Question Ref. No: $61$

A refrigerator uses refrigerant$-134$a as the working fluid and operates on an ideal vapor$-$compression refrigeration cycle between $0\mathrm{.}28$ and $0\mathrm{.}7$ MPa. The mass flow rate of the refrigerant is $0\mathrm{.}053$ kg$/$s$.$ Determine:

a$)$ the rate of heat removal from the refrigerated space $($kW$),$

b$)$the power input to the compressor $($kW$),$

c$)$ the rate of heat rejection to the environment $($kW$),$ and

d$)$ the coefficient of performance.

PLEASE KEEP AND SAVE YOUR CALCULATIONS BECAUSE THE LECTURER WILL RANDOMLY ASK FOR THE PROOF OF YOUR WORK.

s$1($kJ$/$kg$.$K$)$

Format : $0\mathrm{.}7744$

s$2($kJ$/$kg$.$K$)$

Format : $0\mathrm{.}4358$

h$2($kJ$/$kg$)$

Format : $988\mathrm{.}46734230905$

h$3($kJ$/$kg$)$

Format : $68\mathrm{.}75$

h$4($kJ$/$kg$)$

Format : $38\mathrm{.}27$

QL $($kW$)$

Format : $4\mathrm{.}7275$

Win $($kW$)$

Format : $4\mathrm{.}0059$

QH $($kW$)$

Format : $6\mathrm{.}7848$

COPR

Format : $4\mathrm{.}9274$

This is my own work and I do not CHEAT by any means in doing this problem.

A$)$ No

B$)$ Yes

C$)$ Not sure

D$)$ May be

Format : A

For a throttling process, the enthalply remains the same before and after the process.

A$)$ Yes

B$)$ No

C$)$ Depends

D$)$ Impossible

Format : A

In a refrigeration cycle, the amout of work needed for the throttling process is equal to $\_\_\_\_\_\_$

A$)$ QH $-$ QL

B$)$ zero

C$)$ Win

D$)$ Wnet

Format : A

For an ideal vapor$-$compression refrigeration cycle, the process taking is in the compressor is $\_\_\_\_\_\_\_\_\_$ process

A$)$ constant$-$pressure heat absorption

B$)$ a constant$-$pressure heat rejection

C$)$ throttling

D$)$ an isentropic compression

Format : A

Which of the following component is NOT part of the ideal vapor$-$compression refrigeration cycle?

A$)$ condenser

B$)$ compressor

C$)$ turbine

D$)$ evaporator

Format : A

Score: $/$