AMCA InMotion - September 2019 - 17

3

Q (m /s)

1.6

velocities of 1,969, 2,953, and 3,937 fpm (10, 15, and 20

1.4

m/s) and discharge angles of 10, 15, and 20 degrees outward

1.2

and for doors at different open angles with and without

1.0

people in the doorway.
At its highest operating point, with a discharge velocity

0.8

of 3,937 fpm (20 m/s), a 20-degree outward discharge

0.6

angle, and a person in the doorway, the air curtain outper0.4

formed the vestibule within the pressure-difference range

0.2

of −0.028 in. wc to 0.217 in. wc (−7 Pa to 54 Pa) (Figure 4).
Based on the air-curtain correlations obtained from the
CFD portion of the study, whole-building simulations were

0.0
-2

0

conducted using two methods of calculating inﬁltration:
the ASHRAE method,6,3 which uses design pressure values,

A strip mall and an outpatient healthcare facility were
selected as additional reference buildings. Energy simula-

basis in climate zones 3 to 8 when compared with vestibules

6

8

10

14

12

16

18
20
ΔP (Pa)

Single door (CFD)
Single door (Yuill, 1996)
Vestibule (Yuill, 1996)
Air curtain -9.1 m/s
(simulation correlation)
Air curtain -13.75 m/s
(simulation correlation)

Air curtain - 13.75 m/s
(experiment)
Air curtain - 9.1 m/s
(experiment)
Single door (experiment)
Air curtain - 13.75 m/s (CFD)
Air curtain - 9.1 m/s (CFD)

inﬁltration data obtained through airﬂow simulations.

air curtains saved energy on a national-weighted-average

4

-0.4

and the CONTAM to EnergyPlus method, which uses hourly

tions using both methods of calculating inﬁltration showed

2

-0.2

FIGURE 3. Comparison of experimental and
CFD-simulation data for air curtain and
single door.
Q (m3/s)

and in climate zones 1 and 2 when compared with single
doors. Air curtains with a minimum velocity projection
of 400 fpm (2 m/s) at the ﬂoor were found to signiﬁcantly

5
3

reduce total annual inﬁ ltration through entrance doors
1

when compared with vestibules and single doors. Where
testing in accordance with ANSI/AMCA Standard 220,

-30

Laboratory Methods of Testing Air Curtain Units for Aerodynamic

-10

0
-1

10

20

30

40

50

60

Air curtain (20 m/s, 20° out)

Performance Rating, is required, this velocity projection is

-3

the minimum performance requirement for compliance
with both ANSI/ASHRAE/IES 90.1 and the IECC.

The Impact of Wind on Air-Curtain Performance

-20

∆P (Pa)

-5

Air curtain (20 m/s, 20° out),
person in the doorway
Vestibule (Yuill, 1996)
Single door (Yuill, 1996)

FIGURE 4. Inﬁltration and exﬁltration
characteristics.

In the third AMCA-commissioned study, "Wind Effects
on Air Curtain Aerodynamics Performance,"7 completed

University's boundary-layer wind tunnel was utilized for

in March 2018, a wind generator was built to create a

sub-scale testing of varying wind direction.

1,969-fpm (10 m/s) wind ﬁeld directly in front of a large-

Two tests were conducted to evaluate the impact of

scale chamber equipped with an air curtain. Because of

wind on the air curtain:

space limitations in the test laboratory, the wind generator

■

The overall-performance test focused on air-curtain

had to be placed close to the chamber and could produce

performance with variable inﬁltration rates (or building

only a uniformly distributed velocity of 787 fpm (4 m/s).

pressure) and constant wind speed. The air curtain

To complement the wind-generator tests, Concordia

was tested on the large-scale chamber with discharge

w w w. a m c a .o r g

20 19 A M CA i n m o t i o n

17
http://www.amca.org
AMCA InMotion - September 2019

Table of Contents for the Digital Edition of AMCA InMotion - September 2019
