The chamber is designed to resemble a contemporary office while allowing precise control over the levels of temperature, humidity, ventilation, and lighting in the space.

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General Description

Figures 1 & 2. Left, Interior view of the controlled environment chamber (42K jpg). Right, equipment room with mechanical system, computer control system, instrumentation, and then-graduate students Marc Fountain and Lucy Johnston (35K jpg). 

The chamber was completed in 1989, and has been intensely used for many research projects since then. The temperature inside the chamber can be controlled as high as 36 °C, and the relative humidity as high as 95%. The inside surface temperature of the windows can be regulated. It has a raised access floor system and suspended ceiling, providing plenums through which air may be supplied and returned in a great number of configurations. The plenums also provide space for connecting instrumentation, power and communications cables. The Chamber's direct digital control system can be used both to control the chamber and monitor its environmental sensors, operating through a series of graphic screens at the PC-based operator's workstation.

Figures 3 & 4. Left, air system for the controlled environment chamber (50K jpg). Right, gas chromatographs for analyzing indoor air quality, as used in studies of ventilation efficiency provided by innovative air distribution systems (37K jpg). 

A major distinguishing feature of the chamber is its realistic office appearance--carpeted floor, finished gypsum board walls, windows to the exterior, suspended ceiling, dimmable lighting, and typical office workstation furniture. By closely resembling a contemporary office, the Chamber reduces psychological effects associated with 'test cell' experiments of human comfort. 

Research Topics

The Controlled Environment Chamber is used to investigate a wide range of physical and psychological aspects of thermal comfort in indoor environments. Topics of special interest have been: 

Localized 'task ventilation' systems that are controlled by the individual occupant. Such systems are quite new in the U.S. They have the potential to significantly increase the comfort and satisfaction of people in office buildings. If well-designed, they also offer the potential of saving some of the energy used to condition the space. 

Air movement affects comfort in warm conditions. Air movement was the only way to keep people cool in hot-humid climates before the introduction of air conditioning, and is still the method used by most of the tropical world. When done effectively, it can save a tremendous amount of energy that would otherwise go into conditioning interior space, and produce acceptable comfort. With new design and predition tools, it can be used in even the most advanced building designs.

The effects of humidity on comfort and health are still poorly understood. Direct evaporative coolers, which are highly energy-efficient, have the effect of increasing the humidity in the space. Similarly, the energy costs of mechanical dehumidification in humid climates are high, and would ideally be done to an appropriate level. We have been quantifying the comfort and health effects of humidity within realistic building settings, working primarily for the organizations that prepare environmental standards, but preparing climatic design guidelines as well.

In addition to thermal comfort, the Chamber has been used to study ventilation in rooms, including the influence of interior furnishings and partitions on interior air movement and air quality. These topics are important to passive solar and naturally ventilated building design, as well as to 'high-tech' commercial building design.

Additional studies

Figure 5. View of the chamber with three different types of air supply systems installed. On the floor there is a floor-based air supply unit that is typically controlled by the occupant . Under the desk, there is another personally-controlled supply unit that supplies air through nozzles on the desktop. The ceiling has a various types of conventional supply diffusers (30K jpg).

Figure 6. Human subjects engaged in stepping activity during a study of the comfort effects of air movement under warm conditions (27K jpg).

Figure 7. Physiological experiment determining the metabolic rate of the activities simulated in the Chamber thermal comfort studies. The skin temperature and humidity are measured at several points on the subject (in this case Richard de Dear, from Macquarie University, Sydney), and are sent to the datalogger shown at the left side of the picture (42K jpg).

Figure 8. A view of subjects in a study of humidity effects on human thermal comfort (23K jpg).