Refrigeration by absorption is gaining more and more importance nowadays especially in applications where the source of energy used in the generator is renewable. However the major problem of this type of refrigeration lies in the COP, which seems to be weaker than compression machines. The use of an ejector is one of the means that can help overcome this problem. In this work, we are interested in the ammonia-water absorption cycle comprising a gas-gas ejector interposed between the generator and the condenser. We suppose that adding a flash tank between the condenser and the evaporator could help improve the entrainment ratio of the ejector. Simulations using the Hysys software are performed in order to look for the optimal conditions for the work of this machine and to make a comparison in terms of performance with single effect cycles. Results showed a significant improvement in the COP and proved therefore that it has better performance than single effect cycles.

The absorption refrigeration machines represent a good alternative to compression refrigeration machines but the major problem of this type of refrigeration lies in the COP, which seems to be less efficient. Several researches are carried out to improve the performances of these machines such as the combination with the technology of the ejectors. In this work, we are interested in the three ammonia-water absorption cycles: Single effect absorption, Ejector-absorption and Combined ejector-flash tank absorption cycles. A gas-gas ejector would be installed between the generator and the condenser. We suppose that adding a flash tank between the condenser and the evaporator could help improve the entrainment ratio of the ejector. We used simulations in order to compare the performances of these three different cycles. The simulation results demonstrate that the combined ejector-flash tank absorption cycle performs better than others.

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