Proposal of a double ejector-two flash tank absorption refrigeration cycle: Energy, exergy and thermoeconomic evaluation

Abstract

This research presents the proposal of a double ejector-two flash tank absorption refrigeration cycle, in which vapor and liquid ejectors are implemented simultaneously before the condensers and absorbers components. For the vapor ejector simulation, the shock circle approach is used. The internal environment of the vapor ejector, including the chocking phenomenon and the irreversible shock process, is also thoroughly examined. It is proposed that ejectors and flash tanks can improve the system performance. It is possible to improve the ejector entrainment ratio by incorporating a flash tank between the evaporator and condenser, which would also increase the evaporator cooling effect. Moreover, a second flash tank is installed between the generator and the absorber, which allows the generator to operate at a lower temperature and thus reduces the generator heat load. Consequently, the system's COP (coefficient of performance) increases. Furthermore, the unit cost of the final product in a wide range of operational conditions is calculated. The findings revealed up to 56.8% increase in the COP. The improvement of the maximum exergetic efficiency in the new cycle compared to the basic cycle also reaches 22.5%. Moreover, the thermoeconomic investigation show up to 34.6%. reduction in product cost.