English

As a novel air distribution system, diffuse ceiling ventilation combines the suspended acoustic ceiling with ventilation supply. Due to the low-impulse supply from the large ceiling area, the system does not generate draught when supplying cold air. However, heat sources play an important role on thermal comfort in the occupant zone. Another characteristic of this system is its lower pressure drop compared with conventional ventilation systems, which reduces the noise problem and, at the same time, the energy consumption of the fan can be reduced.

Methods of manipulating building envelope wind pressure distributions for application in the natural ventilation of high-rise buildings are presented using computer simulation methods. CFD was used to simulate the external flow while the multi-zone method was used to compute the flow distribution in the building interior. First, a 2-D CFD study was conducted to explore various techniques of manipulating the building envelope wind pressure distribution.

The PerFluorocarbon Tracer (PFT) method is a low-cost approach commonly used for measuring air exchange in buildings using tracer gases. It is a specific application of the more general Continuous-Injection, Long-Term Sampling (CILTS) method. The technique is widely used but there has been little work on understanding the uncertainties (both precision and bias) associated with its use, particularly given that it is typically deployed by untrained or lightly trained people to minimize experimental costs.

Releases of airborne chemicals can rapidly affect wide areas, leading to exposures that may adversely affect public health. A strategy of sheltering indoors has often successfully protected public health, but in some cases it has been ineffective. This paper explores the role of ventilation as one of a number of factors that affect shelter effectiveness.

Numerical modeling is performed to predict airflow patterns, thermal comfort, and ventilation air distribution within an open office space. This analysis is conducted to examine the ability of a three-dimensional airflow simulation model to predict the performance of a linear diffuser and to assess the impact of several parameters on performance. The airflow within a single cubicle within a mechanically ventilated open office area is modeled numerically using the program EXACT3.

The possibility of unacceptable internal air pollution levels can cause concern at the design stage given the potential for cross contamination between building exhausts and ventilation intakes is there. The complexity of airflows around buildings, however, makes it extremely difficult to predict the contamination levels at the intake locations. This paper reports a wind tunnel technique using a model of a proposed building to determine the pollutant levels expected at various inlet locations due to the re-ingestion of noxious emissions from its two stacks.

Carbon monoxide (CO), nitrogen dioxide (NO2), and particulate matter (PM) are harmful air pollutants that pose significant short- and long-term health risks. Emitted from coal-fired power plants, vehicle exhaust pipes, and other combustion sources, they’re among six primary pollutants monitored by the U.S. Environmental Protection Agency (EPA) through the Clean Air Act. These same pollutants are also some of the most common contributors to unhealthy air inside U.S. homes, due in part to a ubiquitous and possibly surprising activity: cooking.

Outdoor thermal condition is one of the important factors for people’s exposure time. This article is the results of a field study had been done in the mid winter 2010 – 2011 in Sheffield, UK. The aim is to find out the relationship between climatic condition, architectural design and peoples behavior. Two outdoor thermal indices that are appropriate for cold condition are used to explain the cold stress situation. To have the related information, the weather data is collected by a mobile Kestrel weather station that is designed for outdoor events.

According to an advancement of exergy research in relations to thermal comfort and built environment for the last fifteen years, the availability of “warm” or “cool” radiant exergy emitted by the interior surfaces of building envelope systems is crucially important in providing building occupants with adaptive opportunity for thermal comfort both in summer and in winter. This paper demonstrates some numerical examples showing how the thermal performance of window systems affects the availability of “warm” and “cool” radiant exergies.

This paper presents an ideal and worst case scenario approach for occupancy modelling in early design stages which can be used in building simulation. It defines the range of impact that occupant behaviour can have on comfort and energy performance in buildings, and can thus contribute to the decision making of architectural projects in early design stages.