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Modelling of indoor air humidity: the dynamic behaviour within an enclosure

El Diasty, R., P. Fazio and I. Budaiwi
1992
Energy and Buildings, 19, pp. 61-73


El Diasty, R., P. Fazio and I. Budaiwi, (1992), "Modelling of indoor air humidity: the dynamic behaviour within an enclosure", Energy and Buildings, 19, pp. 61-73.
Abstract:
Indoor air humidity behaviour within an enclosure has been mathematically modebed. A linear differential equation is used to describe the response of indoor air humidity to different moisture transport processes within the space. The modelled processes include: moisture absorption/desorption, surface condensation, air movement across enclosure boundaries, indoor evaporation, and indoor moisture generation. By using a discrete time step, nonlinear processes, such as surface condensation, can be assumed linear within the time interval. The differential equation is solved as part of a comprehensive numerical formulation through which the behaviour of moisture transport process and its contribution to indoor humidity dynamics are modeled. A theoretical study of indoor air hun-tidity response to different moisture transport processes has revealed the importance of the involved processes in determining indoor air humiditybehaviour. The relative influence of a particular process depends on its time constant, its interaction with other processes, and the continuity of the process. In addition, the impact of a given moisture transport process will also depend on the building physical and functional characteristics, as well as the prevailing outdoor environmental conditions.

References

[8,9] The relationship between indoor humidity and air leakage and ventilation has been modelled to determine the effect of air exchange rate on indoor moisture level and to ezxamine the effect of other parameters, such as occupancy, building characteristics and external environmental prarmeters. Most of these parameters can have a significant impact on indoor humidity, esp. at a lower air exchange rate.

[16]: absorption/desorption process is modelled

[13, 19,20] models for indoor humidity calculations.

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Author Information and Other Publications Notes
Diasty, R.
School of Architecture, Ariona State University, Tempe, AZ 85287-1605 (USA)
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Fazio, P.
Paul Fazio, Professor of Building, Civil & Environmental Engineering, Concordia University, Montreal
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Budaiwi, I.
Associate Professor and Chairman, Architectural Engineering Dept., King Fahd Univ. of Petroleum and Minerals, Dhahran 31261, P.O. Box 1780, Saudi Arabia.
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