School of Sustainability, Arizona State University, Tempe, AZ, USA.
School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, USA.
Int J Biometeorol. 2021 Jun;65(6):967-983. doi: 10.1007/s00484-021-02131-y. Epub 2021 Apr 28.
Thermal comfort research has utilized various sensors and models to estimate the mean radiant temperature (MRT) experienced by a human, including the standard black globe thermometer (SGT), acrylic globe thermometers (AGT), and cylindrical radiation thermometers (CRT). Rather than directly measuring radiation, a temperature is measured in the center of these low-cost sensors that can be related to MRT after theoretically accounting for convection. However, these sensors have not been systematically tested under long-term hot and clear conditions. Further, under variable weather conditions, many issues can arise due to slow response times, shape, inaccuracies in material properties and assumptions, and color (albedo, emissivity) inconsistencies. Here, we assess the performance of MRT produced by various heat transfer models, with and without new average surface temperature ([Formula: see text]) correction factors, using five instruments-the SGT (15 cm, black), tan and black CRTs, gray and black 38 mm AGTs-compared to 3D integral radiation measurements. Measurements were taken on an unobscured roof throughout summer-to-early-fall months in Tempe, Arizona, examining 58 full-sun days. Deviations without correcting for asymmetrical surface heating-found to be the main cause of errors-reached ± 15-20 °C MRT. By accounting for asymmetric heating through [Formula: see text] calculations, new corrective algorithms were derived for the low-cost sensor models. Results show significant improvements in the estimated MRT error for each sensor (i.e., ∆MRT) when applying the [Formula: see text] corrections. The tan MRT improved from 1.9 ± 6.2 to -0.1 ± 4.4 °C, while the gray AGT and SGT showed improvements from -1.6 ± 7.2 to -0.4 ± 6.3 °C and - 6.6 ± 6.4 to - 0.03 ± 5.7 °C, respectively. The new corrections also eliminated dependence on other meteorological factors (zenith, wind speed). From these results, we provide three simple equations for CRT, AGT, and SGT correction for future research use under warm-hot and clear conditions. This study is the most comprehensive empirical assessment of various low-cost instruments with broad applicability in urban climate and biometeorological research.
热舒适研究利用各种传感器和模型来估计人体经历的平均辐射温度（MRT），包括标准黑球温度计（SGT）、丙烯酸球温度计（AGT）和圆柱形辐射温度计（CRT）。这些低成本传感器不是直接测量辐射，而是在其中心测量温度，在理论上考虑对流后，可以与 MRT 相关。然而，这些传感器在长期炎热和晴朗的条件下并未得到系统测试。此外，在多变的天气条件下，由于响应时间慢、形状、材料特性和假设的不准确性以及颜色（反照率、发射率）不一致等问题，可能会出现许多问题。在这里，我们使用五种仪器——SGT（15 厘米，黑色）、tan 和黑色 CRT、灰色和黑色 38 毫米 AGT——评估了各种传热模型产生的 MRT 的性能，以及是否使用新的平均表面温度（[公式：见正文]）校正因子，与 3D 积分辐射测量结果进行比较。在亚利桑那州坦佩的整个夏末初秋期间，在无遮挡的屋顶上进行了测量，共检查了 58 个全日照日。发现未校正非对称表面加热（发现是误差的主要原因）的偏差达到了±15-20°C MRT。通过通过[公式：见正文]计算来考虑非对称加热，为低成本传感器模型推导了新的校正算法。结果表明，当应用[公式：见正文]校正时，每个传感器的估计 MRT 误差（即∆MRT）都有显著改善。tan MRT 从 1.9±6.2°C 改善到-0.1±4.4°C，而灰色 AGT 和 SGT 则分别从-1.6±7.2°C 改善到-0.4±6.3°C 和-6.6±6.4°C 改善到-0.03±5.7°C。新的校正还消除了对其他气象因素（天顶角、风速）的依赖。基于这些结果，我们为 CRT、AGT 和 SGT 提供了三个简单的校正方程，以供未来在温暖炎热和晴朗条件下的研究使用。本研究是对各种低成本仪器进行的最全面的实证评估，具有广泛的城市气候和生物气象学研究应用。
