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

尽管辐射采暖系统——尤其是地板采暖——已经获得了很大的普及，但通过模拟来评估这些系统的热舒适性仍然是基于模型的，这些模型不能准确地反映人体与其热环境之间的辐射热交换。当由于室内空间表面温度差异较大而发生显著的辐射温度不对称时，这可能成为一个问题。在改造旧的、能效较低的、只有中等隔热外墙或窗户的建筑时，规划新的供暖系统尤其如此。现有的舒适模型或侧重于简化辐射条件下的对流换热，或存在其他缺点（无生理参数，不适用于非对称条件等）。在此背景下，本提案的目的是通过包含更详细的人体部位与其热环境之间辐射热交换的子模型来增强现有的热感觉和舒适模型-伯克利舒适模型。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，这些数据收集于在稳定/均匀、稳定/不对称和瞬态/不对称热条件下的气候室实验中，使用新开发的测量单个身体部位辐射热交换的装置。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，整体（全身）感觉和整体热舒适-并将基于统计分析，使用不同的数学方法来实现最佳匹配。为了测量辐射热交换，将设计并建造一个由模块化辐射板和伸缩臂组成的新仪器。模块化面板将由8个相同大小的可移动部件组成。它们的前表面将朝向各自的身体部位，每个模块包括一个加热元件（铜电导体），通过焦耳效应产生热流。对增强型伯克利模型的验证将通过在气候室热不对称条件下对人类受试者进行的进一步实验数据来完成。之后，作为准备就绪的证明，增强的热感觉/舒适模型将用于评估建筑物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场景，并进行参数化研究，调查具有不同隔热水平的房间的热舒适性，从而研究建筑外部部分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).