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Efficacy of Intermittent Ventilation for Providing Acceptable Indoor Air Quality.

DE2004834643

Publication Date	2004
Personal Author	Sherman, M. H.
Page Count	28
Abstract	Ventilation standards and guidelines typically treat ventilation as a constant and specify its value. In many circumstances a designer wishes to use intermittent ventilation, rather than constant ventilation, but there are no easy equivalencies available. This report develops a model of efficacy that allows one to calculate how much intermittent ventilation one needs to get the same indoor air quality as a the continuous value specified. We have found that there is a simple relationship between three dimensionless quantities: the temporal ventilation effectiveness (which we call the efficacy), the nominal turn-over and the under-ventilation fraction. This relationship allows the calculation of intermittent ventilation for a wide variety of parameters and conditions. We can use the relationship to define a critical time that separates the regime in which ventilation variations can be averaged over from the regime in which variable ventilation is of low effectiveness. We have found that ventilation load-shifting, temporary protection against poor outdoor air quality and dynamic ventilation strategies can be quite effective in low-density buildings such as single-family houses or office spaces.
Keywords	Ventilation systems Indoor air quality Standards Guidelines Models Effectiveness Residential buildings Office buildings Design Air flow Flow rate Indoor air pollution Flexibility Recommendations
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Lawrence Berkeley National Lab., CA.; Department of Energy, Washington, DC. Assistant Secretary for Energy
Supplemental Notes	Sponsored by Department of Energy, Washington, DC. Assistant Secretary for Energy Efficiency and Renewable Energy,.
Document Type	Technical Report
NTIS Issue Number	200516

Efficacy of Intermittent Ventilation for Providing Acceptable Indoor Air Quality.

Efficacy of Intermittent Ventilation for Providing Acceptable Indoor Air Quality.
DE2004834643

Publication Date	2004
Personal Author	Sherman, M. H.
Page Count	28
Abstract	Ventilation standards and guidelines typically treat ventilation as a constant and specify its value. In many circumstances a designer wishes to use intermittent ventilation, rather than constant ventilation, but there are no easy equivalencies available. This report develops a model of efficacy that allows one to calculate how much intermittent ventilation one needs to get the same indoor air quality as a the continuous value specified. We have found that there is a simple relationship between three dimensionless quantities: the temporal ventilation effectiveness (which we call the efficacy), the nominal turn-over and the under-ventilation fraction. This relationship allows the calculation of intermittent ventilation for a wide variety of parameters and conditions. We can use the relationship to define a critical time that separates the regime in which ventilation variations can be averaged over from the regime in which variable ventilation is of low effectiveness. We have found that ventilation load-shifting, temporary protection against poor outdoor air quality and dynamic ventilation strategies can be quite effective in low-density buildings such as single-family houses or office spaces.
Keywords	Ventilation systems Indoor air quality Standards Guidelines Models Effectiveness Residential buildings Office buildings Design Air flow Flow rate Indoor air pollution Flexibility Recommendations
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Lawrence Berkeley National Lab., CA.; Department of Energy, Washington, DC. Assistant Secretary for Energy
Supplemental Notes	Sponsored by Department of Energy, Washington, DC. Assistant Secretary for Energy Efficiency and Renewable Energy,.
Document Type	Technical Report
NTIS Issue Number	200516