Teacher’s guide – PASCO TD-8564 THERMAL EFFICIENCY APPARATUS User Manual
Page 29
012-05443A
Thermal Efficiency Apparatus
25
Teacher’s Guide
Experiment 1: Heat Engine and Temperature Difference
Notes on Setup
➁
It may be necessary to prime the pump by sucking
on the output line briefly.
Notes on Calculations
➀
Use the equations
P
H
= V
H
I
H
and
P
W
=
V
W
2
R
➂
efficiency =
P
W
P
H
➃
e
Carnot
=
T
H
– T
C
T
H
Notes on Analysis and Questions
B
B
B
B
B
B
B
J
J
J
J
J
J
J
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
0
10
20
30
40
50
60
70
Efficiency (%)
Temperature Difference (°C)
B
Carnot Efficiency
J
Actual Efficiency
➀
Yes.
➁
,
➂
Both Carnot and actual efficiency increase with
increasing temperature difference. (for a constant
cold temperature)
➃
In these trials, 11-12% of the available energy was
used.
➄
Although the efficiency is low, the reliability is ex-
tremely high. (There are no moving parts in the
Peltier device.) One practical application of these
devices is in satellite power supplies. A small piece
of radioactive material is used as a source of heat,
and a radiation fin is used as a heat sink. Another
similar application is to use the temperature differ-
ence between a nuclear isotope and arctic weather
to run a remote unmanned weather station. Any ap-
plication where the thermal mass of the available
sources is large, the power requirements are small,
and the required reliability is high is good for the
Peltier device.