Abstract
Low temperature heat sources inherently result in lower cycle efficiencies, which can be improved by means of combined power and cooling generation. In order to produce power and cooling, appropriate thermodynamic cycles and working fluids must be used Goswami cycle is a combined cycle that produces power and refrigeration by using ammonia-water mixture for low temperature heat sources. In the present study, a scroll expander is modeled specifically for the cycle operating conditions and a theoretical investigation is conducted to determine the cycle performance. A scroll expander design suitable for the operating conditions improves the power output and thereby overall thermal efficiency. The scroll expander efficiency varied between 0.05 and 0.61 for the pressure ratio between 2.2 and 8.6, with a maximum efficiency of 0.697 achieved at a pressure ratio of about 4.4. An internal heat recovery from the rectifier is proposed along with a flow splitin the strong solution and analyzed for overall cycle energy efficiency improvement. Internal heat recovery from the rectifier increased the first law effective efficiency and the effective exergy efficiency by 7.9 % and 7.8 %, respectively, over the basic configuration.