Pub Date : 2014-04-01DOI: 10.1080/10789669.2014.889986
B. Gu, Z. Tian, F. Liu, Y. Lu, X. Sun, L. Yang
A parallel flow (PF) condenser with mini-channels is commonly used as a condenser in automobile air-conditioning systems. A distributed parameter model (DPM) for the PF condenser (4 passes with 15, 6, 4, and 3 tube numbers, hydraulic diameter Dh = 1.7 mm) was developed based on classical correlations of heat transfer and flow friction. Experiments were performed to investigate the thermal hydraulic performance of PF condenser. The proposed DPM model was verified by experimental data. The optimal design of the PF condenser based on DPM was carried out with heat transfer and pressure drop taken as two objective functions. Genetic algorithm (GA) was utilized to solve the multi-objective problem. The hydraulic diameter and the tube numbers of each pass were chosen as design parameters. Pareto optimal solutions for the PF condenser were obtained. Analyses of variation in hydraulic diameter and tube numbers of the PF condenser are also presented.
{"title":"Distributed parameter modeling and its application in parallel flow condenser optimization design based on genetic algorithm","authors":"B. Gu, Z. Tian, F. Liu, Y. Lu, X. Sun, L. Yang","doi":"10.1080/10789669.2014.889986","DOIUrl":"https://doi.org/10.1080/10789669.2014.889986","url":null,"abstract":"A parallel flow (PF) condenser with mini-channels is commonly used as a condenser in automobile air-conditioning systems. A distributed parameter model (DPM) for the PF condenser (4 passes with 15, 6, 4, and 3 tube numbers, hydraulic diameter Dh = 1.7 mm) was developed based on classical correlations of heat transfer and flow friction. Experiments were performed to investigate the thermal hydraulic performance of PF condenser. The proposed DPM model was verified by experimental data. The optimal design of the PF condenser based on DPM was carried out with heat transfer and pressure drop taken as two objective functions. Genetic algorithm (GA) was utilized to solve the multi-objective problem. The hydraulic diameter and the tube numbers of each pass were chosen as design parameters. Pareto optimal solutions for the PF condenser were obtained. Analyses of variation in hydraulic diameter and tube numbers of the PF condenser are also presented.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"14 1","pages":"351 - 361"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73792558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-04-01DOI: 10.1080/10789669.2014.888899
X. Zhai, Xiaolin Wang, Cong Wang, Ruzhu Wang
Solar energy systems in combination with thermal driven sorption chillers for air conditioning are gaining increasing attention. Since solar energy is available only during daytime and solar cooling systems are usually intermittent and susceptible to the weather, applying cold storage methods to solar air-conditioning systems is favorable to utilize renewable energy and enhance the system stability. A self-developed phase change material (PCM) providing a suitable phase change temperature of 14.97°C and a reasonable phase transition latent heat of 115.1 kJ/kg is used to fabricate a cold storage tank. The aim of this article is to experimentally investigate the performance of the cold storage tank for solar air-conditioning application. The experiment includes a small-scale steady-state testing of a single spherical capsule and a solar air-conditioning system integrated with the PCM cold storage tank. The temperature distribution and phase change interface movement of the capsule are theoretically predicted. Main parameters of the cold storage tank, namely the inlet and outlet water temperature, internal temperature variation of capsules, charging/discharging capacity and charging/discharging rate are analyzed. The experimental results show that the charging and discharging process completed in 230 min and 220 min under steady states. While under unsteady states of a solar air-conditioning system, the charging and discharging process of the phase change cold storage tank completed within 320 min and 110 min with the total amount of charging and discharging capacity of 1016.1 kJ and 942.8 kJ, respectively. The phase change cold storage tank manifests good feasibility and stability for solar air-conditioning application.
{"title":"Experimental investigation of a novel phase change cold storage used for a solar air-conditioning system","authors":"X. Zhai, Xiaolin Wang, Cong Wang, Ruzhu Wang","doi":"10.1080/10789669.2014.888899","DOIUrl":"https://doi.org/10.1080/10789669.2014.888899","url":null,"abstract":"Solar energy systems in combination with thermal driven sorption chillers for air conditioning are gaining increasing attention. Since solar energy is available only during daytime and solar cooling systems are usually intermittent and susceptible to the weather, applying cold storage methods to solar air-conditioning systems is favorable to utilize renewable energy and enhance the system stability. A self-developed phase change material (PCM) providing a suitable phase change temperature of 14.97°C and a reasonable phase transition latent heat of 115.1 kJ/kg is used to fabricate a cold storage tank. The aim of this article is to experimentally investigate the performance of the cold storage tank for solar air-conditioning application. The experiment includes a small-scale steady-state testing of a single spherical capsule and a solar air-conditioning system integrated with the PCM cold storage tank. The temperature distribution and phase change interface movement of the capsule are theoretically predicted. Main parameters of the cold storage tank, namely the inlet and outlet water temperature, internal temperature variation of capsules, charging/discharging capacity and charging/discharging rate are analyzed. The experimental results show that the charging and discharging process completed in 230 min and 220 min under steady states. While under unsteady states of a solar air-conditioning system, the charging and discharging process of the phase change cold storage tank completed within 320 min and 110 min with the total amount of charging and discharging capacity of 1016.1 kJ and 942.8 kJ, respectively. The phase change cold storage tank manifests good feasibility and stability for solar air-conditioning application.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"29 1","pages":"302 - 310"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74923711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-04-01DOI: 10.1080/10789669.2014.889512
Q. Pan, Ruzhu Wang, Zisheng Lu, Liwei Wang
Mass recovery process is an efficient way to improve the performance of adsorption refrigeration system. By researching two kinds of conventional mass recovery cycle (i.e., mass recovery between two beds [TBMRC] and between evaporators [TEMRC]), double mass recovery cycle (DMRC) is proposed to reduce heat loss. Thermodynamic analysis shows that the heat loss of DMRC is less than the other two kinds. Consequently, DMRC system performance should be the best, followed by TEMRC and TBMRC as the worst. A mathematical model of heat and mass transfer was then built and simulation was performed to analyze the system performance. The simulation results show that the optimal cycle time and mass recovery time are 30 mins and 10 s, respectively. Compared with the basic cycle, both coefficient of performance and specific cooling power of mass recovery cycle are much better. The system performance of different kinds of mass recovery cycle is almost the same in most cases, caused by a small reduction of heat loss in DMRC or TEMRC, when compared with the cooling capacity and heating power. However, under some conditions (i.e., large cycle time or high evaporation temperature), performance of DMRC is better than the other two kinds, which is consistent with the thermodynamic analysis results.
{"title":"Thermodynamic analysis and performance simulation of different kinds of mass recovery processes applied in adsorption refrigeration system","authors":"Q. Pan, Ruzhu Wang, Zisheng Lu, Liwei Wang","doi":"10.1080/10789669.2014.889512","DOIUrl":"https://doi.org/10.1080/10789669.2014.889512","url":null,"abstract":"Mass recovery process is an efficient way to improve the performance of adsorption refrigeration system. By researching two kinds of conventional mass recovery cycle (i.e., mass recovery between two beds [TBMRC] and between evaporators [TEMRC]), double mass recovery cycle (DMRC) is proposed to reduce heat loss. Thermodynamic analysis shows that the heat loss of DMRC is less than the other two kinds. Consequently, DMRC system performance should be the best, followed by TEMRC and TBMRC as the worst. A mathematical model of heat and mass transfer was then built and simulation was performed to analyze the system performance. The simulation results show that the optimal cycle time and mass recovery time are 30 mins and 10 s, respectively. Compared with the basic cycle, both coefficient of performance and specific cooling power of mass recovery cycle are much better. The system performance of different kinds of mass recovery cycle is almost the same in most cases, caused by a small reduction of heat loss in DMRC or TEMRC, when compared with the cooling capacity and heating power. However, under some conditions (i.e., large cycle time or high evaporation temperature), performance of DMRC is better than the other two kinds, which is consistent with the thermodynamic analysis results.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"61 1","pages":"311 - 319"},"PeriodicalIF":0.0,"publicationDate":"2014-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90888151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-02-17DOI: 10.1080/10789669.2013.855070
Zong-xing Zhang, Ying Yi, Ming Zhao, Wen Wang, Jian-cheng Qi
High-efficiency air filtration is an important means of preventing harmful aerosol overflow in biosafety laboratories. For convenience in the in situ scanning leak test of a high-efficiency particulate air (HEPA) filter to ensure the filter's intactness, a cylindrical blunt sampling probe is developed. The sampling inlet is of the slot type and the inlet's length equal the width of the HEPA filter. Thus, the entire downstream face of the HEPA filter may be scanned. To evaluate the blunt sampling probe's ability to detect leaks, the scanning leak test performed on a HEPA filter unit was compared with a test using the thin-walled rectangular sampling probe that is recommended by relevant standards. Based on the comparison, the leak penetration determined using the blunt sampling probe was slightly lower than that determined using the reference sampling probe. Additionally, differences were observed according to the location that was tested. However, the blunt sampling probe could detect leaks through the comprehensive analysis of the local penetration of most-penetrating particle size (MPPS) and non-MPPS particles.
{"title":"A blunt sampling probe developed for an in situ leak test of HEPA filters in high-level biosafety laboratory","authors":"Zong-xing Zhang, Ying Yi, Ming Zhao, Wen Wang, Jian-cheng Qi","doi":"10.1080/10789669.2013.855070","DOIUrl":"https://doi.org/10.1080/10789669.2013.855070","url":null,"abstract":"High-efficiency air filtration is an important means of preventing harmful aerosol overflow in biosafety laboratories. For convenience in the in situ scanning leak test of a high-efficiency particulate air (HEPA) filter to ensure the filter's intactness, a cylindrical blunt sampling probe is developed. The sampling inlet is of the slot type and the inlet's length equal the width of the HEPA filter. Thus, the entire downstream face of the HEPA filter may be scanned. To evaluate the blunt sampling probe's ability to detect leaks, the scanning leak test performed on a HEPA filter unit was compared with a test using the thin-walled rectangular sampling probe that is recommended by relevant standards. Based on the comparison, the leak penetration determined using the blunt sampling probe was slightly lower than that determined using the reference sampling probe. Additionally, differences were observed according to the location that was tested. However, the blunt sampling probe could detect leaks through the comprehensive analysis of the local penetration of most-penetrating particle size (MPPS) and non-MPPS particles.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"1 1","pages":"221 - 229"},"PeriodicalIF":0.0,"publicationDate":"2014-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91335835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-02-17DOI: 10.1080/10789669.2013.869104
J. Logue, B. Singer
Range hood use during residential cooking is essential to maintaining good indoor air quality. However, widespread use will impact the energy demand of the U.S. housing stock. This article describes a modeling study to determine site energy, source energy, and consumer costs for comprehensive range hood use. To estimate the energy impacts for all 113 million homes in the United States, we extrapolated from the simulation of a representative weighted sample of 50,000 virtual homes developed from the 2009 Residential Energy Consumption Survey database. A physics-based simulation model that considered fan energy, energy to condition additional incoming air, and the effect on home heating and cooling due to exhausting the heat from cooking was applied to each home. Range hoods performing at a level common to range hoods currently in U.S. homes would require 19–33 TWh (69–120 PJ) of site energy, 31–53 TWh (110–190 PJ) of source energy; and would cost consumers $1.2 to $2.1 billion (US$/2010) annually in the U.S. housing stock. The average household would spend less than $15 annually. Reducing required airflow (e.g., with designs that promote better pollutant capture and have more energy saving potential, on average, than improving fan efficiency).
{"title":"Energy impacts of effective range hood use for all U.S. residential cooking","authors":"J. Logue, B. Singer","doi":"10.1080/10789669.2013.869104","DOIUrl":"https://doi.org/10.1080/10789669.2013.869104","url":null,"abstract":"Range hood use during residential cooking is essential to maintaining good indoor air quality. However, widespread use will impact the energy demand of the U.S. housing stock. This article describes a modeling study to determine site energy, source energy, and consumer costs for comprehensive range hood use. To estimate the energy impacts for all 113 million homes in the United States, we extrapolated from the simulation of a representative weighted sample of 50,000 virtual homes developed from the 2009 Residential Energy Consumption Survey database. A physics-based simulation model that considered fan energy, energy to condition additional incoming air, and the effect on home heating and cooling due to exhausting the heat from cooking was applied to each home. Range hoods performing at a level common to range hoods currently in U.S. homes would require 19–33 TWh (69–120 PJ) of site energy, 31–53 TWh (110–190 PJ) of source energy; and would cost consumers $1.2 to $2.1 billion (US$/2010) annually in the U.S. housing stock. The average household would spend less than $15 annually. Reducing required airflow (e.g., with designs that promote better pollutant capture and have more energy saving potential, on average, than improving fan efficiency).","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"21 1","pages":"264 - 275"},"PeriodicalIF":0.0,"publicationDate":"2014-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83073374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-02-12DOI: 10.1080/10789669.2013.850958
Gang Wang, Li Song, E. Andiroglu, G. Shim
Airflow measurements are not as accurate as needed in air-handling units due to space and cost limitations of physical meters. Generally, the airflow in an air-handling unit is propelled by a fan driven by a motor and, hence, the airflow rate is related to fan-motor system performance, which can be affected by other measurable variables, such as fan head and motor power. Theoretically, a virtual airflow meter can be developed to virtually obtain the airflow rate from measured fan head and motor power along with projected motor and fan efficiency models. Because variable frequency drives have been widely installed in HVAC systems, a comprehensive motor efficiency model is needed to project motor efficiency under variable frequency and voltage. At the same time, an in situ fan efficiency curve needs to be projected through a calibration process corresponding to actual fan head measurement. This article explores a theoretical model of virtual airflow meters in order to identify the relationship of fan airflow rate with measurable fan head, motor power, and power frequency and voltage; then, demonstrates a procedure to implement a virtual airflow meter and validate the virtual fan airflow meter through an experiment. The results show that airflow measurements from the virtual airflow meter match very well with a conventional duct mounted airflow meter with an standard deviation of 0.0177 m3/s (37.5 cubic feet per minute [CFM]) for instant measurement and 0.0142 m3/s (30.1 CFM) for a 5-min moving average with the measured airflow range between 0.45 m3/s (950 CFM) and 0.70 m3/s (1,480 CFM).
{"title":"Investigations on a virtual airflow meter using projected motor and fan efficiencies","authors":"Gang Wang, Li Song, E. Andiroglu, G. Shim","doi":"10.1080/10789669.2013.850958","DOIUrl":"https://doi.org/10.1080/10789669.2013.850958","url":null,"abstract":"Airflow measurements are not as accurate as needed in air-handling units due to space and cost limitations of physical meters. Generally, the airflow in an air-handling unit is propelled by a fan driven by a motor and, hence, the airflow rate is related to fan-motor system performance, which can be affected by other measurable variables, such as fan head and motor power. Theoretically, a virtual airflow meter can be developed to virtually obtain the airflow rate from measured fan head and motor power along with projected motor and fan efficiency models. Because variable frequency drives have been widely installed in HVAC systems, a comprehensive motor efficiency model is needed to project motor efficiency under variable frequency and voltage. At the same time, an in situ fan efficiency curve needs to be projected through a calibration process corresponding to actual fan head measurement. This article explores a theoretical model of virtual airflow meters in order to identify the relationship of fan airflow rate with measurable fan head, motor power, and power frequency and voltage; then, demonstrates a procedure to implement a virtual airflow meter and validate the virtual fan airflow meter through an experiment. The results show that airflow measurements from the virtual airflow meter match very well with a conventional duct mounted airflow meter with an standard deviation of 0.0177 m3/s (37.5 cubic feet per minute [CFM]) for instant measurement and 0.0142 m3/s (30.1 CFM) for a 5-min moving average with the measured airflow range between 0.45 m3/s (950 CFM) and 0.70 m3/s (1,480 CFM).","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"50 1","pages":"178 - 187"},"PeriodicalIF":0.0,"publicationDate":"2014-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74369958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-02-12DOI: 10.1080/10789669.2013.854146
J. S. Brown, C. Zilio, R. Brignoli, A. Cavallini
This article considers the heat transfer and pressure drop performance potentials of halogenated propene isomers during in-tube condensation and in-tube flow boiling using the penalty factor and total temperature penalization concepts, respectively. In particular, five isomers are considered: R-1233xf, R-1233zd(E), R-1234yf, R-1234ze(E), and R-1243zf. In addition, to these five pure fluids, the heat transfer and pressure drop performance potentials are investigated for five R-32/R-1234yf blends and for twenty-seven blends being considered as part of the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) Low-GWP Alternative Refrigerants Evaluation Program. The article also presents thermophysical property estimations for the five pure fluids relative to R-134a or R-123, and the five R-32/R-1234yf blends relative to R-134a. The thermophysical properties considered are the ones that influence the heat transfer and pressure drop performance potentials, and include the thermodynamic properties temperature, pressure, density, latent heat of vaporization, and specific heat, and the transport properties thermal conductivity and viscosity. The article also presents a literature review of relevant articles for condensation and boiling heat transfer and pressure drop of fluorinated propene isomers.
{"title":"Thermophysical properties and heat transfer and pressure drop performance potentials of hydrofluoro-olefins, hydrochlorofluoro-olefins, and their blends","authors":"J. S. Brown, C. Zilio, R. Brignoli, A. Cavallini","doi":"10.1080/10789669.2013.854146","DOIUrl":"https://doi.org/10.1080/10789669.2013.854146","url":null,"abstract":"This article considers the heat transfer and pressure drop performance potentials of halogenated propene isomers during in-tube condensation and in-tube flow boiling using the penalty factor and total temperature penalization concepts, respectively. In particular, five isomers are considered: R-1233xf, R-1233zd(E), R-1234yf, R-1234ze(E), and R-1243zf. In addition, to these five pure fluids, the heat transfer and pressure drop performance potentials are investigated for five R-32/R-1234yf blends and for twenty-seven blends being considered as part of the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) Low-GWP Alternative Refrigerants Evaluation Program. The article also presents thermophysical property estimations for the five pure fluids relative to R-134a or R-123, and the five R-32/R-1234yf blends relative to R-134a. The thermophysical properties considered are the ones that influence the heat transfer and pressure drop performance potentials, and include the thermodynamic properties temperature, pressure, density, latent heat of vaporization, and specific heat, and the transport properties thermal conductivity and viscosity. The article also presents a literature review of relevant articles for condensation and boiling heat transfer and pressure drop of fluorinated propene isomers.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"36 8","pages":"203 - 220"},"PeriodicalIF":0.0,"publicationDate":"2014-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72565639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-02-12DOI: 10.1080/10789669.2013.869126
M. Zaatari, E. Nirlo, Daranee Jareemit, N. Crain, J. Srebric, J. Siegel
Identifying air pollutants that pose potential adverse health exposures in retail stores will facilitate exposure mitigation. Assessing the role of ventilation in mitigating this exposure is important to understand the energy implications of maintaining acceptable indoor air quality. In this work, we summarize results from 28 papers that report ventilation rates and/or pollutant concentrations in retail stores. These results were compared to available standards as well as data collected in non-retail environments. The findings of this review are: (1) half of the stores tested met/exceeded ASHRAE Standard 62.1-2010 (ASHRAE 2010a; or California Code of Regulations Title 24-2010) for ventilation; (2) PM2.5, acrolein, formaldehyde, and acetaldehyde exceeded their established, most conservative limits/reference exposures for a few of the stores tested in the United States, and outside the United States, researchers reported PM10, benzene, and trichloroethylene as additional pollutants found at concentrations that exceeded their limits; (3) alternative control methods would be more effective, and possibly more economical, than ventilation; (4) meeting or exceeding the ventilation requirements does not necessarily negate the presence of pollutants above their suggested limits; and (5) using disability-adjusted-life-year (DALY) as a metric of disease burden, two pollutants were identified as priority hazards in retail stores: PM2.5 and acrolein. Control strategies should focus on decreasing exposure of retail employees to these pollutants generated indoors or infiltrated from outdoors.
{"title":"Ventilation and indoor air quality in retail stores: A critical review (RP-1596)","authors":"M. Zaatari, E. Nirlo, Daranee Jareemit, N. Crain, J. Srebric, J. Siegel","doi":"10.1080/10789669.2013.869126","DOIUrl":"https://doi.org/10.1080/10789669.2013.869126","url":null,"abstract":"Identifying air pollutants that pose potential adverse health exposures in retail stores will facilitate exposure mitigation. Assessing the role of ventilation in mitigating this exposure is important to understand the energy implications of maintaining acceptable indoor air quality. In this work, we summarize results from 28 papers that report ventilation rates and/or pollutant concentrations in retail stores. These results were compared to available standards as well as data collected in non-retail environments. The findings of this review are: (1) half of the stores tested met/exceeded ASHRAE Standard 62.1-2010 (ASHRAE 2010a; or California Code of Regulations Title 24-2010) for ventilation; (2) PM2.5, acrolein, formaldehyde, and acetaldehyde exceeded their established, most conservative limits/reference exposures for a few of the stores tested in the United States, and outside the United States, researchers reported PM10, benzene, and trichloroethylene as additional pollutants found at concentrations that exceeded their limits; (3) alternative control methods would be more effective, and possibly more economical, than ventilation; (4) meeting or exceeding the ventilation requirements does not necessarily negate the presence of pollutants above their suggested limits; and (5) using disability-adjusted-life-year (DALY) as a metric of disease burden, two pollutants were identified as priority hazards in retail stores: PM2.5 and acrolein. Control strategies should focus on decreasing exposure of retail employees to these pollutants generated indoors or infiltrated from outdoors.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"43 1","pages":"276 - 294"},"PeriodicalIF":0.0,"publicationDate":"2014-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85147617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-02-12DOI: 10.1080/10789669.2013.864919
Z. Bolashikov, A. Melikov, M. Spilak, I. Năstase, A. Meslem
Inhaled air quality at a reduced supply of clean air was studied by controlling the airflow interaction at the breathing zone of a person using lobed jets as part of personalized ventilation (PV). Experiments were performed in a full-scale test room at 23°C (73.4°F) with a breathing thermal manikin seated at a workstation, with realistic free-convection flow around the body and a normal breathing cycle. The air in the room was mixed with tracer gas R134a. Clean air was supplied isothermally from three nozzles with circular, four-leafed clover, and six-edged star openings of 0.025 m (0.08 ft) equivalent diameter. The nozzles were positioned frontally at the face within the boundary layer and centered to the mouth. The enhancement of inhaled air quality by changing the initial velocity (0.2–0.6 m/s, 0.66–1.97 fps) and the distance from the mouth (0.02–0.06 m, 0.07–0.20 ft) was studied. The control over the interaction between the inserted jets and the free convection flow was efficient. Over 80% clean PV air was measured in inhalation. The worst performing nozzle was the four-leafed clover: its best performance yielded 23% clean air inhalation, at the shortest distance and the highest velocity. The other lobed nozzle, the six-edged star, performed similarly to the circular nozzle.
{"title":"Improved inhaled air quality at reduced ventilation rate by control of airflow interaction at the breathing zone with lobed jets","authors":"Z. Bolashikov, A. Melikov, M. Spilak, I. Năstase, A. Meslem","doi":"10.1080/10789669.2013.864919","DOIUrl":"https://doi.org/10.1080/10789669.2013.864919","url":null,"abstract":"Inhaled air quality at a reduced supply of clean air was studied by controlling the airflow interaction at the breathing zone of a person using lobed jets as part of personalized ventilation (PV). Experiments were performed in a full-scale test room at 23°C (73.4°F) with a breathing thermal manikin seated at a workstation, with realistic free-convection flow around the body and a normal breathing cycle. The air in the room was mixed with tracer gas R134a. Clean air was supplied isothermally from three nozzles with circular, four-leafed clover, and six-edged star openings of 0.025 m (0.08 ft) equivalent diameter. The nozzles were positioned frontally at the face within the boundary layer and centered to the mouth. The enhancement of inhaled air quality by changing the initial velocity (0.2–0.6 m/s, 0.66–1.97 fps) and the distance from the mouth (0.02–0.06 m, 0.07–0.20 ft) was studied. The control over the interaction between the inserted jets and the free convection flow was efficient. Over 80% clean PV air was measured in inhalation. The worst performing nozzle was the four-leafed clover: its best performance yielded 23% clean air inhalation, at the shortest distance and the highest velocity. The other lobed nozzle, the six-edged star, performed similarly to the circular nozzle.","PeriodicalId":13238,"journal":{"name":"HVAC&R Research","volume":"23 1","pages":"238 - 250"},"PeriodicalIF":0.0,"publicationDate":"2014-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78974211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-02-12DOI: 10.1080/10789669.2013.852902
Jun Wang, E. Long, Xu Zhang
In addition to carbon dioxide, human bioeffluents are emitted during the occupant metabolism process. Human bioeffluents should be chosen to provide the comprehensive indication of indoor air pollution caused by occupant metabolism. The relationship between the “common core” quantity of human bioeffluents in the respiratory region and indoor occupant density was studied. The possibility and reliability of the common core for indicating indoor occupant number variation and indoor air pollution induced by occupant metabolism were evaluated. The results comfirm the existence of the common core in human bioeffluents, including 13 chemical constituents emerging under 3 types of occupant densities. However, the quantity of common core in the respiratory region does not strictly follow with the variation of occupant density. Therefore, it cannot provide an effective indication of indoor air pollution affected by occupant metabolism. Further studies are needed to determine the fundamental mechanisms leading the common core quantity to change and fluctuate.
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