PASCO TD-8564 THERMAL EFFICIENCY APPARATUS - Manual (Page 31)

012-05443A Thermal Efficiency Apparatus
27
Experiment 3: Heat Pump Coefficient of Performance
Typical Results
Note that values of Ph and r were taken from
experiment 2.
T
h
(K) T
c
(K) V
w
I
w
P
w
COP COP
max
COP
adj
% diff
330.9 275.5 3.64 1.63 5.93 1.75 4.97 4.48 9.9%
Answers to Questions
➀ The COP increases when the difference in tempera-
ture decreases.
➁ For the hot reservoir,
∆
S/
∆
t = +0.018. For the cold
reservoir, it is – 0.0215. The net change in entropy
is negative. Work is done by the heat pump to de-
crease the entropy.
Experiment 4: Thermal Conductivity
Answer to Questions
➀
The thermal conductivity, based on the data taken
in experiment 2 of this guide, is 1.79 Watt/mK. By
comparison, the thermal conductivity of copper (at
273 K) is 401 Watt/mK.
The Peltier device is made of Bismuth Telluride,
which has an accepted thermal conductivity of
approximately 1.6 Watt/mK