An ejector refrigeration system has been designed and constructed to operate with hot water. Such a refrigeration system, designed for low pressure refrigerants, can be operated using energy sources such as solar energy, geothermal energy and waste heat. In this study, the effects of the main operating parameters on system performance were experimentally investigated using R-11 as the working fluid and keeping constant the position of the primary nozzle end at the inlet plane of the mixing chamber section of the ejector. The experimental study was performed over a range of vapor generator temperatures from about 90 to 102 C, evaporator temperatures from 0 to 16 C and condenser pressures from 114 to 143 kPa, and a COP up to 0.25 was obtained. It was seen that if higher cooling capacity and also lower evaporator temperature are desired from the system, the vapor generator temperature should be increased considerably. (C) 2006 Elsevier Ltd. All rights reserved.