Contaminant dispersion and potential draft risk in a workshop with displacement venti.la tion were investigated with computational fluid dynamics (CFD) techniques. Three factors were considered: the location of the worker, the temperature of the supply air and the supply air flow rate. The capacity of CFD is demonstrated in optimizing the operation of a ventilation system by weighting two significant aspects, i.e., the indoor air quality and the worker's thermal sensation.

A test room and measurement system were developed for the full-scale measurements of the active displacement air distribution. The room represents a 3-meter wide module of a larger hall. The requirements for the room included minimisation of the errors caused by air leaks, thermal conductance and flow obstacles. The measurement of the flow pattern is carried out with ultrasonic and thermal anemometers. Automated traversing system was built to move the sensors in the vertical symmetry plane of the room.

One of the major factors in human comfort is the air quality, which occupies a specific environment and is usually renewed through natural ventilation. However, isolated underground spaces do not benefit from this factor and are often subject to high relative humidity, poor air quality, pollutant emissions and penetration of moisture from the surrounding soil and ground base. Due to such negative characteristics, underground spaces are generally recognized as undesirable living environments by most of Koreans.

Most standards for air handling systems prescribe a minimum air flow rate per person per hour based on full occupancy of the ventilated space. The number of occupants may fluctuate widely, however, and demand-controlled ventilation (DCV) responds to the actual demand for air renewal. There are now sensors capable of detecting this demand, and these are a prerequisite for DCV and good air quality. Key features of DCV are the incorporation of thermal tolerance bands (heating/cooling, humidification/dehumidification), and special control strategies to reduce or even disable the air flow rate.

The performance and effectiveness of any ventilation and cooling strategy depends largely on the method of air distribution and heat removal system. The consequences of poor air distribution and cooling systems are draughts, air stagnation, large temperature gradients and radiation asymmetry. These factors are the chief cause of the occupants' dissatisfaction with their thermal environment, and are major contributors to the so-called 'sick building syndrome'. Cooled ceilings combined with displacement ventilation, sometimes known as 'comfort cooling', has gained popularity in recent years.

Today, laws and regulations play a major role in just about everything we do. The declining quality of the air in our buildings is causing movement towards regulations relating to how buildings should be designed and operated. It is important that designers and operators are aware of all current design and operating standards. ASHRAE Standard 62, "Ventilation for Acceptable Indoor Air Quality" developed in l 989 and now under revision, has created new challenges for designers and engineers.

It is known that water mist occasionally fonns near ice surfaces in roofed skating facilities depending on the indoor environmental conditions. The mist can lead to problems such as decreased visibility during skating competitions. The objective of the present paper is to clarify the relationship between indoor air conditions and water mist formation and to provide a useful design method for preventing mist formation in roofed skating facilities. In the first section, studies concerning the indoor air conditions for preventing water mist formation near the ice surface are described.