A two dimensional model was developed to predict the infiltration load to a cold room through its doorway. The governing equations were derived and transformed into dimensionless form. The model showed that the infiltration load to a cold room depends on three dimensionless parameters: the Grashof number of the cold room, the aspect ratio of the room (height to width), and the opening ratio (height of doorway to height of the room). 1\ finite difference technique with a control volume approach was used to solve the governing equations.
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.
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.
ASHRAE Research Project 806, Design Criteria for Building Ventilation Inlets, reviews existing knowledge of the placement of ventilation air louvers, produces a design guide, and suggests additional research, all with the intention of improving indoor air quality in commercial and institutional buildings. Decisions about intake and exhaust placements made early in the architectural and H VAC system design processes will impact occupants over the life of a building. Such placement decisions, therefore, require proper consideration.
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.
Blower doors are used to measure the airtightness and air leakage of building envelopes. As existing dwellings in the United States are ventilated primarily through leaks in the building shell (i.e., infiltration) rather than by whole-house mechanical ventilation systems, quantification of airtightness data is critical in order to answer the following kinds of questions: What is the construction quality of the building envelope? Where are the air leakage pathways? How tight is the building? Tens of thousands of unique fan pressurization measurements have been made of U.S.
CO2-based demand-controlled ventilation (DCV), when properly applied in spaces where occupancies vary below design occupancy, can reduce unnecessary over ventilation while implementing target per-person ventilation rates.