Role of Condenser in Chiller?
To understand its role fully, it’s best to see it in the context of the refrigeration cycle:
- Evaporator: Absorbs heat from the building’s chilled water loop, causing the liquid refrigerant to boil and turn into a low-pressure, low-temperature vapor.
- Compressor: Squeezes this refrigerant vapor, significantly increasing its pressure and temperature. It becomes a high-pressure, high-temperature superheated vapor.
- Condenser: This is where the condenser does its job.
- Its primary function is to condense—to turn that high-pressure, high-temperature refrigerant vapor back into a liquid.
- To do this, it must reject heat. The superheated refrigerant vapor enters the condenser coils. As it moves through the coils, it first de-superheats (cools down to its saturation temperature), then it condenses, releasing a massive amount of latent heat.
- This heat is transferred to a medium (water or air) that is cooler than the refrigerant.
- Expansion Valve: The now high-pressure liquid refrigerant passes through an expansion device, where its pressure and temperature drop drastically before entering the evaporator to start the cycle again.
Key Functions of the Condenser:
- Heat Rejection: It is the point in the system where all the heat from the building (absorbed by the evaporator) plus the heat of compression (added by the compressor) is expelled.
- Phase Change: It facilitates the critical phase change of the refrigerant from a gas to a liquid. This liquefaction is essential for the cycle to continue efficiently.
- Subcooling (Bonus Function): After the refrigerant has fully condensed into a liquid, it often continues to give off a little more heat. This process, called subcooling, ensures the refrigerant is 100% liquid and cools it further below its condensation point. This improves system efficiency and prevents flash gas (premature evaporation) before the expansion valve.