The article describes the market appearance of scroll compressors, the market analysis is made, advantages of scroll compressors over other types of compressors are discussed, operating principle of scroll compressors is described, compressor capacity depending of its geometry and the system of spiral elements is analyzed, the fields of compressor application is shown. The capacity of the compressor is analyzed in terms of simplified operational model based on conventional ratios for an ideal gas. Calculation results according to a more complex model taking into account gas leakage inside scroll compressor are analyzed. The obtained results for both models are compared. The influence of spiral parameters on the compressor capacity is evaluated based on the analysis data. The influence of gas leakages inside the compressor on its capacity is analyzed. Their prevalent role in calculating design capacity is highlighted. The design characteristics of the compressor with the use of the developed operating process model are compared with the experimentally observed characteristics of compressors made in Russia and abroad. The newest examples of scroll compressor design with variable geometry are given.