Design optimization of plate heat exchanger absorbers and desorbers for hybrid absorption compression heat pumps

Design optimization of absorber and desorber in hybrid absorption compression heat pumps (HACHPs) is of paramount importance to reduce the installation costs of these systems. This paper presents a simulation framework to optimize the design of plate heat exchangers (PHEs) to be used as absorption and desorption units in HACHPs.

A case study of a single-stage HACHP was chosen as an example to utilize the framework. A PHE design model was coupled with a cycle design tool, and the trade-o between heat transfer area and pressure drop in both absorber and desorber was established by estimating the impact of pressure drops on the heat pump thermodynamic performance.

Corrugation geometry, plate size and count were selected as design variables for the optimization procedure, in order to obtain a diversied range of optimal solutions. It was found that the desorber pressure drop entails a higher degradation of the thermodynamic performance compared to the absorber,and the two limits of maximum allowable pressure drops of 15 kPa and 35 kPa were selected.

The design optimization showed that it is preferred to choose corrugation geometry parameters, such as chevron angle, corrugation pitch and height, with the aim of enhancing the heat transfer at the expense of pressure drop. On the other hand, a diverse range of plate size and count was obtained as output of optimization.The results demonstrate how to select optimal congurations of PHE absorber and desorber for HACHPs.