Download Psychrometric Analysis and Thermodynamics of Cooling Systems and more Exams Engineering in PDF only on Docsity!
nrN.
Iildusfiial Energr l4arywcnf
$ring
?006, Srsm #l
ldarth ?.I,?,W
q\
UF-ID#:
READ THESE INSTR{,FCTIOF.IS CAREFIJLLY1 I^ I
,.,
^I?rereae
10 quctioru,^ You^ have^ 1,5^ buretomwer^ ful
I
--->'
essume<{Z6O hotlE
esr$r
untep o'eeryise sp€cifi€d.
${ake any^ engineering^ assumptiffi^
you (^) may have fo makf b* stab
them clarly. (Thfu^ is^ ourversion^ of^ a^ disctaimer)^
Afiachsd to fre €Drarn is^ a Prychrometic^ ctrut
Foint rnnlts for qtmtiurs^ are listed.^ Frytial credit^ will^ be^ aum&d^
for
ffitain
Broblenns
for legiblc"^ but^ iuamre^ urort.^
If we cdnnrrt euiitt
de#s yM,^ ws, if wifr be^ wrfudrangt^ Yo*^
*at$ thow oII ar.
I have not reseiv$ any" r:naufhorized help during^ thie^ examination:
sigreare
l->
tl Boi*ts^
crch)
e-
t5 Foin€)
i
peirifui
{7foin$
tacil)
hrring t}le Wint€r rrlontftr,^ tk^ Refu^ Unien^
has it$ Air l{flndlss blowine ab at lO,Sg^ ft3/min
61 a i€ffrp€rsinre of B5"F^ and 4tFfa relative^ humidify.^ Furfng^ tfie wmmer,^
asd ta redltce
humidifv- the lfuilding ust be^ $bol€d^ ts 6"F,
]
a) Hcvrr TmlT,v^ tens^ ufcoulingare^ ne*Uf
'oi
If the cost of energy is $O.SsrkWIr, rind^ the^ handfers^ wsrft^
{ar 7,08G trrcfyr, &oqv stuch d+es
?oao )
-, \f
.* o^ ,of
hy
L TrgearFalse
.-t '/
l^"
AnAdiabticsvsernnrsar$tbt:
AU
o (^) a$d
Q=o.
I
Arr Adisbatic Svstam mesns thaf AtI
:
T Ose trn - tnaf AC k 1a000 Bt{r
T (^) -Conductmse
ir Srs r€ciprocal of^ Resistasfie
Coasidcr rat^ d${ias^ an^ irdurfrial^ viit^ rroq see^ a.^
hat fuid tank bmtcd s* l8 fgd fmm the
ffoor. You^ ar€^ coosidorl"g^ recorrcring^ kst^ sut^
ef it erd heaw s€€d to kao'r tbe te*rperefun
af tho tank, Name at^ lca*t^ twn^
inr,fume,nts tlrat will allaw
you
make the meafltr€n€fit without
having tb cfimb^ a tadder.
Co.s-.{-{*4.
3, Cnidsins the hed flaw .4udicns
discuss€d in class show that the sllons oer minute that
flows tlrough e pipe is proportional^ to^ the^
p'ro*!ct of,the condr,rctaacc aad the area ef the
wall-
eftr'i\
=
oL (^) ' ) 'A
: L) (^) 'A 'AT
: q?i'^ 'SID'AT
/- l^<.-J
6
4?q. ffir
!).
soo
I
J
it (^) cos to tave ttre *yrttm rsaniag urds tk€ *m&tions?
t
cFr'\
..oB.aT
I)
23's .
-'.''#
(.F
'.oB'Ot
"
-^?6e
l)
zlT,*r'-.
*ffi
: (^) fo,9s 9}l^^ 'l.o^
'ZS'F
y
:u?o.oogf;.
,##".
.lffi
L2-S'L,^
T\a
(Jto-
"g
o' co1.Lr^ lo*oi
*.\
.
.f*V" .[1ut
..*.kt {Spoints)
-n\o'
r-l* ; (^) ^J,*t+
c-'{ "^''':*,."})-fl'k,^^-
?f i'
^"-1,*=;
}1*
.^r)""- \tr-r-
4.r- (^) 1g.,**\
A'.R^" (^) \tg.;-.s \'-g' o.\t
*{...< $^c-^
=^,*
s-^"1*^
I
""u-r;c;,
a**f'
k
}-**
+*
**^Lt
't" *o',-
fft -.
W,*^^
'L
10. Forthe carndt cycle below,
'ffi*"+
ffi- lffi-v1e
poiot, each)
[$,ot Li}',,tr;W+^l
*t
,.In
the space providgd^ below describe how does a Cooling Tower work, irnd what furrction
t
does it servo?
If C{
:
3U/Z,and R = 8.314 J/1K-mol, answ€r the following:.
a) Whatdothslineg l-2, 2:3,34,4'l represent? | r
, r
^'..t
,o,.r^\
^e,*".h
q- 4alr^ \
nt doths lineg^ 1-2,^ 2:3,34,4'^
represent? , r
a!.\s',\ 4 c..^a\
o1u\r-
S( { $r'r*-t^-:Y.T^:t[-
'l
t
Li*r= l-L
o^tr b^^
r(3s{t?
Li*'=
l-L
a'co D--r^
*t'-lJ(^,aK;o\f.
q***
;t^ 6.=
^*l
a$.:
-6-
Ls.*.s
^^
A
q -(
ctg.es<r'cb
*vl,-/c-c\ro:ear-ts
1v\v--
a /rq"or1 ,srr _^221
b) whdisthoEnthatpy(AfDfiorallstepsifTn:60$tandTr,=60PC^
.
6a.L =^
8t"K'' cDoc^ = 3:3oK
A\
(, AT lt".*
t.^.*\
o."*b oJ"=t"'^
f"*':"\T =o
"
\L''^
AU *- s\q" I -.?-^ ^"
A (^) S -tt
-'\
O
Lp --(rtR^ ''f
-+ =
T i
t^ v''E=^ 'oot3t{tr/*'-o'"
fo.
L-s
A\'
c
Qatarr-8ra'r)
.oe'orBsyf;t)
I -ll'z '\
f*
,
At\ =
C9 ( Sra,r-33i'14\ = t,z\l-\
G> = -ozsrB(
' r!ry'*\
)
\
l-z ,/z- ,
5-'1,, 4-Y^
t
l
lU
--"/
''l'"'
ok
\
V
,.A{ =
A{
?,,=^R T^
?-vo (^) =,.FT
SSlq
,,r1 ::^ ;;;^ ",.i ^$'
L^+*-lS'
-?AV r^ A?a.v Ql'
A{(e, T/^
"
t/
ri
?
' d)
Show that^ for^ the ideal^ gas^ considered^ herg^ in^ any^ Isothermic^
process, the Enthropy ofthe
tY is given by:
AS"y=t"- (^) = nR ln(% / Vr)
: nR ln (h^ lPz)
L"b'
trsJ$rrr*
i: 4-^ c"*olt'^^\
T Ts^ 1p-$'4rc^^
b t\
51"{^ T,{, (^) =?.Y. =} \
,V,
G.^
?
P
'z
t-1"{,i T
is-.*&^\
t A5.1ok*-
=
nR {"^
f!\
'V, I
,
r]-^o- "',R'
a-^(
k
: ^
O-(?\
e) If l mol ofthe system is allowed to^ expand^ (t^ to^ i)^ from 0.01m] to^
0.l0@m3 at 25oC
what is^ the^ entropy^ ofthe^ $ystein?^
(make $re you include the units).
y",,.\ --\
I
/ (^) =
E-t*'. f
v"o.\
'. -'\
Vr-t'\D-
V,
:-.o\
^
.\o
,o)
As:\1...\/
, 2 e.^
=O
AD
: (^) -\rr)
t^.,
\
/-c)For
any of the^ two adiabatic systems^ considered in the^ cycle,^ and^ using the^
relations for
-/tttenkst Law of Themodynamics in your^ class noteg^ show^ that^ the^ Enthalpy^ ofthat
systemisgivenby:
A,jrp.\ah.
t^^p\rcs
t
Q
:c>
