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Future Comforts
Andrew KeoghCarrier Air Conditioning
Air Conditioning Energy Use
• AC can account for over 1/3rd of all electricity used
in a building
• The UK National Grid has now become “summer
peaking”.
• 1,300 MW extra load on hot days, growing at 8%
• Rapid growth in the use of AC is threatening our
Kyoto commitments
Range of Monitored Monthly Cooling Energy Consumption (Phase 1: Data NOT normalised for Load)
0
5
10
15
20
25
30
35
40
All-Air Systems ChilledCeilings
FancoilsSystems
Split DXSystems
VariableRefrigerant
Flow DX
kW
h/m
2Air Conditioning Energy Use
90 %
300 %
Natural Ventilation
• Exposed building fabric
• Low internal gains
• Atrium / Chimney
• High thermal mass
• Open plan
• Shallow floor plan
• Sun shades or blinds
• Away from city centre
• Vents, wind catchers, solar chimneys
Design Constraints
Dry Bulb Wet Bulb Hours
28.1 20.3 11
25.3 18.5 39
22.5 16.9 123
19.7 15.3 390
16.9 13.9 573
14.2 12.3 456
11.4 9.7 528
8.6 7.2 542
5.8 4.8 375
3.1 2.3 290
Design Conditions
Refrigerant R22 R134a R290 R744 R717 R410a
Cooling COP 4.66 4.61 4.54 2.53 4.75 4.39
Pressure ratio 4.03 4.70 3.68 3.15 4.95 3.92
Refrigeration Effect
163 147 279 123 1102 168
Inlet Quality 0.25 0.29 .30 .55 .16 .31
Refrigerant Choice
T1
T2
T
S
COP=T2/(T1-T2)
System Fundamentals
T1 T2 COP
313 275 7.2Air cooled 6/12
System Fundamentals
T1 T2 COP
313 275 7.2
303 275 9.8
Air cooled 6/12
Water cooled 6/12
System Fundamentals
T1 T2 COP
313 275 7.2
303 275 9.8
303 285 15.8
Air cooled 6/12
Water cooled 6/12
Water cooled 16/20
System Fundamentals
Dry Bulb Wet Bulb Hours
28.1 20.3 11
25.3 18.5 39
22.5 16.9 123
19.7 15.3 390
16.9 13.9 573
14.2 12.3 456
11.4 9.7 528
8.6 7.2 542
5.8 4.8 375
3.1 2.3 290
Free Cooling
Dry Bulb Wet Bulb Hours
28.1 20.3 11
25.3 18.5 39
22.5 16.9 123
19.7 15.3 390
16.9 13.9 573
14.2 12.3 456
11.4 9.7 528
8.6 7.2 542
5.8 4.8 375
3.1 2.3 290
Free Cooling
Variable Speed Drives
Heat Pumps?
The Answer
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