ABSTRACT

This chapter covers various aspects of room air distribution as well as recent developments in hybrid components and systems. We first discuss different types of the basic air-water systems to set the stage for subsequent material. Next, we provide an overview of air distribution jets and airflow patterns, resulting from the combined effects of forced flow and natural buoyancy effects inside rooms. This is then followed by a discussion of different design issues and components relevant to fully mixed air distribution systems. Next, we describe other air distribution systems, such as the underfloor and the ventilation displacements methods We then discuss ceiling-mounted chilled beams, a device gaining popularity, which are hydronic devices that provide sensible cooling to the space by convection. Hybrid secondary systems are being increasingly used due to the flexibility they provide along with energy and indoor air quality advantages over traditional-air systems. One such system, namely, the dedicated outdoor air system (DOAS) is presented. Finally, we treat two other low-energy cooling techniques, namely, evaporative cooling and desiccant cooling technologies and systems. Evaporative processes using water can reduce energy consumption in many ways, including reducing cooling loads, meeting part of the sensible load, or improving the performance of air-cooled condensers on chiller plants. Desiccant systems pre-dry the supply or ventilation airstream, thereby reducing the load on the mechanical cooling systems and the electrical demand. The thermal energy needed to regenerate the desiccant can be obtained from low-temperature low-grade energy sources.