40
60
80
0
10
12
Barrel of Oil Cost ($)
District Cooling Power & Cost savings

38. Case Residential
Study Areas
Power Plant Savings
Saved Power (50% saving) 39,586 KW
Capital Costs
Power Generation 400 KD/KW 15,834,400
Distribution Saving 50 KD/KW 1,979,300
Total KD 17,813,700
Annual Energy Saving (40% on average) 73 GW-HR
Power Generation & Distribution 60 Fils/Unit 4,138,000
Total KD 4,138,000
District Cooling Power & Cost savings

39. Case Residential
Study Areas
Water Generation Costs Cost (KD)
Plant Capital Cost
Peak Day Water Requirement 7048 M3
Desalination Cost - RO Plant @ 820 KD/m3 5,779,360
Production & Distribution
Annual Water Requirement 1,156,000 M3
Fresh Water Cost @ 768 Fils/M3 887,808
(3,494) (1000 Gal)
District Cooling Power & Cost savings

40. Case Residential
Study Areas
Capital and Running Cost Savings
Potential Savings in Capital Cost = KD12,034,340
Case Study
Potential Savings (Opportunity) = KD 3,250,192/year
@ 90$ US/barrel
District Cooling Power & Cost savings

41. Case Residential
Study Areas
Extract from MEW R-6
“HVAC design report shall include detailed feasibility study highlighting energy savings potential and cost
effectiveness over a 30 year life for plant and equipment”
Suggested incentives to achieve cost effectiveness
 Passover some of the savings by Government to the DC Provider
 Pass over some of the capital savings by:
 Covering cost of chilled water pipe installation (same as other piped
utilities)
 Provide land (as for sub-stations)
 Set chilled water generation charges based on ‘unsubsidized rates’ with
incentives linked to production efficiencies
District Cooling Power & Cost savings

42. Case Residential
Study Areas
The Main Environmental Benefits
• Smaller Carbon Emission Foot Print
• Energy Conservation
• Less Noise From Air- Cooled Units
• Less Thermal Impact on Local Environment
• Better usage of built space (roof garden etc.)
• More Efficient Temperature Control
District Cooling Power & Cost savings

43. Case Residential
Study Areas
Carbon Emission Savings
• Every MW-Hr Demand Produces 0.788 Tons of CO2
• 41,700TR DC Plant Reduces CO2 Emission by 65,800 Tons per Year
District Cooling Power & Cost savings

44. Inner-City
Inner-City Area Design
Case Study based on
Abdullah Al-Ahmed Street
District Cooling Power & Cost savings

45. Case
Study Inner-City
Perspective – Abdullah Al-Ahmed Street
District Cooling Power & Cost savings

46. Case
Study Inner-City
District Cooling Power & Cost savings

47. Case
Study Inner-City
Building Type Built Up Area (m2)
Residential 124,630
Offices 436,800
Commercial 133,463
Total 694,463
District Cooling Power & Cost savings

48. Case
Study Inner-City
DC Plant integrated in Car Park Building to optimize on Parcel Usage District Cooling Power & Cost savings

49. Case
Study Inner-City
Ground Floor Plan – Chiller Plant Layout District Cooling Power & Cost savings

50. Case
Study Inner-City
Detail view
Basement Plan – Pump Room Layout District Cooling Power & Cost savings

51. Case
Study Inner-City
Images
Ice Storage Tank Lay-out Schematic – Detail view District Cooling Power & Cost savings

52. Case
Study Inner-City
Charging Mode
Discharging Mode
Charging / Discharging Mode (Internal Melt Ice Storage) District Cooling Power & Cost savings

53. Case
Study Inner-City
Site-Wide Chilled Water Pipe Distribution Network District Cooling Power & Cost savings

54. Case
Study Inner-City
Power & Energy
District Cooling Power & Cost savings

55. Case
Study Inner-City
District Cooling Power & Cost savings

56. Case
Study Inner-City
District Cooling Power & Cost savings

57. Case
Study Inner-City
Plant Item Plant Cooling Capacity
KWh Ton-hr KW TR
Water Cooled Chillers 1,270,880 361,363 54,162 15,400
Glycol Chiller Capacity 419,920 119,387 30,950 8,800
Thermal Ice Storage 144,860 41,189 23,145 6,581
Total DC Plant Capacity 1,835,660 521,939 108,257 30781
Plant Efficiency – KW/TR 0.805
District Cooling Power & Cost savings

58. Case
Study Inner-City
Energy Demand Profile (DCS Ice Storage vs.
Conventional Water-Cooled System)
District Cooling Power & Cost savings

59. Case
Study Inner-City
Energy Demand Profile (DCS Ice Storage vs. A mix of 70% Capacity
Conventional Water-Cooled System & 30 % Air Cooled
District Cooling Power & Cost savings

60. Case
Study Inner-City
District Cooling Power & Cost savings

61. Case
Study Inner-City
Economical Consideration
&
Sustainable Design
District Cooling Power & Cost savings

62. Case
Study Inner-City
EXCERPTS FROM LATEST MEW/R-6 REGULATION (2010)
• Clause 8.5 Use of Partial Cool Storage (Chilled Water Storage)
“Building with part-day occupancy pattern and chilled water systems serving
building peak load of 100 RT or above, partial cool storage is mandatory.
Some examples of building with part-day occupancy are: commercial offices,
community centers, schools, public offices, banks, games and sports
centers, gymnasiums, clubs etc.”
District Cooling Power & Cost savings

63. Case
Study Inner-City
why District Cooling?
• Larger chiller plant better efficiency (less power)
• Better energy management through better qualified staff
• Reduces building construction cost by removing central plant and improving building
net-to-gross efficiency
• Can help improve building aesthetics
• Allows End User to better focus on core business.
• Less noise generation
District Cooling Power & Cost savings

64. Case
Study Inner-City
Incentive Factors
• Pass over savings in central plant and building costs by the developer to the DC
Provider (capacity and connection charges)
• Pass over running costs savings (operation, maintenance, consumables)
• Introduce Government incentives to offset capital costs –
 allow integration of DC plants within multistory car parks or provide land
 allow incentive schemes based on DC plant efficiencies (KW/TR)
District Cooling Power & Cost savings

65. Case
Study Inner-City
Sustainable Design Considerations
• Match capacity of the central chiller plant with the buildings
• Select pipe sizes & material based on economical factors
• Match Primary & Secondary flow arrangements (variable flow)
• Install controls with good response times
• Provide thermal storage to help operate plant at optimum condition
• Maintain highest Chilled water ΔT possible
• Maintain highest chilled water flow temperature possible
• Use high efficiency motors
• Consider Variable speed cooling tower fans
• Use Water conservation and backwash recovery
District Cooling Power & Cost savings

66. 03
Animation
District Cooling Power & Cost Savings

67. District
Cooling Animation
District Cooling Power & Cost savings

68. Thank you
District Cooling Power & Cost savings