Q15Basic Mechanical Engineering
Question
What is air conditioning? Draw and describe different component used in it.
Answer
Air conditioning is the comprehensive treatment of indoor air to strictly control temperature, humidity, purity, and motion. It relies on a compressor, condenser, expansion valve, and evaporator.
What is Air Conditioning? Air conditioning goes beyond simple refrigeration. It is the simultaneous and precise control of the physical and chemical qualities of air within a designated space to meet the physiological comfort requirements of human occupants (Comfort AC) or the strict environmental demands of a manufacturing process (Industrial AC). The core parameters controlled are Dry Bulb Temperature, Relative Humidity, Air Purity (filtration), and Air Velocity.
Core Components (The VCR Cycle inside an AC):
- 1. Compressor: The electrically driven heart of the system. It sucks in low-pressure, low-temperature refrigerant gas from the evaporator and violently compresses it, raising its pressure and temperature significantly.
- 2. Condenser Coil: Located in the outdoor unit. The blazing hot, high-pressure gas flows through these coils. A large fan blows outdoor ambient air over the coils. Because the gas is much hotter than the outside air, it rejects massive amounts of heat to the atmosphere, condensing back into a high-pressure liquid.
- 3. Expansion Device (Capillary Tube): This acts as a severe bottleneck. The high-pressure liquid is forced through a tiny orifice, causing a massive pressure drop. This sudden drop causes the refrigerant to flash and its temperature plummets instantly, becoming a freezing cold liquid-vapor mixture.
- 4. Evaporator Coil: Located in the indoor unit. The freezing refrigerant flows through these coils. The indoor blower fan sucks warm, humid room air and blows it over the freezing coils. The refrigerant absorbs the room's heat, boiling completely into a gas, simultaneously cooling the air. Excess humidity in the air condenses on the cold coils and drains away.