Thermal comfort assessment
There are many thermal sensation and thermal comfort scales and models used to asses human thermal comfort.
- The PMV / PPD model
This model was developed by Professor Ole Fanger, and it is a widely used metric in thermal comfort research that predicts the average vote of a large group of people on a 7-point thermal sensation scale ranging from cold (-3) to hot (+3). This model defines two indexes, Predicted Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD), which is functionally dependent on PMV. PMV index is based on assessment of heat balance between occupants body and environment, so it considers factors like air temperature, humidity, air velocity, clothing insulation, and metabolic rate to estimate how comfortable or uncomfortable people feel in a particular environment. Then, it is possible to calculate PPD index from PMV, which shows the percentage of dissatisfied people in the environment. This model is suitable for assessing thermal comfort in homogenous conditions, thus it is mainly used in HVAC system design to ensure indoor environments are comfortable for occupants.You can read more about the PMV (Predicted Mean Vote) index in various research papers or these standards:- ASHRAE Standard 55 Thermal Environmental Conditions for Human Occupancy
This standard by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers is a key reference for understanding PMV in the context of building environments - ISO 7730 Ergonomics of the thermal environment
The International Organization for Standardization provides detailed guidelines on PMV, focusing on thermal comfort in moderate environment.
- ASHRAE Standard 55 Thermal Environmental Conditions for Human Occupancy
- Berkeley Thermal Sensation scale
This scale made by researchers at the University of California, Berkeley was developed with attention to human comfort and perception in different environmental conditions. The scale is widely used in environmental psychology and thermal comfort studies, especially in fields like architecture, HVAC (Heating, Ventilation, and Air Conditioning) design, and ergonomics. The Berkeley model is based on real-time, empirical data, capturing the immediate thermal sensations of individuals and thus it is more suitable for transient environments, where conditions like temperature and humidity change rapidly.To read more about the Berkeley Thermal Sensation scale, you can explore research articles and publications from the Center for the Built Environment at the University of California, Berkeley.
- Principle of Equivalent temperature Teq
Equivalent temperature is a temperature of a homogenous space, with mean radiant temperature equal to air temperature and zero air velocity, in which a person exchanges the same heat loss by convection and radiation as in the actual conditions under assessment. The equivalent temperature provides a unified, physical measure of the climatic effects on the human dry heat exchange. Based on that, it is possible to predict the conditions for heat balance under conditions in or close to the thermoneutral zone. People’s thermal sensation is primarily influenced by general and local levels and variations in skin surface heat flux. Values for the equivalent temperature of a defined environment have been found to be closely related to how people perceive thermal conditions when exposed to the same environment. This can be used for the interpretation of the Teq value and assessment of the quality of the environment. This method is suitable for assessing thermal comfort in inhomogeneous conditions, thus it is mainly used in automotive or transportation to assess comfort in the cabins.You can read more about the Equivalent temperature in various research papers or these standard:- ISO 14505 Ergonomics of the thermal environment — Evaluation of thermal environments in vehicles
The International Organization for Standardization provides detailed guidelines on the assessment of the thermal conditions inside a vehicle compartment with use of equivalent temperature.
- ISO 14505 Ergonomics of the thermal environment — Evaluation of thermal environments in vehicles
- Thermal physiology modelling
Thermal physiological modelling is used in various fields such as environmental ergonomics, thermal comfort studies, and health-related research. There are multiple models available. Our systems are coupled with JOS-3 model. JOS-3 is a numerical model designed to simulate human thermal physiology, including parameters like skin temperature, core temperature, and sweating rates across 17 different body parts as well as the whole body. It was developed by the Tanabe Laboratory at Waseda University.To learn more about JOS-3, you can visit its GitHub repository – https://github.com/TanabeLab/JOS-3. This repository provides comprehensive details about the model, including its development, features, and how it simulates human.
Let us help you
Do you want a non-binding offer?
For more information, please reach out to info@pt-teknik.dk or use the following contact-form