1. Air Conditioning System − 2
Created by: David Chadderton
8 November 2018

2. Packaged Room Air Conditioner and Evaporative Cooling Principal Operation
8 November 2018

3. Packaged air conditioning − RAC
Through the wall room air conditioner used in small rooms, offices, workshops, motel rooms and homes.
Noisy.
Reverse cycle heat pump.
Same as car air conditioning system.
Same as refrigerator operation.
Hermetically sealed refrigerant reciprocating piston compressor and electric motor, scrapped on failure.
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9. Condenser, cools and liquefies the refrigerant at 40oC
Heat rejection
Condenser, cools and liquefies the refrigerant at 40oC
8 November 2018

10. Hot high pressure gas, 50oC
Heat rejection
Condenser, cools and liquefies the refrigerant at 40oC
Warm liquid high pressure, 30oC
8 November 2018

11. Condenser, cools and liquefies the refrigerant at 40oC
Hot high pressure gas, 50oC
Heat rejection
Condenser, cools and liquefies the refrigerant at 40oC
Outside air,
0oC to 40oC
Warm liquid high pressure, 30oC
8 November 2018

12. Condenser, cools and liquefies the refrigerant at 40oC Heat absorption
Hot high pressure gas, 50oC
Heat rejection
Condenser, cools and liquefies the refrigerant at 40oC
Heat absorption
Evaporator, boils the liquid the refrigerant at 5oC
Outside air,
0oC to 40oC
Low pressure liquid and flash vapour, 5oC
Warm liquid high pressure, 30oC
8 November 2018

13. Condenser, cools and liquefies the refrigerant at 40oC Heat absorption
Hot high pressure gas, 50oC
Heat rejection
Condenser, cools and liquefies the refrigerant at 40oC
Heat absorption
Evaporator, boils the liquid the refrigerant at 5oC
Cooling coil in air conditioning
Outside air,
0oC to 40oC
Warm liquid high pressure, 30oC
Low pressure liquid and flash vapour, 5oC
8 November 2018

14. Cold low pressure vapour, 5oC
Hot high pressure gas, 50oC
Heat rejection
Condenser, cools and liquefies the refrigerant at 40oC
Heat absorption
Evaporator, boils the liquid the refrigerant at 5oC
Cooling coil in air conditioning
Outside air,
0oC to 40oC
Warm liquid high pressure, 30oC
Low pressure liquid and flash vapour, 5oC
8 November 2018

15. Ground Source/Sink Heat Pump
Condenser
Underground
In-ground plastic pipe coils to reject heat from the air conditioning system refrigerant condenser. This replaces the use of a cooling tower. No maintenance requirement. Running cost of only one pump, same as with a cooling tower, but minus the cooling tower fan and water treatment chemicals. Can be suitable for small buildings on well-drained sloping grassland by a river to ensure heat removal from the soil.
8 November 2018

16. Evaporative Cooling
Directly evaporating mains cold water within a ventilated air handling unit is used in hot dry climates such as southern Australia where the atmospheric humidity is usually in the range of 20% to 40% year round, unless it is actually raining. (This is not very often!)
It is the same principal as used by a cooling tower, except that air is the medium being cooled. This is the air breathed within the building.
Characteristics of individual units and ducted systems:
Very low energy use
Low water consumption
High air change rate − up to 60 per hour, one a minute
Noticeable high air flow
Can be noisy
Individual units on roof
Ducted systems
Indoor air becomes more humid − 70%, noticeable
Low cost
Highly effective
Minimal maintenance
8 November 2018

17. Ducted, roof mounted direct contact evaporative cooler
Water spreader
Mains cold water
Supply air duct to room passing humid cooled air
Filter material
Hot dry external air, 30oC+ and 25% percentage saturation
Axial fan
Overflow from water tank
8 November 2018

18. End
8 November 2018