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air movement

The effective use of simulated natural air movement in warm environments

In that study, two air supply devices were investigated in order to simulate the characteristic of natural wind. The paper demontrates that the simulated natural air movement had an acceptability, for the subjects exposed, higher than the artificial air movement. With simulated natural air movement comfort may improve with energy saving in warm climates.

Air movement - good or bad ?

This paper, on the basis of existing literature, sums up the factors that influence the human perception of air movement and it also tries to specify in general terms when air movement is desirable and when it is not.

Passive Cooling: A Case Study of the Evaporation Phenomena

Passive cooling strategies require strict adherence to the physical world. Ones imagination creates the flow of ideas that can blossom into a comfortable setting, but the reality of design, construction and cooperation has to be observed and accepted. Physical laws govern as natural processes follow the path of least resistance. In order for us to overcome these laws extra energy is required. That is why passive cooling designers must investigate how to create a comfortable setting by understanding how natural procedures work.

Sick building syndrome: ventilation aspects.

Many occupants of a Swedish office building reported symptoms typical of sick building syndrome (SBS). Tests showed that the supply airflows were inadequate, but there was poor air movement in the rooms. Much of the supply air never reached the occupants but went direct to the exhaust system. Reducing the temperature of the supply air improved its dispersion. Instead of rising, the air sank towards the floor and then circulated through the entire room.

Convection in loose-fill attic insulation - simulations and large-scale measurements.

Heat transfer in loose-fill attic insulation was investigated in a large-scale model of a ventilated attic built in a climatic chamber. The particular aspect of this study was heat transfer by convection and its effect on heat losses through the attic floor. It was shown by thermal resistance measurements that the measured and calculated thermal resistance of the attic floor is within the margin of error. Air movements were detected in the insulation, sufficient to cause a decrease in the thermal resistance of the attic floor.

Numerical simulation and analysis of particle movement in ventilation systems.

A mathematical model has been set up for the multizone structure region in this paper. By the way of numerical simulation, the analyses are conducted of air flow and aerosol particle travel under the mechanised ventilation condition. The results of such analyses provide useful data for ventilation system design and the indoor air quality control.

The influence of furniture and equipment layouts on airflow pattern in a clean room.

States that the layout of the production line in any clean rooms is likely to change in accordance with the production process, and that this poses a problem for post clean room maintenance. One of the many problematic issues often found in the clean room environment is air velocity, and the ongoing problem should be addressed at upgrade time. The paper looks at the characteristics of airflow distribution within a clean room, as a result of changes to the production process. The study was conducted for a class 100 clean room at a manufacturing firm for disk drives.

Very low pressure fan for natural ventilation assistance.

The main problem in natural ventilation is that its efficiency depends very tightly on the meteorological conditions : high wind velocity and outside temperature lower than inside are optimal conditions for efficient ventilation. Consequently, air renewal inside buildings is very fluctuating from one moment to another, and extreme comportments can be reached from one season to another : in winter, ventilation is usually very satisfying, whereas in summer unwanted reverse airflows can hardly be avoided.

Behaviour of inclined jet on room cooling.

States that when used with ice storage systems, cold air distribution systems are popular since they require less operating and capital costs. Stresses the importance of a consideration of occupant comfort. The study looked at air circulation and temperature distribution in a room, considering different orientation, velocities and sizes of jet for a given vertical location of air inlet and outlet on opposing walls. A control volume method was used to solve the Navier-Stokes equations and an energy equation in two dimensional rectangular Cartesian coordinates.

Using models to support smoke management design.

Discusses methods of overcoming the limitations of algebraic equations with small-scale physical and network flow models, as well as computer-based zone and CFD models.