135 research outputs found
Modulated air layer heat amd moisture transport by ventilation and diffusion from clothing with open aperture
No full textA two-dimensional model is developed for the modulated internal airflow, due to walking, in the gap between clothing and skin surface in the presence of clothing apertures. The normal airflow renewing the air layer through the fabric is modeled using the Ghali et al. three-node fabric ventilation model with corrected heat and moisture transport coefficients within the fabric voids to include the diffusion-dominated transport processes in the fabric at low normal flow rates that occur near the open aperture. The parallel flow is induced by a periodic pressure difference between environmental pressure at the aperture of the clothing system and trapped air layer pressure. The parallel flow in the trapped air layer is assumed to be locally governed by the Womersley solution of time-periodic laminar flow in a plane channel. The two-dimensional (2D) model that uses, in the parallel direction, the Womersley flow of the trapped air layer has predicted significantly lower flow rates than a model based on an inertia-free quasi-steady Poisueille flow model (valid only at low ventilation frequencies). In addition, the model predicted lower sensible and latent heat losses from the sweating skin in the presence of open apertures in the clothing system. The percentage drop in total heat loss due to open aperture is 7.52percent, and 2.63percent, at ventilation frequencies of 25, and 35 revolution per minute, respectively. The reported results showed that under walking conditions, a permeable clothing system with an open aperture reduced heat loss from the skin when compared to a normal ventilation model (closed aperture). These results were consistent with previously published empirical data of Lotens and Danielsson on air layer resistance for open and closed apertures in high air permeable fabrics. Copyright © 2005 by ASME.ASTM, 1996, D73796 ASTM; DANIELSSON U, 1993, THESIS ROYAL I TECHN; FARNWORTH B, 1986, TEXT RES J, V56, P653, DOI 10.1177-004051758605601101; GAGGE AP, 1986, ASHRAE T B, V2; Ghaddar N, 2003, INT J THERM SCI, V42, P605, DOI 10.1016-S1290-0729(03)00026-7; Ghali K, 2002, J HEAT TRANS-T ASME, V124, P530, DOI 10.1115-1.1471524; Ghali K, 2002, INT J HEAT MASS TRAN, V45, P3703, DOI 10.1016-S0017-9310(02)00088-1; GHALI K, 2004, P INT C THERM ENG TH; Ghali K, 2002, J POROUS MEDIA, V5, P17; HAVENITH G, 1990, ERGONOMICS, V33, P67, DOI 10.1080-00140139008927094; HAVENITH G, 1990, ERGONOMICS, V33, P989, DOI 10.1080-00140139008925308; HOLMAN JP, 1997, HEAT TRANSFER, P488; Hyland R.W., 1983, ASHRAE T, V89, P500; JONES BW, 1993, ASHRAE T 1, V98, P189; JONES BW, 1990, P INT C ENV ERG AUST, P66; JONES BW, 1985, P CLIMA 2000 WORLD C, V4, P1; LAMOREUX LW, 1971, B PROSTHET RES, P3; Li Y, 1998, TEXT RES J, V68, P389, DOI 10.1177-004051759806800601; LOTENS W, 1993, THESIS TNO I PERCEPT, P34; McCullough EA, 1989, ASHRAE T, V95, P316; Morton W.E., 1975, PHYS PROPERTIES TEXT; Straatman AG, 2002, PHYS FLUIDS, V14, P1938, DOI 10.1063-1.1476673; WOMERSLEY JR, 1955, PHILOS MAG, V46, P199; WOMERSLEY JR, 1957, 56614 TR WADC AER RE79
Ghali Amin Oral History
No full textGalal Amin was an economics professor the American University in Cairo from the late 1970s through the early 2000s, in addition to being a renowned Egyptian public intellectual, author, and columnist. He describes his father, a prominent academic, and outlines his own early education and life as a graduate student in London, and early career as an economist in Kuwait. He mentions early teaching stints at AUC starting in 1967, contrasting the social class of students then with those in later years, and tells how he came permanently to AUC later in the 1970s. Amin briefly outlines changes in the Economics department over the years, and offers some commentary on AUC students (specifically changes in academic quality over time). He also speaks about the university’s relationship with Egyptian politics and government, including an anecdote about an AUC committee he served on after the 1973 war. His research interests and writings are also covered
Letter 25 from Waguih Ghali to Diana Athill on November 24, 1964
No full textLetter, 3 pagesPersonal names mentioned in the letter: Brian Moore (author of "An Answer from Limbo"); Herbert Zander; Edda; Kurt; Rolf; Agatha Christie; Detective Hercule Poirot; Fyodor Dostoevsk
Convection and ventilation in fabric layers
No full text[No abstract available]Acheson D J, 1990, ELEMENTARY FLUID DYN; American Society for Testing and Materials, 1983, D73775 ASTM; AMIRI A, 1994, INT J HEAT MASS TRAN, V37, P939, DOI 10.1016-0017-9310(94)90219-4; Amiri A, 1998, INT J HEAT MASS TRAN, V41, P4259, DOI 10.1016-S0017-9310(98)00120-3; [Anonymous], 1997, ASHRAE HDB; DANIELSSON U, 1993, THESIS ROYAL I TECHN; Fanger PO, 1982, THERMAL COMFORT ANAL, P156; FARNWORTH B, 1986, TEXT RES J, V56, P653, DOI 10.1177-004051758605601101; FONSECA GF, 1965, TEXT RES J, V35, P95, DOI 10.1177-004051756503500201; FOURT L, 1971, CLOTHING COMFORT FUN; Ghaddar N, 2005, INT J HEAT MASS TRAN, V48, P3151, DOI 10.1016-j.ijheatmasstransfer.2005.03.001; GHADDAR N, 2005, P ASME 2005 SUMM HEA; Ghaddar N, 2005, J HEAT TRANS-T ASME, V127, P287, DOI 10.1115-1.1857949; Ghaddar N, 2003, INT J THERM SCI, V42, P605, DOI 10.1016-S1290-0729(03)00026-7; Ghali K, 2002, J HEAT TRANS-T ASME, V124, P530, DOI 10.1115-1.1471524; GHALI K, 2004, P 1 INT C THERM ENG; Ghali K, 2002, INT J HEAT MASS TRAN, V45, P3703, DOI 10.1016-S0017-9310(02)00088-1; Ghali K, 2002, J POROUS MEDIA, V5, P17; HARTER KL, 1981, TEXT RES J, V51, P345, DOI 10.1177-004051758105100506; HAVENITH G, 1990, ERGONOMICS, V33, P67, DOI 10.1080-00140139008927094; HAVENITH G, 1990, ERGONOMICS, V33, P989, DOI 10.1080-00140139008925308; HONG S, 1992, THESIS KANSAS STATE; JONES BW, 1992, ASHRAE TRAN, V98, P189; JONES BW, 1990, P INT C ENV ERG AUST, P66; JONES BW, 1985, P CLIMA 2000 WORLD C, V4, P1; Kerslake D.M., 1972, STRESS HOT ENV; Kuznetsov AV, 1998, TRANSPORT PHENOMENA IN POROUS MEDIA, P103, DOI 10.1016-B978-008042843-7-50005-2; Kuznetsov AV, 1997, INT J HEAT MASS TRAN, V40, P1001, DOI 10.1016-0017-9310(96)00179-2; KUZNETSOV AV, 1993, INT J HEAT MASS TRAN, V37, P3030; LAMOREUX LW, 1971, B PROSTHET RES, P3; Lee DY, 1999, INT J HEAT MASS TRAN, V42, P423, DOI 10.1016-S0017-9310(98)00185-9; LI Y, 1997, THESIS KANSAS STATE; Lotens W, 1988, ENV ERGONOMICS, P162; Lotens WA, 1993, THESIS TNO I PERCEPT; McCullogh E., 1985, ASHRAE T, V91, P29; McCullough EA, 1989, ASHRAE T, V95, P316; MINCOWYCZ WJ, 1999, INT J HEAT MASS TRAN, V42, P3373; Morris G. J., 1953, J TEXT I, V44, P449; Morton W.E., 1975, PHYS PROPERTIES TEXT; NIELSEN R, 1985, ERGONOMICS, V28, P1617, DOI 10.1080-00140138508963299; NISHI Y, 1970, ASHRAE T, V75, P137; REES WH, 1941, J TEXT I, V32, P149; Straatman AG, 2002, PHYS FLUIDS, V14, P1938, DOI 10.1063-1.1476673; Vafai K., 1990, ASME, V112, P690; VOKAC Z, 1973, TEXT RES J, V42, P474; Womersley J. R., 1957, ELASTIC TUBE THEORY, P56; Woodcock A.H, 1962, TEXT RES J, V32, P628, DOI 10.1177-00405175620320080246
Ventilation rates of micro-climate air annulus of the clothing-skin system under periodic motion
No full textA novel three-dimensional dynamic model is developed from first principles of mass and energy conservation of the modulated internal airflow in the variable annulus size between the clothing and the skin surface in presence of clothing apertures. The developed model solves for the flow and heat transfer problem in a finite length cylindrical annulus where the inner cylinder is oscillating within an outer fixed cylinder of porous fabric boundary. The changing annulus size induces pressure variations that cause air flow in the angular and the radial directions. In addition, axial airflow is present due to clothing open aperture to the atmosphere at one end of the annulus (sleeve or neck opening). The axial and angular flows in the trapped air layer are assumed locally governed by Womersley solution of time-periodic laminar flow in a plane channel in each direction. The 3-D model predicted the ventilation radial airflow through the fabric, the angular and axial airflow induced by the motion of the inner cylinder, and the sensible and latent heat losses from the skin due to ventilation with the presence of an open or closed aperture. Experiments were conducted using tracer gas method to measure time and space-averaged air ventilation rates induced by inner cylinder periodic motion within a fabric cylindrical sleeve at spacing amplitude ratio with respect to the mean of 0.8 for both closed and open aperture cases. The ventilation rates within the annulus predicted by the 3-D model agreed well with experimental data at higher frequencies. For closed aperture situation at an amplitude ratio of 0.8, the mean percentage errors of the measurements compared with the predicted values of the model were 52percent, 27.5percent and 6.7percent corresponding to the frequencies of 30 rpm, 40 rpm, and 60 rpm, respectively. Measured ventilation rates for open aperture agreed well with predicted ventilation rates at high frequencies giving lower values of total air renewal than the closed aperture results where the measured reductions in total ventilation rate compared to closed aperture were 8.5percent and 14.3percent corresponding to the frequencies of 40 rpm and 60 rpm, respectively. In addition, the model results showed that under walking conditions, a permeable clothing system with an open aperture reduced the heat loss from the skin by less than 1percent when compared to the closed aperture clothing system. These results are consistent with previously published empirical data on air layer resistance for open and closed aperture of high air permeable fabric. © 2005 Elsevier Ltd. All rights reserved.Acheson D J, 1990, ELEMENTARY FLUID DYN; American Society for Testing and Materials, 1983, D73775 ASTM; DANIELSSON U, 1993, THESIS ROYAL I TECHN; GHADDAR N, 2004, P 2004 ASME HEAT TRA; Ghaddar N, 2003, INT J THERM SCI, V42, P605, DOI 10.1016-S1290-0729(03)00026-7; Ghali K, 2002, J HEAT TRANS-T ASME, V124, P530, DOI 10.1115-1.1471524; Ghali K, 2002, INT J HEAT MASS TRAN, V45, P3703, DOI 10.1016-S0017-9310(02)00088-1; GHALI K, 2004, P INT C THERM ENG TH; Ghali K, 2002, J POROUS MEDIA, V5, P17; HAVENITH G, 1990, ERGONOMICS, V33, P67, DOI 10.1080-00140139008927094; HAVENITH G, 1990, ERGONOMICS, V33, P989, DOI 10.1080-00140139008925308; Hyland R.W., 1983, ASHRAE T, V89, P500; JONES BW, 1990, P INT C ENV ERG AUST, P66; JONES BW, 1985, P CLIMA 2000 WORLD C, V4, P1; LAMOREUX LW, 1971, B PROSTHET RES, P3; Li Y, 1998, TEXT RES J, V68, P389, DOI 10.1177-004051759806800601; LOTENS W, 1993, THESIS TNO I PERCEPT, P34; LOTENS WA, 1995, ERGONOMICS, V38, P1092, DOI 10.1080-00140139508925176; LOTENS WA, 1991, ERGONOMICS, V34, P233, DOI 10.1080-00140139108967309; Straatman AG, 2002, PHYS FLUIDS, V14, P1938, DOI 10.1063-1.1476673; WOMERSLEY JR, 1955, PHILOS MAG, V46, P199; WOMRSLEY JR, 1957, ELASTIC TUBE THEORY, P5622222
Simplified heat transport model of a wind-permeable clothed cylinder subject to swinging motion
No full textThe effect of ventilation induced by the swinging motion of a clothed cylinder in uniform wind derived from Ghaddar et al.'s periodic ventilation model is incorporated into Lotens' simple heat resistance network model to predict the mean steady periodic heat loss from the clothed cylinder. Experiments are conducted to measure the sensible heat loss from the inner cylinder for the case of a swinging inner cylinder enclosed within a clothed cylinder at different frequencies of motion and for open and closed clothing apertures at the one end of the clothed cylinder. The heat model predictions of time-averaged steady-periodic sensible heat loss agree well with the experimentally measured values at different swing frequencies between 40 and 80 rpm from experiments conducted in a controlled environmental chamber at T∞ = 25°C and relative humidity (RH) = 50percent (air velocity is less than 0.05 m-s) and in a low-speed wind tunnel (for air speed between 2 and 4 m-s). The model results showed that the rate of heat loss increased with increased ventilation frequency. Heat transfer by ventilation presented more than 50percent of total heat loss from a clothed cylinder at f = 80 rpm in the absence and presence of wind. When accurate ventilation rates of clothed swinging cylinder are estimated from first principles, the simplified heat resistance model predicted the heat loss from the isothermal cylinder surface with reasonable accuracy. The model will be a convenient tool for predicting segmental walking human body heat losses.ALOTHMANI M, 2008, INT J HEAT IN PRESS; [Anonymous], 2007, 11079 ISO; [Anonymous], 2006, 7730 ISO; [Anonymous], 2007, 9920 ISO; [Anonymous], 2002, 7933 ISO; Danielson U, 1993, THESIS ROYAL I TECHN; Fan JT, 2000, INT J HEAT MASS TRAN, V43, P2989, DOI 10.1016-S0017-9310(99)00235-5; FARNWORTH B, 1983, TEXT RES J, V53, P717, DOI 10.1177-004051758305301201; FARNWORTH B, 1986, TEXT RES J, V56, P653, DOI 10.1177-004051758605601101; Fiala D, 2001, INT J BIOMETEOROL, V45, P143, DOI 10.1007-s004840100099; Fu G, 1995, THESIS KANSAS STATE; Ghaddar N, 2005, INT J HEAT MASS TRAN, V48, P3151, DOI 10.1016-j.ijheatmasstransfer.2005.03.001; Ghaddar N, 2003, INT J THERM SCI, V42, P605, DOI 10.1016-S1290-0729(03)00026-7; GHADDAR N, 2008, ASME, V130; Ghali K, 2002, J HEAT TRANS-T ASME, V124, P530, DOI 10.1115-1.1471524; Ghali K, 2002, INT J HEAT MASS TRAN, V45, P3703, DOI 10.1016-S0017-9310(02)00088-1; Ghali K, 2006, J HEAT TRANS-T ASME, V128, P908, DOI 10.1115-1.2241811; Ghali K, 2002, J POROUS MEDIA, V5, P17; GIBSON P, 1996, NATICKTR95004 US ARM, P115; Gibson P, 2006, THERMAL AND MOISTURE TRANSPORT IN FIBROUS MATERIALS, P542, DOI 10.1533-9781845692261.3.542; GIBSON P, 1997, J SOC FIBER SCI TECH, V35, P183; HAVENITH G, 2005, P 12 INT C ENV ERG Y; HAVENITH G, 1990, ERGONOMICS, V33, P67, DOI 10.1080-00140139008927094; HAVENITH G, 1990, ERGONOMICS, V33, P989, DOI 10.1080-00140139008925308; Havenith G, 2004, EUR J APPL PHYSIOL, V92, P636, DOI 10.1007-s00421-004-1113-6; Havenith G, 2002, ENERG BUILDINGS, V34, P581, DOI 10.1016-S0378-7788(02)00008-7; Havenith G, 1999, ANN OCCUP HYG, V43, P339, DOI 10.1016-S0003-4878(99)00052-6; HAVENITH G, 2000, ENV ERGONOMICS, V10, P125; Holmer I, 1995, ANN OCCUP HYG, V39, P809, DOI 10.1016-0003-4878(95)00041-0; Huizenga C, 2001, BUILD ENVIRON, V36, P691, DOI 10.1016-S0360-1323(00)00061-5; JONES BW, 1992, ASHRAE TRAN, V98, P189; Kerslake D.M., 1972, STRESS HOT ENV; LI Y, 1992, TEXT RES J, V62, P211; Lotens WA, 1993, THESIS TNO I PERCEPT; Salloum M, 2007, INT J THERM SCI, V46, P371, DOI 10.1016-j.ijthermalsci.2006.06.017; Tanabe S, 2002, ENERG BUILDINGS, V34, P637, DOI 10.1016-S0378-7788(02)00014-2; Zhang H., 2003, THESIS U CALIFORNIA; ZHAO J, 1995, THESIS KANSAS STATE67
Phase change in fabrics
No full text[No abstract available]Bryant Y. G., 1992, TECHT S, P1; FARNWORTH B, 1986, TEXT RES J, V56, P653, DOI 10.1177-004051758605601101; Fengzhi L., 2004, NUMER HEAT TRANSFE B, V45, P249, DOI 10.1080-10407790490268814; Ghali K, 2004, TEXT RES J, V74, P205, DOI 10.1177-004051750407400304; GIBSON P, 1996, NATICKTR97005; Gibson PW, 1997, INT COMMUN HEAT MASS, V24, P709, DOI 10.1016-S0735-1933(97)00056-0; HAVENITH G, 1984, WHAT ACTUALLY IS ADV; HENRY PSH, 1948, DISCUSS FARADAY SOC, V3, P243, DOI 10.1039-df9480300243; Jintu Fan, 2004, International Journal of Heat and Mass Transfer, V47, DOI 10.1016-j.ijheatmasstransfer.2003.10.033; Jones F. E., 1992, EVAPORATION WATER, P25; KEIGHLEY JH, 1985, J COATED FABRICS, V15, P89, DOI 10.1177-152808378501500203; LOTENS W, 1993, THESIS ROYAL I TECHN; LOTENS WA, 1995, ERGONOMICS, V38, P1114, DOI 10.1080-00140139508925177; NASRALLAH SB, 1988, INT J HEAT MASS TRAN, V31, P957, DOI 10.1016-0017-9310(88)90084-1; PAUSE BH, 1995, TEXTILE ASIA, V26, P81; QINGYONG Z, 2000, INT C APPL FLUID DYN, P621; RUCKMAN JE, 1997, J COATED FABRICS, V26, P293, DOI 10.1177-152808379702600405; SHIM H, 1999, THESIS KANSAS STATE; Shim H, 2001, TEXT RES J, V71, P495; Shim H, 2000, P INT C SAF PROT FAB; SHUYE L, 1997, J TSINGHUA U, V37, P86; VAFAI K, 1986, J HEAT TRANS-T ASME, V108, P132; VAFAI K, 1986, J HEAT TRANS-T ASME, V108, P667; VANDELINDE FJG, 1983, P INT C MED BIOPH AS, P260; VANDELINDE FJG, 1987, WORK IMPERMEABLE CLO; XIAOYIN C, 2004, INT J THERM SCI, V43, P665; ZHONGXUAN L, 2004, J COMPUTATIONAL APPL, V163, P199, DOI DOI 10.1016-J.CAM.2003.08.06512
The influence of wind on outdoor thermal comfort in the city of Beirut: A theoretical and field study
No full textThis article studies the outdoor comfort in the city of Beirut to improve the quality of open spaces and better explain the people's tolerance and acceptance of outdoor environmental conditions. Field experiments were conducted to develop statistical correlations for thermal sensation and thermal comfort of people in the outdoors to environmental parameters. A transient bioheat model was developed to study the effect of wind speed and frequency in the physiological responses of the human body and its effect on the overall body thermal sensation and comfort state. The model was experimentally validated and simulated for three different wind frequencies of 0.15, 0.25, and 0.35 Hz, representing a range of wind frequencies encountered during an average summer day. For each of these wind frequencies, simulations were performed for two air velocity ranges: V1 = 0.5 m-s to 2.8 m-s (1.64 ft-s to 9.18 ft-s) and V2 = 0.5 m-s to 1.8 m-s (1.64 ft-s to 5.9 ft-s) at air temperatures of 30°C and 34°C (86°F and 93.2°F) and relative humidity of 40percent and 70percent. The numerical results showed that for velocity range V1, the overall comfort improved from -1.15 to -0.82 with the increase of wind frequency, while at velocity range V2, comfort improved from -1.27 to -0.99 with wind frequency for the same air temperature and relative humidity. It is concluded that the positive effect of wind frequency and velocity amplitude in making people more tolerant of outdoor conditions decreases with the increase in air temperature and relative humidity. Copyright © 2011 American Society of Heating, Refrigerating and Air-Conditioning Engineers.ASHRAE, 2007, 6222007 ASHRAE; BROWN RD, 1986, INT J BIOMETEOROL, V30, P43, DOI 10.1007-BF02192058; BROWN R.D., 1995, MICROCLIMATIC LANDSC; Candido C, 2010, BUILD ENVIRON, V45, P222, DOI 10.1016-j.buildenv.2009.06.005; COSTA L, 2005, P INT C PASS LOW EN; Fanger P.O., 1982, THERMAL COMFORT ANAL; GAGGE AP, 1986, ASHRAE T B, V2; Ghaddar N, 2003, INT J THERM SCI, V42, P605, DOI 10.1016-S1290-0729(03)00026-7; Ghali K, 2009, TEXT RES J, V79, P1043, DOI 10.1177-0040517508101460; GIOVANI B, 2003, ENERG BUILDINGS, V35, P77; Havenith G, 2004, EUR J APPL PHYSIOL, V92, P636, DOI 10.1007-s00421-004-1113-6; Hoppe P, 2002, ENERG BUILDINGS, V34, P661, DOI 10.1016-S0378-7788(02)00017-8; Johansson E, 2006, INT J BIOMETEOROL, V51, P119, DOI 10.1007-s00484-006-0047-6; JONES BW, 1992, ASHRAE TRAN, V98, P189; JONES BW, 1999, AIAA 33 THERM C JUN; Kenny NA, 2009, INT J BIOMETEOROL, V53, P415, DOI 10.1007-s00484-009-0226-3; Kenny NA, 2009, INT J BIOMETEOROL, V53, P429, DOI 10.1007-s00484-009-0227-2; Lin TP, 2009, BUILD ENVIRON, V44, P2017, DOI 10.1016-j.buildenv.2009.02.004; Nikolopoulou M, 2001, SOL ENERGY, V70, P227, DOI 10.1016-S0038-092X(00)00093-1; OLIVEIRA S, 2008, P 18 INT C BIOM TOK; Ouyang Q, 2006, BUILD ENVIRON, V41, P418, DOI 10.1016-j.buildenv.2005.02.008; XIA Y, 2000, AIR DISTRIBUTION ROO, P41; Zhang H., 2003, THESIS U CALIFORNIA; ZHAO R, 2006, BUILD ENVIRON, V42, P392656
Effect of stove asymmetric radiation field on thermal comfort using a multisegmented bioheat model
No full textThe multinode multisegment bioheat model of Salloum et al. [Salloum M, Ghaddar N, Ghali K. A new transient bio-heat model of the human body. In: Proceedings of the ASME 2005 summer heat transfer conference, 17-22 July 2005, San Francisco, Paper no. HT2005-72303] is integrated with a space heat model to study human thermal response when subjected to radiant asymmetry in stove-heated domestic spaces in Lebanon. For any given person position, the overall comfort level is based on Frank et al. model correlations [Frank SM, Srinivasa NR, Bulcao CF, Goldstein DS. Relative contribution of core and cutaneous temperatures to thermal comfort and autonomic responses in humans. Journal of Applied physiology 1999;86(5):1588-93]. The assessment of local comfort level is based on the maximum deviation of the clothed segments skin temperature from the mean skin temperature and its relation to the radiant temperature asymmetry. Experiments were run on human subjects at steady-state conditions to measure the variation of the skin temperature at different locations of the human body segments while standing in an asymmetric thermal radiation field generated by a stove-heating unit. The experiments were conducted to validate the applicability of the bioheat model in predicting skin temperature in asymmetric conditions. The measured skin temperature of various body segments and the radiative asymmetry agreed within ±5percent of values predicted by the bioheat model [Salloum M, Ghaddar N, Ghali K. A new transient bio-heat model of the human body. In: Proceedings of the ASME 2005 summer heat transfer conference, 17-22 July 2005, San Francisco, Paper no. HT2005-72303]. The space heat model and the bioheat model are applied to a case study to predict both overall thermal comfort and local thermal discomfort in a typical radiant heat space at different standing positions of the person. Strong thermal discomfort exists within the vicinity of the stove high-temperature surface. The local discomfort is considered at values of maximum SD1.1 °C derived from consideration of Fanger et al. [Fanger PO, Ipsen BM, Langkilde G, Olesen BW. Comfort limits for asymmetric thermal radiation. Energy and Buildings 1985;8(3):225-36] data of comfort limits and skin temperature measurements for asymmetric thermal radiation. © 2007 Elsevier Ltd. All rights reserved.[Anonymous], 1992, 55 ASHRAE; BERGLUND LG, 1968, ASHRAE T, V93, P497; FANGER BO, 1982, THERMAL COMFORT ANAL; Fanger P. O., 1980, ASHRAE T, V86, P141; FANGER PO, 1985, ENERG BUILDINGS, V8, P225, DOI 10.1016-0378-7788(85)90006-4; Frank SM, 1999, J APPL PHYSIOL, V86, P1588; Gan G, 2001, BUILD SERV ENG RES T, V22, P95, DOI 10.1191-014362401701524154; Ghaddar N, 2006, HEAT TRANSFER ENG, V27, P29, DOI 10.1080-01457630600742480; Ghali K, 2005, INT J GREEN ENERGY, V2, P287, DOI 10.1080-01971520500198825; Hodder SG, 1998, ENERG BUILDINGS, V27, P167, DOI 10.1016-S0378-7788(97)00038-8; HOWEL RH, 1987, RP394 ASHRAE; Huizenga C, 2001, BUILD ENVIRON, V36, P691, DOI 10.1016-S0360-1323(00)00061-5; ISO, 1984, 7730 ISO; Jones B.W., 1992, ASHRAE T, V98; Jones EC, 1998, REC ADV TOB, V24, P3; Markov D., 2002, ANN INT COURSE VENTI, P158; McNall PE, 1970, ASHRAE T, V76, P123; Miriel J, 2002, APPL THERM ENG, V22, P1861, DOI 10.1016-S1359-4311(02)00087-X; SALLOUNI M, 2005, P ASME 2005 SUMM HEA; Smith CE, 1991, THESIS KANSAS STATE; Zmeureanu R, 2003, BUILD ENVIRON, V38, P427, DOI 10.1016-S0360-1323(02)00133-644
Simplified model of contaminant dispersion in rooms conditioned by chilled-ceiling displacement ventilation system
No full textThe aim of this paper is to develop and experimentally validate a simplified model to predict carbon dioxide transport and distribution in rooms conditioned by chilled-ceiling displacement ventilation (CC-DV) system for known supply thermal and flow conditions and chilled-ceiling temperature. The transport model of carbon dioxide considers upward convective flow by the rising thermal wall and source plumes, the CO2 lateral diffusion into plume-adjacent air layers, and vertical CO2 diffusion in air inside and outside the plumes. Experiments were performed for different supply air CO2 concentrations, supply air flow rates, and strengths of heat sources. Experimental measurements of the vertical profile of air temperature, and carbon dioxide concentration compared well with values calculated by the model. The indoor air quality is assessed based on levels of carbon dioxide concentration in the radiant-cooled space. The model can be put to practical use in finding the maximum acceptable fraction of return air to be mixed with the supply while the air quality in the breathing zone remains acceptable. © 2010 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.ASHRAE, 2007, 6222007 ASHRAE; Ayoub M, 2006, HVACandR RES, V12, P1005, DOI 10.1080-10789669.2006.10391448; Bahman A., 2008, ASHRAE T, V115, P587; Behne M, 1999, ENERG BUILDINGS, V30, P155, DOI 10.1016-S0378-7788(98)00083-8; CHEN Qingyan, 1998, ENERG BUILDINGS, V28, P137, DOI 10.1016-S0378-7788(98)00020-6; ECKERT ERG, 1951, 1015 NACA; Ghaddar N, 2008, ASHRAE TRAN, V114, P574; Ghali K, 2007, INT J ENERG RES, V31, P743, DOI 10.1002-er.1266; Goodfellow H. D., 2001, IND VENTILATION DESI; He GQ, 2005, ASHRAE TRAN, V111, P646; Kofoed P, 1991, THESIS AALBORG U DEN; Kosonen R, 2006, ENERG BUILDINGS, V38, P1130, DOI 10.1016-j.enbuild.2006.01.002; MIDDLETON JH, 1975, J FLUID MECH, V72, P753, DOI 10.1017-S0022112075003266; MORTRON BR, 1956, ROYAL SOC LONDON A, V234, P1; Mossolly M, 2008, ASHRAE TRAN, V114, P541; Mundt E., 1996, THESIS KTH STOCKHOLM; Nielsen PV, 2007, HVACandR RES, V13, P987, DOI 10.1080-10789669.2007.10391466; Novoselac A, 2002, ENERG BUILDINGS, V34, P497, DOI 10.1016-S0378-7788(01)00134-7; Rees S, 1998, THESIS LOUGHBOROUGH; Rees SJ, 2001, INT J HEAT MASS TRAN, V44, P3067, DOI 10.1016-S0017-9310(00)00348-3; Rouse H., 1952, TELLUS, V4, P201, DOI 10.1111-j.2153-3490.1952.tb01005.x; SKISTAD H, 2002, GUIDEBOOK, V1; STYMNE H, 1991, P 12 AIVC C AIR MOV; SUZUKI T, 2008, 6 INT C IND AIR QUAL; Xu M, 2001, INDOOR AIR, V11, P111, DOI 10.1034-j.1600-0668.2001.110205.x; YAMANAKA T, 2002, P ROOMVENT 2002 COP; YAMANAKA T, 2007, P ROOMVENT 2007 HELS; YUAN X, 2001, ASHRAE T, V107, P78; Yuill DP, 2008, HVACandR RES, V14, P345, DOI 10.1080-10789669.2008.1039101366
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