Evaluation of Equivalent Temperature Using Thermal Factors : Validation of a Calculation Method Based on ISO 14505-4:2021 in a Vehicle cabin
2022-01-0215
03/29/2022
- Content
- This paper describes equivalent temperature evaluation in vehicle cabins based on new international standard ISO 14505-4 published in 2021. ISO 14505-4 defines two simulation methods of a thermal comfort index “equivalent temperature”. One is the method using numerical thermal manikin model and the other is that calculating from thermal factors. Authors proposed the former method and presented it at SAE WCX 2019. The present paper discusses the latter method. At first, the calculation method of equivalent temperature from thermal factors, such as air temperature, radiant temperature, solar radiation and air velocity, are explained. Then the experiments to measure equivalent temperature in an actual vehicle cabin are described. In the experiments, equivalent temperature was measured by a thermal manikin under two conditions: a summer cooling condition with solar radiation and a winter heating condition without solar radiation. Subsequently, thermal environment in the vehicle cabin under the experimental conditions were simulated by Computational Fluid Dynamics (CFD). A 3D-CAD vehicle shape data, same model as the vehicle in the experiments, was used for the simulations. View factors, which were used for radiant temperature calculation, were also calculated from the 3D-CAD data. Equivalent temperature on each body segment was calculated from the thermal factors simulated by the CFD. Finally the calculated equivalent temperatures were compared with the measured values by the experiments. The results showed good correlation, within 4 degrees Celsius difference. It indicated that thermal sensation can be estimated within an accuracy of 1 point on the ASHAE 7-point thermal sensation scale. In order to evaluate the equivalent temperature on each body segment accurately, the accuracy of air velocity on the segments that wind hit directly is significant.
- Citation
- Oi, H., Ozeki, Y., Suzuki, S., Matsumoto, A. et al., "Evaluation of Equivalent Temperature Using Thermal Factors : Validation of a Calculation Method Based on ISO 14505-4:2021 in a Vehicle cabin ," SAE Technical Paper 2022-01-0215, 2022, .