Tanskyi, Oleksandr (2015-07). Zeolite Membrane Water Vapor Separation for Building Air-Conditioning and Ventilation Systems. Doctoral Dissertation.
Thesis
This dissertation presents the findings of a microporous molecular sieve zeolite composite membrane experimental study for dehumidification in building ventilation and air-conditioning systems. The dependence of membrane water and air permeance from inlet airflow parameters (flow rate, humidity, temperature), and permeate total pressure was experimentally studied. Based on the obtained results, the membrane dehumidification system and the membrane air-conditioning system's annual energy efficiency were estimated in an actual building located in a hot and humid climate. Membrane dehumidification process application was considered in three main areas: an energy recovery ventilation (ERV) system, an outdoor air dehumidification for dedicated outdoor air system (DOAS), and an air-conditioning system that combines an evaporative cooling and the membrane dehumidification system. Application of the membrane separation process for building air-conditioning provides several advantages: improvement of an occupant's health and comfort due to better ventilation rate, better energy efficiency, operation without fluorocarbon refrigerant, capability to collect pure water from the airstream during dehumidification process, no condensation during dehumidification provides mold resistant system, and separate control of sensible and latent load. The experimental data revealed, that with the existing technology studied zeolite membrane average effective air permeance does not exceed (3+-0.5)E-9 kmol/(kPa-m2-s), and average effective water permeance is at least (5+-2)E-6 kmol/kPa-m2-s that provides a membrane selectivity coefficient above 1500. The analytical model of the membrane ERV systems showed that at the design conditions, the ERV system can provide 0.78 cross-flow enthalpy effectiveness with a membrane area of 0.25 m2/cfm (0.42 m2/ (m3/h)). The application of the membrane dehumidification system in a typical office building can provide an increase in dehumidification process energy efficiency from coefficient of performance of 4.1 to 7.4. This change in the coefficient of performance will provide energy savings between 6% and 10% for a conventional HVAC system. The membrane air-conditioning system analysis show that the system operating in actual weather conditions of College Station, Texas can provide annual energy efficiency of 0.98 kW/TR with further possibility to reduce energy consumption to 0.62 kW/TR (COP 5.7).
