English

A good performance of air diffuser is essential for an efficient ventilation and thermal comfort. Because of the Coanda effect and the influence of buoyancy, conventional diffusers cannot introduce effectively the warm air into the occupied zone in winter. So, thermodynamic diffusers have been designed to solve that problem. Both experimental and numerical models have been built, and their performances have been compared with the conventional ones.

The authors have tested a combined system of chilled ceiling, displacement ventilation and dessicant dehumidification. Each part is analyzed with its advantages and shortcomings. It appears that the combination of the three parts are consistent on cooling source demand and complementary on indoor comfort.
Their conclusion is that a better Comfort, IAQ and energy saving can be achieved with the association of the three technologies.

This paper presents a numerical method for the study of cross-ventilation with respect to the use of local dynamic similarity model. That model is a ventilation model which predicts the discharge coefficient and the inflow angle at the opening of a cross-ventilated building. Results indicate that the flow rate either calculated directly by CFD or using the local dynamic similarity model is acceptable.

For that study, surveys were first performed to study the relationship between indoor temperature and air conditioner On control. Then, a control behavior model including cross ventilation, based on the survey results was devised. Finally, the results simulated with that method were compared to those with the typical method.

In California, the relocatable classrooms are typically under ventilated : such conditions affect the quality education and the student health. The authors are developing a new HVAC system addressing the problems of noise and energy inefficiency. A prototype was operated in a relocatable classroom test-bed to characterize its performances. Then during one year, ten of the new HVAC systems are being monitored in parallel with the current standard HVAC systems in four schools in Northern and Southern California.

The distributions of air velocity, temperature and humidity are affected by the types and shapes of diffusers for supply air in an occupied zone. So it is important to select proper diffusers in the design procedure of the HVAC systems. The aim of that study is to propose a selection guide for a proper line diffuser in a room when perimetric heating load exists.

This paper discusses how to calculate the LCC (life cycle cost) for different indoor climate systems in typical Swedish buildings in the aim to help the client in choosing the most appropriate indoor climate system in a certain situation. Office buildings and residential buildings are considered, industrial buildings are not considered.
It would be interesting to extend the analysis to include the LCC for the entire building and not just the indoor climate system.

For the investigation of the personalized ventilation efficiency and the study of human exposure in a displacement and mixing ventilated room, a seated computational thermal manikin with the geometry of a real human body has been used. A RNG k-e model with low Reynolds number has been used for the simulation.
The thermal plume around the human body plays a key role for the determination of the inhaled air quality.
According to the authors, the application of personalized ventilation is able to improve the inhaled air quality greatly.

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The ventilation potential of buildings is widely affected by the building location, wind direction, space between buildings : so when high-rise buildings are too close, the influence of adjacent buildings on the availability of cross-ventilation has to be taken into account.
This paper reports the results of CFD simulation studies on that effect.

Filter performance of two new systems of simple respirators are investigated in this paper : a new method is used to quantify the real value of face seal leakage. The results show that respirators can't perform well because of the important leakage of airflow when they are mounted on the headform.
The study shows that physical characteristics of respirators such as the resistance and face fitting geometry are main factors to decide the leakage.