Effects Of Mechanical Ventilation And Natural Ventilation On Indoor Environment In Severe Cold Zone

With the improvement of people’s living standards in China,more and more people care about the indoor environment of the house.Indoor climate and indoor air quality are important indicators of indoor environment.Poor indoor climate and indoor air quality not only affect the living experience of the residents but also threaten the health of the residents.The use of inferior building materials and furniture that generate a large amount of chemical pollution in residential buildings is the main cause of indoor air quality problems,and the main way to solve this problem is ventilation.Natural and mechanical ventilation are two common types of ventilation,both of which provide a healthier indoor environment by introducing external fresh air into the room.The fresh air entering the room will also change the indoor climate while affecting the indoor air quality,especially in the very cold outdoor winter.In order to analyze the impact of ventilation methods on indoor climate and indoor air quality in China’s severe cold regions,a long-term monitoring system was used to monitor the indoor air quality of residential buildings and the behavior of users’ switch windows.The system has been monitoring five mechanical ventilation houses and four natural ventilation houses in Urumqi for one year.The temperature,relative humidity and CO2 sensors used in this calibration were calibrated to ensure the accuracy of the monitoring.This study also set up a formaldehyde sensor calibration platform to achieve calibration of the formaldehyde sensor.Data analysis of questionnaires and long-term monitoring in Urumqi indicated that the indoor climate in Urumqi is dry in winter and comfortable in other seasons.Compared to natural ventilation,the use of a mechanical ventilation system in the winter will reduce the indoor temperature by 1.6oC,the indoor relative humidity by 3%,and reduce the probability of indoor CO2 concentration exceeding the standard by 19%.Naturally ventilated houses have obvious overheating in the winter.Although the mechanical ventilation system reduces the indoor temperature,the temperature in the mechanically ventilated house is still suitable.The use of natural ventilation in winter significantly reduces the relative humidity in the room,while reducing ventilation also degrades the air quality in the room.It necessary to humidify naturally ventilated homes.The use of a mechanical ventilation system makes it easier for residents to feel dry and to humidify the room more frequently.Therefore,for Urumqi’s residences,whether it is a mechanically ventilated house or a naturally ventilated house,humidification is necessary in winter.