answer all please

$3\mathrm{.}47$ A $2-$ton window air$-$conditioner needs to remove $8\mathrm{.}4$ kW of heat from its condenser. In the condenser, the inlet temperature of air is $3FC$ and the refrigerant condenses at $57C.$ Jenore the effect of desuperheating and subcooling in the condenser. U$/$A for this air$-$conditioner is $700\frac{W}{K}.$ Assume the specific heat of air as $1\mathrm{.}0k\frac{J}{k}g*K.$ Use any appropriate information from this or any other book, and determine the airflow rate through the condenser as:

$($a$)1k\frac{g}{s}$

$($b$)0\mathrm{.}7k\frac{g}{s}$

$($c$)0\mathrm{.}5k\frac{g}{s}$

$($d$)1\mathrm{.}5$ kz $?$

$($e$)$ can't tell

Hind. Assume the exponent to $e$ to be an integer.

$3\mathrm{.}48$ For Question $3\mathrm{.}47,$ the air temperature rise will be:

$($a$)10C$

$($b$)6C$

$($c$)12C$

$($d$)20C$

$($e$)$ can't tell ${?}^{-1}$

$3\mathrm{.}49$ A I$-2$ TEMA E shell$-$and$-$tube exchanger has the temperature effectiveness of $0\mathrm{.}09$ and heat capacity rate ratio of $10.$ At this operating point, the log$-$mean temperature difference correction factor $F$ will be approximately:

$($a$)0\mathrm{.}65$

$($b$)0\mathrm{.}75$

$($c$)0\mathrm{.}85$

$($d$)0\mathrm{.}95$

$($c$)$ cas't tell

$351$ An unmixed$-$unmixed crossflow exchanger has $z=60\%$ and $F=0\mathrm{.}95$ at NTU $=1$ for $C^{**}=0\mathrm{.}2.$ To demonstrate how $F$ varies with NTU, we increase NTU $=3$ at $C^{**}-02.$ In that case, the exchanger effectiveness $$ increases to $90\%.$ The corresponding $F$ value will be:

$($a$)0\mathrm{.}98$

$($b$)0\mathrm{.}88$

$($c$)1\mathrm{.}00$

$($d$)0\mathrm{.}01$

$3\mathrm{.}52$ Consider a clean counterflow heat exchanger with desired $6=85\%$ at $C+1.$ If the heat kakage to the ambient is $2\%,$ approximately how much will be an increase in heat transfer sarface area on each fluid side to increase the cold$-$fluid temperature at the same level of the no$-$heat$-$leakage case? Consider all other geometric and operating parameters of the exchanger remaining the same and $(\frac{n}{h}at(A){)}^{**}=1.$

$($a$)0\%$

$($b$)2\%$

$($c$)6\mathrm{.}4\%$

$($d$)128\%$

$($c$)$ can't tell