1. Compressor
2. Condenser
3. Expansion valve
4. Evaporator
Besides those, Air Conditioner needs refrigerant as work fluid. Refrigerant encircle at each main component and undergo the process accordant each component.
Figure 1. Scheme Of Refrigeration Cycle
Figure 1. is scheme of refrigeration cycle. At figure 1, there is four main components which are connected by lines with narrow. The lines are describe as a pipe and the narrows are describe the direction of cycle.
REFRIGERATION COMPONENTS
1. Compressor
Compressor can be analogized with heart in our body. Compressor has function in suction refrigerant from evaporator and flows it to condenser. The difference pressure can be happened because of component compressor and expansion valve. Compressor discharge refrigerant and the expansion valve hampers flow of refrigerant, so that the pressure after compressor until expansion valve become high.
Figure 2. Compressor (Source figure: americanhvacparts.com)
2. Condenser
Condenser is a refrigeration component which has function to condense the refrigerant from gas phase to liquid phase. To condense gas phase to liquid need remove heat. The heat from condenser is removed to anything surrounding the condenser, in common Air Conditioner usually remove heat to air surrounding the condenser. Condenser is put outside the room or building that will be cooled.
Figure 3. Condenser (Source: picsicio.us)
Common Air Conditioner, Condenser is a Heat Exchanger which consist pipe and fins. Air is flown to fins of heat exchanger then the heat transfer occur from condenser to the air. It is because of condenser temperature is higher than surrounding air.
3. Expansion valve
Pressure drop is the main function of expansion valve. It has a small section area, so that the refrigerant flow is hampered by it. The pressure of refrigerant before through the expansion valve is high, then the pressure suddenly drop after pass the expansion valve. The temperature also drop because the pressure drop. At figure 4, it is described how the basic principle the refrigerant flow through the expansion valve.
Gambar 4. (a) Scheme of refrigerant flow in Expansion Valve
(b) contoh gambar katup ekspansi
4. Evaporator
Like its name, evaporator has function to evaporate refrigerant that flow through it. To evaporate refrigerant need energy (heat). The heat energy is come from the object which will be cooled. The object of air conditioner system is air in the room or building.
Same with condenser, evaporator is a heat exchanger which consist pipe and fins, but has reverse function. Air in the room is flown through the fins, so that heat transfer from air to evaporator occur.
Gambar 5. Contoh Evapoartor (sumber gambar: diytrade.com)
Pressure, temperature, and phase in refrigeration cycle
As known, temperature has proportional relation with pressure. Increase the pressure then increase the temperature. Pressure, temperature, and phase which are shown at the points number 1 until number 4 in figure 1 are explained bellow:
1. Output from evaporator then will enter the compreesor, Pressure: Low, Temperature: Low, Phase: Gas
2. Output from compressor then will enter the condenser. Pressure: high, Temperature: high, Phase: gas (Super-heated)
3.Output from condenser then will through expansion valve. Pressure: high, temperature: high, Phase: liquid
4. Output from expansion valve then will enter evaporator. Pressure: Low, temperature: Low, Phase: mix liquid-gas (most of them are liquid).
