Membrane modules for building ventilation

"Sick Building Syndrome" occurs as a result of efforts to make our homes airtight and energy efficient. For good health, 8 liters per second per person of fresh air must be brought into buildings to replace stale indoor air and maintain air quality (ASHRAE, 1989). A tightly insulated house can provide much less than this. Opening a window provides fresh air, but wastes energy. This energy can be recovered with a heat exchanger. While conventional heat exchangers can help to retain the sensible heat of this outgoing air, an equal amount of energy may be lost in the humidity, i.e., the latent heat.; Various water vapor exchangers have been proposed to retain the latent heat of the exchanged air. These exchangers are of two types: rotary regenerators, which rely on a rotating disk of desiccant to move water from one air stream to another; and cross-flow exchangers, which mimic conventional heat exchangers with porous paper separating the air-streams. While both of these technologies may be viable, neither may be the optimal choice for transferring water vapor from one air stream to another.; In this work we propose using a hollow fiber module for heat and mass exchange. We hypothesized that the hollow fiber module would provide advantages over the flat sheet module. We constructed modules with both flat sheets and hollow fibers in order to compare the properties of the membranes as well as their overall performance within modules of different geometries. We examined the effect of varying both module length and packing fraction. By varying the former, we are able to simulate shell-side baffling and study its effects on transport and pressure drop. By varying the latter, we can test the limits of our hypothesis that hollow fiber modules offer improved area per volume over other geometries.; Each module was tested for water vapor transfer and pressure drop. Sensible heat transfer was estimated by analogy to mass transfer and verified experimentally. Data from these experiments are compared to existing correlations and used to create a model for the design of an ideal air-to-air exchanger device.