Schaff, Francesco Nima (2014-08). Design and Development of a Vacuum Dehumidification Test Facility. Master's Thesis.
A test facility was designed and constructed with the capability of isolating critical variables for controlling the novel membrane dehumidification-enabled cooling system's operation parameters as well as for acquiring preliminary membrane and cooling system performance measurements. The completed test facility consisted of two systems: 1) the feed-air system, which simulated the inlet-air conditions and performed the feed-air dehumidification and sensible cooling and 2) the vacuum system, which enabled the feed-air dehumidification by evacuating the membrane permeate side. The feed-air system as constructed was able to supply membrane-inlet flow rates up to 10 scfm over a range of temperature and relative humidity conditions, including 90?F and 90%RH, which was specified by the project sponsor. In addition, the feed-air system components included a membrane module installation site for dehumidification as well as a sensible cooling system to cool the membrane-outlet air to the 55?F and 50%RH conditions again specified by the sponsor. Measurement stations were placed at the membrane-inlet, membrane-outlet, and the sensible cooler outlet to measure the temperature and relative humidity at these critical locations. The vacuum system as built used a Pfeiffer DUO 10 Vacuum Pump with a 7 cfm pumping capacity, which was preceded by a 60 plate heat exchanger with an effective area of 2.05m^(2) and an Oerlikon-Leybold WA 250 roots blower. The air leakage in the vacuum system was calculated to be less than 1% of the theoretical air permeation through the membrane module. Finally, the apparatus was constructed with the capability of measuring the power consumption of the equipment used for the dehumidification and sensible cooling process.
The functionality of the test facility was demonstrated through preliminary testing of the membrane module and the operation of the complete cooling system. The results suggested that the membrane material exhibited an increase in water vapor permeance from temperatures of 70 to 100?F, with calculated permeance values ranging from to 3.93 ? 10^(-6) to 5.88 ? 10^(-6) kmol/kPa-m^(2)-s. In addition, the results indicated that the novel membrane dehumidification-enabled cooling system was capable of achieving the specified operating conditions at a feed-air flow rate of 0.16 scfm by using a membrane module area of 0.024m^(2).