Study On Ventilation And Indoor Air Quality For Residential Building

Natural ventilation in buildings can improve indoor air quality and thermal comfort and reduce air-conditioning use except for highly polluted area.Utilizing natural ventilation requires knowing how the wind enters the community and how it enters the building.In addition,Chinese kitchen emit a lot of gaseous pollutants and particulate matter,natural ventilation could not guarantee the air quality and thermal comfort of the kitchen.This study is to understand the flow mechanism of how the wind from the suburban meteorological station flows into the urban area and finally enters the building interior and proposes a reasonable numerical calculation method.In addition,this study also aims to propose reasonable ventilation,makeup air and air conditioning technology to improve indoor environment in Chinese residential kitchens.According to the verification by experimental measurement,this investigation could provide guideline for the indoor and outdoor environmental design and air quality control of building.This study has conducted the following investigations: 1)This study proposed a full-scale model which was able to produce the wind velocity distribution in the community by using wind information from a meteorological station that was 11 km away.This investigation then explored the influence of surrounding buildings on the wind flow around the target building with different geometrical models.2)This investigation proposed a correlation method for converting the hour-by-hour wind velocity from a meteorological station to minute-by-minute velocity,using data measured on the rooftop of the building of interest.Experimental measurement was conducted to validate the accuracy of this correlation method.3)Given natural ventilation could not guaranttee the thermal comfort and air quality in the kitchen,this study reviews the published literature on indoor thermal environment and air quality in Chinese-style residential kitchens and summarizes measures to control and improve the environment inside CRKs.And then,this investigation proposed one integrated kitchen ventilation and exhaust system to provide organized conditioned air and makeup air for the kitchen to improve the thermal environment and air quality in kitchens.The study led to the following conclusions: 1)This study proposed a full-scale model which was able to produce the wind velocity distribution in the community by using wind information from a meteorological station that was 11 km away.The wind velocity computed by the full-scale model was 20% higher than the experimental data2)The mean wind velocity computed by the simplified model was 5.5% higher than that computed by the detailed model inside the urban configuration.The simplified full-scale model used only 69% of the grid number used by the detailed full-scale model.Thus,the simplified model can reduce the computing time by at least one-third.3)By using the maximum dimension of the building,L,as the scale,this study found that the region within at least a 3L radius of the building should be simulated with detailed building structures in order to obtain sufficiently accurate wind flow and pressure distributions around the building.4)With the modified minute-by-minute data,the variation trend of the wind speed at the rooftop measuring location and indoor cross ventilation can be reproduced satisfactorily by the unsteady CFD simulation.The mean relative error between the CFD simulation results of rooftop wind speed and the cross-ventilation rate and the experimental data was 24.4% and14%,respectively.5)This investigation used upward air curtain around the stove to control the spillage of cooking pollutants and used air-conditioner located in the lower part of the cabinet under the stove to improve thermal comfort.The measured capture efficiency of the range hood ranged from 96.2% to 97.1%.The proposed system could maintain good air quality and thermal environment in kitchens.