Investigation of the Effect of Radiant Heat Flux on Thermal Sensation and Thermal Comfort

虽然辐射供暖系统-特别是地板供暖-已经得到了很大的普及，通过模拟这些系统的热舒适性的评估仍然是基于模型，这并不占人体和其热环境之间的辐射热交换的精确表示。当由于室内空间的表面温度的较大差异而发生显著的辐射温度不对称时，这可能成为问题。在翻新旧的、节能性较低的建筑物时，尤其是在规划新的供暖系统时，外墙或窗户只有中等隔热性。现有的舒适度模型要么集中在对流传热与简化的辐射条款或显示其他缺点（没有生理参数，不适用于不对称的条件，等）。在此背景下，本提案的目的是通过包括用于人体部位与其热环境之间的辐射热交换的更详细的子模型来增强现有的热感觉和舒适度模型-伯克利舒适度模型。该子模型将通过将主观（人类受试者的反应）和客观数据（物理测量）相关联来开发，这些数据是使用新开发的用于测量单个身体部位辐射热交换的设备在稳定/均匀、稳定/不对称和瞬态/不对称热条件下从气候室中的实验中收集的。增强将考虑伯克利模型的四个部分模型-局部感觉，局部舒适度，整体（全身）感觉和整体热舒适度-并将基于统计分析，使用不同的数学方法进行最佳拟合。为了测量辐射换热，设计并建造了一种新型的辐射换热测量装置，该装置由一个模块化辐射板和一个伸缩臂组成，模块化辐射板由8个相同尺寸的可移动部件组成。它们的前表面将朝向各自的身体部位，每个模块都包括一个加热元件（铜电导体），通过焦耳效应产生热通量。增强型伯克利模型的验证将利用在气候室中热不对称条件下对人类受试者进行的进一步实验的实验数据进行。之后，作为准备就绪的证明，增强的热感觉/舒适度模型将用于评估建筑物中实际边界条件下的辐射供暖系统。为此，将设计一个案例研究方案，并进行参数研究，调查不同隔热水平的房间的热舒适性，从而外部建筑部件的表面温度以及辐射供暖系统（地板，天花板）的不同表面温度。

Although radiant heating systems - especially floor heating - have gained great popularity, the evaluation of thermal comfort of these systems through simulation is still based on models, which do not account for a precise representation of radiant heat exchange between the human body and its thermal environment. This might become an issue when significant radiant temperature asymmetries occur due to larger differences in surface temperatures of an indoor space. This could particularly be the case when planning a new heating system during renovation of older, less energy-efficient buildings with only medium-insulated exterior walls or windows. Existing comfort models either focus on convective heat transfer with simplified radiation terms or show other shortcomings (no physiological parameters, not applicable for asymmetrical conditions, etc.).Against this background, the objective of this proposal is to enhance an existing thermal sensation and comfort model – the Berkeley Comfort Model – by including a more detailed sub-model for radiant heat exchange between human body parts and their thermal environment. This sub-model will be developed by correlating subjective (responses from human subjects) and objective data (physical measurements), collected from experiments in a climate chamber under steady/uniform, steady/asymmetric, and transient/asymmetric thermal conditions using a newly developed device for measuring radiant heat exchange with single body parts. The enhancement will consider the Berkeley model's four partial models – local sensation, local comfort, overall (whole-body) sensation and overall thermal comfort – and will be based on statistical analysis, using different mathrmatical approaches for an optimal fit. For measuring the radiant heat exchange a new apparatus will be designed and built, which is composed of a modular radiant panel and a telescopic arm. The modular panel will consist of eight movable parts of the same size. Their front surfaces will be directed towards the respective body part and each module includes a heating element (copper electrical conductors), which creates the heat flux by the Joule effect.Validation of the enhanced Berkeley Model will be done with experimental data from further experiments with human subjects under thermally asymmetric conditions in a climate chamber. After that, as a prove of readiness, the enhanced thermal sensation/comfort model will be used to assess radiant heating systems under realistic boundary conditions in buildings. For this purpose, a case study scenario will be designed and a parametric study will be performed investigating thermal comfort in a room with varying insulation levels and thus surface temperatures of the exterior building parts as well as different surface temperatures of the radiant heating system (floor, ceiling).