Research in 88 central Florida commercial buildings during the last decade has found that 26% of the air distribution systems had substantially unbalanced return air. Unbalanced return air occurs when there is a restriction to airflow between the supply discharge and the return air, creating positive and negative pressure fields throughout the building.

Field research performed in 70 central Florida homes found that return grilles are almost always located in the central zone of the house and that individual rooms rarely have ducted returnair or return transfer pathways. When interior doors were closed, the closed rooms went to +0.0249 inches of water gauge (in. w.g.) (+6.2 pascals [Pa]) wrt outdoors (wrt = with respect to) and thecentral zone went to 0.0116 in. w.g. (2.9 Pa) wrt outdoors.Room pressures as high as +0.150 in. w.g. (+37.3 Pa) and central zone pressure as low as 0.059 in. w.g. (14.7 Pa) wrt outdoors were found.

The objective of this field investigation was to compare the impacts on thermal comfort due to vertical location of return air inlets in a residential forced-air system operating in the cooling mode. Design guidelines for forced-air cooling systems recommend placing return air inlet locations above
the occupied zone in order to improve circulation of stagnant air and reduce thermal stratification. A companion study of the heating mode is under way. Results from the research will be used to recommend optimal return air inlet locations for yearround performance.

In this study, computational fluid dynamics (CFD) models are used to evaluate how ceiling height affects the overall performance of the air distribution system within a data center environment. First, an underfloor air delivery system is examined while keeping all operational parameters constant and

Contamination sources and prevention is a topic that all facility planners and designers must consider in the data processing environment. Contaminants can be grouped into one of three categories: gaseous, solids (particulates) and liquids. Although very small and at times not easily seen without the aid of magnifying lenses or laboratory analysis, contamination can have a disastrous impact on equipment reliability and availability. Information technology (IT) equipment

This paper summarizes a laboratory investigation into the effects that range top diversity, range accessories (including shelving and a salamander) and hood dimensions (including hood height and depth and reservoir volume) have on hood performance with respect to the minimum exhaust rate required for complete capture and containment of cooking effluent. The appliances used for the study include a six-burner gas range, a gas salamander, an underfired gas broiler, a twovat

This paper summarizes the primary results from ASHRAE Research Project RP-1202, a laboratory investigation into the effects that appliance diversity and position have on exhaust hood performance. The objective was to quantify the impact that appliance position and diversity, side panels and front overhang had on the minimum exhaust rate required to provide capture and containment. The appliances included a gas broiler in the heavy-duty category, a two-vat gas fryer in the medium-duty category and an electric full-size convection oven in the light-duty category.

Prior to 2005, there was not a recognized test method in the United States for determining the grease removal efficiency of mechanical filters used in kitchen ventilation systems. It wasnt uncommon for manufacturers to claim 90% grease removal efficiencies or higher based on test results that simulated conditions not representative of commercial kitchens. It has only been in the last few years that data on the true character of grease emissions from common kitchen applianceshave been available.

The Iowa Association of Municipal Utilities (IAMU) office and training headquarters is a pioneering building designed in 1997 that helped define and embody high-performance sustainable design on a speculative office building budget.This project was selected by the American Institute of Architects National Committee on the Environment as one of its Top Ten Green Projects in the United States in 2002.For this 12,500 ft2 (1,161 m2) office and training facility, effective interior daylighting became a main organizing element for the architectural concept.

In line with the mission of the National Park Service, the Zion National Park Visitor Center was designed to use 70% less energy than a comparable visitor center built to Federal Energy Code 10 CFR 435 (DOE 1995). The authors and NPS staff used an integrated design process, including extensive simulations, to minimize the energy consumption. The result was a passive solar commercial building that has a good thermal envelope, daylighting and natural ventilation. Passive