Measurement method of multi-zone airflow rate using human ... · 1152 2nd PALENC Conference and...

1152 2nd PALENC Conference and 28th AIVC Conference on Building Low Energy Cooling and Advanced Ventilation Technologies in the 21st Century, September 2007, Crete island, Greece

Measurement method of multi-zone airflow rate using human expirationflow rate using human expirationlow rate using human expiration

H. Yoshino, M. Fujikawa, R. Takaki, M. Fujikawa, R. TakakiM. Fujikawa, R. Takaki, R. Takaki R. TakakiTohoku University, Japan JapanJapan

H. OkuyamaShimizu Corporation, Japan

M. HayashiMiyagi Gakuin Women’s University, Japan’s University, Japans University, Japan, Japan

M. SugawaraMiyagi University of Education, Japan, Japan

Fig.1. The full-scale test house

2. OUTLINE OF EXPERIMENT

Forced supply and exhaust ventilation system was used and airflow rate between rooms was controlled by the compact fans. Airflow rate between the rooms wasAirflow rate between the rooms was measured. Outdoor airflow rate was measured by us-Outdoor airflow rate was measured by us-ing the constant concentration tracer gas (SF6) method. In line with the actual state of residence, various be-haviour patterns of a human being were included in the experiment, and COCO2 concentration from human expira- from human expira-tion was measured. The rate of outdoor airflow entering was measured. The rate of outdoor airflow entering. The rate of outdoor airflow entering The rate of outdoor airflow enteringThe rate of outdoor airflow entering the house and the airflow rate between the rooms were were estimated by the system identification theory. The es-the system identification theory. The es-system identification theory. The es-The es-timated results were compared with the measurement results in order to validate its accuracy. Table 1. Equivalent leakage of the house envelope

Zone Equivalent leakage area of the houseenvelope a Acm2

1F 131.9

ABSTRACT

Investigation of ventilation measurement method was of ventilation measurement method wasof ventilation measurement method was ventilation measurement method was measurement method was was carried out in a full-scale test house. The aim of this study was to examine the ventilation rate via human expiration. The adopted method is able to measure multi-zone airflow rates. Airflow rate between rooms was monitored and the outdoor airflow rate was measured and the outdoor airflow rate was measuredthe outdoor airflow rate was measuredoutdoor airflow rate was measured by using the constant concentration tracer gases. The. The rate of outdoor airflow entering the house and the airflow rate between the rooms were estimated by the ventilation measurement method via human expiration based on system identification theory. The estimated results were compared with the measurement results in order to validate its accuracy.

1. INTRODUCTION

The method for estimating ventilation rate via humanhe method for estimating ventilation rate via human expiration based on system identification theory was was investigated in this work. The adopted method is able. The adopted method is ableThe adopted method is able to measure multi-zone airflow rates. Also, it is a sim-ple and cost effective method that suitable to apply in domestic places. In addition, the method will only have minimal interference in the daily life of the residents concerned. Experiment using this measurement meth-Experiment using this measurement meth- using this measurement meth-this measurement meth- measurement meth-od was carried out in a full-scale test house in order to in order toin order to to investigate the accuracy..

PALENC 2007 - Vol 2.indd 1152 7/9/2007 1:26:23 µµ

11532nd PALENC Conference and 28th AIVC Conference on Building Low Energy Cooling and Advanced Ventilation Technologies in the 21st Century, September 2007, Crete island, Greece

1W 31.92E 34.42W 11.1

2.1 Full-scale test house and ventilation systemFull-scale test house and ventilation system(1) Description of the test houseThe experiment was carried out in a full-scale test house located at the Tohoku University, Japan. The featureat the Tohoku University, Japan. The feature Tohoku University, Japan. The featurefeature of test house and its floor plan are shown in Fig.1 and and its floor plan are shown in Fig.1 andfloor plan are shown in Fig.1 andare shown in Fig.1 and shown in Fig.1 and and Fig.2 respectively. The total floor area is 78.9 m The total floor area is 78.9 m2 and the volume of the house is 163.9 m3. The equivalent leakagehe equivalent leakagee equivalent leakage area of the house envelope per floor area was aboutwas about about 1.0cm2/m2 measured by the fan pressurization method.d by the fan pressurization method. the fan pressurization method. An air-conditioning unit is installed in each room except for the hall areas. There are two internal doors between each rooms and the hall. A wellhole is located between wellhole is located between 1st and 2and 22nd floors, at the southern part of the housefloors, at the southern part of the house.

Fig.2. Floor plan and location of measuring points

(2) Zones for experimentThe test house was divided into four zones within whichtest house was divided into four zones within which within which four COour CO2 sensors were placed (Fig.2). West room doors were placed (Fig.2). West room doors (Fig.2). West room doors were closed with extruded polystyrene insulation andextruded polystyrene insulation and and regarded as one zone. The equivalent leakage areas pers per per zone of the house envelope are shown in Table 1. East side of 1st floor has the largest leakage area (Table 1). (3) Ventilation airflow control between rooms Compact fans were fixed on the extruded polystyrene insulations in order to control airflow rate between rooms (Fig.2). to control airflow rate between rooms (Fig.2). The wellhole between 1st and 2and 22nd floorsfloors was also closed with insulation and same fan was fixed for controllingcontrolling airflow rate. Flexible duct and compact fans were set for mixing indoor air between hall and east side room (Fig.2). (4) Ventilation systemForced supply and exhaust ventilation system was used.. All zones, except 1E, were conducted forced supply and, except 1E, were conducted forced supply and except 1E, were conducted forced supply and, were conducted forced supply and were conducted forced supply andsupply and exhaust ventilations. Because zone 1E has large leakage,s. Because zone 1E has large leakage,. Because zone 1E has large leakage, therefore a huge amount of infiltration from outdoor arises. Airflow rate of ventilation system and compact fans was controlled by transformers [Note 1]. All rooms [Note 1]. All room [Note 1]. All room temperature was set to 20 °C bymeansofair-conditioning.by means of air-conditioning.air-conditioning.-conditioning.conditioning.ing..

2.2 Measurement item and methodMeasurement item and method(1) Discharge quantity of CO2 estimated by the heart rate [Note 2]One subjected person put on a portable heart rate monitor subjected person put on a portable heart rate monitorput on a portable heart rate monitorheart rate monitor rate monitor and moved following each case of the experiment under each case of the experiment undereach case of the experiment under case of the experiment under various behaviour patterns. The access to 2 The access to 2The access to 22nd floor fromfrom 1st floor and is through an external staircase. Dischargeis through an external staircase. Discharge through an external staircase. Dischargethrough an external staircase. Discharge external staircase. Discharge quantity of CO2 was estimated based on measured heart rate referring to literatures on exercise physiology (Ikai,referring to literatures on exercise physiology (Ikai, to literatures on exercise physiology (Ikai,s on exercise physiology (Ikai, on exercise physiology (Ikai,xercise physiology (Ikai,physiology (Ikai,hysiology (Ikai, (Ikai, 1985 Nakanishi, 1993 Nakayama, 1985). Heart rate was measured by 5 seconds.s..

Fig.3. Concept of the ventilation systemTable 2. Summary of experimental cases and behaviour patterns

(2) CO2 concentration Portable CO2 sensors were set at center of each room (Fig.2) and outdoor. CO2 concentration was measured by 1 minute.(3) OccupancyInfra-red sensors for occupantsnfra-red sensors for occupants were set at corner of each room. Infrared change was detected by 1 minute. Perceptible area is 110 degree °(two-dimensional angle) and 15 m (distance).(4) Airflow rate at each inlet of supply air, outlet of exhaust air and compact fans between rooms It was measured by the airflow meter 3 times before and measured by the airflow meter 3 times before andmeasured by the airflow meter 3 times before andeasured by the airflow meter 3 times before andby the airflow meter 3 times before and the airflow meter 3 times before andthe airflow meter 3 times before andairflow meter 3 times before and3 times before and times before and after each experiment respectively. (5) Outdoor airflow rate entering the roomsIt was measured by using the constant concentration tracer gas method. SF6 was used as a tracer gas. The



gas injection was controlled so that the indoor SF6 gas concentration was maintained at 5 ppm. The test equipment consisted of a B&K 1302 multi-gas monitor-gas monitorgas monitor and two B&K 1303 multi-point samplers and dosers.-point samplers and dosers.point samplers and dosers. Diverged type of gas tube and compact fans were usedas tube and compact fans were usedcompact fans were usedompact fans were usedwere used used (except ‘Case5’) to ensure that injected gas could be‘Case5’) to ensure that injected gas could beCase5’) to ensure that injected gas could be’) to ensure that injected gas could be) to ensure that injected gas could beto ensure that injected gas could be that injected gas could becould be be distributed sufficiently.

Fig.3. Measurement results of Case1

(6) Indoor and outdoor temperaturesThese were measured by measuring function of theeasured by measuring function of thethe portable CO2 sensors for temperature and small data loggers with sensor in 1 minute interval.in 1 minute interval. 1 minute interval.(7) Outdoor wind velocity and directionWind sensor was set at a height of 8m and measured ina height of 8m and measured in8m and measured inm and measured in and measured inin 10 minutes interval.(8) Input data for calculation by system identification theoryCO2 concentration, discharge quantity of CO2 and human occupancy were input into SPID-C, system identification calculation program (Okuyama, 1984), as, as as parameters for estimating ventilation rate.for estimating ventilation rate. estimating ventilation rate.ing ventilation rate. ventilation rate. (9) Experiment periodEach experiment was carried out in six hours. Thein six hours. Thesix hours. The measurement period was from 9/2/2007 to 26/2/2007 [Note 3].

2.3 Experimental conditionExperimental conditionIn line with the actual state of residence, various behav-iour patterns of a human being were included in the ex-periment. Summary of experimental cases and behaviour Summary of experimental cases and behavioururr patterns are shown in Table 2. ‘Case1’ was set as the are shown in Table 2. ‘Case1’ was set as theare shown in Table 2. ‘Case1’ was set as the shown in Table 2. ‘Case1’ was set as theTable 2. ‘Case1’ was set as the. ‘Case1’ was set as the ‘Case1’ was set as the‘Case1’ was set as theCase1’ was set as the’ was set as the was set as theset as the standard condition. More than two COcondition. More than two CO. More than two CO More than two COMore than two CO2 concentration peaks accompanying human occupancy were observed.were observed.. In addition, all rooms were occupied by the subject.occupied by the subject.by the subject.

These were set for increasing accuracy (Ohta, 2004). ‘Case2’ was observed only one COCase2’ was observed only one CO’ was observed only one CO was observed only one COobserved only one CO only one CO2 concentration peak. ‘Case2-a’ was occupied in 45 minutes of each roomCase2-a’ was occupied in 45 minutes of each room’ was occupied in 45 minutes of each room was occupied in 45 minutes of each room occupied in 45 minutes of each room 45 minutes of each roomof each room each room while ‘Case2-b’ was 90 minutes in each room. ‘Case3’ ‘Case2-b’ was 90 minutes in each room. ‘Case3’‘Case2-b’ was 90 minutes in each room. ‘Case3’Case2-b’ was 90 minutes in each room. ‘Case3’’ was 90 minutes in each room. ‘Case3’ was 90 minutes in each room. ‘Case3’in each room. ‘Case3’ each room. ‘Case3’‘Case3’Case3’’ was the case for “not staying room (1W)”. ‘Case4’for “not staying room (1W)”. ‘Case4’ “not staying room (1W)”. ‘Case4’“not staying room (1W)”. ‘Case4’not staying room (1W)”. ‘Case4’”. ‘Case4’. ‘Case4’‘Case4’Case4’’ was the case with short period of “window opening”.with short period of “window opening”. short period of “window opening”.period of “window opening”.window opening”.”.. Assuming winter cross ventilation, the window was window waswas opened for 15 minutes two times. ‘Case5’ was the case‘Case5’ was the caseCase5’ was the case’ was the case was the case that indoor air was not mixed at all. All compact fans not mixed at all. All compact fans mixed at all. All compact fans for mixing indoor air were stopped including those of constant concentration tracer gas method. In addition, all air-conditioners were also stopped.-conditioners were also stopped.conditioners were also stopped.

(a) Measured airflow rate

(b) System identification calculationFig.4. Comparison of measured results and estimated results (Case1)

3. RESULTS AND COMPARISONS AND COMPARISON AND COMPARISON

The result of total air change rate and airflow rateresult of total air change rate and airflow rate between rooms are compared and shown in Fig.7 and compared and shown in Fig.7 and shown in Fig.7 and Table 3 respectively.able 3 respectively.

3.1 Case1 (Standard condition)Case1 (Standard condition)The measurement results are shown in Fig.3. The measurement results are shown in Fig.3. Theresults are shown in Fig.3. The are shown in Fig.3. Theare shown in Fig.3. The shown in Fig.3. The average of CO2 discharge quantity was 16.3[l/h]. The air change rate was generally found stable. Fig.4generally found stable. Fig.4 stable. Fig.4Fig.4 shows the estimated results from system identificationestimated results from system identifications from system identification from system identificationfrom system identification system identification


11552nd PALENC Conference and 28th AIVC Conference on Building Low Energy Cooling and Advanced Ventilation Technologies in the 21st Century, September 2007, Crete island, Greece

calculation and measurement results from airflow meters from airflow meter from airflow meterfrom airflow meter airflow meter and constant concentration tracer gas method (here- constant concentration tracer gas method (here-here-after, ‘Measured airflow rate’). The estimated value, ‘Measured airflow rate’). The estimated value‘Measured airflow rate’). The estimated valueMeasured airflow rate’). The estimated value’). The estimated value). The estimated valueThe estimated valueestimated valueed value value of the total air change rate was 14.5% less than that was 14.5% less than that 14.5% less than that14.5% less than that that of measured value. Outdoor airflow rate was slightly measured value. Outdoor airflow rate was slightly slightly under -estimated. However, good agreement was gener-gener-ally obtained. Occurred error may be due to;. Occurred error may be due to;Occurred error may be due to; error may be due to;may be due to;a) Occurred error in the system identification calculation,ccurred error in the system identification calculation,red error in the system identification calculation,ed error in the system identification calculation, error in the system identification calculation,in the system identification calculation, system identification calculation,,b) Different discharge quantity of COof CO CO2 from the actual value.

Fig.5. Each measurement data (Case4)

3.2 Case2Case2Case2-aThe estimated value of the total air change rate wasestimated value of the total air change rate wased value of the total air change rate was value of the total air change rate was of the total air change rate was was 23.4% less than that of measured value. Large discrep-less than that of measured value. Large discrep- that of measured value. Large discrep- measured value. Large discrep-Large discrep- discrep-discrep-ancy was observed at was observed atobserved at at Outdoor → 2W, between 2W and 2E with airflow rate between rooms.

(a) Measured airflow rate

(b) System identification calculationFig.6. Comparison of measured results and estimated results (Case4)

Fig.7. Comparison of total air change rate of each caseTable 3. Comparison of airflow rate between rooms of each case

Case2-bThe estimated value of the total air change rate wasestimated value of the total air change rate wased value of the total air change rate was value of the total air change rate was of the total air change rate was was 24.6% less than that of measured value. The error was% less than that of measured value. The error was that of measured value. The error was measured value. The error wasThe error was error was almost as much as Case2-a. However, little error of air-little error of air- error of air-of air-flow rate between rooms was generally found in com-parison to Case2-a. Case2-a.

3.3 Case3Case3The estimated value of the total air change rate wasestimated value of the total air change rate wased value of the total air change rate was value of the total air change rate was of the total air change rate was was 14.9% less than that of measured value. Large variance9% less than that of measured value. Large variance% less than that of measured value. Large variance that of measured value. Large variance measured value. Large varianceLarge variance variancevariance was obtained atobtained at at Outdoor → 1W, between 1W and 1E with airflow rate between rooms. Huge error was arisen with 1W (Not staying room) as a result.

3.4 Case4Case4The measurement results are shown in Fig.5. CO measurement results are shown in Fig.5. COresults are shown in Fig.5. CO are shown in Fig.5. COare shown in Fig.5. CO shown in Fig.5. CO5. CO CO2 concentration in 2E dropped considerably when thedropped considerably when the considerably when thethe



window was opened, as a result air change rate in-, as a result air change rate in-as a result air change rate in-air change rate in-ir change rate in-in-creased up to 2.5[1/h]. The estimated results from up to 2.5[1/h]. The estimated results fromThe estimated results from estimated results froms from system identification calculation and measured airflow rate are compared and shown in Fig.6. The estimatedcompared and shown in Fig.6. The estimatedshown in Fig.6. The estimatedThe estimatedestimateded value of the total air change rate was 32.5% less than of the total air change rate was 32.5% less than was 32.5% less than 32.5% less than% less than that of measured value. Large difference was found at measured value. Large difference was found atLarge difference was found at difference was found atdifference was found at was found atfound at at Outdoor → 2E, between 1E and 2E with airflow rate between rooms. Huge error was arisen with 2E (The room that window was opened) as a result.

3.5 Case5Case5The estimated value of the total air change rate wasestimated value of the total air change rate wased value of the total air change rate was value of the total air change rate was of the total air change rate was was 18.3% less than that of measured value. The error was% less than that of measured value. The error was that of measured value. The error was measured value. The error wasThe error was error was similar to that of Case1. However, the error of airflow to that of Case1. However, the error of airflow. However, the error of airflow However, the error of airflowthe error of airflowerror of airflow of airflow airflow rate between rooms was more in comparison to Case1, between rooms was more in comparison to Case1, Case1,, especially atspecially at Outdoor → 1E and 2E → 2W.

4. COMPARISON BETWEEN EACH CASE

Case1 generated the least error in term of total airin term of total air total air change rate while the biggest error was found in Case4 rate while the biggest error was found in Case4 while the biggest error was found in Case4 the biggest error was found in Case4the biggest error was found in Case4he biggest error was found in Case4found in Case4 in Case4Case4ase4 (cf. Fig.7). With a few exceptions (atcf. Fig.7). With a few exceptions (atFig.7). With a few exceptions (at Outdoor → 1W, 1E → 2E, between 2W and 2E), Case1 generated the least error with airflow rate between rooms (cf. Table airflow rate between rooms (cf. Tableairflow rate between rooms (cf. Tablecf. TableTable 3). Comparing between each case, following conditionsbetween each case, following conditions each case, following conditions were found to be necessary for estimation accuracy.a) More than two CO2 concentration peaks accompanying human occupancy would occur.b) Stay as long time as possible. c) All rooms need to be occupied more than once duringoccupied more than once during more than once during measurement period.d) All windows has to be closed.ll windows has to be closed.windows has to be closed.s has to be closed.has to be closed.e) Indoor air should be mixed sufficiently.

5. CONCLUSIONS

1) Measured airflow rate and estimated results fromMeasured airflow rate and estimated results froms from fromfrom system identification calculation showed relativelyed relatively relatively good correspondence as a result of experiment in a con-con-trolled -environment full-scale test house. -environment full-scale test house. 2) The impact on estimation accuracy made by occupantThe impact on estimation accuracy made by occupant behaviour was investigated. NOTES

[Note 1] 1) 1W, 2W: The airflow rate was controlled to be around 0.5[1/h] converted to air change rate of each zone..2E: 0.4[1/h] air change rate. 1E: Only exhaust ventilation was installed and the air change rate was controlled to be around 0.5[1/h]. 2) 1st floor: The air change rate was controlled to be around 0.5[1/h].

Wellhole between 1st and 2nd floor: 0.5[1/h] air change rate. 2nd floor: 0.5[1/h] air change rate of 2W. [Note 2] The relationship between O2 intake of male perintake of male per person (Y[l/h]) and heart rate (X[bpm]) is defined as following,,Y=1.848X-124.02Next, 0.85 is multiplied as the gas exchange ratio. Gasmultiplied as the gas exchange ratio. Gas as the gas exchange ratio. Gas exchange ratio is defined as the ratio of COthe ratio of CO ratio of CO2 discharge quantity to O2 intake.The bottom line of CO2 discharge quantity was set to 11.2[l/ h] per person.[Note 3] Six hours measurement per one operation was conducted in previous experiment carried out by Tukidate et al (Tukidate, 2004). Burden of occupant was taken into consideration. Based on this case, same time settingBased on this case, same time setting this case, same time settingsetting was carried out in the current experiment. in the current experiment..

ACKNOWLEDGEMENTSS

This study was supported by the scientific research of the Ministry of Education, Culture, Sports, Science and Technology of Japan (Grant #18656162). The authors18656162). The authors). The authors would like to express their appreciation to Isamu OhtaIsamu Ohta (Researcher, Misawa Homes Co., Ltd, Japan) forResearcher, Misawa Homes Co., Ltd, Japan) for, Misawa Homes Co., Ltd, Japan) for precious advice and instruction to the experiment.the experiment. experiment.

REFERENCES

Ikai, Michio (1985). Shintai-Undo no Seirigaku (Physiology of physical exercise), Tokyo: Kyorin-Shoin. Nakanishi, Mitsuo (1993). Undo-Seirigaku Nyumon (Introduction of exercise physiology), Tokyo: Gijutsu-Shoin. Nakayama, Akio (1985). Onnetsu-Kankyo Seirigaku (Physiology of thermal environment), Tokyo: Rikogakusha PubrishingRikogakusha Pubrishingg Co.,Ltd..Ohta, Isamu (2004). Consideration on a simplified measuring method for ventilation rate of detached house (Part1) - The outline of the measuring method - . Summaries of Technical Papers of Annual Meeting Architectural Institute of Japan 2004, Architectural Institute of Japan 2004,Architectural Institute of Japan 2004, D-2: pp751-752.Okuyama, Hiroyasu (1984). State Equation of General Diffusion System Using Network Concepts and Theory of System Parameter Identification. Transactions of the Architectural Insti-Transactions of the Architectural Insti- Architectural Insti-Architectural Insti-tute of Japan, Vol.344: pp103-115., Vol.344: pp103-115.Tukidate, Tukasa (2004). Consideration on a simplified measuring method for ventilation rate of detached house (Part2) - A field test of the measuring method - . Summaries of Technical Papers of Annual Meeting Architectural Institute of Japan 2004, D-2: pp753-754.


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