Design of adsorption chillers under rolling conditions in naval applications: Experimental and numerical approaches

Abstract

International shipping is one of the major contributors to the overall greenhouse gases emissions and therefore its decarbonization is a key priority worldwide. Among the possible energy efficiency measures, the use of waste heat for cooling through adsorption chillers has gained significant attention. However, the proper integration of such kind of chillers on board needs to consider the effect of the rolling movement of the ship. In the present work, two different sorption modules (i.e the couple of adsorber + evaporator/condenser) are experimentally tested in horizonal position and at different inclinations, considering permanent tilting or continuous moving. The results were subsequently used for the implementation in a dynamic simulation model and the design of the chiller for application on passengers’ vessels. Results showed that operation under constant inclination of 30° resulted in a reduction of the cooling energy supplied by 22.5 % for the module with zeolite and by 55.8 % for the module with silica gel. The highest specific cooling energy (SCE) is 0.26 kWh/kg for the zeolite module and 0.18 kWh/kg for the silica gel module. The main issues underlined under tilted operation is the progressive reduction of the water level in the evaporator, which causes incorrect operation of capillary-driven evaporation. Accordingly, the increase of water level in the evaporator was suggested as mitigation strategy. It was however found out that the issue is only relevant if prolonged operation in a tilted condition is foreseen, but not under typical rolling operation with continuous movement.