This paper discusses the behavior of methanol through an ejector operating in a refrigeration system with a medium temperature thermal source. For detailed calculation of the proposed system, a method has been developed, which employs analytical functions describing the thermodynamic properties of methanol. The proposed cycle has been compared with a Carnot cycle working at the same temperature levels. The influences of three major parameters, generator, condenser and evaporator temperatures, on ejector efficiency and coefficient of performance are discussed. Also, the maximum value of COP was estimated by correlation of the above three temperatures for constant superheated temperature 150 degreesC, and it was 0.139-0.467. The design conditions were generator temperature 117.7-132.5 degreesC, condenser temperature 42-50 degreesC and evaporator temperature -10-5 degreesC. (C) 2004 Elsevier Ltd. All rights reserved.