Many chemical processes require refrigeration over a broad range of low temperatures. Gas-phase refrigeration systems can provide cooling down to cryogenic temperatures, using auto refrigeration to cool the refrigerant before it is expanded. The economics of these systems are dominated by the shaftwork supplied to the compressors and the capital cost of the rotating equipment, both the compressors and the turboexpanders. A shaftwork targeting method has been developed for gas-phase refrigeration systems that require a continuous cooling load from ambient to some minimum temperature. The method involves the use of a number of gas-phase refrigeration loops which are matched against the grand composite curve. The targeting method is used to demonstrate the relationship between the expansion/compression pressure ratio and the heat-exchange design parameter Delta T-min. The potential for shaftwork recovery from surplus cold streams is also explored. Some interesting insights from the targeting are the relative insensitivity of the pressure ratio and the importance of the isentropic efficiency especially for energy recovery from cold streams.