Challenges and objectives
Thermal comfort represents a new major development axis in the design of future mobility vectors. With increasingly extreme geographic constraints and environmental conditions (global warming, heat peak), and increasing transport flows, the variables defining thermal comfort have a greater significance in the dimensioning of cars, trains and buses.
Air conditioning systems must be ever more powerful to compensate for these new phenomena.
Conversely, environmental standards are becoming more and more restrictive in terms of energy consumption. The consumption/comfort ratio must be dimensioned as accurately as possible to achieve the desired performance criteria.
Thermal comfort is a real complexity, since the temperature of a volume is not the only factor that characterises the comfort: draughts, vertical temperature variations, ground temperature, and metabolic activity can influence the sensation of thermal comfort.
In addition, the issue of fine particles, gas release harmful to man, and more generally the environmental issues must be addressed in such dimensioning. The study of thermal comfort in 3D CFD calculation makes it possible to determine the so-called 'dead' zones where the accumulation of particles, harmful gases, and bacteria can be visualised, which can then be optimised.
The development of these systems presents a challenge, as it consists of ensuring comfort while limiting energy consumption and health risks.
- Pre-dimensioning by system approach of air conditioning / heating characteristics (power, flow)
- Creation of an air conditioning / heating dimensioning tool
- Calculation of air renewal and circulation rates
- 3D digital simulation using parameterised designs
- Validation of temperatures, humidity, and thermal comfort
- Qualification of thermal comfort by Fanger criteria (PMV, PPD) or as prescribed by law
- System optimisation (reduction of pressure drop, air distribution, thermal bridges)
- Reduced energy consumption of the air conditioning and heating system
Keywords: thermal comfort, dimensioning, air conditioning, air renewal rate, mixing, humidity, speed, power, flow, CFD, numerical simulation, 3D calculations, PMV, PPD, pressure drop, thermal bridges.
Tools: STAR-CCM+, modeFRONTIER