Microline’s calorimeter measures the performance (C.O.P) of single/three phase hermetic refrigeration compressors, according to norms EN 13771-1 / ISO 917 / ASHRAE 23. This equipment has many functional options and has been implemented and re-projected: among its strengths are the built-in climatic chamber and the double measurement circuit to guarantee high accuracy. The calorimeter features the following news: improved sensors configuration for a better accuracy of calculation of cooling capacity and C.O.P.; conditioning by water chiller (climatic chamber temperature, condensing, subcooling) to increase temperatures stability and wider temperatures rangeability; possibility to set the air flow around the compressor to test the compressor without ventilation; new vessel (redesigned to reduce mass and increase cooling capacity range) for faster regulation and wider cooling capacity rangeability; gas circuit redesigned to minimise oil deposit; and downsize of the test rig for a easier positioning.As well as C.O.P. tests, the calorimeter can also carry out startability and break down tests. It comes with one or more work stations, with integrated or separate climatic chamber. The interface software is used to define, view and monitor the test sequences, and the numerical and graphic presentation of the results assists in defining improvements to be made in order to develop the project.