Development of a test rig to investigate refrigerant-vapour absorption on a vertical structured plate

Absorption heat pumps have the potential to abrogate the consistent increase in the demand for space cooling and heating, due to their utilisation of solar energy, industrial waste heat, or fuel gas instead of electricity. These heat pumps typically employ shell-and-tube heat exchangers and are relatively new to the residential sector. However, in order to be apt for domestic use, a more compact, effective design using plate heat exchangers is required. In this regard, this research aims to develop a test-rig to optimise vapour-refrigerant absorption on a vertical plate, adhering to a selected optimal plate structure to maximise wetting and thus heat and mass transfer phenomena. The test rig was developed as a set of identical, pairwise plate heat exchangers and simulated on Engineering Equation Solver at 6 different operating points for 2 configurations: 1 – generator/absorber (OPs 1,2,3,5) and 2 – evaporator/condenser (OPs 4,6). Additionally, several thermodynamic parameters were varied in order to observe the impact of this variation on the test rig and to therefore obtain a comprehensive understanding of the functioning of the test rig. Operating point 5 for configuration 1 yielded the highest values for the saturation temperature Tsat, internal pressure p0, internal temperature Ti and capacity Q. On the other hand, operating point 1 resulted in the lowest values for Tsat and p0, and operating point 2 with the lowest values for Ti and Q. With respect to configuration 2, the higher values for Tsat, Ti, p0 and Q were obtained for operating point 6, with the lower values being obtained in operating point 4. Recommendations have been made for further testing on the test rig. The literature review also provides a recommendation for selecting the initial plate design, using detailed examples outlined in this research. Various plate structures should be experimented on using the test rig.