| Abstract | Dehumidification technologies in building air conditioning systems become more important as sensible load decreases with thermal improvements in passive systems (i.e., air tightness, insulation). An isothermal dehumidifier, which has a separate membrane
and uses a vacuum pump to generate a partial vapor gradient between the membranes,
can significantly reduce energy consumption because it only manages latent cooling,
regardless of temperature fluctuations. A single vacuum pump-based membrane
dehumidifier, on the other hand, has a low coefficient of performance (COP). This is
because the vacuum pump has to work at a high compression ratio (over 101) to create a
partial vapor pressure difference. In this study, we proposed a cascade vacuum pump-
based membrane dehumidifier to reduce the isothermal dehumidifier's energy
consumption. To reduce the vacuum pump's compression ratio, the system incorporates
multiple vacuum pumps and heat exchangers. We made a thermodynamic model of the
suggested system and tested how well it worked in terms of energy and dehumidification
under different operating conditions, such as air flow and vacuum pumps, and
membrane properties, such as permeance and selectivity. The result showed that the
energy performance (i.e., COP) of the proposed system is 30% higher than the
conventional membrane dehumidifier by reducing the compression ratio and improving
heat rejection from vacuum pump operation. |
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