PASCO TD-8564 THERMAL EFFICIENCY APPARATUS User Manual
Page 30
Thermal Efficiency Apparatus
012-05443A
26
Experiment 2: Heat Engine Efficiency (Detailed Study)
Notes on Setup
➁
It may be necessary to prime the pump by sucking
on the output line briefly.
Sample Data
Mode
T
h
(
°
C)
T
c
(
°
C)
V
h
I
h
V
w
V
s
Engine
57.9
3.5
10.00
2.02
0.890
Open
57.9
3.3
8.99
1.815
1.495
Calculated Values
Mode
T
h
(K)
T
c
(K)
P
h
P
w
I
w
Engine
330.9
276.5
20.2
0.40
0.45
Open
330.9
276.3
16.3
Internal Resistance: r = 1.36
Ω
Results
Actual
Adjusted
Maximum
(Carnot)
% Difference
Efficiency
1.96%
17.13%
16.44%
-4.23%
Note that these results were obtained using slightly
lower initial voltage than recommended in the lab.
In general, mid-range temperatures give better
results than extremely large or small temperature
differences.
Answers to Questions
➀
If the temperature difference was decreased, the ef-
ficiency would also decrease.
➁
See experiment 1, question 5.
➂
For the hot reservoir,
∆
S/
∆
t was -0.061. For the
cold reservoir, it was 0.073. The total change in en-
tropy is positive. In any non-reversible process, the
entropy will increase.