There have been several recent developments that have affected the design and operation of refrigerator compressors. The most significant changes have been brought about through legislation concerning the use of CFCs and those relating to the close control of chilled food storage cabinets. Other developments affecting the selection and operation of refrigerator compressors include the steady fall in the cost of electronic components, which has challenged designers to produce innovative control systems. In addition, the recent application of advanced scroll and screw compressors, and developments in heat exchanger technology, have lead to more compact and efficient refrigeration systems.