displacement ventilation in schools

8/7/2019 Displacement Ventilation in Schools

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Displacement Ventilation in Schools

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Price Displacement Ventilation in Schools

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Occupied

Zone

Displacement VentilationMixing Ventilationx ng en a on

Introduction

Displacement Ventilation (DV) originated in industrial facilities in Europe as

an effective way to remove contaminants from the occupied zone. It has

since gained popularity in a variety of applications in both Europe and North

America due to its superior air quality, thermal comfort, and energy efficiency.

Mixing Systems Displacement Ventilation Benet o DV

55F supply air 65-68F supply airImproved thermal comort

and energy eciency

Mix the entire space No mixing in the space Improved indoor air quality

Diusers drive air motion

via high velocity supply air

Heat sources drive air motion

via thermal plumes

Improved thermal comort

and layout fexibility

Uniorm temperature Stratied temperature Improved thermal comort

Conditions entire roomOnly conditions the occupied

zone (the rst six eet o a space)

Improved energy

eciency

High supply velocity (minimum

150 pm 1 t rom ace)

Low supply velocity

(40 pm average at ace)Improved thermal comort

Displacement provides high temperature, low velocitysupply air, relying on the buoyancy orces o air to

drive air motion.

The result is high ventilation eectiveness and

improved thermal comort delivered in an energy

ecient manner.

Displacement diers rom traditional overhead mixing systems in several undamental ways:


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Indoor Environmental Quality (IEQ)

Displacement ventilation systems produce environments with extremely high

indoor environmental quality, producing the following IEQ benefits that are all

critical design criteria in schools.

Superior Air Quality and Ventilation Eectiveness

In DV systems, the supply air must pass through the breathing

zone beore being exhausted, because it travels rom a low

level to ceiling mounted returns. As it does this, it carries

contaminants away rom the occupant, leading to a high

ventilation eectiveness compared to mixing systems.

High Thermal Comort

DV delivers supply air at an average o 40 pm and at a

temperature no more than 10F cooler than the room air.

This high temperature, low velocity supply air results in less

drat and a lower percentage o people dissatised per

ASHRAE Standard 55-2010.

A Quiet Environment and Improved Acoustics

Displacement diusers distribute supply air at a very low velocity

into a room, resulting in whisper quiet operation.

Displacement

results in a high

ventilation effectiveness

(1.2 or higher) compared

to mixing systems (1.0

or below).

Displacement systems

typically achieve NC

levels of 15 to 20


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Beneits o

Improved IEQin Schools

Indoor Environmental Quality

(IEQ) has been proven by

several independent studies

to have a major impact on

the health, perormance and

attendance o students and

teachers.

Student Health

CHPS Literature Review:

Higher IAQ resulted in reduced asthma,

colds, fus, and headaches

CHPS Literature Review

CHPS Literature Review

Smedje and Norback, 2000

Smedje and Norback, 2000:

Swedish study o 39 schools over a two

year period

69% reduction in asthma or children

attending schools with displacement

systems

100 %

90%

80%

70%

60%

50%

40%

30%

20%

10%

100 %

90%

80%

70%

60%

50%

40%

30%

20%

10%

14%

12%

10%

8%

6%

4%

2%

0%

85.0%Cold

85.0%Cold

AustralianResidence

Liu et al1996

Jaakkda&

Miettinen1995

Wargocki1998

Brundageet al1985

Wieslanderet al1997

Frisk &Rosendfeld

1995

Frisk &Rosenfek

1995

Jaakkdeet al1994

Bourbeauet al1997

Sundell1996

BeigingResidence

Liu et al1996

Drinkaet al1996

61.5%Asthma,Allergies

67.0%SBS

47.0%SBS

46.0%Resipatory

23.6%Asthma

35.0%SBS

21.4%Asthma,Mucosal

33.6%SBS

33.0%SBS

20.0%Resipation

%I

mprovement/ReductioninSy

mptoms

%Improvement/ReductioninSymptoms

Pollen/petallergy

Asthmaever

Currentasthma

Any asthmasymptoms

More asthmasymptoms in95 than 93

New ventilation system

No new ventilation system


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Student Performance

Shaughnessy et al., 2006:

Studied the eect o ventilation rate on

student perormance in standardized testing

in 54 schools

Found perormance improvements in

classrooms with higher ventilation rates

Teacher Retention

Buckley, Schneider, and Shang, 2004:

Rated satisaction o 835 teachers in

89 schools based on IEQ

Improving satisaction with IEQ resulted in a 5%

increase in retention.

Shaughnessy et al., 2006

Shield and Dockrell, 2003Shield and Dockrell, 2003

Buckley, Schneider, and Shang, 2004

Shield and Dockrell, 2003:

Studied the relationship between classroom

noise and student perormance

21% test score improvement or students

with less than 50 dBA background noise

70%

60%

50%

40%

30%

110

100

90

80

70

60

50

40

Noise

Dirty or opaque windows

inoperable windows

Lighting

Temperature

Indoor air quality

48.7

56.3

47.7

61.8

50.6

64.4

53.3

64.5

Score

Ventilation Rate (I/s person)

Reading Math


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Applying DV in Schools

Displacement ventilation is a lexible method o air distribution that

can be used throughout an educational acility to improve air quality

and thermal comort, while saving energy and reducing utility cost.

Locker Rooms Classrooms Lecture Halls

Labs Libraries

Lobbies/Corridors

Oces

Kitchens/Caeterias

Gymnasiums


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Displacement Ventilation

in ClassroomsClassrooms orm a large portion o most buildings by square

ootage and are where students and teachers spend most o their

time. The indoor air quality, thermal comort, and low noise levels o

displacement ventilation make it ideal or this application.

These rooms are generally densely occupied or extended

periods o time, making minimizing drat and maximizing

usable space o primary concern.

Minimize Drat Zone

Use Price Room Designer sotware to test diuser layout

or thermal comort.

Integrate Diusers

DF1C corner mounted and DF1R recessed diusers are

excellent choices or maximizing usable space in aclassroom.

Custom diusers can be integrated into urniture and

millwork.

Improved Ventilation Eectiveness

The improved ventilation eectiveness o DV ensures that

students receive clean resh air sooner.

Air changes can be reduced without compromising air

quality to achieve energy savings.

Acoustics

Low noise levels are critical to a successul learning

environment. DV can help schools achieve classroom

noise levels under NC 20, resulting in improved

concentration and perormance.

Price DV Room Designer Sotware

DF1C

DF1R


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Sample Classroom Applications

1. Air Handling Unit

2. DR90 or DF1C corner

mounted diuser

Integrating diusers witharchitectural elements

maximizes usable space

3. DLE-H linear enclosure

with integrated heat

or perimeter heating requirements

1. Dedicated Outdoor Air System

2. DF1L lay-in displacement

diuser

Provides displacement cooling

while maximizing usable space

1

2

3

1

2


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DV in Auditoriums/Lecture Halls

The whisper quiet operation and superior air quality o displacement

make it ideally suited or densely populated auditoriums.

In addition, since only the occupied space is cooled, energy is not wasted cooling the signicant lighting

loads and large amount o space near the ceiling.

DF1W Wall Diusers integrate

seamlessly into the sidewall to save

foor space

RFDD or ARFHD Underfoor

Displacement Diusers provide

cool, resh air to the occupants romthe plenum beneath the foor

DV in Caeterias and KitchensDisplacement ventilation ensures that

clean, resh air is delivered to kitchen

and caeteria occupants, eectively

removing contaminants and odors.In the kitchen, the low velocity air does not disrupt the

unction o the exhaust hoods. The cooling load is also

decreased, as heat generated by cooking equipment

rises to the ceiling rather than being recirculated

throughout the room.

DR90 or DF1C Corner Diusers

adjust air fow to accommodate various

room loads

Right: Stainless steel DR90 diusers in a school kitchen


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DV in GymnasiumsDV in Gymnasiums

DV in Libraries

Similar to theaters, gymnasiums typically have high ceilings.

Conditioning these spaces with displacement cools only the

occupied zone, resulting in signiicant energy savings.

Libraries are oten mixed-use spaces

in schools, with areas or computer

use, book storage, reading, and

meetings. The ability to reconigure

the space quickly and economically

is o great value.

An access foor and underfoor air distribution oers this

fexibility, as diusers can be relocated quickly, oten without

having to modiy ductwork. Price oers several diusers that

combine the fexibility o UFAD with the superior air quality and

thermal comort o displacement, including RFDD and ARFHD

round foor diusers and DFG displacement foor grilles.

Diusers in gymnasiums

can produce higher ace

velocities, and typically

have upgraded

construction.

Price oers industrial grade diusers with heavy gauge aces capable o handling the abuse taken in a

gymnasium. These spaces can also tolerate a higher ace velocity

due to the high activity levels o the occupants.

Above: Price Displacement Ventilation

products installed in a library


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CHPS and LEED or SchoolsThe Collaborative or High Perormance Schools is a national K-12 green

school rating system in the United States whose goal is to improve student

perormance and educational experience by applying high perormance

building criteria and the best possible building technology to schools.

Collarborative or High Perormance Schools (CHPS)

CHPS recommends Displacement Ventilation as the preerred air distribution method

and awards up to 4 CHPS points or its use.

Leadership in Energy and Environmental Design (LEED)

The United States Green Building Councils Leadership in Energy and Environmental

Design (LEED) program has a rating system specically designed or schools or which

displacement ventilation can earn points.


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Sotware Tools

Room Designer or Displacement

Ventilation

Our revolutionary Room Designer or Displacement

Ventilation allows a designer to select and lay outPrice displacement diusers based on drat risk

comort data.

The sotware calculates comort using ASHRAE

ormulae based on local air temperature and local

air velocity, responding in real-time to diuser

placement.

The sotware is specically designed to

accommodate school design criteria, including

ventilation rates.

Visit www.price-hvac.com/Sotware/

Roomdesigner to download Room

Designer today!

All-In-One Selection Sotware

Prices All-In-One Selection sotware allows an

engineer to perorm air volume calculations,

evaluate system perormance and select products,

including displacement ventilation diusers, with

speed and accuracy.

Visit www.price-hvac.com/Sotware/AIO/ to

download All-In-One today!

Price oers the best sotware tools in the HVAC industry or selecting

and evaluating displacement ventilation diusers as they apply to

schools.


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Price Engineers HVAC Handbook

The Most Comprehensive Guide to

HVAC Fundamentals

The Price Engineers Handbook is a compilation o the

engineering knowledge related to the application o air

distribution and noise control products and approaches

gained at Price over the past 60 years.

The Handbook contains chapters on Displacement

Ventilation and its applications, including liberal use o

examples and graphics to help illustrate and explain

concepts and systems.

Chapter 15: Displacement Ventilation

Chapter 16: Applications o

Displacement Ventilation

Contact your local Price sales representative to reserve

your copy.

Price Sustainable Building Website

The Price Sustainable Building Website is the ultimate

online resource or those looking to learn more about

sustainable HVAC technologies like displacement

ventilation.

The site eatures:

Product Inormation

Research Papers

Case Studies

Training Modules

Smoke Test Videos

Product Videos

Visit www.price-hvac.com/sustainable today!



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Resources and SupportPRCN: Price Research Center North

Prices state-o-the-art research laboratory, Price Research Center North, eatures the most advanced

displacement fow visualization chambers, testing acilities, and mock-up rooms in North America.

Flow visualizations and mock-ups allow designers to simulate eld conditions and evaluate system

perormance giving them condence that their space will perorm as expected in the eld.

Ask about our mock-up services on your next job, or better yet,

visit PRCN yoursel and tour the acilities.

Computational Fluid Dynamics Modeling

CFD provides a means to validate design beore

construction and gives condence that the system

will perorm as intended in the eld. Price has an

experienced and procient CFD team and we

encourage designers to work with us to validate

their designs.


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Applications Support

Price is a service oriented company and has a

dedicated Displacement Ventilation applications

team devoted to answering your questions quickly,

completely, and correctly. We are here to help!

Our applications team regularly provides

support on:

Model Selection

Layout Assistance

Calculation Assistance

On-site Training

On-site Perormance Validation

Price Training Programs and Webinars

The Price Training Programs (PTP) provides

Consulting and Design Engineers with the training

needed to speciy and select air distribution

equipment to best meet their design criteria. The

displacement course covers everything you need

to know about displacement products, including:

Overview o DV

Theory and Design Considerations

Displacement Products

PRCN and Engineering Support

Our webinars are another excellent way to learn

about specic topics while gaining proessional

development hours.

Visit www.price-hvac.com/ptp to register today!



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Grilles & Diusers CriticalEnvironments

Terminals &Controls

SustainableBuilding

Noise Control

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displacement ventilation in schools

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