This work explores three patterns of occupants’ control of window blinds and the potential influence on daylight performance of an office room in a tropical climate. In this climate, windows are frequently obstructe...This work explores three patterns of occupants’ control of window blinds and the potential influence on daylight performance of an office room in a tropical climate. In this climate, windows are frequently obstructed by curtains to avoid glare, despite the daylighting and the exterior view. The consequences are obstructed outside view, poor daylight quality and dependency on artificial lighting. This paper assesses the impact on available daylight using parametric analysis based on daylighting dynamic computer simulations using Grasshopper and Daysim software, combining WWR （window-to-wall ratio） （40% and 80%）, SVF （sky view factor） （small and large） and occupant behavior （active, intermediate and passive users）. The user patterns are based in an office buildings survey that identifies preferences concerning daylight use and control of shading devices. The daylight performance criteria combine UDI （useful daylight illuminance） （500-5,000 lux） and illuminance uniformity distribution. Results confirm the impact of occupant behavior on daylighting performance. The optimum combination of external shading devices, high SVF and high window size results in a useful daylighting for 1/3 of the time for passive users and 2/3 for active users.展开更多
Thermal comfort and indoor air quality as well as the energy efficiency have been recognized as essential parts of sustainable building assessment. This work aims to analyze the energy conservation of the heat recover...Thermal comfort and indoor air quality as well as the energy efficiency have been recognized as essential parts of sustainable building assessment. This work aims to analyze the energy conservation of the heat recovery ventilator and to investigate the effect of the air supply arrangement. Three types of mixing ventilation are chosen for the analysis of coupling ANSYS/FLUENT （a computational fluid dynamics （CFD） program） with TRNSYS （a building energy simulation （BES） software）. The adoption of mutual complementary boundary conditions for CFD and BES provides more accurate and complete information of indoor air distribution and thermal performance in buildings. A typical office-space situated in a middle storey is chosen for the analysis. The office-space is equipped with air-conditioners on the ceiling. A heat recovery ventilation system directly supplies flesh air to the office space. Its thermal performance and indoor air distribution predicted by the coupled method are compared under three types of ventilation system. When the supply and return openings for ventilation are arranged on the ceiling, there is no critical difference between the predictions of the coupled method and BES on the energy consumption of HVAC because PID control is adopted for the supply air temperature of the occupied zone. On the other hand, approximately 21% discrepancy for the heat recovery estimation in the maximum between the simulated results of coupled method and BES-only can be obviously found in the floor air supply ventilation case. The discrepancy emphasizes the necessity of coupling CFD with BES when vertical air temperature gradient exists. Our future target is to estimate the optimum design of heat recovery ventilation system to control CO2 concentration by adjusting flow rate of flesh air.展开更多
文摘This work explores three patterns of occupants’ control of window blinds and the potential influence on daylight performance of an office room in a tropical climate. In this climate, windows are frequently obstructed by curtains to avoid glare, despite the daylighting and the exterior view. The consequences are obstructed outside view, poor daylight quality and dependency on artificial lighting. This paper assesses the impact on available daylight using parametric analysis based on daylighting dynamic computer simulations using Grasshopper and Daysim software, combining WWR （window-to-wall ratio） （40% and 80%）, SVF （sky view factor） （small and large） and occupant behavior （active, intermediate and passive users）. The user patterns are based in an office buildings survey that identifies preferences concerning daylight use and control of shading devices. The daylight performance criteria combine UDI （useful daylight illuminance） （500-5,000 lux） and illuminance uniformity distribution. Results confirm the impact of occupant behavior on daylighting performance. The optimum combination of external shading devices, high SVF and high window size results in a useful daylighting for 1/3 of the time for passive users and 2/3 for active users.
基金Project supported by Grant-in-Aid for Scientific Research (JSPS KAKENHI for Young Scientists (S), 21676005)
文摘Thermal comfort and indoor air quality as well as the energy efficiency have been recognized as essential parts of sustainable building assessment. This work aims to analyze the energy conservation of the heat recovery ventilator and to investigate the effect of the air supply arrangement. Three types of mixing ventilation are chosen for the analysis of coupling ANSYS/FLUENT （a computational fluid dynamics （CFD） program） with TRNSYS （a building energy simulation （BES） software）. The adoption of mutual complementary boundary conditions for CFD and BES provides more accurate and complete information of indoor air distribution and thermal performance in buildings. A typical office-space situated in a middle storey is chosen for the analysis. The office-space is equipped with air-conditioners on the ceiling. A heat recovery ventilation system directly supplies flesh air to the office space. Its thermal performance and indoor air distribution predicted by the coupled method are compared under three types of ventilation system. When the supply and return openings for ventilation are arranged on the ceiling, there is no critical difference between the predictions of the coupled method and BES on the energy consumption of HVAC because PID control is adopted for the supply air temperature of the occupied zone. On the other hand, approximately 21% discrepancy for the heat recovery estimation in the maximum between the simulated results of coupled method and BES-only can be obviously found in the floor air supply ventilation case. The discrepancy emphasizes the necessity of coupling CFD with BES when vertical air temperature gradient exists. Our future target is to estimate the optimum design of heat recovery ventilation system to control CO2 concentration by adjusting flow rate of flesh air.
