The modern air conditioning system cools an indoor space by using the refrigeration cycle. Some parts of the system have energy-packed refrigerant that is ready to release heat, whereas other parts have energy-depleted refrigerant that is ready to absorb heat. The Four Core Components Four core components (the compressor, the condenser, expansion valve, and the evaporator) work together to control when/where refrigerant is absorbing heat, and when//where refrigerant is absorbing heat, and when/where it is releasing heat.