ABSTRACT
The multiplicity of three-stage configurations is now used as an example to demonstrate the diversity of multistage configurations. The most general four-stage absorption configuration contains 13 exchange units and 4 independent working fluid streams. A method is presented to calculate the COP of advanced absorption cycles very quickly if the efficiencies of single-stage absorption heat pumps or absorption heat transformers are known. The method provides detailed results for the heat input and output of individual exchange units. To account for irreversibilities of the pump, an efficiency could be introduced into the equations. The mechanical work, which is converted to heat due to irreversibilities, mainly increases the heat load of the absorber, but also reduces slightly the input into the generator. With the method based on the superposition principle, the COP can be estimated for complicated advanced absorption cycles within an accuracy of about 10%.
