This paper considers the numerical modeling of room airflows and illustrates the usefulness of computational fluid dynamics as a design tool for ventilation systems. A computer code, which simulates steady, buoyant, turbulent, three-dimensional flows in Cartesian coordinates, was developed. The time-averaged equations for conservation of mass, momentum, and energy are solved. A low Reynolds number kE model is used to simulate the turbulent transport. The code was validated by comparing it to benchmark data for both liddriven and buoyancy-driven cavity flows.
Wintertime window condensation problems were reported on the top two floors of a five-story, multi-unit residential building in central New York (7200, base 65° F heating degreedays ). Initially built as a five-story brick hotel at the turn of the century, the building was rehabbed into low-income apartments in the early 1990s. Ventilation in each unit consisted of operable windows and a single bath exhaust. Condensation on windows was severe enough to support fungal contamination in the first winter of occupancy.
Video camera calibrations and field tests for air change rates in a test house were performed to develop a new method of measuring air change rates using a video imaging technique. From the camera calibrations, it was found that good correlation was achieved between image signals and luminous reflectance of achromatic color chips by appropriately adjusting the pedestal level of the video camera so that the image signals were made equal to zero for the black level of the picture.
This paper proposes a new approach to thermostat design. For many years, thermostats have been "dumb" devices, meaning that they react to their environment either by direct user control or by previous user programming. This new approach details an intelligent thermostat that learns about the behavior of the occupants and their environment and controls ambient temperature to maintain comfort according to human specifications. In that way, the thermostat reduces the number of interactions with the user and eliminates the need for them to learn how to program the device.
Recent ASHRAE forums have revealed an increased interest in information and guidance relative to designing and applying ventilation systems for areas where smoking is permitted. There are few data currently available through ASHRAE for the engineer challenged with designing a cigar bar, a smoking lounge, or a bar or restaurant with smoking permitted. This paper applies laboratory data about the acceptance of environmental tobacco smoke to real-world applications.
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