ASHRAE Journal - June 2019 - 36

TECHNICAL FEATURE 

FIGURE 9  Contours of temperature at the central plane for non-isothermal conditions with heat source near the ceiling show uniform temperature distribution at very low sup-

ply airflow rate and decreasing thermal gradient between the cold air jet and the surrounding air with increasing supply airflow rate.

b) 400 cfm (188.8 L/s)

a) 200 cfm (94.4 L/s)

c) 600 cfm (283.2 L/s)

d) 800 cfm (377.6 L/s)

parameter (n) and the computed value is presented
below.
	
	

A Arr = n

Q

V Ts (l ++ w ) 	(1)
3

2g
n=
	
ρcp

where
Q	
V	

(1a)

=	 sensible cooling load in the space, Btu/h (W)
=	discharge velocity of the supply air from a
laminar diffuser, ft/min (m/s)
Ts	
=	supply air temperature, R (K),
l and w	=	length and width of a laminar diffuser array,
respectively, ft (m)
g	
=	gravitational acceleration 32.17 ft/s2 (9.81 m/s2)
ρcp	
=	heat capacity of the air, 0.018 Btu/ft3·R
(1206 W/m3·K)
The calculated value of n from the parameters listed
above using the Equation 1a is as follows:
36

A S H R A E J O U R N A L   a s h r a e . o r g   J U N E 2 0 19

Example:
Consider a hospital operating room (OR) with a 3 ×
3 array of 2 × 4 ft (0.6 × 1.2 m) laminar diffusers with
a sensible cooling load of 7541 Btu/h (2210 W) and the
supply air temperature of 67°F (19.4°C). Compare the
Archimedes number for 15 and 30 fpm (0.1 and 0.2 m/s)
discharge velocities.
For 15 fpm (0.1 m/s)
	

A Arr =

214, 467 × 7, 541

(15) × (67 + 459.7) × 3( 2 + 4)
3

= 50.5

For 30 fpm (0.2 m/s)
	

A Arr =

214, 467 × 7, 541

(30) × (67 + 459.7) × 3( 2 + 4)
3

= 6.3	

	


https://www.ashrae.org/

ASHRAE Journal - June 2019

Table of Contents for the Digital Edition of ASHRAE Journal - June 2019

Contents
ASHRAE Journal - June 2019 - Intro
ASHRAE Journal - June 2019 - Cover1
ASHRAE Journal - June 2019 - Cover2
ASHRAE Journal - June 2019 - 1
ASHRAE Journal - June 2019 - Contents
ASHRAE Journal - June 2019 - 3
ASHRAE Journal - June 2019 - 4
ASHRAE Journal - June 2019 - 5
ASHRAE Journal - June 2019 - 6
ASHRAE Journal - June 2019 - 7
ASHRAE Journal - June 2019 - 8
ASHRAE Journal - June 2019 - 9
ASHRAE Journal - June 2019 - 10
ASHRAE Journal - June 2019 - 11
ASHRAE Journal - June 2019 - 12
ASHRAE Journal - June 2019 - 13
ASHRAE Journal - June 2019 - 14
ASHRAE Journal - June 2019 - 15
ASHRAE Journal - June 2019 - 16
ASHRAE Journal - June 2019 - 17
ASHRAE Journal - June 2019 - 18
ASHRAE Journal - June 2019 - 19
ASHRAE Journal - June 2019 - 20
ASHRAE Journal - June 2019 - 21
ASHRAE Journal - June 2019 - 22
ASHRAE Journal - June 2019 - 23
ASHRAE Journal - June 2019 - 24
ASHRAE Journal - June 2019 - 25
ASHRAE Journal - June 2019 - 26
ASHRAE Journal - June 2019 - 27
ASHRAE Journal - June 2019 - 28
ASHRAE Journal - June 2019 - 29
ASHRAE Journal - June 2019 - 30
ASHRAE Journal - June 2019 - 31
ASHRAE Journal - June 2019 - 32
ASHRAE Journal - June 2019 - 33
ASHRAE Journal - June 2019 - 34
ASHRAE Journal - June 2019 - 35
ASHRAE Journal - June 2019 - 36
ASHRAE Journal - June 2019 - 37
ASHRAE Journal - June 2019 - 38
ASHRAE Journal - June 2019 - 39
ASHRAE Journal - June 2019 - 40
ASHRAE Journal - June 2019 - 41
ASHRAE Journal - June 2019 - 42
ASHRAE Journal - June 2019 - 43
ASHRAE Journal - June 2019 - 44
ASHRAE Journal - June 2019 - 45
ASHRAE Journal - June 2019 - 46
ASHRAE Journal - June 2019 - 47
ASHRAE Journal - June 2019 - 48
ASHRAE Journal - June 2019 - 49
ASHRAE Journal - June 2019 - 50
ASHRAE Journal - June 2019 - 51
ASHRAE Journal - June 2019 - 52
ASHRAE Journal - June 2019 - 53
ASHRAE Journal - June 2019 - 54
ASHRAE Journal - June 2019 - 55
ASHRAE Journal - June 2019 - 56
ASHRAE Journal - June 2019 - 57
ASHRAE Journal - June 2019 - 58
ASHRAE Journal - June 2019 - 59
ASHRAE Journal - June 2019 - 60
ASHRAE Journal - June 2019 - 61
ASHRAE Journal - June 2019 - 62
ASHRAE Journal - June 2019 - 63
ASHRAE Journal - June 2019 - 64
ASHRAE Journal - June 2019 - 65
ASHRAE Journal - June 2019 - 66
ASHRAE Journal - June 2019 - 67
ASHRAE Journal - June 2019 - 68
ASHRAE Journal - June 2019 - 69
ASHRAE Journal - June 2019 - 70
ASHRAE Journal - June 2019 - 71
ASHRAE Journal - June 2019 - 72
ASHRAE Journal - June 2019 - 73
ASHRAE Journal - June 2019 - 74
ASHRAE Journal - June 2019 - 75
ASHRAE Journal - June 2019 - 76
ASHRAE Journal - June 2019 - 77
ASHRAE Journal - June 2019 - 78
ASHRAE Journal - June 2019 - 79
ASHRAE Journal - June 2019 - 80
ASHRAE Journal - June 2019 - Cover3
ASHRAE Journal - June 2019 - Cover4
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_XCODFR
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_QSLFGO
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ILKVNM
https://www.nxtbook.com/nxtbooks/ashrae/ashraemexico_2021
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_OPDJKD
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_VJKSRY
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SDHUTC
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_JPPKRR
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SDLTTH
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_CKLLES
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_SLDOX
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_HJETUK
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_OLUHGE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2020october
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2020october_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ZERDGH
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_QVMNEO
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_RTPOKE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_BBATRE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_STUBMW
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_TPEMPE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_JNMKDS
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_FBTTPA
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_WQMMNE
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_TVBRYN
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_showguide2020
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_KTUZMA
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_ABEDGD
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201910
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201909
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2019septmeber_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2019september
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201908
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201907
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201906
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201905
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201904
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2019april
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201903
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2019march
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201902
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201901
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_showguide2019
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2018december
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2018november
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2018fall_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2018fall
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_2018october
https://www.nxtbook.com/nxtbooks/ashrae/ashraemexico_2018
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201810
https://www.nxtbook.com/nxtbooks/ashrae/ashraeinsights_201806
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201805
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201804
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201803
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201712
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201711
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201710
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2017fall_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2017fall
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201709
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201705
https://www.nxtbook.com/nxtbooks/ashrae/ashrae_meetinginsert_201610
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2016fall_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2016fall
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_acrexindia
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2015summer_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_amca_2015summer
https://www.nxtbook.com/nxtbooks/amca/2014summer2
https://www.nxtbook.com/nxtbooks/amca/2014summer
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_acma_2014summer
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201311
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201309
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_acmasupp_2013fall
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201305
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201303
https://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2013winter
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201211
https://www.nxtbook.com/nxtbooks/ashrae/achr_expo_mexico2012
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201209
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201208_v3
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201208_v2
https://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2012summer
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201205
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201203
https://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2012winter
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201111_v2
https://www.nxtbook.com/nxtbooks/ashrae/ashraejournal_201109_v2
https://www.nxtbook.com/nxtbooks/ashrae/pubcatalog_2011summer
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201105
https://www.nxtbook.com/nxtbooks/ashrae/meetingplanner_201103
https://www.nxtbookmedia.com