Performance evaluation of air terminal devices for personalized ventilation in the tropics

PERFORMANCE EVALUATION OF AIR TERMINAL DEVICES FOR PERSONALIZED VENTILATION IN THE TROPICS ZHOU WEI NATIONAL UNIVERSITY OF SINGAPORE 2005 PERFORMANCE EVALUATION OF AIR TERMINAL DEVICES FOR PERSONALIZED VENTILATION IN THE TROPICS ZHOU WEI (B.Eng., Tsinghua Univ.) A THESIS SUBMITTED FOR THE DEGREE OF MASTER OF SCIENCE (BUILDING) DEPARTMENT OF BUILDING NATIONAL UNIVERSITY OF SINGAPORE 2005 ACKNOWLEDGEMENTS I would like to express my sincere gratitude to my supervisor, Associate Professor Tham Kwok Wai, Ph.D., for giving me the opportunity to perform my Master programme, for his enlightening supervision, valuable advice, constructive suggestions, and fruitful discussions, and for his great help and encouragement Being his student has been an enjoyable and memorable experience I am very grateful to him for being always friendly and available whenever he is approached for solving problems I am grateful to Associate Professors Chandra Sekhar and David Cheong, whose doors are always open, for freely sharing with me their valuable knowledge, experience, and expertise on any issues related to experiments with personalized ventilation I would like to thank Associate Professor Arsen Melikov for kindly mailing the papers from Denmark to me and Professor David Wyon for offering viewpoints and sharing expertise on personalize ventilation during his visiting residence in the department Warmest thanks to my colleagues with whom I have had the privilege to work: Mr Gong Nan for setting up the air terminal devices on the workstations and laying out the sensors, for familiarizing me with the operation of the whole system and sharing his experience, as well as for taking the lead in conducting the subjective experiments and offering constructive suggestions for the objective experiments with the manikin; Ms Sun Wei for her passionate and sustained assistance in conducting the experiments and analyzing the data Mr Henry Cahyadi Willem for freely sharing his knowledge and valuable experience as a senior fellow student and always friendly and patiently teaching me how to write and speak English properly whenever I turn to him i I would like to extend my sincere appreciation to the staffs in the department: Mr Tan Cheow Beng for being very instrumental in solving any electromechanical problems encountered in the chamber; Mr Zaini bin Wahid for his technical support in constructing the workstations and assembling and mounting the air terminal devices; Mr Zuraimi Bin Mohd Sultan for sharing his expertise on indoor air quality and teaching me how to manipulate the instruments involved in the experiments; and Ms Christabel Toh for her help on administrative issues Furthermore, I am thankful to my friends, especially Mr Sun Liang, Ms Li Ying, Ms Lou Junying, Mr Dong Bing, Mr Xie Yongheng, Ms Li Yan, Ms Song Jiafang, and Mr Chen Yu for their help, encouragement, and companionship Finally, but certainly not least, I am grateful to Miss Qu Chang for her constant understanding, great encouragement, and true love, without which I would not have sustained and completed the study Singapore, July 2005 Zhou Wei ii TABLE OF CONTENTS ACKNOWLEDGEMENTS i TABLE OF CONTENTS iii SUMMARY vi LIST OF TABLES ix LIST OF FIGURES x LIST OF SYMBOLS xvii CHAPTER INTRODUCTION 1.1 Background 1.2 Research objectives 1.3 Outline of thesis CHAPTER LITERATURE REVIEW 11 2.1 Typical PV systems 11 2.1.1 Desktop-based systems 11 2.1.2 Partition-based systems 17 2.1.3 Floor-based systems 18 2.1.4 Ceiling-based systems 19 2.2 Physical measurements 21 2.3 Human response to PV 32 2.4 Studies in hot and humid climates 39 CHAPTER RESEARCH METHODOLOGY 43 3.1 Introduction 43 3.2 Method for objective measurements 43 3.2.1 Experimental facilities 43 3.2.1.1 Indoor environmental chamber 43 3.2.1.2 Mixing ventilation system 45 3.2.1.3 Personalized ventilation system 45 3.2.1.4 ATDs for personalized ventilation system 47 3.2.1.4.1 Circular perforated panel (CPP) 47 3.2.1.4.2 Desktop-mounted grille (DMG) 48 3.2.1.5 Breathing thermal manikin 49 3.2.2 Experimental design and conditions 52 3.2.3 Measuring procedure and instrumentation 55 3.2.3.1 Preparatory measurements and calibrations 55 3.2.3.1.1 Manikin calibration 55 3.2.3.1.2 Personalized air flow rate measurement 57 3.2.3.2 Actual measurements 58 3.2.3.2.1 Ambient air temperature and relative humidity measurements 58 3.2.3.2.2 Personalized air velocity, temperature, turbulence intensity, and relative humidity measurements 59 3.2.3.2.3 Manikin skin temperature and heat loss measurements 62 iii 3.2.3.2.4 Manikin inhaled temperature 63 3.2.3.2.5 Tracer gas concentration measurements 64 3.2.4 Performance evaluation indices 66 3.2.5 Limitations of objective measurements 70 3.2.5.1 Non-sweating manikin 70 3.2.5.2 No humidification and generation of CO2 in manikin’s exhaled air 71 3.2.5.3 Relative humidity 72 3.3 Method for subjective assessments 73 3.3.1 Experimental facilities 74 3.3.2 Experimental design 74 3.3.2.1 Experimental conditions 74 3.3.2.2 Subjects 75 3.3.2.3 Experimental procedures 75 3.3.2.4 Data collection and analysis 78 CHAPTER RESULTS AND DISCUSSIONS: Circular Perforated Panel (CPP) 79 Performance of Low-Tu CPP 81 4.1.1 Personalized air velocity profile 81 4.1.2 Air quality 82 4.1.2.1 Inhaled air temperature 82 4.1.2.2 Personal exposure effectiveness 85 4.1.3 Cooling effect 88 4.2 Performance of High-Tu CPP 90 4.2.1 Personalized air velocity profile 90 4.2.2 Air quality 91 4.2.2.1 Inhaled air temperature 91 4.2.2.2 Personal exposure effectiveness 93 4.2.3 Cooling effect 95 4.3 Performance comparison between two ATDs 96 4.3.1 Air velocity profile 97 4.3.2 Inhaled air quality 99 4.3.3 Facial and whole-body cooling effect 104 4.3.4 Draft rating 108 4.4 Summary 110 CHAPTER RESULTS AND DISCUSSIONS: Desktop-Mounted Grille (DMG) 111 5.1 Typical experimental conditions and grille vanes’ angle 111 5.1.1 Personalized air velocity profile 111 5.1.2 Personal exposure effectiveness 112 5.1.3 Inhaled air temperature 114 5.1.4 Cooling effect 115 5.1.5 Draft rating 119 5.2 Impact of ambient air temperature 120 5.2.1 Personal exposure effectiveness 120 5.2.2 Inhaled air temperature 122 5.2.3 Cooling effect 122 iv 5.2.4 Draft rating 124 5.3 Impact of vanes’ angle 125 5.3.1 Personal exposure effectiveness 125 5.3.2 Inhaled air temperature 129 5.3.3 Cooling effect on facial parts 131 5.4 Comparison between DMG and Low-Tu CPP 133 5.4.1 Personal exposure effectiveness 134 5.4.2 Inhaled air temperature 136 5.4.3 Cooling effect 136 5.4.4 Draft rating 138 5.5 Summary 139 CHAPTER RESULTS AND DISCUSSIONS: Tropically Acclimatized Human Response to Personalized Ventilation 142 6.1 Results of subjective measurements 142 6.1.1 Perceived inhaled air temperature 142 6.1.2 Perceived inhaled air quality 145 6.1.3 Facial thermal sensation 150 6.1.4 Whole-body thermal sensation 153 6.1.5 Facial air movement perception and acceptability 158 6.1.5.1 Facial air movement perception 158 6.1.5.2 Facial air movement acceptability 162 6.1.6 Multiple linear regression analysis 168 6.2 Comparison of subjective responses and physical parameters 169 6.3 Summary 183 CHAPTER CONCLUSIONS AND RECOMMENDATIONS 185 7.1 Conclusions 185 7.2 Recommendations 190 BIBLIOGRAPHY 193 APPENDIX A: Constants C for manikin’s body segments 200 APPENDIX B: Calibration curves of personalized air flow rate as a function of PV fan frequency for the three ATDs 202 APPENDIX C: Questionnaires 204 v SUMMARY Personalized ventilation delivers conditioned outdoor air directly to occupant’s breathing zone and provides him/her with individual control over the local thermal environment, making it possible to compensate for the large individual differences in preferred environmental variables By far most reported studies on PV were performed in temperate climates but few in hot and humid climates The present study was embarked upon with the objectives of evaluating the performance of three prototypes of air terminal devices (ATD) for PV and investigating tropically-acclimatized subjects’ response to the local environment created with PV This study consisted of three series of physical measurements of the local environment created with the three ATD prototypes and a small-scale subjective experiment involving 24 tropically acclimatized participants The three ATD prototypes involved in this series of physical measurements were: circular perforated panel supplying personalized air at low initial turbulence intensity (Low-Tu CPP), circular perforated panel supplying personalized air at high initial turbulence intensity (High-Tu CPP), and desktop-mounted grille with adjustable horizontal vanes (DMG) The measurements were performed with a breathing thermal manikin in a controlled environmental chamber The performance of the ATDs were evaluated using indices including personal exposure effectiveness (εp), inhaled air temperature (tinh), facial and whole-body cooling effect (∆teq), and draft rating (DR) The Low-Tu CPP and High-Tu CPP were tested under identical conditions: four combinations of ambient and personalized air temperatures (26/26, 26/23.5, 23.5/23.5, and 23.5/21°C) and personalized air flow rates ranging from to 17L/s for Low-Tu CPP and to 18.8L/s for High-Tu CPP Results have shown that both CPPs were able to enhance the portion of fresh vi personalized air in the inhaled air, lower the tinh, and provide more cooling effects (∆teq) as compared with reference conditions without PV Under a given temperature combination, personalized air with low turbulence intensity led to significantly higher εp, lower tinh, and greater facial ∆teq over the flow rate range studied Under an identical condition, the Low-Tu CPP also yielded significantly greater DR than High-Tu CPP because the effect of the low air temperature and high velocity achieved with the former at the measuring point outweighed that of the high turbulence intensity generated by the latter The DMG with its adjustable vanes directed towards the manikin’s breathing zone, i.e approximately 60° from the horizontal, was tested under temperature combinations of 26/26, 26/23.5, 26/21, 23.5/23.5, and 23.5/21°C at 10 flow rates ranging from to 12.2L/s At flow rate of 12.2L/s, the DMG reached the maximum εp of 0.7, maximum decrease of tinh by 5.1°C, and maximum ∆teq (-7.2°C for facial parts and -0.9°C for whole-body) Decrease in ambient temperature from 26°C to 23.5°C resulted in lower εp and ∆teq due to the increased strength of the free convection flow around the manikin Additional measurements performed with the vanes at 45° and 20° indicated that the 60° was the optimal angle to deliver inhaled air of best quality (εp and tinh) and strongest facial ∆teq Comparison between the DMG and Low-Tu CPP revealed that the DMG yielded a significantly higher εp but slightly higher tinh than the Low-Tu CPP under a given condition The relative difference in facial ∆teq and DR between the two ATDs depended upon the flow rate The three series of physical measurements with the breathing thermal manikin were supplemented with a small-scale experiment with tropically acclimatized subjects The experiment was aimed at investigating responses of tropically acclimatized subjects to the local thermal environment created with the Low-Tu and the High-Tu CPPs respectively, with emphasis being placed upon their perception of inhaled air quality and temperature, facial and whole-body thermal sensation, as well as facial air movement perception and acceptability Twenty-four subjects in group of participated in 15-minute exposures to 48 experimental conditions – vii temperature combinations by personalized air flow rates by CPPs – in a reasonably randomized order The results revealed large individual variability in perception of air quality and thermal environment created Subjects’ perceptions were strongly affected by the personalized air flow rate, temperature, turbulence intensity, and the ambient air temperature Fairly strong correlations were found between facial and whole-body thermal sensation and between facial air movement perception and acceptability and multiple linear regression models were established for perceived inhaled air quality and temperature as a function of other responses Mean subjective responses were found to be well correlated with the corresponding physical parameters measured with the manikin with the exception of inhaled air quality A noteworthy observation was that calculated draft rating below 60% was judged to be acceptable by the tropically acclimatized subjects: higher facial air movement acceptability despite higher draft rating This underpinned the previous finding of the PV pilot study in tropical climate (Sekhar et al., 2003a, 2005) and identified a much broader range of draft rating (up to 60%) within which facial air movement were perceived by the tropically acclimatized subjects to be increasingly acceptable at higher draft rating values When the draft rating was higher than 60%, the acceptability decreased The significant implication of this finding is the tropically acclimatized subjects’ preference to cool and strong air movement to a great extent eliminates the need to make a comprise between improved inhaled air quality and intensified risk of local thermal discomfort due to draft – a problem that applications of PV in temperate climates have widely identified and been confronted with Thus, in tropical climates, the design of PV ATD aiming for delivering cool inhaled air containing high percentage of fresh personalize air would be less constrained by the consideration of potential draft risk caused by close position of ATD in relation to occupants and strong local air movement A properly-designed PV system, applied in tropical context, would have greater potential to achieve good quality of inhaled air and promote thermal comfort simultaneously viii Bibliography ISO Standard 7730 (International Organization for Standarization) (1994) Moderate thermal environments – Determination of the PMV and PPD indices and specification of the conditions for thermal comfort, Geneva: ISO Johnson Controls (2005) Personal Environments Retrieved 16 March, 2005 from the World Wide Web: 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577-582 Melikov, A K., Cermak, R and Majer, M (2002) Personalized ventilation: evaluation of different air terminal devices, Energy and buildings, Vol 34, pp 829-836 196 Bibliography Melikov, A K., Halkjaer, L., Arakelian, R S and Fanger, P O (1994a) Spot cooling-part 1: human responses to spot cooling with air jets, ASHRAE Transactions, 100(2), 476-499 Melikov, A K., Arakelian, R S., Halkjaer, L and Fanger, P O (1994b) Spot cooling-part 2: recommendations for design of spot-cooling systems, ASHRAE Transactions, 100 (2), 500-510 Melikov, A K and Zhou, G (1996) Air movement at the neck of the human body, Proceedings of Indoor Air '96, Nagoya, Japan, 1, 209–214 Melikov, A K., Cermak, R., Kovar, O and Forejt, L (2003) Impact of airflow interaction on inhaled air quality and transport of contaminants in rooms with personalized and total volume ventilation, Proceedings of Healthy Buildings 2003, Singapore, 2, 592-597 Melikov, A K (2004) Personalized ventilation, Indoor Air, 14 (Suppl 7), 157-167 Menzies, D., Pasztor, J., Nunes, F., Leduc, J and Chan C (1997) Effect of new ventilation system on health and well-being of office workers, Archives of Environmental Health, 52 (5) September/October, 360-367 Meyer, B (1983) Indoor Air Quality, Addison-Wesley Pub Co., Boston Naydenov, K., Pitchurov, G., Langkilde, G and Melikov, A K (2002) Performance of displacement ventilation in practice, Proceedings of Roomvent 2002, Copenhagen, Denmark, 483 486 Nilsson, H (2004) Comfort Climate Evaluation with Thermal Manikin Methods and Computer Simulation Models, PhD Thesis, Department of Civil and Architectural Engineering at Royal Institute of Technology, Sweden & Department of Technology and Built Environment at University of Gävle, Sweden Nilsson, H., Holmér, I., Bohm, M and Norén, O (1997) Equivalent temperature and thermal sensation - comparison with subjective responses, Associatione Tecnica Del’Automobile, Bologna Sekhar, S C., Gong, N., Maheswaran, C R U., Cheong, K W D., Tham, K W., Melikov, A and Fanger, P O (2003a) Preliminary findings of a pilot study of personalized ventilation in a hot and humid climate, Proceedings of Healthy Buildings 2003, Singapore, 2, 825-830 Sekhar, S C., Gong, N., Maheswaran, C R U., Cheong, K W D., Tham, K W., Melikov, A and Fanger, P O (2003b) Energy efficiency potential of personalized ventilation system in the tropics, Proceedings of Healthy Buildings 2003, Singapore, 2, 686-691 Sekhar, S C., Gong, N., Tham, K W., Cheong, K W D., Melikov, A K., Wyon, D P and 197 Bibliography Fanger, P O (2005) Findings of personalized ventilation studies in a hot and humid climate, International Journal of Heating, Ventilating, Air-Conditioning and Refrigerating Research (HVAC&R), USA (to appear) Schiller, G E., Arens, E A., Bauman, F S and Benton, C (1988) A field study of thermal environments and comfort in office buildings, ASHRAE Transactions, 94 (2), 280–308 Summer, W (1971) Odour pollution of air: causes and control, London: Engineering Series Tanabe, S., Arens, E A., Bauman, F S., Zhang, H and Madsen, T L (1994) Evaluating thermal environments by using a thermal manikin with controlled skin surface temperature, ASHRAE Transactions, 100 (1), 39 – 48 Tham, K W., Willem, H C., Sekhar, S C., Wyon, D P., Wargocki, P and Fanger, P O (2003a) The SBS symptoms and environmental perceptions of office workers in the Tropics at two air temperatures and two ventilation rates, Proceedings of Healthy Buildings 2003, Singapore, 3, 182-187 Tham, K W., Willem, H C., Sekhar, S C., Wyon, D P., Wargocki, P and Fanger, P O (2003b) Temperature and ventilation effects on the work performance of office workers (study of a call center in the tropics), Proceedings of Healthy Buildings 2003, Singapore, 3, 280-286 Tham, K W., Sekhar, S C., Cheong, K W D and Gong, N (2004a) Experimental study of draft perception of tropically acclimatized subjects under personalized ventilation, Proceedings of Roomvent 2004, Coimbra: DEM-FCT, Univ of Coimbra Tham, K W., Sekhar, S C., Cheong, K W D and Gong, N (2004b) Thermal sensation of tropically acclimatized subjects under fixed air flow of personalized ventilation, Proceedings of Roomvent 2004, Coimbra: DEM-FCT, Univ of Coimbra Toftum, J., Zhou, G and Melikov., A (1997) Airflow direction and human sensitivity to draught, Proceedings of CLIMA 2000, Brussels: REHVA Toftum, J., Melikov, A K., Tynel, A., Bruzda, M and Fanger, P O (2002) Human preference for air movement, Proceedings of Roomvent 2002, Copenhagen, Denmark, 301-304 Tsuzuki, K., Arens E A., Bauman, F S and Wyon, D P (1999) Individual thermal comfort control with desk-mounted and floor-mounted task/ambient conditioning (TAC) systems, Proceedings of Indoor Air 1999, Edinburgh, Vol 2, pp 368 – 373 Wargocki, P., Wyon, D P., Baik, Y K., Clausen G and Fanger, P O (1999) Perceived air quality, Sick Building Syndrome (SBS) symptoms and productivity in an office with two different pollution loads, Indoor Air, 9, 165-179 198 Bibliography Wargocki, P., Wyon, D P., Nielsen, J B and Fanger, P O (2002) Call center occupant response to new and used filters at two outdoor air supply rates, Proceedings of Indoor Air 2002, Monterey, CA, 3, 449–454 Wyon, D P (1996) Individual microclimate control: required range, probable benefits and current feasibility, Proceedings of Indoor Air 96, Nagoya, Japan, 1, 1067-1072 Yang, J., Melikov, A., Fanger, P O., Li, X and Yan, Q (2002) Impact of personalized ventilation on human response: comparison between constant and fluctuating airflows under warm condition, Proceedings of Roomvent 2002, Copenhagen, 305–308 Yang, J., Kaczmarczyk, J., Melikov, A and Fanger, P O (2003) The impact of personalized ventilation system on indoor air quality at different levels of room air temperature, Proceedings of Healthy Buildings 2003, Singapore, 2, 345–350 Zeng, Q., Kaczmarczyk, J., Melikov, A and Fanger, P.O (2002) Perceived air quality and thermal sensation with personalised ventilation system, Proceedings of Roomvent 2002, Copenhagen, 61–64 Zuo, H G., Niu, J L and Chan, W T (2002) Experimental study of facial air supply method for the reduction of pollutant exposure, Proceedings of Indoor Air 2002, Monterey, CA, 1090-1095 199 Appendix A: Constants C for manikin’s body segments 200 Constants C for manikin’s body segments determined through calibration No 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 All Body segments L Foot R Foot L Low leg R Low leg L Front Thigh R Front Thigh L Back thigh R Back thigh Pelvis Back side Skull (forehead) L face R Face Back of neck L Hand R Hand L Forearm R Forearm L Upper arm out R Upper arm out L Upper arm in R Upper arm in L Chest R Chest L Back R Back Whole body Constants C values (K.m2/W) 0.221 0.221 0.190 0.192 0.259 0.272 0.311 0.303 0.371 0.260 0.493 0.239 0.203 0.314 0.165 0.157 0.170 0.161 0.249 0.265 0.345 0.340 0.357 0.353 0.311 0.308 0.242 201 Appendix B: Calibration curves of personalized air flow rate as a function of PV fan frequency for the three ATDs 202 High Tu CPP 20 18 y = 0.0026x + 0.2277x + 0.67 R2 = 0.9974 Flow rate (L/s) 16 14 12 10 0 10 15 20 25 30 35 40 45 50 Fan frequency (Hz) Low Tu CPP 20 18 y = 0.001x + 0.2921x - 0.1964 R2 = 0.9998 Flow rate (L/s) 16 14 12 10 0 10 15 20 25 30 35 40 45 50 40 45 50 Fan frequency (Hz) DMG 22 20 y = 0.0018x + 0.3248x + 0.594 R2 = 0.9994 18 Flow rate (L/s) 16 14 12 10 0 10 15 20 25 30 35 Fan frequency (Hz) 203 Appendix C: Questionnaires 204 Questionnaire (used to assess the environment under PV) When time = 5, 10, 15 minutes or at reference condition Thermal Sensation Please enter a number in each of the boxes in the diagram below to indicate the thermal sensation of each body section The 7-value numerical scale to be used appears in the table below: +3 +2 +1 -1 -2 -3 Hot Warm Slightly warm Neutral Slightly cool Cool Cold Please also assess your thermal sensation for your whole body: 205 Air Movement Perception Please enter a number in each of the boxes in the diagram below to indicate the air movement perception of each body section The 7-value numerical scale to be used appears in the table below If you don’t feel any air movement, just choose “No” in the corresponding box +3 +2 +1 -1 -2 -3 much too breezy too breezy slightly breezy just right slightly still too still much too still a1 Please assess the air movement on the facial part Just Acceptable Very Unacceptable Very Acceptable Just Unacceptable 206 a2 Please indicate the change in the air movement preferred on the facial part? Less air movement Same air More air movement movement b If you feel any air movement other than facial part, b1 Please assess the air movement on neck Very Just Acceptable Very Unacceptable Acceptable Just Unacceptable b2 Please indicate the change in the air movement preferred on neck? Less air movement Same air More air movement movement b3 Please assess the air movement on chest, shoulder and upper arm Very Just Acceptable Very Unacceptable Acceptable Just Unacceptable b4 Please indicate the change in the air movement preferred on chest, shoulder and upper arm? Less air movement Same air More air movement movement b5 Please assess the air movement on lower arm and hands 207 Just Acceptable Very Unacceptable Very Acceptable Just Unacceptable b6 Please indicate the change in the air movement preferred on lower arm and hands? Less air movement Same air More air movement movement b7 Please assess the air movement on lower body Just Acceptable Very Unacceptable Very Acceptable Just Unacceptable b8 Please indicate the change in the air movement preferred on lower body? More air Less air movement Satisfied movement 208 Questionnaire (Thermal comfort, IAQ, SBS, productivity) When time = 15 minutes or reference condition Thermal Comfort for your body: Just Acceptable Very Unacceptable Very Acceptable Just Unacceptable Indoor Air Quality a Please assess the inhaled air temperature : Cold Hot b Please assess the inhaled air humidity: Humid Dry c Please assess the inhaled air quality : Just Acceptable Very Unacceptable Very Acceptable Just Unacceptable d Please assess the odour of inhaled air: No Odour Overwhelming Odour e Please assess the freshness of inhaled air: Air Stuffy Air Fresh 209 Feeling of the Environment Evaluation of noise level: Satisfied Dissatisfied Evaluation of lighting level: Satisfied Dissatisfied Evaluation of ergonomics level: Satisfied Dissatisfied Additional info: Do you wear contact lens? Yes No 210 [...]... for manikin body segments Contaminant concentration in the inhaled air of a person SF6 concentration in the inhaled air Contaminant concentration at a point in the room SF6 concentration in personalized air Contaminant concentration in the exhaust air SF6 concentration in the climate chamber Contaminant concentration in the outdoor supply air Draft rating Manikin sensible heat loss Resistance of Craftemp®... Outline of thesis The present chapter briefly discusses the characteristics of conventional total-volume ventilation, points out its intrinsic limitations in accommodating the widely recognized large individual differences in preference for thermal environment, and introduces the concept of the state -of- the- art personalized ventilation (PV) The objectives of the study are stated Chapter 2, consisting of. .. transmitter of gases, and of fine dust (Meyer, 1983) Normally, in non-industrial buildings, IAQ problems arise when there is an inadequate quantity of ventilation air being provided for the amount of air contaminants present in a given space Therefore, standards, guidelines, and regulations pertaining to indoor environment have established certain requirements on minimum quantities of ventilation air, maximum... productivity by 6.5% in the amount of typed text The study repeated by Lagercrantz et al (2000) in a Swedish test room confirmed the findings of Wargocki et al (1999) The presence of pollution source increased the percentage dissatisfied with the air quality, the intensity of dizziness and difficulty 4 Chapter 1 Introduction in thinking, and decreased the performance A study conducted in a call center... panel containing adjustable sliders that allow the control of the speed of the air emerging from the nozzles, its temperature, the surface temperature of a 200-Watt radiant heating panel located in the knee space, the dimming of the user’s task light, and a white noise generator for acoustical masking The control panel also contains an infrared movement sensor that keeps the PEM switched on when the workstation... due primarily to increase in building airtightness, increasing use of textile floor covering and furnishing with high emission rate of pollutants, increasing use of computers and other office equipments, reduction in ventilation rates for energy saving, and so forth (Awbi, 2003) Some studies have identified certain relationship between the quality of indoor environment, occupants’ complaints and reported... as most of other TAC studies performed in 1990’s or earlier, the air supplied from the TAC systems was either entirely recirculated from the room, or a mixture of recirculated room air and outdoor air Few supplied 100% conditioned outdoor air In view of the obvious positive impact of the outdoor air on occupant’s perception, health, and performance, the TAC systems should supply air containing as much... placed inside a flexible duct (Ø80mm) The ATD was made of aluminum It was shaped as a half-cylinder with a round opening, Ø80mm, from one side for air inlet and a rectangular opening, 240mm×75mm, in the front for the air outlet An experimentally defined aluminum profile was mounted inside to ensure uniform air distribution The front of the 15 Chapter 2 Literature review ATD was covered with a perforated... high local air movement This suggests that, contrary to existing notions of air movement leading to draft as undesirable in temperate climates, air movement might be an important and positive factor in improving thermal comfort for the tropics Furthermore, the enthalpy difference between outdoor and indoor air in the tropics consumes considerable energy to cool and dehumidify the outdoor air before it... whereby the entire volume of air in the space can be maintained at the desired set-point temperature and adequate quantity of conditioned outdoor air is delivered to the occupants Nevertheless, the supply diffusers, usually mounted overhead, are far from the occupants and thus the supply air at a low contaminant concentration is mixed with the contaminated room air by the time it reaches the inhalation .. .PERFORMANCE EVALUATION OF AIR TERMINAL DEVICES FOR PERSONALIZED VENTILATION IN THE TROPICS ZHOU WEI (B.Eng., Tsinghua Univ.) A THESIS SUBMITTED FOR THE DEGREE OF MASTER OF SCIENCE (BUILDING)... the researchers with the purpose of increasing air supply volume (improving ventilation performance) but decreasing the air velocities at the location of the occupants (reducing the effects of. .. for manikin body segments Contaminant concentration in the inhaled air of a person SF6 concentration in the inhaled air Contaminant concentration at a point in the room SF6 concentration in personalized