An experimental study has been undertaken to evaluate some theoretical studies on the compression and heat transfer process in reciprocating compressors. A two cylinder unit was equipped with suitable pressure sensors to measure and store the pressure-time function of the refrigerant. From the known geometry of crank-piston mechanism and the related thermodynamic relations the heat transferred between refrigerant and cylinder wall can be obtained. The position of the Top Dead Center can be defined either in a thermodynamic way or by a magnetic pick-up. The influence of the rotating speed is examined by taking measurements at different speeds. The results are compared to existing heat transfer relations to investigate their efficiency. The model used predicts with sufficient accuracy the heat transfer process.