Air cooled chillers– These are basically refrigeration systems which are mostly used in commercial and industrial facilities to cool fluids or dehumidify air. Mostly, they are used in hotels, corporate events, restaurants, sporting events, industrial and manufacturing plants etc. They are mostly installed externally, either on the roof or at ground level. This is because they do not require cooling tower, though they shack their heat in the ambient air and therefore require lots of fresh air, to reject unwanted heat.
FEATURES OF AIR-COOLED CHILLERS
Air cooled chillers uses air to fuel condensers cooling. They are easier and less expensive in maintenance. They are easy to install and can be installed outside a building without any extra space. In short, it requires less space.
The most important feature is that they don’t require cooling tower. So, they cost less. But on the other hand, they require more energy or power. They are more prone to blockages.
HOW DO AIR COOLED CHILLERS WORK?
Air-cooled chillers actively soak up heat from process water; after that they simply transfer the same heat into the air around the chiller unit. This type of unit is typically used in areas where additional heat discharge is not an issue at all, but it works as a benefit.
Now exactly what happens- cycle starts with the evaporator/heat exchanger. This Evaporator has a liquid refrigerant that runs over the evaporator tube bundle. Now in this process, heat is soaked from the chilled water which is circulating through the evaporator tube bundle. Now the work of the compressor began, and it pulls the refrigerant vapor from the evaporator. The compressor is then assigned with pumping the refrigerant vapor to the condenser, which increases temperature and pressure, and refrigerant condenses when it’s in the condenser tubes only, freeing its internal heat to the external air. The high-pressure liquid then moves through the expansion device and enter into the evaporator; in this process the refrigerant pressure is decreased along with the temperature. To finish the continuous cycle, the refrigerant rush back over the chilled water coils and suck up more heat.
COMPONENTS OF AIL COOLED CHILLER
The essential components of air-cooled chiller are the Compressor, Condenser, condenser fans, Evaporator, Expansion Valve.
- Compressor– It provides the driving force for moving the refrigerant. It is fixed between the evaporator and the condenser. It has an electric motor as the driving force, which is either mounted outside or laid internally. Basically, it is the heart of the air-cooled chiller.
- Condenser– A condenser is placed close to the expansion valve and compressor. The main task of the condenser is to remove the heat from the refrigerant that is picked up in the evaporator. Condensers are of two types, i.e., air-cooled condensers and water-cooled condensers.
- Condenser Fans– these fans show the basic difference between air cooled chiller and the water-cooled chiller. As and when they move air across the condenser, unwanted heat is removed in the system and released in the open air.
- Expansion Valve- The expansion valve expands the refrigerant and enlarge its volume, which allows the refrigerant to pick up heat in the evaporator. There are different types of expansion valves, but the most common and important type is the thermal expansion valve which is pilot operated.
- Evaporator– An evaporator is used to pick up heat from the building and throw it to the refrigerant so that it can be sent to the cooling tower. An evaporator is laid between the compressor and the expansion valve. when the heat is extracted, the water became cool. Now this chilled water is sent throughout the building for the purpose of air conditioning.
TYPES OF AIR-COOLED CHILLERS
- Stationary air-cooled chillers- When excess heat is not an issue, Stationary air-cooled chillers are used.
- Portable air-cooled chillers- These chillers are functional as stationary chiller and are portable in nature. This is the only difference between both air-cooled chillers.