3B SCIENTIFIC PHYSICS 1000820 Manual Del Usuario página 14

Note: After the compressor has automatically
been switched off by the excess pressure safety
switch, read off the time and then add it to the
time measured when you have restarted.
8.2 Mollier diagram
An ideal cycle can be represented by a Mollier
diagram by measuring pressures p(3) and p(4)
before and after the expansion valve and the tem-
perature T(1) before the compressor:
T(1) and p(4) determine point 1 of the Mollier di-
agram (see Fig. 5). The intersection of the corre-
sponding isentropes with the horizontal line p(3)
= constant defines point 2. The intersection of the
horizontal with the line representing the boiling
point gives point 3, then a perpendicular down to
the horizontal p(4) = const. provides point 4.
Additionally, measuring temperatures T(2), T(3)
and T(4) provides an extra insight into the pro-
cesses taking place inside the heat pump:
The temperature T(4) measured externally is in
agreement with the overall temperature read from
the temperature scales of the corresponding ma-
nometer to within the precision of the equipment.
This temperature scale is based on the curve rep-
resenting work done by the refrigerant. The meas-
urement therefore shows that the refrigerant be-
yond the expansion valve is in a mixture of liquid
and gaseous states.
The externally measured temperature T(3), how-
ever, differs from the temperature read from the
manometer on the high-pressure side. The refrig-
erant at this point contains no gas content. It is
entirely liquid.
The following equipment is recommended for tak-
ing external measurements (see section 4. ac-
cessories):
Temperature sensor NTC
with measurement terminal
VinciLab
Coach 7 License
8.3 Theoretical efficiency
The theoretical efficiency of the ideal cycle can
be calculated from specific enthalpies h
h , which can be read directly from the Mollier di-
3
agram:
 
q h h
  
2 2 3
th
 
w h h
2 1
8.4 Mass flow rate of refrigerant
Once the enthalpies h
are known as well as the amount of heat ΔQ
plied to the water reservoir in a time interval Δt,
then it is possible to estimate the mass flow rate
of the refrigerant.
1021797
1021477
, h
1 2
and h for the ideal cycle
2 3
2
 
m Q
 
2
 
t t
Fig. 6 Energy monitor
Key
Reset button
RESET
UP button
SET button
FUNC button
and
Setting the time:

Press the FUNC button until CLOCK appears
at the bottom right of the display.

Hold down the SET button until the hours
flash. Set the hours using the UP button and
confirm this by pressing SET. Proceed in the
same way to set the minutes
Display measuring functions:
sup-

Briefly press the FUNC button to display the
following information in turn: current con-
sumption, watts, consumption.
6
1

h h
2 3
9. Energy monitor
Function
Press with pointed ob-
ject to clear all data in
memory including cur-
rent time and all pro-
grams
Set current time, price,
price programs in
combination with SET
button
Set current time, price,
price programs in
combination with UP
button
Toggle display mode