Overview
ISO 14505-4:2021 - "Ergonomics of the thermal environment - Evaluation of thermal environments in vehicles - Part 4" specifies a standardized numerical manikin method to determine the equivalent temperature for vehicle thermal comfort assessment. The standard extends the equivalent temperature concept (defined in ISO 14505-2) to predictive, numerical simulations and sets out calculation methods that can be used as an alternative to physical thermal manikins.
Key topics and technical requirements
- Numerical manikin definition: A virtual thermal manikin model that replicates a physical manikin’s thermal behavior for calculation purposes.
- Heat exchange mechanisms: Prescribed treatment of convective, radiant, and conductive heat transfer around the manikin and within the vehicle cabin.
- Calculation frameworks:
- Coupled calculation methods for flow and thermal fields around the manikin.
- Use of thermal factors and options for different calculation modes (constant temperature, constant heat flux, comfort-equation mode).
- CFD integration: Annex A provides guidance on applying computational fluid dynamics (CFD) techniques to simulate airflow and temperature distributions as inputs to the numerical manikin.
- Outputs and metrics: Procedures to compute equivalent temperature and related outputs that integrate local measurements into whole-body thermal assessment.
- Symbols, terms and calibration: Standardized symbols and definitions (aligned with ISO 13731 and ISO 14505-2) and methods for calculating transfer coefficients (h) and segmental heat fluxes.
Applications
ISO 14505-4:2021 is tailored for assessing non-uniform thermal environments in vehicle cabins and other enclosed spaces where thermal comfort is critical. Typical applications include:
- Virtual evaluation of vehicle HVAC designs and climate control strategies.
- Thermal comfort prediction during early-stage prototype development when physical testing is limited.
- CFD-based studies to optimize seat heating/cooling, ventilation outlets, or glazing effects.
- Comparative assessment of design variants to reduce hotspots and passenger complaints.
- Regulatory or ergonomic assessments where reproducible, standardized numerical results are required.
Who should use this standard
- Automotive engineers and HVAC system designers
- CFD specialists and thermal simulation engineers
- Human factors and ergonomics professionals
- Vehicle manufacturers and suppliers involved in cabin climate systems
- Research institutions studying thermal comfort and vehicle microclimates
Related standards
- ISO 14505-2: Determination of equivalent temperature (physical thermal manikin method)
- ISO 13731: Vocabulary and symbols for thermal environment ergonomics
Keywords: ISO 14505-4:2021, numerical manikin, equivalent temperature, thermal comfort, vehicle cabin, CFD, thermal environment, ergonomics.