3B Scientific Heat Pump D User Manual
3B SCIENTIFIC
Instruction sheet
12/08 ELWE/ALF
®
PHYSICS
Heat pump U8440600
1 On/off switch for Compressor
2 Condenser
3 Stirrer
4 Overpressure cut-out switch
5 Reset overpressure cut-out switch
6 Manometer for the high-pressure side
7 Manometer for the low-pressure side
8 Energy monitor
9 Expansion valve
10 Evaporator
11 Stirrer
12 Viewing window
13 Compressor
1. Safety instructions
If the heat pump is tipped to one side, it must remain in an upright position for at least seven hours
before being operated again.
• Always keep the heat pump in an upright posi-
tion during storage, transport and operation.
• Carry the heat pump only at the carrying handles.
• Do not lift the heat pump by its copper pipes or
they may get bent.
Caution: the voltage in the compressor circuit is
dangerous to touch!
• Do not thermally insulate the compressor or it
may overheat.
• After shut-down by the overpressure cut-out
switch wait for 10 minutes to press the green reset button.
2. Description
Demonstration model of an electrically powered
compressor heat pump for demonstrating how a
heat pump or a refrigerator operates. Can be operated as a water-air or water-water heat pump.
The demonstration model of an electrically powered
compressor heat pump consists of a compressor with
a drive motor, an evaporator, a condenser and an
expansion valve. These components are connected in
a closed system by means of pipes and built onto a
base.
The energy monitor allows to record and display the
electrical performance data of the compressor.
1
Button Function
Zeit (Time) displays the time / operating time of
the compresor (ED)
(changes when you press the button)
Strom (Current)
Spannung
displays the current consumption of
the compresor
displays the mains voltage
(Voltage)
Leistung
(Power)
Energie
displays the momentary power consumption
displays the energy, (unit: Wh)
3.1 The processes in a heat pump circuit
In the most important and widely used type of heat
pump, the compressor heat pump, a substance in
the form of a liquid with a low boiling point circulates in a closed loop. It passes through four different processes. It is evaporated, compressed, condensed and then allowed to expand (see Fig. 1).
(Energy)
Zeit (Time)
> 6s
Reset function for time, ED and
energy
The evaporator and condenser are constructed as
coils of copper piping and each is immersed in a
beaker filled with 2000 ml of water that serves as a
reservoir of heat in order to determine the quantity
of energy absorbed or emitted. Two additional thermometers are required in order to measure the
temperature of the water in the beakers.
Two large manometers display the pressure of the
refrigerant in both heat exchangers. An overpressure
cut-out switch disconnects the heat pump from the
mains if the excess pressure reaches 15 bars.
So that the properties of the refrigerant in liquid and
gaseous states and the processes of conversion can
be viewed, the heat pump is equipped with viewing
Fig. 1 Circulation in a heat pump
A Evaporator
B Compressor
C Condenser
D Expansion valve
P
windows. These allow the interior of the pump to be
seen and the state of the refrigerant to be observed
immediately after the evaporator or condenser.
p High pressure in the condenser segment from
The heat pump is available for two different mains
volatages. U8440600-230 is designed for 230 V (±10
%), 50 Hz mains supplies, while the U8440600-115
T
model is for 115 V (±10 %), 60 Hz supplies.
T Temperature of the medium (usually centrally
3. Technical data
Compressor power: 120 W, power consump
tion dependent on operat ing state
Evaporator temperature: -10° C
Refrigerant (CFC-free): R 134A (Tetrafluorethan, C
2H2F4
Boiling point: -26° C
Manometer: 160 mm dia., evaporator
(suction intake) up to 9
bars; condenser (pressure
pipe) up to 24 bars
Overpressure cut-off: disconnects compressor
from the mains at 15 bars
T
rator at pressure p
T
after compression
)
T* Boiling point of the refrigerant in the con-
denser at pressure p
Q
Q
W Work performed by the compressor
3.1.1 Evaporation
Power supply: 115 V, 60 Hz or 230 V, 50 Hz
Dimensions: 750 x 350 x 540 mm
3
Weight: 21 kg approx.
4. Operating principle
Low pressure in the evaporator segment from
0
the outlet of the expansion valve to the input
of the compressor
the outlet of the compressor to the input of
the expansion valve
Temperature of the medium (soil, water, air)
0
surrounding the evaporator from which a
quantity of heat Q
is absorbed
a
heated water), surrounding the condenser
which absorbs a quantity of heat Q
* Boiling point of the refrigerant in the evapo-
0
Temperature of the refrigerant vapour
h
Heat absorbed by the evaporator
a
Heat emitted by the condenser
Z
0
z
In the evaporator the liquid refrigerant experiences a low pressure p
. The temperature T0 in
0
the medium surrounding the evaporator is higher
than the boiling point of the refrigerant T
responding to the pressure p
. This tempera-
0
* cor-
0
2
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