Fundamental Study on System Efficiency of Vacuum-based Membrane Dehumidification System

In recent years, the sensible heat load of buildings has been decreasing due to the promotion of energy conservation, and the sensible heat factor is expected to decrease. In response, the conventional dehumidification method using overcooled condensation is likely insufficient to handle latent heat, and an advanced dehumidification method is required. The authors have focused these issues and development on a dehumidification method using membranes. Membrane dehumidification systems (MDS) are relatively simple, then it is expected to be next-generation dehumidification system. Therefore, to evaluate the energysaving performance of MDS, this study developed an energy consumption balance equation for a system that uses overcooled & reheating and MDS, and verified energy-saving performance under different conditions. The results of the study quantitatively showed the system efficiency (Specific energy consumption, vacuum pump consumption per unit of dehumidification) of MDS, which is the amount of energy saved by MDS compared to the conventional system under the specified COP of the cooled heat source equipment and reheating equipment. The system efficiency at which MDS is superior under different room sensible heat factors and membrane utilization methods are also clarified. This enables determining the required system efficiency when considering the introduction of a MDS, and understanding the conditions for introducing a system in which MDS is competitive.