Experimental analysis and simplified modelling of a hermetic scroll refrigeration compressor

The first part of this paper presents a detailed analysis of the results obtained in a previous experimental study. In the frame of that study, a hermetic scroll compressor has been equipped with internal sensors by the manufacturer. The analysis reveals the main processes affecting the refrigerant mass flow rate as well as the compressor power and the discharge temperature. Based on these experimental results, a simplified model of the scroll compressor is proposed. It assumes that the refrigerant mass flow rate is affected by a suction temperature increase due to heat gained from a uniform wall temperature. This fictitious wall is supposed to gain heat from the electromechanical losses and from the discharged gas and to loose heat to the suction gas and to the ambient. The compression process is considered to be isentropic up to the 'adapted' pressure and then isochoric until the discharge pressure. The model is able to compute variables of primary importance, like the mass flow rate, the electric power and the discharge temperature, as well as secondary variables such as suction heating-up, discharge cooling-down, and ambient losses.