General analytical mass transfer model for VOC emissions from multi-layer dry building materials with internal chemical reactions

Xinke Wang,Yinping Zhang

doi:10.1007/s11434-010-4254-5

Xinke Wang, Yinping Zhang

Open Access

https://doi.org/10.1007/s11434-010-4254-5

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Abstract

A general mass transfer based model was developed for analyzing volatile organic compound (VOC) emissions from dry multi-layer building materials with two emission surfaces. This model adds to an earlier multi-layer model by considering chemical reactions within the materials. Consequently, it can be used to analyze the effect of these chemical reactions on removing VOCs, and for characterizing secondary VOC emissions from the building material. The model was validated with literature data and our experimental results. Some typical secondary emissions were analyzed using this model, and obviously differed from the primary emissions. The model is a useful tool for predicting, analyzing and “designing” the VOC emission characteristics, including secondary emissions, of building materials.

Highlights

A general mass transfer based model was developed for analyzing volatile organic compound (VOC) emissions from dry multi-layer building materials with two emission surfaces
The mass transfer model developed by Little et al [8] is considered the first mass transfer model for analyzing VOC emissions from dry building materials
This paper aimed to develop a general analytical mass transfer model for analyzing the VOC emissions from multi-layer building materials taking into consideration the chemical reactions within the material layers

Summary

Model development

Transient mass diffusion through the material is governed by the following equation:. (4b) where m 0 (t) and m N +1(t) are the emission factors at each emission surface, hm,0 and hm,N+1 are the convective mass transfer coefficients at the emission surfaces, Ki is the material/air partition coefficient of VOC for the ith layer material, and C0,s and CN+1,s are the gas phase VOC concentrations adjacent to the material surfaces. Βn (n=1,2,...) are the positive roots of following transcend equation: v1,1 v1,2 Emission factors of both sides can be derived from eqs. The first term represents the influence of the VOC concentration difference between two rooms separated by the material. Compared with an earlier model [20], the present model includes a term for the influence of chemical reaction within the building material (S(βn,t)). Where V is the volume of the rooms separated by the material, A is the emission area, and Q is the air flow rate

Comparison with experimental results for single layer building materials

Validation of the model with an internal chemical reaction

Example of model application

Conclusions