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

kWh/

m2

Air 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 Hours28.1 20.3 1125.3 18.5 3922.5 16.9 12319.7 15.3 39016.9 13.9 57314.2 12.3 45611.4 9.7 5288.6 7.2 5425.8 4.8 3753.1 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 Hours28.1 20.3 1125.3 18.5 3922.5 16.9 12319.7 15.3 39016.9 13.9 57314.2 12.3 45611.4 9.7 5288.6 7.2 5425.8 4.8 3753.1 2.3 290

Free Cooling

Dry Bulb Wet Bulb Hours28.1 20.3 1125.3 18.5 3922.5 16.9 12319.7 15.3 39016.9 13.9 57314.2 12.3 45611.4 9.7 5288.6 7.2 5425.8 4.8 3753.1 2.3 290

Free Cooling

Variable Speed Drives

Heat Pumps?

The Answer