FeatureTechnology for Improving Indoor Thermal Environment
The indoor thermal environment is related to human comfort, and improving the environment leads to improved comfort and productivity.
One of the challenges concerning the indoor thermal environment in winter is the deterioration of the environment around windows.
Understanding the causes and taking action will make it possible to create a better thermal environment.
A technology that makes it possible to explain in detail the phenomena occurring around windows (under laboratory conditions)
and to study them at the design stage is introduced in this article.
Explaining airflow around windows in a test room
that simulates the real thing
During the cold season, it is common for cold air to flow around people (especially around their feet) near window panes. This situation is largely due to a cold draft (i.e., cold air flow); namely, indoor air cooled by the window descends and spreads to the floor. On the contrary, air heated by heaters rises and creates a temperature difference between the ceiling and floor of the room, which makes one’s head feel hot and one’s feet cold.
Since the mechanisms of heat transfer near windows and the characteristics of airflow generated by facilities and equipment are not fully understood, the airflow distribution within a room can only be determined with precision by analyzing experimental data in conjunction with numerical simulations.
Results of analysis of wind-speed vectors and contours
At Kajima, we have installed a large single-pane glass window in a test room that simulates winter temperature settings (room temperature: 22°C; outdoor air temperature: 2°C) and are measuring the airflow distribution near the window. By generating oil mist in a darkened room and shining a laser beam onto it to visualize the airflow, it becomes possible to measure the detailed distribution of airflow direction and speed without contacting the airflow.
Overview of test room
Kajima can make optimal proposals based on numerical simulations and experimental data of airflow around windows, such as cold drafts, when considering design of facilities for customers’ buildings.
