DC-inverter split air-conditioner is widely used in Chinese homes as a result of its high-efficiency and energy-saving. Recently, the researches on its outdoor unit have focused on the influence of surrounding structu...DC-inverter split air-conditioner is widely used in Chinese homes as a result of its high-efficiency and energy-saving. Recently, the researches on its outdoor unit have focused on the influence of surrounding structures upon the aerodynamic and acoustic performance, however they are only limited to the influence of a few parameters on the performance, and practical design of the unit requires more detailed parametric analysis. Three-dimensional computational fluid dynamics（CFD） and computational aerodynamic acoustics（CAA） simulation based on FLUENT solver is used to study the influence of surrounding structures upon the aforementioned properties of the unit. The flow rate and sound pressure level are predicted for different rotating speed, and agree well with the experimental results. The parametric influence of three main surrounding structures（i.e. the heat sink, the bell-mouth type shroud and the outlet grille） upon the aerodynamic performance of the unit is analyzed thoroughly. The results demonstrate that the tip vortex plays a major role in the flow fields near the blade tip and has a great effect on the flow field of the unit. The inlet ring＇s size and throat＇s depth of the bell-mouth type shroud, and the through-flow area and configuration of upwind and downwind sections of the outlet grille are the most important factors that affect the aerodynamic performance of the unit. Furthermore, two improved schemes against the existing prototype of the unit are developed, which both can significantly increase the flow rate more than 6 %（i.e. 100 m3·h～（-1）） at given rotating speeds. The inevitable increase of flow noise level when flow rate is increased and the advantage of keeping a lower rotating speed are also discussed. The presented work could be a useful guideline in designing the aerodynamic and acoustic performance of the split air-conditioner in engineering practice.展开更多
Aim: To investigate the effect of air-conditioner exposure on semen quality. Methods: The data came from the healthy male volunteers, aged 22 to 30 years, who went to centers for maternity and children health for prem...Aim: To investigate the effect of air-conditioner exposure on semen quality. Methods: The data came from the healthy male volunteers, aged 22 to 30 years, who went to centers for maternity and children health for premarital physical examination in Shanghai, Henan, Zhejiang and Hebei from December 1998 to February 2000. The sampling size is 304. Results: Among the subjects, 90 (29.6 %) had air-conditioner at home and the rest did not. X2-test and multiple logistic regression analyses showed that, the difference between the exposure and control groups was statistically significant in semen volume, sperm density and proportion of sperm with normal morphology. The three indexes were lower in the exposure group. Conclusion: Air-conditioner exposure possibly influences the semen quality.展开更多
To explore the relationship between summer office set air-conditioning temperature and energy consumption related to air conditioning use to provide human thermal comfort,a comparison experiment was conducted in three...To explore the relationship between summer office set air-conditioning temperature and energy consumption related to air conditioning use to provide human thermal comfort,a comparison experiment was conducted in three similar offices at temperatures of 24,26 and 28 ℃ respectively. A thermal comfort questionnaire survey was conducted. It is demonstrated that air-conditioner energy consumption at the set temperature of 28 ℃ is 113% and 271% lower than at 26 ℃ and 24 ℃,respectively. A linear relationship exists between air-conditioner energy consumption and the indoor and outdoor temperature difference. When comfortably dressed,over 80% of research participants accept the set temperature of 28 ℃. The regression analysis leads to a neutral temperature of 26.2 ℃ and an acceptable temperature of 28.2 ℃ for over 80% of the research participants subjects,indicating that the current 26 ℃ set temperature for offices in summer,required by Chinese General Office of the State Council,can be increased to 28 ℃. Moreover,analysis of predicted mean vote(PMV) index shows that a set temperature of 27 ℃,not 26 ℃,is sufficiently comfortable for office staff wearing long-sleeve shirts,long pants and leather shoes.展开更多
Facility management and maintenance of the Thermal-Energy-Storage Air-Conditioning(TES-AC)system is a tedious task at a large scale mainly due to the charging load that can increase energy consumption if needed to be ...Facility management and maintenance of the Thermal-Energy-Storage Air-Conditioning(TES-AC)system is a tedious task at a large scale mainly due to the charging load that can increase energy consumption if needed to be charged at peak hours.Besides,maintenance of TES-AC at a large scale gets complex as it contains many sensor data.By utilizing deep learning techniques on the sensor data,charging load prediction can be made possible,so facility managers can prepare in advance.However,a deep learning-based application will be unusable if it is not deployed in a user-friendly manner where facility managers can benefit from this application.Hence,this research focuses on gathering design guidelines for a deep learning-based application and further validates the design considerations with a developed application for efficient human-computer interaction through qualitative analysis.The approach taken to gather design guidelines demonstrated a positive correlation between expert-suggested features and the user-friendly aspect of the application as 67.08%of participants found the features suggested by experts to be most satisfactory.Furthermore,it evaluates user satisfaction with the advanced developed application for TES-AC according to the gathered design guidelines.展开更多
基金Supported by Program for Changjiang Scholars and Innovative Research Team in University,Ministry of Education of China(PCSIRT)
文摘DC-inverter split air-conditioner is widely used in Chinese homes as a result of its high-efficiency and energy-saving. Recently, the researches on its outdoor unit have focused on the influence of surrounding structures upon the aerodynamic and acoustic performance, however they are only limited to the influence of a few parameters on the performance, and practical design of the unit requires more detailed parametric analysis. Three-dimensional computational fluid dynamics（CFD） and computational aerodynamic acoustics（CAA） simulation based on FLUENT solver is used to study the influence of surrounding structures upon the aforementioned properties of the unit. The flow rate and sound pressure level are predicted for different rotating speed, and agree well with the experimental results. The parametric influence of three main surrounding structures（i.e. the heat sink, the bell-mouth type shroud and the outlet grille） upon the aerodynamic performance of the unit is analyzed thoroughly. The results demonstrate that the tip vortex plays a major role in the flow fields near the blade tip and has a great effect on the flow field of the unit. The inlet ring＇s size and throat＇s depth of the bell-mouth type shroud, and the through-flow area and configuration of upwind and downwind sections of the outlet grille are the most important factors that affect the aerodynamic performance of the unit. Furthermore, two improved schemes against the existing prototype of the unit are developed, which both can significantly increase the flow rate more than 6 %（i.e. 100 m3·h～（-1）） at given rotating speeds. The inevitable increase of flow noise level when flow rate is increased and the advantage of keeping a lower rotating speed are also discussed. The presented work could be a useful guideline in designing the aerodynamic and acoustic performance of the split air-conditioner in engineering practice.
文摘Aim: To investigate the effect of air-conditioner exposure on semen quality. Methods: The data came from the healthy male volunteers, aged 22 to 30 years, who went to centers for maternity and children health for premarital physical examination in Shanghai, Henan, Zhejiang and Hebei from December 1998 to February 2000. The sampling size is 304. Results: Among the subjects, 90 (29.6 %) had air-conditioner at home and the rest did not. X2-test and multiple logistic regression analyses showed that, the difference between the exposure and control groups was statistically significant in semen volume, sperm density and proportion of sperm with normal morphology. The three indexes were lower in the exposure group. Conclusion: Air-conditioner exposure possibly influences the semen quality.
基金Project(50838009) supported by the National Natural Science Foundation of ChinaProjects(2006BAJ02A09,2006BAJ02A13-4) supported by the National Key Technologies R & D Program of China
文摘To explore the relationship between summer office set air-conditioning temperature and energy consumption related to air conditioning use to provide human thermal comfort,a comparison experiment was conducted in three similar offices at temperatures of 24,26 and 28 ℃ respectively. A thermal comfort questionnaire survey was conducted. It is demonstrated that air-conditioner energy consumption at the set temperature of 28 ℃ is 113% and 271% lower than at 26 ℃ and 24 ℃,respectively. A linear relationship exists between air-conditioner energy consumption and the indoor and outdoor temperature difference. When comfortably dressed,over 80% of research participants accept the set temperature of 28 ℃. The regression analysis leads to a neutral temperature of 26.2 ℃ and an acceptable temperature of 28.2 ℃ for over 80% of the research participants subjects,indicating that the current 26 ℃ set temperature for offices in summer,required by Chinese General Office of the State Council,can be increased to 28 ℃. Moreover,analysis of predicted mean vote(PMV) index shows that a set temperature of 27 ℃,not 26 ℃,is sufficiently comfortable for office staff wearing long-sleeve shirts,long pants and leather shoes.
文摘Facility management and maintenance of the Thermal-Energy-Storage Air-Conditioning(TES-AC)system is a tedious task at a large scale mainly due to the charging load that can increase energy consumption if needed to be charged at peak hours.Besides,maintenance of TES-AC at a large scale gets complex as it contains many sensor data.By utilizing deep learning techniques on the sensor data,charging load prediction can be made possible,so facility managers can prepare in advance.However,a deep learning-based application will be unusable if it is not deployed in a user-friendly manner where facility managers can benefit from this application.Hence,this research focuses on gathering design guidelines for a deep learning-based application and further validates the design considerations with a developed application for efficient human-computer interaction through qualitative analysis.The approach taken to gather design guidelines demonstrated a positive correlation between expert-suggested features and the user-friendly aspect of the application as 67.08%of participants found the features suggested by experts to be most satisfactory.Furthermore,it evaluates user satisfaction with the advanced developed application for TES-AC according to the gathered design guidelines.
