The concept behind an underfloor air distribution system is to create a stratified condition from floor to ceiling, rather than mixed, and rely on the natural buoyancy. Since air is supplied in much closer proximity to the. The conditioned air is injected upward into the occupied zone. This approach employs standard air handling equipment and uses duct supply temperatures in the normal air conditioning. Underfloor air distribution ufad is an air distribution strategy for providing ventilation and space conditioning in buildings as part of the design of a hvac system. Overhead systems typically utilize duct pressures of. Paper open access thermal environmental case study of.
Cost competitive benefits of an under floor air distribution system. Climaflair under floor air distribution system duration. A series of energyplus simulations shows performance differences between the two distribution systems. A majority of these systems include a raised floor system with which underfloor plenums are used to deliver conditioned air to the space through floor grills, or in conjunction with the workstation furniture and partitions.
Lower installation and energy costs are just the beginning of the savings that an airfixture underfloor air distribution system can bring. The net result of these changes is a 50% reduction in minimum required outdoor air from 44% for the overhead distribution to 22 % for the underfloor. The underfloor air distribution systems provide a good flexibility layout since there is the provision that the distribution channels can be branched as per the requirement. Access floor systems allowed plenty of open space to run cabling and a generous pathway to supply large quantities of cooling air under the intense heat of the. If overhead systems have a return air pressure restriction, the room might become pressurized, but comfort will mostly be maintained. In 1997 titus introduced the tafr diffuser and the tafg grommet.
Commissioning of underfloor air distribution systems lessons learned from the field. An underfloor air distribution ufad system is an hvac system that uses the open space underfloor plenum between the structural slab and the underside of a raised floor to deliver conditioned air to supply outlets located at or near floor level within the occupied zone up to 6 ft. Basic concepts a traditional underfloor air distribution system uses the floor space between the structural floor and the access floor as a supply air plenum. Figure 1 shows the schematic diagram of the underfloor air distribution system ufad. Underfloor air distribution ufad case studies project contract number. Analysis of cooling load calculations for underfloor air. Underfloor air distribution systems sustainable facilities tool.
Underfloor air distribution system sacramento states first underfloor system integrates mechanical and telecommunication infrastructure into a single underfloor plenum. Plenum facilitates it and power cabling air distribution simplified by floor plenum economical accommodation of space reconfiguration churn economical provision of personal hvac control improved indoor air quality because of stratification of contaminants why underfloor air distribution. Lessons learned about the author h by allan daly, p. However, this does not generate any savings compared to an overhead system, as just as many ducts, if not more, would be required.
This paper discusses the fluid dynamics of an underfloor air distribution ufad ventilation system in which, in contrast to conventional airconditioning systems, cool air is delivered from diffusers in the floor rather than from overhead vents. Study of residential underfloor air distribution ufad. Energy benefit of the underfloor air distribution system for. File type pdf underfloor hvac design guide underfloor hvac design guide diy slide wire canopy kit learn about award wining modualr infinity canopy shade system hvac training underfloor air distribution this unit of the price training module explores the concepts behind underfloor air distribution, its benefits, and how it compares to. The interest in underfloor air distribution ufad has increased significantly in the u. Optimization of energy and space, faster construction time, more flexibility. The system ventilation efficiency increases from 0. Underfloor air distribution is the next generation in air conditioning systems. Provides a medium for easier installation of other trades. Hui and miss zhou yichun department of mechanical engineering, the university of hong kong pokfulam road, hong kong email. Underfloor air distribution ufad design guide semantic scholar. The contractor shall furnish and install a complete access floor air distribution system as shown.
This manual covers a system offered by carrier corporation see fig. This guide, authored by cbe research specialist fred bauman and allan daly of taylor engineering, is the product of collaborative research and documentation by. The work presented here is a comparative study on the ventilation and thermal comfort performance between underfloor air distribution ufad and overhead air distribution ohad systems set in a typical office environment. Listed and labeled as defined in nfpa 70, article 100 by a testing agency acceptable. Flexsys underfloor air distribution system johnson controls. Challenges and failures in green building design using underfloor air distribution. The typical underfloor air distribution system delivers air to the space between 63f and 68f. The system most adaptable to an existing raised floor would be a fully ducted system. Underfloor air distribution ufad is a strategy for providing ventilation and space conditioning in buildings as part of an hvac system. Why the simple underfloor air distribution system isnt. This synergistic combination of building systems gives the building owner an. Underfloor air distribution suggested specification.
A typical ufad system uses an underfloor supply plenum and a raised access floor to supply the conditioned air through the supply vents at the floor level. Vac systems using underfloor air distribution ufad promise multiple benefits. Often cited as an initial cost benefit of underfloor air distribution, removing the supply ducts, terminals, and diffusers from the ceiling. In this paper we briefly describe the significant features, potential advantages, and design. In fact, the singlemultizone thermal models are not able to predict indoor thermal behaviours or building energy demands accurately, if a nonuniform environment in a room or building is created by a single or multiple heating, ventilation, and air conditioning hvac. Basics of underfloor air distribution underfloor air distribution engineering guide while the total amount of stratification that occurs in the zone is affected by a number of factors, it is generally desirable for stratification to occur because it will lead to advantages similar to those found in a zone with traditional displacement ventilation. Underfloor air distribution ufad designing buildings wiki. Ufad systems use an underfloor supply plenum located between the structural concrete slab and a raised floor system to supply conditioned air through floor diffusers directly into the occupied zone of the building. Benefits of an underfloor air distribution system the concepts of air delivery were especially critical and the team was leaning towards using the ufad system. Solution overview there are several varieties of underfloor air distribution systems. Underfloor air distribution ufad systems are innovative meth ods for delivering space conditioning in offices and other commercial buildings. Analysis of cooling load calculations for underfloor air distribution systems dr. The fluid dynamics of an underfloor air distribution system. An underfloor air distribution ufad system uses the open space below a raised floor system to deliver conditioned air to supply outlets located in the floor.
Design guide to underfloor air distribution in height would result in a reduction of overall building shell cost. Ufad systems use the underfloor plenum beneath a raised floor to provide conditioned air through floor diffusers directly to the occupied zone. Pdf influence of design and operating conditions on underfloor air. An integral part of a underfloor air distribution system are the ufad diffusers that are installed within it. Background system description ufad technology benefits ufad technology needs whats ahead background underfloor air distribution ufad is a method of delivering space conditioning in offices and other commercial buildings that is increasingly being considered as a serious alternative to conventional ceilingbased air distribution systems because of the significant. Underfloor air distribution ufad systems are somewhat different from traditional overhead ventilation systems.
Energy benefit of the underfloor air distribution system. Design guide to underfloor air distribution ufad system benefits without special air handling several types of underfloor system designs exist. This paper identifies types of air distribution systems for heating and cooling in buildings and addresses the potential energy benefit of an underfloor air distribution ufad or uad system over the conventional ceiling air distribution system. An experimental study on the indoor environment using. Since air is supplied in much closer proximity to occupants than in oh. Enhances a buildings ability to change and adapt to its own needs and requirements. Instead of air being introduced through a ducted overhead system, air is distributed via the plenum.
Sources and search engines include ashrae abstract archives 19801997, elsevier. Furnish and install price underfloor fan powered terminal units fdbu of the sizes and. Pdf underfloor air distribution case study yoon soo. There are three concepts normally associated with providing floor level. The ufad system delivers a stratified space in terms of temperature, leaving little room for these hot and cold pockets of air, therefore creating a comfortable environment. Each building and space will have different needs that can be, in part, met by a choosing the right kind of diffuser. It is best to think of an ufad as an upside down alternative to conventional overhead oh air distribution. Underfloor air distribution ufad system, which is a relative new method of providing conditioned air and ventilation to the commercial buildings and data centers, is focused by researchers and. The use of access floors with under floor air distribution ufad systems in new buildings is nothing new. Vac systems using underfloor air distribution ufad promise mul tiple benefits. The development of this design guide on underfloor air distribution ufad is the result of a cooperat ive research agreement between the american society of heating, refrigerating and airconditioning engineers, inc. The readily adaptable system provides a convenient solution to cable management and will expedite future technology and.
Challenges and failures in green building design using. Sacramento state underfloor air distribution system. Flexible ufad system design underfloor air distribution duration. Underfloor air distribution ufad is an alternative to traditional overhead air distribution that. Ashrae, and th e center for the built environment cbe at the university of california, berkeley, for ashrae research project. There are two primary types of diffusers, both of which with their own sets of uses. A postoccupancy monitored evaluation of the dimmable. Underfloor air distribution in a commercial high rise. Publications ashrae design guides the underfloor air distribution ufad design guide is available from the ashrae. Pdf underfloor air distribution case study yoon soo yoonsu. Those systems are seldom concerned with return air pressure drop. Commissioning of underfloor air distribution systems.
A study of the thermal comfort and ventilation performance. The complete solution for your underfloor air distribution needs, our high quality air distribution system delivers clean, conditioned air directly into occupant breathing zones, reducing particulates in the air. Case study underfloor air distribution in kauffman. There is currently several million square feet of access floor air distribution systems being designed across the country. Pdf various methods are used to design and operate underfloor air distribution ufad systems. Energy benefit of the underfloor air distribution system for reducing. Basics of room air distribution dan inthout chief engineer krueger richardson texas 3222011. Underfloor air distribution in a traditional underfloor air distribution system the floor space between the structural floor and the access floor is used as supply air plenum, while the return air is drawn from the plenum into the false ceilings. Improved comfort improve indoor air quality as clean, conditioned air is delivered directly. In humid climates, a discharge air temperature of at least 55f off the cooling coil will be needed to dehumidify the air, but air this cold cannot be supplied to the space without significant comfort complaints. Carefully integrated displacement and underfloor systems allowed price to meet the demanding aesthetic requirements of the kauffman center, resulting in a stunning symphony of architecture and air. Hvac overview of the underfloor air distribution ufad an underfloor air distribution ufad system uses the open space below a raised floor system to deliver conditioned air to supply outlets located in the floor. You will also realize benefits in the form of a reduction of materials, as well as faster tenant improvement. Underfloor airdistribution applications webinar youtube.
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