Name:
12.04.2008
ID:
ME 212
Midterm 1
1)
Refrigeration cycle using R134-a is shown below. Compressors are working isentropically and
the rate of heat removal from the refrigerated space is 5kW.
P
1
=0.08 MPa = P
7
;
P
2
=0.3 MPa=P
3
=P
6
;
P
4
=1 MPa=P
5
;
X
1
=1;
X
3
=1;
X
5
=0;
Olduguna gore
a)
Draw T-s diagram.
b)
Calculate mass flow rates of the fluids through the compressors.
c)
Calculate COP of the system.
Evaporator
Condenser
V
3
2
1
4
5
6
7
Compressor 1
Compressor 2

This
** preview**
has intentionally

**sections.**

*blurred***to view the full version.**

*Sign up*
2)
A gas turbine cycle is shown below. Properties of air at different points in the cycle are given
below.
P
1
=100 kPa, T
1
=27 °C
P
2
=500 kPa=P
3
=P
4
=P
5
;
T
3
=300°C, T
4
= 750°C
T
5
=800°C
P
7
=P
8
=P
9
=P
10
=P
1
=100 kPa;
The first turbine drives the compressor and the second turbine produces a power of 1500 kW.
Every 0.6 kg of 1 kg air leaving the compressor passes through the turbine 1. Assuming that the
compressor and the turbine work isentropically ,the air is ideal, C
p
and C
v
are constant;