International Journal of
Environmental Research and Public Health Article
Optimum Installation of Sorptive Building Materials Using Contribution Ratio of Pollution Source for Improvement of Indoor Air Quality Seonghyun Park 1 and Janghoo Seo 2, * 1 2
*
The Graduate School of Architecture, Kookmin University, Seoul 02707, Korea;
[email protected] School of Architecture, Kookmin University, Seoul 02707, Korea Correspondence:
[email protected]; Tel.: +82-2910-4593; Fax: +82-2910-4113
Academic Editor: Derek Clements-Croome Received: 14 January 2016; Accepted: 28 March 2016; Published: 1 April 2016
Abstract: Reinforcing the insulation and airtightness of buildings and the use of building materials containing new chemical substances have caused indoor air quality problems. Use of sorptive building materials along with removal of pollutants, constant ventilation, bake-out, etc. are gaining attention in Korea and Japan as methods for improving such indoor air quality problems. On the other hand, sorptive building materials are considered a passive method of reducing the concentration of pollutants, and their application should be reviewed in the early stages. Thus, in this research, activated carbon was prepared as a sorptive building material. Then, computational fluid dynamics (CFD) was conducted, and a method for optimal installation of sorptive building materials was derived according to the indoor environment using the contribution ratio of pollution source (CRP) index. The results show that a method for optimal installation of sorptive building materials can be derived by predicting the contribution ratio of pollutant sources according to the CRP index. Keywords: optimum installation; sorptive building materials; contribution ratio of pollution source; indoor air quality
1. Introduction Reinforcing the insulation and airtightness of buildings and the use of building materials containing new chemical substances has caused indoor air quality problems, such as sick house syndrome, affecting not only the health of residents but also causing economic loss through work efficiency loss. The use of sorptive building materials along with the removal of pollutants, constant ventilation, bake-out, etc. are gaining attention in Korea and Japan as methods for improving such indoor air quality problems [1–3]. In particular, sorptive building materials have the advantage of reducing the energy load related to the operation of ventilation equipment, as they reduce pollutants in building materials [4]. The development and use of sorptive building materials are increasing, and the test standard widely used in Korea and Japan has been extended to that recommended by the International Organization for Standardization. According to the International Organization for Standardization, the pollutant concentration reducing performance of sorptive building materials is determined according to the mass transfer coefficient of the surface of sorptive building materials, adsorption characteristics (adsorption isotherm) of sorptive building materials, and pollutant spreading resistance (molecular) diffusion of sorptive building materials. In particular, to conduct an accurate performance evaluation of sorptive building materials according to the chamber method, it is important to recreate the conditions of the actual indoor environment by maintaining the air current of the surface of the test sample. In addition, the International Organization for Standardization states that maintaining environmental
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current of the surface of the test sample. In addition, the International Organization for environmental variables, including temperature, relative 2 of 9 humidity, amount of ventilation, loading factor, and mass transfer coefficient, is essential for comparing sorptive building materials [5]. variables, including temperature, relative humidity,previous amount of ventilation, factor,ofand mass On the other hand, reviewing and validating studies on the loading performance sorptive transfer coefficient, is essential for comparing sorptive building materials [5]. building materials to reduce pollutant concentration and the human body’s ability to reduce On the other hand, reviewing and validating studies on the performance of sorptive pollutant inhalation volume in a real-scale space previous are necessary. Experiments on the human body building materials to reduce pollutant concentration and the human body’s ability to reduce regarding the pollutant inhalation volume entail several risks. In addition, once sorptivepollutant building inhalation volume in a real-scale space are necessary. Experiments onthe theoptimal human installation body regarding materials are installed, it is difficult to move them, which means that plan the pollutant inhalation volume entail several risks. Inconcentration addition, oncereducing sorptiveperformance building materials should be reviewed in advance so that the pollutant of the are installed, it is materials difficult to move them, which means that the optimal installation plan should be sorptive building can be maximized. Computational fluid dynamics (CFD) analysis does not reviewed advance so that thethe pollutant concentration reducing performance theoptimal sorptive building cause anyin risks resulting from experiment and has the advantage of derivingofan installation materials can be maximized. Computational fluid dynamics (CFD) analysis does not cause any risks plan for sorptive building materials by reviewing the influence of pollutants and indoor environmental resulting from the experiment and has the advantage of deriving an optimal installation plan for factors at the design stage. sorptive building by reviewing influence of pollutants and indoor environmental In this study,materials an experiment on the the pollutant reducing performance of activated carbon,factors which at the design stage. has been proven to have a significant effect on reducing indoor pollutant concentration, was In this study, ansustainability experiment onofthe reducing activatedbased carbon, conducted and the thepollutant performance wasperformance analyzed. Inofaddition, onwhich these has been CFD provenanalysis to have awas significant effectto on evaluate reducing indoor pollutant concentration, wasaround conducted results, conducted the concentration of pollutants an and the sustainability of the performance analyzed. In addition, on these results, occupant’s breathing area according to thewas air diffuser method inside based the space resulting fromCFD the analysis wasofconducted to evaluate the concentration of pollutants around and an occupant’s breathing installation sorptive building materials and the posture of the occupant, methods for optimal area according to the air diffuser method inside the space resulting from the installation of sorptive installation of sorptive building materials for reducing pollutant inhalation volume of an occupant building materials andthe theCRP posture of the occupant, and methods for optimal installation of sorptive were reviewed using 2 * index. building materials for reducing pollutant inhalation volume of an occupant were reviewed using the CRP 2 * index. of Sorptive Building Materials 2. Performance Standardization states that maintaining Int. J. Environ. Res. Public Health 2016, 13, 396
The pollutant reducingBuilding performance of activated carbon, selected as the sorptive building 2. Performance of Sorptive Materials material in this study, was evaluated according to the test method suggested in ISO 16000-23, 24, The pollutant reducing performance of activated carbon, selected as the sorptive building material and the results are shown in Table 1 and Figure 1. in this study, was evaluated according to the test method suggested in ISO 16000-23, 24, and the results are shown inTable Table1. 1Results and Figure 1. of pollutant concentration reducing performance of activated carbon. Equivalent Total Sorption Table 1. Results of pollutant concentration reducing performance of activated carbon. Exhaust Sorption Supply Ventilation Rate per Value for Concentration Flux Concentration Unit Area Toluene after 7 Supply Exhaust Equivalent Ventilation Total Sorption 3) Sorption ·h) (μg/m3) (μg/m2Flux (μg/m 3/h·m Supply Gases Concentration Concentration Rate(m per Unit2)Area Value for(μg/g) Toluene Days 2 ¨ h) (µg/m (µg/m3 ) (µg/m3 ) (m3 /h¨ m2 ) after 7 Days (µg/g) Toluene 280 48 52 1.1 9.6 Toluene 280 48 52 1.1 9.6 Ethyl 305 305 5555 56 1.0 -Ethyl benzene 56 1.0 benzene P-xylene 104 18 19 1.1 P-xylene 104 300 1850 19 1.1 -Styrene 55 1.1 Styrene 300 50 55 1.1 Supply Gases
Figure 1. Adsorption isotherm of activated carbon with respect to toluene.
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Figure 1. Adsorption isotherm of activated carbon with respect to toluene.
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A previous previous study A study on on the the pollutant pollutant adsorption adsorptionperformance performanceofofactivated activatedcarbon carbon(AC) (AC)using usinga at aa aboundary boundarylayer-type layer-typesmall smalltest testchamber chamber(BLTSTC) (BLTSTC)showed showedthat that when when toluene toluene was was injected injected at 33, the total pollutant inhalation volume detected after 7 days was 9.6 μg/g, concentration of 280 μg/m concentration of 280 µg/m , the total pollutant inhalation volume detected after 7 days was 9.6 µg/g, which indicates indicates that that the the adsorption adsorption volume volume was was not not that that significant significant [4,6]. [4,6]. However, However, the the adsorption adsorption which isotherm of of Figure Figure 11 shows shows that that the the adsorption adsorption volume volume of of toluene toluene by by the the AC AC increased increased as as the the isotherm concentration of toluene increased. This means that when the concentration of indoor toluene is concentration of toluene increased. This means that when the concentration of indoor toluene is high, a corresponding improvement in toluene adsorption performance can be expected. high, a corresponding improvement in toluene adsorption performance can be expected. Accordingly, Accordingly, this research, was used as the sorptive material in this research,inactivated carbonactivated was used carbon as the sorptive building material andbuilding toluene was set asand the toluene was set as the pollutant to be adsorbed. pollutant to be adsorbed. 3. Outline Outlineof ofCFD CFDAnalysis Analysis
3.1. Geometry Geometry and and Conditions Conditions of of Case Case 3.1. The CFD CFD analysis analysis model model for for reviewing reviewing the the diffusion diffusion and and adsorption adsorption of of pollutants pollutants in in the the indoor indoor The space isisshown shownininFigure Figure 2. Mechanical ventilation operated in a space measuring m in space 2. Mechanical ventilation waswas operated in a space measuring 3 m in 3length, length, width, and height, and the area of the inlet and outlet was identically set to 0.16 m2. 2 width, and height, and the area of the inlet and outlet was identically set to 0.16 m . To review the To review the thermal andnear air distribution near the surface according to the heat of an thermal diffusion and airdiffusion distribution the surface according to the heat of an occupant, a human occupant, a human structure similar a real sizehuman of the body inlet model of the body structure similarbody to a real body was used.toThe sizebody of thewas inletused. of the The applied 2, based on data from previous studies [7,8]. applied human body model was about 9.8 cm 2 was about 9.8 cm , based on data from previous studies [7,8].
Figure Figure 2. 2. Model used for CFD analysis. analysis.
In addition, addition, aa case case study study was was conducted conducted to to determine determine the the pollutant pollutant concentration concentration reducing reducing In effect of of sorptive sorptive building building materials materials and and an an optimal optimal installation installation plan plan for for sorptive sorptive building building materials materials effect considering four types of air diffuser methods and two types of occupant postures, as shown in considering four types of air diffuser methods and two types of occupant postures, as shown in Figure 3; the corresponding case conditions are shown in Table 2. Figure 3; the corresponding case conditions are shown in Table 2.
Figure 2. Model used for CFD analysis.
In addition, a case study was conducted to determine the pollutant concentration reducing effect of sorptive building materials and an optimal installation plan for sorptive building materials Int. J. Environ. Res. Public Health 2016, 13, 396 4 of 9 considering four types of air diffuser methods and two types of occupant postures, as shown in Figure 3; the corresponding case conditions are shown in Table 2.
Figure 3. Air diffuser types and types of occupant posture in the case study. Table 2. Case for CFD analysis. Air Diffuser
Posture (A) Standing (B) Sitting
Case 1
Case 2
Case 3
Case 4
Case 1-A Case 1-B
Case 2-A Case 2-B
Case 3-A Case 3-B
Case 4-A Case 4-B
3.2. Numerical Model This study used the species transport model for CRP calculation. The gas inside the space consisted of three types, all of which included air gas (representing fresh air) and the pollutant toluene. Accordingly, each gas was assumed to be an incompressible ideal gas with temperature dependence. For the turbulence model, the re-normalization group (RNG) k-epsilon turbulence model was used, considering natural convection by buoyancy. Equations (1)–(3) show the equations of continuity, motion, and energy, respectively: B$ ` ∇¨ p$uq “ 0 (1) Bt B p$uq ` ∇¨ p$uuq “ ´∇ p ` $g ` ∇¨ pµ∇uq ´ ∇¨ τt Bt ˜ ¸ ´ ¯ ÿ B p$eq ` ∇¨ p$euq “ ∇¨ k e f f ∇ T ´ ∇¨ hi ji Bt
(2) (3)
i
where $ is density of fluid, t is time, u refers to fluid velocity vector, p is pressure, g is vector of gravitational acceleration, µ is molecular dynamic viscosity, e is specific internal energy, keff is effective heat conductivity, T stands for fluid temperature, hi refers to specific enthalpy of fluid, and ji is mass flux of the i-th constituent. The last term on the right hand side of Equation (2) is the divergence of the turbulence stresses (Reynolds stresses), τ t accounts for auxiliary stresses due to velocity fluctuations. For the CRP calculation, it is necessary to calculate the quantitative amount of pollutants from each pollution source. Therefore, an ID was given to each component gas, and the partial differential transport equations of each gas that passed through the control volume (CV) of the 3D space are given by Equation (4) [9]: BYi ` ∇¨ p$Yi uq “ ´∇¨ ji (4) Bt where Yi is mass fraction of the i-th air constituent. Due to the reasonably low thermal parameters (pressure and temperature) of air, it can be treated as a rarified mixture. The initial toluene concentration, before the introduction of pollutants to the target space, was assumed to be Ca = 0. This was set to rule out changes in the sorptive performance of the sorptive building materials caused by any variable other than the pollutants. This study evaluated the improvement in pollutant inhalation rate by occupants after the application of sorptive building materials using the CRP index proposed by Hayashi et al. [10]. The CRP is classified into CRP 1 and CRP 2. Among them, CRP 2 is an index indicating how much the
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pollutant generated from each pollution source contributes to the total pollutant inhalation volume of the occupant. Thus, the sum of the contribution ratio of each pollution source affecting the indoor occupant is always 100%, and is calculated by the following Equation (5): CRP 2i “
qi qtotal
ˆ 100%, qtotal “
ÿ
qi
(5)
i
where qi is the pollutant inhalation volume (g/h) of the occupant from source i and
ř
qi is the total
i
pollutant inhalation volume (g/h) of the occupant according to each source. CRP 2 is an index indicating the contribution ratio of each pollution source with respect to the inhalation volume of the generated pollutant by a human body and has a relative value. Thus, under the assumption that fresh outdoor air is supplied into the indoor space through the inlet at a constant air volume, it becomes possible to evaluate the concentration reducing effect of sorptive building materials based on the ratio of fresh outdoor air to the total human body inhalation volume by calculating CRP 2 including the influence of inflow air. Thus, the contribution ratio including fresh air was defined as CRP 2 * in this research, and the optimal installation plan for sorptive building materials was derived using this rate. 3.3. Conditions of CFD Analysis The CFD analysis conditions used for calculating CRP 2 * are shown in Table 3. The velocity of air flowing through the inlet was 1.0 m/s. For the mesh of the object in 3D space, a triangular mesh was created around the human body model and hexa mesh was created for other spaces in consideration of symmetry. In order to increase the convergence of natural convection according to buoyancy, PRESTO was used as a solution for the continuity equation, and the heating volume of the human body model and the respiration volume at the normal state were applied based on the existing literature [7]. Additionally, this research does not account for the impact of humidity. Table 3. Conditions for CFD analysis. RNG k-ε Model
Turbulent Flow Model Number of Meshes U in Inflow Boundary
Around 3,000,000 ´ ¯2 3 1m , k in “ Uy, in ˆ 0.05 , Temperature “ 26 ˝ C “ s 2 3 k in 2 1 ε in “ Cu ˆ , Lin “ , Lo “ 0.4 m Lin 7Lo
Outflow Boundary
Uout,mouth “ out f low (Mass flow conservation) Flow rate weighting, outlet = 0.99, mouth = 0.01
Wall Boundary
No-slip
Breath Boundary
14.4 L/min (Human standard)
Flux Boundary
Hhuman “ 22.8 W{m2 , (Heat transfer rate of person = 33.8 W)
4. Results of CFD Analysis 4.1. Air Distribution of Object Space Figure 4 shows the air distribution maps for each air diffuser condition when the occupant was standing. Regardless of the case, the velocity of the air current around the inlet was observed to be the highest. In Case 2, where the inlet and outlet were placed on the upper side, the velocity of airflow was somewhat low because the introduced air current escaped through the outlet without being distributed in the air flow. In addition, it was revealed that temperature changed around the occupant’s body surface due to the heat generated by the occupant, as illustrated in Figure 5.
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(a) Scalar distribution. (a) Scalar distribution.
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(b) Vector velocity distribution. (b) Vector velocity distribution. Figure 4. Air flow (Plan ABCD in Figure 2). (a) Scalar distribution; (b) vector velocity distribution. Figure 4. Air flowflow (Plan ABCD ininFigure distribution; Vector velocity distribution. Figure 4. Air (Plan ABCD Figure2). 2).(a) (a) Scalar Scalar distribution; (b)(b) vector velocity distribution.
Figure 5. Temperature distribution around the human model (Plan ABCD in Figure 2). Figure 5. Temperature distribution around the human model (Plan ABCD in Figure 2).
Figure 5. Temperature distribution around the human model (Plan ABCD in Figure 2).
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4.2.4.2. Contribution Ratio of of Each Pollution Contribution Ratio Each PollutionSource Sourceon onIndoor Indoor Occupants Occupants In this research, toluene was was usedused as theaspollution sourcesource and CRP * was2 calculated by assigning In this research, toluene the pollution and2CRP * was calculated by a pollutant condition (mass fraction = 1.0) to each wall’s surface. shows 6the assigningconcentration a pollutant concentration condition (mass fraction = 1.0) to each wall’sFigure surface.6 Figure shows the mass fractionofdistribution of fresh outdoor airtointroduced the indoor space mass fraction distribution fresh outdoor air introduced the indoortospace through thethrough inlet. The the inlet. The indoor concentration diffusionair of was the outdoor air was highly dependent onthe theair indoor concentration diffusion of the outdoor highly dependent on the velocity of velocity the showed air current and thus showed a tendency similardistribution. to the air current current andofthus a tendency similar to the air current The distribution. contributionThe ratio, contribution ratio, calculated in order to consider the optimal installation plan for sorptive building calculated in order to consider the optimal installation plan for sorptive building materials around the materials aroundinthe occupant, shown in Figure 7. Theofsum of CRP 2 *100%, in each occupant, is shown Figure 7. Theissum of the percentage CRPof2the * inpercentage each case was set to and case was set to 100%, and the change in the contribution ratio of each pollution source was to the change in the contribution ratio of each pollution source was observed to be larger according to be larger according to the air diffusion method rather than the posture of the occupant. the observed air diffusion method rather than the posture of the occupant. This is deemed to be because the This is deemed to be because the breathing areas formed by the occupant while standing or sitting breathing areas formed by the occupant while standing or sitting do not have a large effect. However, do not have a large effect. However, in Case 4, where the air supply and exhaust were at the ceiling, in Case 4, where the air supply and exhaust were at the ceiling, the ratio of fresh outdoor air to the the ratio of fresh outdoor air to the respiration volume of the occupant was the highest. This means respiration volume of the occupant was the highest. This means that in subject spaces where the length, that in subject spaces where the length, height, and width are identical to each other and a constant height, and air width are identical to each otherceiling and aair constant volume is supplied indoors, outdoor volume is supplied indoors, supplyoutdoor systemsair cause the highest amount of ceiling air supply systems cause the highest amount of fresh outdoor air to be present in the breathing fresh outdoor air to be present in the breathing area of the occupant. In Case 2, the age of the air areawas of the occupant. In Case 2, theair age of the air was through lowest as the freshwithout outdoor air was discharged lowest as the fresh outdoor was discharged the outlet being disturbed by through the outlet without being disturbed by the flow of air current, and therefore the contribution the flow of air current, and therefore the contribution ratio of the fresh outdoor air to the respiration ratio of the of fresh air to the respiration volume of the indoor occupant was about 26.3%. volume the outdoor indoor occupant was about 26.3%.
Figure 6. Air MassFraction Fractiondistribution distribution according airair for for each casecase (Plan(Plan ABCD in Figure 6. Air Mass accordingtotofresh freshoutdoor outdoor each ABCD Figure 2). in Figure 2).
(a) Case 1-A (a) Case 1-A.
(b) Another case (b) Another case.
Figure 7. CRP 2 * calculation results for each case. (a) Case 1-A; (b) Another case. Figure 7. CRP 2 * calculation results for each case. (a) Case 1-A; (b) another case.
Figure 7. CRP 2 * calculation results for each case. (a) Case 1-A; (b) Another case.
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4.3. Change in Contribution Ratio per Indoor Pollution Source according to the Installation of Sorptive 4.3. Materials Change in Contribution Ratio per Indoor Pollution Source according to the Installation of Sorptive Building Building Materials
Calculating the contribution ratio (CRP 2 *) of each pollution source before installing sorptive Calculating the contribution ratio (CRP 2ratio *) of of each beforefrom installing sorptive building materials showed that the contribution thepollution pollutantsource generated the side vertically building materials showed that the contribution ratio of the pollutant generated from the side closest to the inlet turned out to be the highest in every case. Accordingly, it was confirmed that the vertically closest to the inlet turned out to be the highest in every case. Accordingly, it was floor in Case 4 and the back wall in the remaining cases had the highest contribution rate; the pollution confirmed that the floor in Case 4 and the back wall in the remaining cases had the highest source with the highest ratio set as the object while theobject change in the contribution rate; the contribution pollution source withwas the highest contribution ratio reviewing was set as the while contribution rate the fresh air according sorptive building materials for determining reviewing theofchange in outdoor the contribution rate of to thethe fresh outdoor air according to the sorptive the optimal installation plan for sorptive addition, as a control sorptive building materials for determining thebuilding optimal materials. installation In plan for sorptive buildinggroup, materials. building materials installed the pollution with theinstalled lowest at contribution (Alt 2). In addition, as were a control group,at sorptive buildingsource materials were the pollutionratio source with the lowest contribution ratio (Alt 2). The results from both cases were compared to each other. The results from both cases were compared to each other. Figure 8 shows the change in the contribution Figure 8 shows the change in the to contribution ratio of the fresh building outdoor materials air according to applied the ratio of the fresh outdoor air according the installation of sorptive on the installation of sorptive building materials on the applied sides. In the case where sorptive building sides. In the case where sorptive building materials were installed at the pollution source with the materials were installed at the pollution source with the highest contribution ratio (Alt 1) before the highest contribution ratio (Alt 1) before the installation of sorptive building materials (Standard), the installation of sorptive building materials (Standard), the ratio of the fresh outdoor air to the ratio of the fresh outdoor air to the respiration volume of the occupant increased from 25.6% to a respiration volume of the occupant increased from 25.6% to a maximum of 42.3%. When compared maximum 42.3%. When to ratio the control group, the contribution ratio of the fresh to the of control group, thecompared contribution of the fresh outdoor air increased when compared tooutdoor the air increased when compared to the ratio before the installation of the sorptive building materials, ratio before the installation of the sorptive building materials, and the case where sorptive building and the case wherewere sorptive building installed in the place the highest source materials installed in thematerials place withwere the highest pollution sourcewith contribution ratiopollution showed the contribution ratio showed the best pollutant reducing effect around the occupant. best pollutant concentration reducing effectconcentration around the occupant.
Figure 8. CRP 2 *2for Standard: Before the installation of sorptive Figure 8. CRP * foreach each case. case. Standard: Before the installation of sorptive building building materials. materials. Alt 1: Alt 1: Sorptive Sorptivebuilding building materials installed the pollution the contribution highest contribution materials werewere installed at theatpollution source source with thewith highest ratio. building materials were installed pollution with the lowest contribution ratio. ratio. Alt Alt2: Sorptive 2: Sorptive building materials wereat the installed atsource the pollution source with the lowest contribution ratio. 5. Conclusions
5. Conclusions In this study, optimal installation plans for sorptive building materials were reviewed to reduce pollutant inhalation volumes of indoor occupants using the corrected CRP 2 * index among
In this study, optimal installation plans for sorptive building materials were reviewed to reduce other CRP indexes. Reviewing the contribution ratio of each pollution source according to the air pollutant inhalation of indoor occupants thethat corrected CRP 2to* index among other CRP diffuser methodvolumes and the posture of the occupantusing showed it is possible select an air diffuser indexes. Reviewing the contribution ratio of each pollution source according to the air diffuser method to reduce the respiration volume of pollutants by occupants to a minimum, regardlessmethod of and the of the occupant showed that it isby possible to select an of airthe diffuser methodair. to reduce theposture installation of sorptive building materials, identifying the age fresh outdoor In addition, CRP 2 *, which is the contribution ratio of atopollution source,regardless was calculated andinstallation a method of the respiration volume of pollutants by occupants a minimum, of the for building optimal application of sorptive building materials, a passive method reducingCRP pollutant sorptive materials, by identifying the age of the fresh outdoor air. Infor addition, 2 *, which was suggested. Activated carbon, which adsorbs excellently, was application chosen as of is the concentration, contribution ratio of a pollution source, was calculated andtoluene a method for optimal the sorptive building material to validate its effectiveness; for this, a control group was prepared sorptive building materials, a passive method for reducing pollutant concentration, was suggested. Activated carbon, which adsorbs toluene excellently, was chosen as the sorptive building material to validate its effectiveness; for this, a control group was prepared and analyzed, and the results were
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compared. The comparison showed that the installation of sorptive building materials based on CRP 2 * had the best pollutant concentration reducing effect. Thus, an optimal installation plan for sorptive building materials targeting occupants or a certain space can be derived by calculating CRP 2 *. For this research, it was assumed that the performance of the sorptive building materials is high, regardless of the indoor environment. For future research, however, the change in performance of sorptive building materials will be reviewed while accounting for the humidity and moisture. Acknowledgments: This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (NRF-2013R1A2A2A01007787, NRF-2015R1C1A1A01052784). Author Contributions: Seonghyun Park conceived and designed the CFD analysis and drafted the manuscript; Janghoo Seo participated in the design of the experiments and in the analyses. All authors were involved in critically evaluating the manuscript. Conflicts of Interest: The authors declare no conflict of interest.
Abbreviations The following abbreviations are used in this manuscript: CFD CRP AC BLTSTC
computational fluid dynamics contribution ratio of pollution source activated carbon boundary layer-type small test chamber
References 1. 2. 3. 4. 5. 6.
7.
8. 9.
10.
Wargocki, P.; Bakó-Biró, Z.; Clausen, G.; Fanger, P.O. Air quality in a simulated office environment as a result of reducing pollution sources and increasing ventilation. Energy Build. 2002, 34, 775–783. [CrossRef] Kosonen, R.; Tan, F. The effect of perceived indoor air quality on productivity loss. Energy Build. 2004, 36, 981–986. [CrossRef] Kavgic, M.; Mumovic, D.; Stevanovic, Z.; Young, A. Analysis of thermal comfort and indoor air quality in a mechanically ventilated theatre. Energy Build. 2008, 40, 1334–1343. Seo, J.; Kato, S.; Ataka, Y.; Chino, S. Performance test for evaluating the reduction of VOCs in rooms and evaluating the lifetime of sorptive building materials. Build. Environ. 2009, 44, 207–215. Seo, J.; Kato, S.; Ataka, Y.; Yang, J. Influence of Environmental Factors on Performance of Sorptive Building Materials. Indoor Built Environ. 2010, 19, 413–421. [CrossRef] Ataka, Y.; Kato, S.; Murakami, S.; Zhu, Q.; Ito, K.; Yokota, T. Study of effect of adsorptive building material on formaldehyde concentrations: Development of measuring methods and modeling of adsorption phenomena. Indoor Air 2004, 14, 51–64. [CrossRef] [PubMed] Hayashi, T.; Ishizu, Y.; Kato, S.; Murakami, S. CFD analysis on characteristics of contaminated indoor air ventilation and its application in the evaluation of the effects of contaminant inhalation by a human occupant. Build. Environ. 2002, 37, 219–230. [CrossRef] Gao, N.; Niu, J. Transient CFD simulation of the respiration process and inter-person exposure assessment. Build. Environ. 2006, 41, 1214–1222. [CrossRef] Bulinska, ´ A.; Popiołek, Z.; Bulinski, ´ Z. Experimentally validated CFD analysis on sampling region determination of average indoor carbon dioxide concentration in occupied space. Build. Environ. 2014, 72, 319–331. [CrossRef] Hayashi, T.; Kato, S.; Murakami, S.; Zhu, S. Numerical analysis on pollution of inhaled air with chemical contaminant in Room (Part 8)—CFD analysis on contribution ratio of pollution source to inhaled air in a stagnant room. In Proceedings of The Society of Heating, Air-Conditioning and Sanitary Engineers of Japan, Tokyo, Japan, 10 August 2000; pp. 13–16. © 2016 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons by Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).
