design of air duct in hospital

8/10/2019 Design of Air Duct in Hospital

1/36

DESIGN OF AIR DUCT

DESIGN CONDITIONS:

Inside room conditions

Temperature ------------------------------------------------------DBCo22

------------------------------------------------------

WBCo16

Outside room conditions

Temperature ------------------------------------------------------

DBCo

34

------------------------------------------------------

WBCo27

Temperature of supply air ----------------------------------------------CO15

Mass of outside air,mo ----------------------------------------- Smof%10

Mass of recirculated air, mR ----------------------------------------- Smof%90

21


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Air Properties

From ASHRAE PSYCHROMETRIC CHART M!E!T!C p"#e $%

Outside room conditions WBCDBC oO 2732!

kg

kJh

kg

m

kg

kgW OO

da

v

O 6"#5$#9#"0$0199"03

===

Inside room conditions WBCDBC oO 1622!

kg

kJh

kg

m

kg

kgW OO

da

v

O 45$#4#"0$00#9"03

===

M"ss o& supp'( "ir mS

% &% &

srpa

s

SsrpaSs ttc

QmttcmQ

-'$-'

()ere*

Sm ' mass of supply air

pac ' specific )eat of air, KkgkJ +0062"1

rt ' iside room temperature, C22

st ' supply air temperature, C+15

T)erefore,

( ) sec66"32

15-220062"1

037"230 kg

KKkg

kJ

kW

mO

O

S =

=

M"ss o& outside "ir mO

RoS mmmmm $'' 41

22


3/36

()ere*

Sm ' mass of supply air, skg66"32

Rm ' mass of recirculated air, Smof%90

T)erefore,

( ) ( ) sec266"39"01sec66"329"01 kgkgmm SO ===

)o'ume &'o* r"te o& outside "ir )o

OOO mV '

()ere*

Om ' mass of outside air, skg266"3

O ' specific .olume of outside air, kgm3

#9#"0

T)erefore,

sec93"2#9#"0

sec266"3

33 m

kg

mkgVO =

=

M"ss o& recircu'"ted "ir m

R

OSRRoS mmmmmm $ =+=

()ere*


Om ' mass of outside air, sec266"3 kg

T)erefore,

sec39"29sec266"3sec66"32 kgkgkgmR ==

)o'ume &'o* r"te o& recircu'"ted "ir )R

iRR mV '

23


4/36

()ere*

Rm ' mass of recirculated air, skg39"29

i ' specific .olume of iside air, kgm3#4#"0

T)erefore,

sec93"24#4#"0

sec39"29

33m

kg

mkgVR =

=

Temper"ture o& "ir enterin# t+e AHU t,

From t+e &i#ure considerin# point ,

/y temperature alace,

S

ROoSROo

m

tmtmttmtmtm 4224 $

+==+

()ere*


Ot ' temperature of outside air, CO

34


4t ' iside air temperature, Co22


T)erefore,

( )( ) ( )( ) Ckg

CkgCkgt

OOO

56"23sec66"32

22sec93"2934sec266"32 =+=

C"p"cit( o& AHU -AHU

14 -' hhmQ SCDA

()ere*

24


5/36


4h ' et)alpy of air eteri t)e , kgkJ

1h ' et)alpy of air lea.i t)e , kgkJ

Ent+"'p( o& "ir enterin# t+e AHU 2h

From t+e &i#ure considerin# point ,

/y )eat alace,

S

ROo

SROo m

hmhm

hhmhmhm

4

224 $

+==+

()ere*


Oh ' et)alpy of outside air, kgkJ6"#5


4h ' et)alpy of recirculated air, kgkJ45


T)erefore,

( ) ( ) ( ) ( )kg

kJ

kg

kgkJkgkgkJkgh #"49

sec66"32

45sec93"296"#5sec266"34 =

+=

Ent+"'p( o& "ir 'e".in# t+e AHU 3h

( )S

TST

m

QhhhhmQ -$- 4334 ==

()ere*

25


6/36

TQ ' total )eat load, TkW22#"476


4h ' et)alpy of iside air, kgkJ45

T)erefore,

kg

kJ

kg

kW

kg

kJh T 42"30

sec66"32

22#"476-45

3 ==

T)us,

( ) TORorkWkg

kJkgQAHU 9#"1799"63242"30-#"49

sec66"32 =

=

)o'ume o& supp'( "ir )S

1' mV SS

()ere*


1 ' specific .olume of supply air, kgm3

From ASHRAE PSYCHROMETRIC CHART M!E!T!C p"#e $%

kgkJhDBCO 42"3015! 1 =

kg

m3

1 #24"0=

T)erefore,

( )( ) sec9"26#24"0sec66"323

3 m

kgmkgVS ==

26


7/36

AIR DUCT SI/ING

DESIGN CONDITIONS:

olume flo rate of supply air ----------------------------------- sec9"26 3m

uct dimesios ------------------------------------------------------( ' 4

8o" of uits ------------------------------------------------------2

8o" of rac) tae-off ---------------------------------------------5

8o" of outlet per rac) tae off ------------------------------------

4

Met)od of calculatio ------------------------------------------------------

:itti data

;lo, ier outer radii ratio -------------------------- 2"0

le, turs ad rac)es ----------------------------------- O90

27


8/36

)o'ume &'o* r"te o& supp'( "ir per 0r"nc+ t"1e2o&& -3

sec3#"55

sec9"26 33 mm

offTakBra!cho"#m$r

V

Q

S

B ===

)o'ume &'o* r"te o& supp'( "ir per out'et -O

sec345"1

4

sec3#"5- 33

mm

O#t%tsof"#m$r

offTakBra!chprAirS#pp%&ofRat'%o(Vo%#mQO ===

Duct Si4es

For t+e m"in duct &rom t+e &"n out'et to point O

:rom &i#ure 52, Pressure drop in str"i#+t circu'"r s+eet met"' ducts

R;:R


9/36

( )( ) 25"0

625"0

" 30"1$a

a$D f*

+=

()ere*

a ' H' )ei)t of t)e rectaular duct, m

' W' idt) of t)e rectaular duct, m

@ustituti, HW 4= to t)e eBuatio ao.e

( )( ) ( )( ) ( )( ) HHHHHWHHWD f* 0677"25430"15430"130"1 25"025"025"1625"0

25"0

625"02

25"0

625"0

" ===+

=

T)us,

*#atio!(orki!gDHf* =

"4#36"0

For t+e +ei#+t 'OH

( ) mmH'O 694"0436"14#36"0 ==

For t+e *idt+ 'OW

( ) mmW'O 7#"2694"04 ==

For t+e si4e o& duct, 'OA

22 193093"17#"2694"0 mmmm+mW+HA 'O'O'O ====

Run O to A t*o 0r"nc+ t"1e 8 o&& supp'ied

29


10/36


R;:R


11/36

( ) mmHOB 6316"0306"14#36"0 ==

( ) mmWOB 52"2324"04 ==

259"152"26316"0 mm+mW+HA OBOBOB ===

Run 3 to C 9 3r"nc+ t"1e 8 o&& supp'ied


R;:R


12/36

Run C to D 0r"nc+ t"1e 8 o&& supp'ied


R;:R


13/36

mD f* 756"0" =

T)erefore,

( ) mmHCD 3656"0756"04#36"0 ==

( ) mmWCD 46"13656"04 ==

2533#"046"13656"0 mm+mW+HA CDCDCD ===

3r"nc+ out'et dimensions

Note:

@ice t)e umer of outlets i eac) rac) tae C off are eBual for t)e )ole

system, oly oe rac) tae C off ill e cosidered i computi for t)e duct

dimesios ad t)e .alues otaied ill e replicated i all se.e %7& rac) outlets"

Considerin# 3r"nc+ T"1e 8 o&& A

Run A 8 ; out'ets supp'ied


R;:R


14/36

( ) mmHA 3656"0756"04#36"01 ==

( ) mmWA

4624"13656"041

==

2

111 5347"04624"13656"0 mm+mW+HA AAA ===

Run ; 8 , 9 out'ets supp'ied


R;:R


15/36


16/36

sec937"1393"1

sec9"262

3

0

0 mm

m

A

Q

'

''A ===

()ere*

'OQ ' 26"9 sm3

'OA ' 1"932

m

Run A23 AB

sec53"1359"1

sec52"212

3

mm

m

A

Q

AB

AB

AB ===

()ere*

ABQ ' 21"52 sm3

ABA ' 1"592

m

Run 3 2C BC

sec26"12

316"1

sec14"162

3

m

m

m

A

Q

BC

BC

BC ===

()ere*

BCQ ' 16"14 sm3

BCA ' 1"3162

m

Run C 2 D CD

sec325"12#73"0

sec76"102

3

mm

m

A

Q

CD

CD

CD ===

()ere*

CDQ ' 10"76 sm3

36


17/36

CDA ' 0"#732

m

Run D 2 E D,

sec07#"10533#"0

sec3#"52

3

mm

m

A

Q

D,

D,D, ===

()ere*

D,Q ' 5"3# sm3

D,A ' 0"533#2m

3r"nc+ Out'ets

Note:

@ice t)e umer of outlets i eac) rac) tae C off are eBual for t)e )ole

system, oly oe rac) tae C off ill e cosidered i computi for t)e duct .elocities

ad t)e .alues otaied ill e replicated i all se.e %7& rac) outlets"

Run A 2 ; 1A

sec06"105347"0

sec3#"52

3

1

1

1 mm

m

A

Q

A

A

A ===

()ere*

1AQ ' 5"3# sm3

1AA ' 0"53472

m

Run ; 2 , 12

sec#02"#45#4"0

sec035"42

3

12

12

12 m

m

m

A

Q===

37


18/36

()ere*

12Q ' 4"035 sm3

12A ' 0"45#42

m

Run , 2 9 23

sec57"#314"0

sec69"22

3

23

23

23 mm

m

A

Q===

()ere*

23Q ' 2"69 sm3

23A ' 0"3142

m

Run 9 2 34

sec77"7173"0

sec345"12

3

34

34

34 mm

m

A

Q===

()ere*

34Q ' 1"345 sm3

34A ' 0"173 2m

Determin"tion o& Pressure Drops

3#


19/36

Considerin# t+e Run4321 AAAA'OA

Run FO Str"i#+t Duct

( ) ( ) )am)amm)-) 'O'O 95#"65"163#7"4 ===

Run O Turn

:rom &i#ure 5 8 7 Pressure 'osses in rect"n#u'"r e'0o*sR;:R


20/36

,= 1#"17# 1"2041

@ice t)e temperature of t)e supply air is at 15

0

?, y iterpolatio,

! 15 ?' 1"2254 D m3

T)erefore,

( ) ( ) ( ) ( ) ( ) )amkgmv) airOBOT 75"292

2254"1sec937"1325"0

225"0

322

===

Run OA Str"i#+t Duct

( ) ( ) )am)amm)-) OAOA 654"155"14360"10 ===

3r"nc+ t"1e 8 o&& A Turn

:rom &i#ure 5 8 7 Pressure 'osses in rect"n#u'"r e'0o*sR;:R, 13"937 m D sec

T)erefore,

( ) ( )

( ) ( ) ( )

)a

mkgmv

)

airOB

AT 75"292

2254"1sec937"13

25"0225"0

322

===

Run AA; Str"i#+t Duct

( ) ( ) )am)amm)-)AAAA

255"35"11703"211 ===

40


21/36

Run AA

,

Str"i#+t Duct


6623"#5"17749"522 ===

Run AA9 Str"i#+t Duct


4195"145"1613"933 ===

Run AA Str"i#+t Duct


6951"1#5"14634"1244 ===

T)erefore,

( )

)a)

)a

)))))))))

'OBA

AAAAAAAAATOAOT'O'OA

1439"127

6951"1#4195"146623"#225"375"29654"1575"2995#"6

7

4 4321

=+++++++=

+++++++=

Considerin# t+e Run 4321 BBB'OBB

41


22/36


( ) ( ) )am)amm)-) 'O'O 95#"65"163#7"4 ===

Run O Turn

:rom &i#ure 5 8 7 Pressure 'osses in rect"n#u'"r e'0o*sR;:R/, 13"937 m D sec

T)erefore,

( ) ( ) ( ) ( ) ( ) )amkgmv) airTOTO 75"292

2254"1sec937"1325"0

225"0

322

===

3r"nc+ t"1e 8 o&& A Duct Str"i#+t T+rou#+

:rom E6u"tion 5 8 ;5R;:R


23/36

( )( )

( ) ( )( )

)a)

m)

V

VV)

ADST

ADST

AB

OAairOAADST

03#"0

937"13

53"1314"0

2

2254"1sec53"13

14"02

22

22

=

=

=

Run O3 Turn


T)erefore,

( ) ( ) ( ) ( ) ( ) )amkgmv) airTOBTOB 04"2#2

2254"1sec53"1325"0

225"0

322

===

Run O3 Str"i#+t Duct

( ) ( ) )am)amm)-) OBOB 204"275"1136"1# ===

43


24/36

Run 33; Str"i#+t Duct

( ) ( ) )am)amm)-)BBBB

5442"35"1362#"211 ===

Run 33, Str"i#+t Duct


9511"#5"19674"522 ===

Run 339 Str"i#+t Duct

( ) ( ) )am)amm)-) BBBB 70#"145"1#055"933 ===

Run 33 Str"i#+t Duct


9#3#"1#5"16559"1244 ===

T)erefore,

(

)a)

))))))))))

'OBA

BBBBBBOBTOBDSTATO'OBBB'OBB

1771"13#

170#"149511"#5442"3204"2704"2#03#"075"2995#"6

7

3214321

=++++++++=

++++++++=

Considerin# t+e Run 4321 CCC'OCC

44


25/36


( ) ( ) )am)amm)-) 'O'O 95#"65"163#7"4 ===

Run O Turn


T)erefore,

( ) ( ) ( ) ( ) ( ) )amkgmv) airTOTO 75"292

2254"1sec937"1325"0

225"0

322

===


45


26/36



27/36

T)erefore,

( ) ( ) ( ) ( ) ( ) )amkgmv) airTOCTOC 0234"232

2254"1sec26"1225"0

225"0

322

===

Run OC Str"i#+t Duct

( ) ( ) )am)amm)-) OCOC 754"3#5"1#36"25 ===

Run CC; Str"i#+t Duct

( ) ( ) )am)amm)-)CCCC

623"35"14153"211 ===

Run CC, Str"i#+t Duct


029#5"95"10199"622 ===

Run CC9 Str"i#+t Duct


7#7"145"1#5#"933 ===

Run CC Str"i#+t Duct


0626"195"170#4"1244 ===

T)erefore,

47


28/36

)a)

)a

)))))))))

CCC'OCC

CCCCOCTOCDSTBDSTATO'OCCC'OCC

05#3"145

0626"197#7"14029#5"9

623"3754"3#0234"2303245"003#"075"2995#"6

4321

214321

=

+++

++++++=

++++++++=

Considerin# t+e Run 4321 DDD'ODD


( ) ( ) )am)amm)-) 'O'O 95#"65"163#7"4 ===

Run O Turn

4#


29/36


T)erefore,

( ) ( ) ( ) ( ) ( ) )amkgmv) airTOTO 75"292

2254"1sec937"1325"0

225"0

322

===




30/36

( )( )

( ) ( )( )

)a)

m)

V

VV)

BDST

BDST

BC

OBairBCBDST

03245"0

53"13

26"1214"0

2

2254"1sec26"12

14"02

22

22

=

=

=

3r"nc+ t"1e 8 o&& C Duct Str"i#+t T+rou#+

:rom E6u"tion 5 8 ;5R;:R, 12"325 m D sec

50


31/36

T)erefore,

( ) ( ) ( ) ( ) ( ) )amkgmv) airTODTOD 26#"232

2254"1sec325"1225"0

225"0

322

===

Run OD Str"i#+t Duct

( ) ( ) )am)amm)-) ODOD 304"505"1536"33 ===

Run DD; Str"i#+t Duct

( ) ( ) )am)amm)-)DDDD

9#96"25"19931"111 ===

Run DD, Str"i#+t Duct


#56"#5"1904"522 ===

Run DD9 Str"i#+t Duct


9579"125"163#6"#33 ===

Run DD Str"i#+t Duct


7746"165"11#31"1144 ===

T)erefore,

51


32/36

)a)

)a

)))))))))

DDD'ODD

DDODTODDSTDDSTBDSTATO'ODDD'ODD

932"151

7746"169579"12#56"#9#96"2

304"5026#"23001046"003245"003#"075"2995#"6

4321

14321

=

++++

++++++=

+++++++=

Considerin# t+e Run 4321 ,,,'O,,


52


33/36

( ) ( ) )am)amm)-) 'O'O 95#"65"163#7"4 ===

Run O Turn


T)erefore,

( ) ( ) ( ) ( ) ( ) )amkgmv) airTOTO 75"292

2254"1sec937"1325"0

225"0

322

===




34/36

3r"nc+ t"1e 8 o&& 3 Duct Str"i#+t T+rou#+



35/36


36/36

Run EE, Str"i#+t Duct

( ) ( ) )am)amm)-),,,,

316"#5"15437"522 ===

Run EE9 Str"i#+t Duct

( ) ( ) )am)amm)-),,,,

6939"125"14626"#33 ===

Run EE Str"i#+t Duct

( ) ( ) )am)amm)-),,,,

#"165"120005"1144 ===

T)erefore,

)a)

)))))))))

,,,'O,,

O,TO,DSTDDSTCDSTBDSTATO'O,,,'O,,

122"156

#"166939"12316"#295"3

#54"61557"15#27"0001046"003245"003#"075"2995#"6

4321

4321

=

++++

+++++++=

+++++++=

design of air duct in hospital

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