AIR-CONDITIONING SYSTEM

AIR-CONDITIONING SYSTEM

1. Definition: Process altering properties of air to favorable condiotions

   • Objectives/Functions: 1. Control air temperature 2. Control Air Quality 3. Control Air Circulation 4. Control Air Humidty
     • Process: 1. Heating/Cooling 2. Humidification 3. Filtration/Purification 4. Ventilation&AHU circulation
       • Importance: Prevent noise&environmental control, Ventilated, Humidity Control, Good Air Circulation
         • Factors influence design: Airspace, Environment, Building Orientation, Activities&Facilities
           • Principles: Every air-conditioner comprises of compressor, condenser, expansion valve, evaporator

2. REFRIGERATION CYCLE

   • Cooling the air in an area while extracting the hot air and remove it from vicinity
   • Closed cycle of: Evaporation, Pressure change, condensation and refrigerant
   • Refrigeration Process
     • Evaporation
       • Remove heat
       • Warm air from room is blown across the evaporator coil by fan, pipe that comprising the coil are supplied with cold liquid refrigerant
       • When warm air passes through evaporator coil it is cooled, and the cool air delivered back to the room
       • Refrigerant inside is evaporating/boiling, change from liquid to gas
       • At this point, refrigerant is a cool gas in a small pipe that carry the heat energy away

3. COMPRESSION

   • The vaporized but cool refrigerant carry heat from data center into a compressor
     • Function compressor: 1. Push the refrigerant that carry heat energy around refrigeration loop. 2. Compresses the gaseous refrigerant
       • The compression of gas causes temperature to rise. Therefore, moving gaseous refrigerant exiting the compressor is hot. This temperature rise due to ability of refrigeration loop to eject heat to outdoor.

4. CONDENSATION

   • Hot compressed refrigerant carries heat energy from compressor to Condensor Coil
     • This coil transfer heat to another medium like air
       • Condenser coil operate at higher temperature than the air
         • Air flowing is heated by the coil, hot gaseous refrigerant flowing through the coil is conversely cooled
           • The air blown across the hot coil by a fan

5. EXPANSION

   • Refrigerant exits Condenser Coil as high pressure liquid
     • Then passes to an expansion valve before return to Evaporator Coil
       • Precisely regulate high pressure refrigerant into low pressure evaporator coil that maintain an optimal difference in pressure to ensure all refrigerant is evaporated
         • High pressure refrigerant expanded as gas as it escapes Expansion Valve
           • Causes temperature to fall. Refrigent is cooled by release of pressure. Then re-enters to Evaporator Coil

6. TYPES OF AIR-CONIDITIONER

   • Window system
     • Commonly used for single room and cheapest
       • All components enclosed in a single box
         • Advantages: Easy to install, Room's temperature under control, Cost effective, No piping required. Disadvantages: Heavy weight, Space is needed, wall need to be hacked for installation
   • Split system
     • Comprises two parts: Outdoor and Indoor Unit
       • Outdoor unit: Compressor, Condenser, Expansion Valve. Indoor unit: Evaporator, Cooling fan
         • Advantages: Can used to cool 1/2 more rooms, Unit are removable, Do not have to slot at wall
   • Packaged system
     • Used to cool larger space
     • Possible arrangements
       • All components housed in a single box. Cooled air is thrown by high capacity blower, flows through ducts laid through various rooms.
       • Compressor and condenser housed in a single casing. Compressed gas passed through individual units, comprised of expansion valve cooling coil.
   • Centralized system
     • Cooling big building. Have huge compressor that has capacity to produce tons of air-conditioning.
       • In Typical Split System, Compressor and Condensor located in outdoor unit, evaporator is mounted in AHU. In Package System, all components located in single outdoor unit that can be located on the ground or roof.

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