P r o c e s s H e a t G r o u p �

M a j o r C h a l l e n g e s �

L e c t ure 2 �

22.033 / 22.33 – N uc l e a r E ngi ne e ri n g D e s i gn P r oj e c t �

S e pt e m be r 14, 2011 �

T h e T h re e C h a l l e n g e P r o b l e m s �

He a t e x ch a n g er ( H x ) d e s ig n He a t tran s p ort

He a t s tora g e (if n ec e s s ary )

F i rs t , S o m e N o m e n c l a t u r e �

S e n s i b le h e a t in g – te m pe ra ture c h a ng e

. �

Q  m c p  T

L a te nt he a ti n g – p ha s e c h a ng e

.

Q  m h f g

Bo n d e n erg y s to r a g e – e n th alp y o f c h e mic a l re a c t io n s

W h e r e D o W e F i n d Th e m ? �

Courtesy of the Generation IV International Forum. Used with permission.

So u r ce: ht t p : / / w w w . g e n - 4 .o r g / T ec h no l o gy / s y s t em s / gf r .h t m

H e a t E x c ha n g e rs – F u n d a m e n t a l P a r a m e t e rs

H x e f f e c t i ve ne s s (ε )

– M e a s ure s ho w m uc h he a t i s t ra ns f e rre d c om pa re d t o h ow m uc h i s pos s i bl e

ε= 1 is ide a l, bu t

© American Institute of Physics. All rights reserved. This content is excluded from our Creative Commons license. For more information, see http://ocw.mit.edu/fairuse .

Sou r ce: D ean B a r t l et t . “ T h e Fun dam ent al s o f H eat E xc ha nge r s ” T h e I nd us t r i al Phy s i ci s t , A I P, p . 20 ( 1 996 )

p r a c t i c a l l y i m pos s i bl e ( bi g H x)

H e a t E x c ha n g e rs – F u n d a m e n t a l P a r a m e t e rs

Diagram of heat exchanger removed due to copyright restrictions. See lecture video for details.

** *Sou r c e: R am es h K . S h a h , D u s an P. Se k ul i c. Fun dam ent a l s of H eat E xch a n ger D es i gn . J o hn W i l ey & Son s , I nc. p. 102 ( 20 03 ) .

H e a t E x c ha n g e rs – F u n d a m e n t a l P a r a m e t e rs

Q = U ·A ·F·Δ T lm

Q = H ea t t ra n s fe r ra te (W) �

U = T h erm a l co n d u c t a n c e (W/m 2 K ) �

A = H ea t t ra n s fe r a re a (m 2 ) �

Δ T l m = L og me a n te mp e r a tu re d i ffe ren c e (K ) �

F = Fac to r (fo r fl o w c o n f ig u ratio n )

H e a t E x c ha n g e rs – L o g M e a n T e m p e r a t u r e D i f f e re n c e (L M T D )

 T 

  T H   T C 

l m   T 

l n   H 

 T C 

L M T D i s a good m e a s ure of t he e f f e c t i ve ne s s of s i m l a r he a t �

e xc ha nge r s o f di f f e r e nt de s i gns �

O f t e n, L M T D (c ount e r fl ow ) > L M T D (pa r a l l e l f l ow ) �

H e a t E x c ha n g e rs – F i n d i n g K e y P a r a m e t e rs

F i gure 1 – A bi g, c om p l i c a t e d h e a t � e x c ha nge r c ha rt �

Sou r ce : W o l v er i n e T u b e H ea t T r an s f e r D a t a B o o k , p . 93 ( 2 00 1 ) , a cce s s e d a t h t t p : / / w w w .w l v .c om / p r o d u ct s / d a t a bo o k

/ c h 2_ 5 .pd f

Courtesy of Wolverine Tube, Inc. Used with permission.

H e a t E x c ha n g e rs – F u n d a m e n t a l P a r a m e t e rs

F or a l l f l ow c onf i gur a t i ons

Hx is “balanced” when C* = 1

N T U = N um be r of T ra ns fe r U ni t s

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** *Sou r c e: R am es h K . S h a h , D u s an P. Se k ul i c. Fun dam ent a l s of H eat E xch a n ger D es i gn . J o hn W i l ey & Son s , I nc. p. 116 , 11 8- 11 9 ( 2 00 3) .

H x F l o w T y p e s �

Image by MIT OpenCourseWare.

** * After R am es h K . S h a h & D u s an P. Se k ul i c. Fun dam ent a l s of H eat E xch a n ger D es i gn . J o hn W i l ey & Son s , I nc. ( 2 003 ) .

P a r a l l e l F l o w v s . C o u n t er f l o w �

Parallel-flo w

Count er-flow

t pi

t pi

 t i

 t i

t po

 t o

t

t po

so

t so  t o

t si

t si

Image by MIT OpenCourseWare.

See ht t p: / / w w w .e ng i n ee r i n gt o o l b o x . c o m / ar i t h m e t i c- l o g a r i t h m i c- m ea n- t em p er at u r e- d _4 3 6 .ht m l

H x F l o w C o n f i g u ra t i o n s �

Image by MIT OpenCourseWare.

After R a m es h K . Sh a h , D u s an P . Se k ul i c. Fun dam ent a l s of H eat E xchang er D es i gn . J o hn W i l ey & Son s , I nc. ( 2 003 ) .

H x F l o w C o n f i g u ra t i o n s - T u b u l a r �

Courtesy of Wikipedia User:H Padleckas. Used with permission. Courtesy of Harlan Bengtson. Used with permission.

S ourc e : W i ki m e di a Co m m ons

H x F l o w C o n f i g u ra t i o n s – P l a t e

P l a t e (br a z e d) t ype S pi r a l t ype

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© Jooshgostar Equipments Manufacturing Company (JEMCO). All rights reserved. This content is excluded from our Creative Commons license. For more information, see http://ocw.mit.edu/fairuse .

S ourc e : ht t p: / / www.alfa-biz.com/Gasketed-Plate-Heat- Exchanger.asp S ourc e : ht t p: / / w w w .hi w t c .c om / ph o t o/ pr oduc t s / 16/ 02/ 14/ 21470.j p g

H x H e a t T r a n s f e r M e c h a n i s m s �

Oth er d es ig n p a r a m ete rs s h o uld la rge ly d e te r m in e this c h o ice

Image by MIT OpenCourseWare.

After R a m es h K . Sh a h , D u s an P . Se k ul i c. Fun dam ent a l s of H eat E xchang er D es i gn . J o hn W i l ey & Son s , I nc. ( 2 003 ) .

H e a t E x c ha n g e rs - Q u e s t i o n s �

W h at t y pe t o u se ? �

W h at w or ki n g f l ui ds? �

W h at g e o m e t r y? Fl ow co nsi d e r a t i o ns? L am i n a r o r �

t u r bul ent ?

W h er e i s t h e t r adeof f b e t w e en cost & pe r f or m a n c e? M a t e r i a l s con c er n s?

S e e a l s o : T . K u p p a n . “ H e a t e x c h a n g e r d e s i g n h a n d b o o k . ” a n d S o m , “ I n t r o d u c t i o n T o H e a t T r a n s f e r .

H e a t T r a n s p o rt �

M a i n p r o b le m: G e t p roc e s s h e at f ro m th e re a c t o r to th e h y d rog e n & b iofu e ls p l a n ts

Ho w? M us t c o n s i d e r:

– Te m p er at ur es

– Loss e s

– Fl ow r a t es

– Fl ow t r a n si e n t s

H e a t T r a n s p o rt – L o n g D i s t a n c e �

Ho w to m od e l it?

– Ther m al r esi st ance s

– FEM

– Loo p a n a l ys i s

Ho w to p u mp it? F o rc ed ? Gra v it y ?

Dis tan c e fro m Rx to H 2 , b io fue l p la nt is o ne o f t h e m o s t i m p o rt a n t p a ram e t e rs

H e a t T r a n s p o rt - Q u e s t i o n s �

Wh a t a r e t h e c o n s t ra in t s ? (T H -R x , T C- H 2 , T C -b i o ) Ho w fa r d oe s th e h e a t h av e to g o ?

Wh e r e t o t a k e th e h e at f ro m ?

Ho w to tran s p o r t i t?

Ho w to m od e l it? W h at/w he re a re lo s s e s ? S h o uld s o m e o f it b e s tore d ...

H e a t S t o r a g e �

He a t s tora g e is a w a y to b ala n c e o ut l o a d in s tab ilit ie s ( c a p ac iti v e effe c t )

– St or e som e h e at t o r u n t ur bi n e s a n d/ or pr o duct f ac t o r i es du r i ng t r ansi ent s

– C an hel p a v oi d o r del ay p l ant s l oad- du m pi n g or l o a d - f ol l o w i n g

M u s t b ala n c e b en e fi ts ga in e d v s . h e at los t b y s to rag e

H e a t S t o r a g e – E l e c t r i c a l A n a l o g y �

S o u rc e L o a d, l o s s e s

s w i t c h ( t ra ns p or t ,

di s s i pa t i ve , hydr a ul i c ) �

I

Re a c t or H e a t s t or a ge

P ow e r ( c u rre nt )

Courtesy of Prof. Eric C. Toolson. Used with permission.

s ys t e m

I m age s ou r ce: ht t p : / / w w w .un m .e d u/ ~ t o ol s on / r c_ci r cui t .ht m l

H e a t S t o r a g e T e c h n o l o g i e s �

S e n s i b le h e a t s t o ra ge

– Si m pl y a p pl y h ot f l ui d t o a m a t er i a l , r eve r se f l ow w hen r e qu i r e d

L a te nt he a t s to r a g e

– U ses phase chang e m at er i a l s ( PC M s) �

– D ependen t o n m el t i ng p oi n t , hea t of f u si on

Bo n d e n erg y s to r a g e

– Dep e n d ent on react i on t em p eratu re, ent h a l p y

H e a t S t o r a g e – S e n s i b l e H e a t

E xa m pl e : H ot g a s o n a l um i na f l ui d i z e d b e d

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S o u r c e : R . S h i n n a r e t a l . “ A n o v e l s t o r a g e m e t h o d f o r

c o n c e n t r a t i n g s o l a r p o w e r p l a n t s a l l o w i n g o p e r a t i o n a t h i g h t e m p e r a t u r e . ” D o E P r e s e n t a t i o n , B o u l d e r , C O ( 2 0 1 1 ) .

H e a t S t o r a g e – S e n s i b l e H e a t �

Oth er p r o p o s ed & de m o ns tra t e d s to r a g e �

m e d i a : M o lten s a lt, c on c rete

Thermocline test at Sandia National Laboratories

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C on c r e t e T E S a t U . S t ut t ga rt

See h t t p: / / w w w .nr e l .gov / cs p / t r o ugh net / t h er m al _ener gy_s t or age.ht m l

H e a t S t o r a g e – P h a s e C h a n g e M a t e ri a l s

S o u r c e : M . D e m i r b a s . “ T h er m al E n er g y St or a g e a nd P h as e C ha nge M a t e r i a l s : A n Ov e r v i e w .” E n er g y So u r c es , Par t B , 1: 85–95, 2 0 06.

M or e c om pa c t La yout c a n be m or e

c om pl i c a t e d

S a l t s c a n b e c or r os i ve Gr a phi t e f oi l s h a ve

be e n u s e d t o

i m p r o ve he a t

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s pr e a di ng

H e a t S t o r a g e – B o n d E n e r g y �

Ab s o r b /R ele a s e c he m ica l e n e rgy by s h ifti n g c h e mic a l e q uilib r iu m re ac tio ns

– C h ange t em per at u r e, p r essu r e

– Exam pl es: hy dr at i on , hy dr i di n g, am m on i a / sal t r ea ct i on s

– C h em i cal r e act i on sh oul d b e r ev e r si bl e

H e a t S t o r a g e – Q u e s t i o n s �

Wh a t tem p era tu re(s ) is /are re q u i re d ? �

Wh a t ma te ri a ls to u s e ? �

Wh a t c ap a c i ty t o us e ? (k Wh , M W h, G w h) �

Ho w d o es co s t s c a l e with s ize ? � Wh a t a r e l o s s ra tes & pa th wa y s ? � Wh e n wo u ld it b e u s ed , if a t a ll ? � Wh e r e wo u ld it b e loc a te d? �

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22.033 / 22.33 Nuclear Systems Design Project

Fall 20 11

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