Contribution of an internal heat exchanger to the performance of a liquid desiccant dehumidifier operating near freezing conditions

The aim of the present study is to analyze numerically the effect of an internal heat exchanger (IHX) in a liquid-desiccant based dehumidification system operating near freezing conditions that are typical of a refrigerated warehouse. The study is based on previous work done by the authors that showed reduced ice formation on the surface of a cooling coil by dehumidifying the air using liquid desiccants. The results of the present study show that IHX effectiveness has a direct impact on the inlet temperature of the liquid desiccant leaving the absorber. High IHX effectiveness results in high absorber effectiveness. However, IHX effectiveness less than 60% leads to a desorption process where the liquid desiccant concentration increases, augmenting the humidity ratio of the air going through the mass exchanger.

► An internal heat exchanger enhances air dehumidification of a liquid desiccant absorber inside a refrigerated warehouse.
► The dry air leaving the absorber delays frosting of cooling coils.
► An internal heat exchanger effectiveness below 60% leads to liquid desiccant regeneration.
► The operating conditions used in the simulations are typical of cold storages.