# Thermo dynamics and RAC

Thermo dynamics and RAC
Question:-
Option (A)
low pressure
Option (B)
high pressure
Option (C)
high temperature
Option (D)
combination of (a) & (c)
Correct Option:
D
Question:-
Option (A)
0.00886 kg/kg d.a
Option (B)
0.00876 kg/kg d.a
Option (C)
0.00846 kg/kg d.a
Option (D)
0.00806 kg/kg d.a
Correct Option:
A
Question Solution:
Mass flow rate of 1 = 30/0.83 = 36.145 kg/min
Mass flow rate of 2 = 12.5/0.86 = 14.535 kg/min
Sp. humidity of mixture w3 =

= 0.00886 kg/kg d.a
Question:-
Option (A)
increases the referigerating effect
Option (B)
decreases the referigerating effect
Option (C)
increases the work of compression
Option (D)
has no effect on referigerating effects
Correct Option:
D
Question:-
Option (A)
ΔU, Q, W are same
Option (B)
ΔU is same
Option (C)
Q, W are same
Option (D)
ΔU, Q are different
Correct Option:
B
Question:-
Option (A)
free expansion
Option (B)
throttling process
Option (C)
parabolic expansion
Option (D)
isentropic expansion
Correct Option:
B
Question:-
Option (A)
Option (B)
Option (C)
Option (D)
Correct Option:
A
Question Solution:
1 → 2 = Isentropic compression
3 → 4 = Isentropic expansion
network input (Wc) = (h2 – h1) – (h3 – h4)
= (h2 – h3) – (h1 – h4)

COP =

= =