Measurement of indoor climate using acoustic travel-time tomography

决定乘员热舒适的两个主要标准是空气温度和气流速度。为了监测这些参数，通常在室内环境中安装原位传感器。这种传统方法的缺点之一是只能在某一特定位置进行测量，而不能测量包括居住区域在内的整个房间的目标参数分布。此外，直接在测量环境中安装多个传感器（例如，气流传感器）是有问题的，因为它们对测量参数本身有干扰作用。声波走时层析成像（ATOM）技术作为一种遥感方法，是克服传统传感器上述缺点的一种解决方案。ATOM利用了声速对空气温度和介质流速的依赖关系。沿着传播路径的平均声速是由在换能器之间对定义的声信号的传播时间估计确定的。通过适当的层析成像算法，可以将探测到的声速转换成空间分布的空气温度和气流速度。该项目的主要目标是开发一个基于ATOM方法计算室内空气温度和气流速度分布的测量系统。在气候室进行的研究过程中，通过将发射器和接收器放置在最佳位置，成功地测量了空气温度分布的三维表示。扩展该方法，使其包括平行于空气温度的风速测量是本项目的任务之一。此外，测量系统将根据实际工作场所的占用房间条件开发。为了提高分辨率，从数值方法和实际测量的角度定义了几个任务。为了得出测量精度的结论，将在不同的气候条件下进行所需的比较测量。

The two main criteria determining thermal comfort of occupants are the air temperature and the airflow velocity. To monitor these parameters, in-situ sensors are usually mounted in the indoor environment. One of the drawbacks of this conventional method is the measurement at a certain location instead of the distribution of target parameters in the whole room including the occupant zone. Moreover, mounting multiple sensors directly in the measurement environment (e.g., airflow sensors) is problematic due to their interference effect on the measured parameters itself. Acoustic travel-time tomography (ATOM) technique as a remote sensing method is a solution to overcome the mentioned shortcoming of traditional sensors. ATOM utilizes the dependency of the sound velocity on the air temperature and flow velocity in the medium. The average sound velocity, along propagation paths, is determined by travel-time estimation of a defined acoustic signal between transducers. This detected sound velocity can be converted into spatially distributed air temperature and airflow velocity by using a proper tomographic algorithm. The primary goal of the project is to develop a measurement system for calculating both room air temperature and airflow velocity distribution based on the ATOM method. Over the course of studies conducted in the climate chamber of the BUW, a three-dimensional representation of the air temperature distribution was successfully measured by placing a transmitter and a receiver at optimal positions. The extension of the method to include the airflow velocity measurement in parallel to the air temperature is one of the tasks of this project. Furthermore, the measuring system will be developed for an occupied room condition considering an actual workplace. With the aim of resolution enhancement, several tasks are defined in terms of numerical methods and practical measurements. To draw conclusions about the measurement accuracy, required comparative measurements will be conducted under different climatic conditions.