Investigation on the Performance of a Compact Three-Fluid Combined Membrane Contactor for Dehumidification in Electric Vehicles

Abstract

In this paper, the performance of a compact Three-Fluid Combined Membrane Contactor (3F-CMC) is investigated using Computational Fluid Dynamics (CFD), supported and validated with a good agreement by an experimental campaign made on a fully working prototype. This internally-cooled membrane contactor is the core component of a hybrid air conditioning system for electric vehicles (EVs) developed in a successful H2020 project called XERIC. In the adopted numerical approach, the conjugate heat and mass transfer inside the 3F-CMC is described by non-isothermal incompressible flows and vapor transport through a PTFE hydrophobic membrane. The sensitivity of the 3F-CMC performance to air/desiccant flow rates, temperature, humidity, and desiccant concentration is analyzed numerically through the validated CFD codes. According to this study, the moisture removal increases by the inlet humidity ratio, nearly linearly. Under the considered conditions (where the inlet air temperature is 26.2 °C), when the inlet relative humidity (RH) is 75% the moisture removal is about 450% higher than the case RH = 37%, while the absorption effectiveness declines about 45%. Furthermore, this study shows that the amount of absorbed vapor flux rises by increasing the airflow rate; on the other hand, the higher the airflow rate, the lower is the overall absorption efficiency of the 3F-CMC. This investigation gives important suggestions on how to properly operate a 3F-CMC in order to achieve the requested performance, especially in hot and humid climates.

Dynamic Modelling and Performance Prediction of a Multi-unit Baseline Air Conditioning System for a Generic Bus under Part-Load Conditions

“…In recent years, various studies have been conducted on the AC functionality and thermal comfort, mostly for buildings [1] or passenger cars [2,3,4,5], while very little research has been published on buses [6,7,8]. On top of that, these studies can be categorized into two main groups based on whether the emphasis is on the cooling system or just indoor space.…”

“…On top of that, these studies can be categorized into two main groups based on whether the emphasis is on the cooling system or just indoor space. In fact on one hand, some studies have emphasized the thermal modelling of indoor/cabin spaces trying to evaluate the thermal loads and the comfort condition by means of detailed CFD (Computational Fluid Dynamics) [5,9,10,11] or lumped-parameter models. For example, Marcos et al [2] developed a thermal model of the cabin in passenger vehicles using Simulink-MATLAB.…”