POLO develops research activities with the objective of evaluating the performance of reciprocating compressors when in a refrigerator. In most refrigerators, the operation is typically transient and characterized by alternate periods at which the compressor is either operating (on) or idle (off). Currently, experimental tests are being conducted to evaluate several parameters of interest in a compressor operating in a refrigerator. These parameters include the temperatures of several compressor components, the mass flow rate, power consumption, and indicated power, among others.  The experimental data will be employed to validate a simulation model under development, which will allow the characterization of compressor performance under typical operating conditions of a refrigerator. Furthermore, an object-oriented equation-based programming language, called Modelica, is being used to develop part of the model, which is based on the C++ language. The experimental and numerical results will allow a deep analysis of the performance of reciprocating compressors in refrigerators, with focus on the main thermodynamic, mechanical and electrical losses under real operating conditions.