This paper evaluates the operating cost savings and overall economics associated with these two different ventilation load reduction technologies : demand-controlled ventilation (DCV) and enthalpy exchangers. A specialized simulation tool was developed and used to perform the evaluations. For both technologies, the savings potential and economic payback are better in more extreme climates., particularly in cold climates because the ventilation load is a larger portion of the overall load.

This paper shows how a combined air-to-air heat and energy recovery system design problem can be formulated for HVAC cabinet units and solved for the least life-cycle cost system while still retaining a small time period payback. Mathematical expressions are presented to address the complicating interaction between the components of the unit to facilitate the design process. The design process is illustrated for the city of Chicago where both large heating and cooling loads occur in HVAC applications.

A stereoscopic particle image velocimetry (SPIV) system was used to measure airflow characteristics in an irregularly shaped test room. These measurements were compared with air velocity measurements obtained by a sonic anemometer instrument, hot-wire instrument, and draft instrument. All of the measurements were taken at five measurement locations along the center plane of the test room. For each measuement location, numerous pairs of SPIV, sonic, hot-wire, and draft data were collected and averaged to determine the average velocity.

An initial study to develop a numerical tool using CFD methods for investigating the potential of disease transmission in commercial aircraft is completed. To gain insight of the general airflow pattern, a detailed CFD model of a small section in the passenger cabin of a B767-300 passenger cabin was built and a Reynolds-averaged Navier-Stokes (RANS) simulation was performed. By comparing with the available test date, the RANS simulation substantially underpredicted the turbulence intensity, especially in and around the breathing zone.

An initial study to develop a numerical tool using CFD methods for investigating the potential of disease transmission in commercial aircraft is completed. To gain insight of the general airflow pattern, a detailed CFD model of a small section in the passenger cabin of a B767-300 passenger cabin was built and a Reynolds-averaged Navier-Stokes (RANS) simulation was performed. By comparing with the available test date, the RANS simulation substantially underpredicted the turbulence intensity, especially in and around the breathing zone.

A hot and uncomfortable kitchen contributes to productivity loss, employee turnover, and eventually profit loss for the restaurant operator. Using thermal displacement ventilation in kitchen environment allows for a reduction in space temperature without increasing the air-conditioning system capacity. Application of two systems is compared in a typical kitchen environment using CFD modeling. Often kitchen exhaust hoods are provided with untempered makeup air.

Designers of HVAC systems serving educational facilities face considerable acoustical challenges in applying equipment that complies with the acoustical levels specified in ANSI/ASA Standard S12.60-2002. Like all ANSI standards, the imposition of S12.60 is voluntary, therefore, its evolution as a regulatory document is likely to be a gradual process. However, the lobby that led to its adoption over many industry concerns is strong and will likely speed its integration and the need for HVAC systems that comply with its mandated space noise levels.

The air distribution in the room is mainly controlled by buoyancy forces from the heat sources, although the flow from the textile terminal can be characterized as a passive displacement flow with a downward direction in areas without thermal load. A variant of the system is supplied with horizontal jets from openings in the textile terminal to generate a mixing flow in the room. Both systems are compared with mixing ventilation based on a wall-mounted diffuser and with displacement ventilation with a wall-mounted low velocity diffuser.

This research studies the effects of source type and location on contaminant dispersion and exposure in a displacement ventilated room. A full-scale environmental chamber is used to measure the airflow and contaminant distributions in a mockup office setting. A point source is positioned at four different locations to examine the sensitivity of the contaminant distribution of source locations. This is followed by the exposure measurements in the same room with an area of contaminant sources on the floor.

The purpose of this paper is to review the existing material emission models, as well as to analyze the experimental methods. It was found that existing physical mdoels for describing VOC emission from dry building materail can be classified as one-phase models and multi-phase models. Further detailed analysis showed that these models could be converted from one form into another as long as the linear sorption isotherm is used in both approaches.