The heat pump chiller working principle is divided into two main parts: cooling mode (refrigeration cycle) and heating mode (heating cycle).
 Cooling Mode (Refrigeration Cycle):
Compressore:  
   The high temperature, high pressure refrigerant gas from the discharge outlet enters the four-way reversing valve.
Condensatore:  
   In the condenser, the refrigerant releases heat and condenses into a highpressure liquid.
 Liquid Receiver Tank:  
   The liquid refrigerant flows through one-way valve 1 into the liquid receiver tank.
 Valvola di espansione:  
   The high-pressure liquid refrigerant passes through the expansion valve and reduces its pressure, becoming a low-pressure liquid.
 Evaporatore:  
   The low-pressure liquid refrigerant enters the evaporator, absorbs heat from the environment, and evaporates into a low-pressure gas.
 Cycle Completion:  
   The low-pressure gas refrigerant returns to the compressor’s suction side via the fourway valve and liquid separator, completing the refrigeration cycle.
 
 Heat Pump Chiller Heater (Heating Cycle):
Compressore:  
   The high-temperature, high-pressure refrigerant from the discharge port passes through the four-way reversing valve into the shell heat exchanger, where it condenses into a high-pressure liquid.
 Liquid Receiver Tank:  
   The high-pressure liquid refrigerant flows through one-way valve 2 into the liquid receiver tank
 Valvola di espansione:  
   The high-pressure liquid refrigerant goes through the expansion valve, turning into a low-pressure liquid.
 Finned Heat Exchanger:  
   The low-pressure liquid refrigerant enters the finned heat exchanger, absorbs heat, and evaporates into a low-pressure gas.
 Cycle Completion:  
   The low-pressure gas refrigerant returns to the system through the compressor’s suction port, completing the heating cycle.