[0001] The invention relates to a method for operating a laundry treatment apparatus and
a laundry treatment apparatus having a heat pump system.
[0002] DE 10 2005 041 145 A1 discloses a laundry dryer having a heat pump system with a variable-speed compressor.
A control unit of the dryer is adapted to switch-off the compressor when a temperature
threshold of hot-gas in the heat pump system is exceeded. A method for operating the
laundry dryer prevents an emergency switch-off of the compressor due to high hot-gas
temperature. When the temperature threshold is close to be reached, the control unit
is adapted to operate the variable-speed compressor at a low power level, such that
the hot-gas temperature does not reach the temperature threshold.
[0003] AU 2011 253 568 A1 discloses to switch OFF the compressor of a heat pump system when a temperature sensor
detects a temperature over a temperature threshold and to switch ON the compressor
again when the temperature falls below the temperature threshold.
[0004] US 2010/037480 A1 discloses to switch OFF the heat pump before an air temperature of 65°C.
[0005] It is an object of the invention to provide an improved method for operating a laundry
treatment apparatus having a heat pump system and an improved laundry treatment apparatus.
[0006] The invention is defined in claims 1 and 18, respectively. Particular embodiments
are set out in the dependent claims.
[0007] According to claim 1, a method for operating a laundry treatment apparatus is provided,
wherein the treatment apparatus may be a heat pump tumble dryer or a washing machine
having a drying function. The apparatus comprises a heat pump system and a laundry
treatment chamber (e.g. laundry drum) for treating laundry using process air. The
heat pump system comprises a first heat exchanger (evaporator) for heating a refrigerant
fluid, a second heat exchanger (condenser) for cooling the refrigerant fluid, an expansion
device and a refrigerant loop, in which the refrigerant fluid is circulated through
the first and second heat exchangers and the expansion device. A compressor is provided
for circulating the refrigerant fluid through the refrigerant loop.
[0008] The method for operating the laundry treatment apparatus comprises detecting at least
one first temperature signal. For example the at least one temperature signal may
be a refrigerant temperature detected at the exit of the second heat exchanger, a
temperature of electronic boards (e.g. power board, compressor control board) or a
temperature detected in an inner volume within apparatus cabinet. As a further example
the at least one temperature signal may be detected by means of a temperature sensor
arranged internal or external the apparatus cabinet and/or a temperature sensor may
be arranged in a cooling air flow path (e.g. cooling air flow for cooling the compressor).
In an embodiment the temperature signal is a signal derived from two, three or more
temperature sensors arranged at different locations within the dryer cabinet. The
locations of the temperatures sensors or the type of temperature to be detected thereby
(e.g. refrigerant or ambient temperature) are given in the present description for
different examples which are all comprised here by 'temperature signal' or 'sensor'.
A mathematical function may be applied to two or more detected temperature signals
to calculate or determine the 'detected' temperature signal.
[0009] The method further comprises selecting in dependency of the at least one detected
first temperature signal at least one predetermined temperature threshold value for
switching the compressor ON and/or OFF. If the selected temperature threshold value
is exceeded during a program cycle of the treatment apparatus, the compressor is switched-off.
For example the at least one predetermined threshold value may be compared to the
above mentioned detected first temperature signal. For this purpose the respective
temperature signal may be permanently or repeatedly detected during apparatus operation.
Alternatively, the at least one predetermined temperature threshold value may be compared
to any of the other temperature signals described above. For example a temperature
signal indicative of an operating condition of the treatment apparatus, in particular
an operating condition of the heat pump system.
[0010] In case the at least one temperature threshold value is selected in dependency of
a first temperature signal (indicative of) the ambient temperature, the selected temperature
threshold value(s) is (are) set in dependency of the environment condition where the
treatment apparatus is placed. If a "cold" temperature environment (e.g. below 15°C)
or a "normal" temperature environment (e.g. 15-30°C) is detected, the selected predetermined
temperature value(s) for switching the compressor ON/OFF may be set higher in comparison
to predetermined temperature level(s) selected for a "hot" environment (e.g. above
30°C). Vice versa, if a high ambient temperature is detected, the selected temperature
threshold value(s) are set lower in comparison to selected threshold value(s) for
normal/cold ambient temperature. Thus in high ambient temperature conditions the compressor
is switched-off at a lower temperature (in relation to "normal" or "cold" environment).
[0011] The above method safely prevents an overheating of the compressor which results in
a longer life time of the compressor. Further the method is intended to reduce or
avoid overheat safety switch-off of the compressor which is reactive to over-temperature
and which results in long switch-off durations inefficiently extending total laundry
treatment times. Thus the treatment apparatus performance is improved, in particular
in high ambient temperature environment or in an environment where heat generated
by the apparatus during operation cannot be dissipated easily (e.g. when the apparatus
is positioned in a niche or wall recess).
[0012] For example, a first temperature threshold value may be selected for switching the
compressor ON and a second temperature threshold value may be selected for switching
the compressor OFF. In this case the control unit is adapted to switch the compressor
OFF when the temperature reaches or exceeds the first threshold value and is adapted
to switch the compressor ON when the first temperature underruns or falls below the
second threshold value.
[0013] Alternatively only one temperature threshold value may be selected, wherein the compressor
is switched-off when the threshold value is reached or exceeded from a lower temperature
level (lower than the threshold value) and the compressor is switched-on when the
same threshold value is underrun from a higher temperature level (higher than the
selected threshold value).
[0014] Exemplary temperature threshold values (switch-OFF/switch-ON) to be selected for
the respective detected first temperature signal (ranges) may be: "cold" environment:
75°C/ 65°C; "normal" environment: 70°C/ 60°C; "hot" environment: 65°C/ 50°C. Cold
environment is for example Tx < 15°C, normal environment is for example 15°C ≤ Tx
< 28°C and hot environment is for example 28°C ≤ Tx. As described above, during an
operation of the treatment apparatus, the compressor may be switched-on and/or -off
in dependency of a (permanently or repeatedly) detected temperature signal, which
may be the same as the detected first temperature signal for selecting the temperature
threshold value(s) or may be any of the other temperature signal(s) described above
or below. For example the compressor is switched-off/-on in dependency of the state
of the heat pump system, in particular in dependency of the refrigerant temperature.
For example, if the detected temperature signal indicates a "normal" environment temperature,
the compressor may be switched-off when the or a temperature signal reaches 70°C.
When the detected temperature signal falls below 60°C the compressor is switched-on
again. Thus the compressor switch-off time is adapted to the actual (temperature)
condition of the apparatus or heat pump system, such that compressor switch-off time
is minimized.
[0015] The above method additionally provides that emergency switch-offs of the compressor
by means of a safety device like a thermoprotector are prevented. For example the
treatment apparatus may comprise a safety device to switch-off the compressor to prevent
damage of the compressor in a critical (temperature) condition. An emergency switch-off
by means of a safety device is generally long and not well controllable. Thus a drying
operation is suspended unnecessarily when an emergency switch-off occurs. In general,
a compressor safety device intervenes for a combined effect of compressor temperature
and current absorbed by the compressor. I.e. the safety device is not controlled by
a temperature signal indicating the condition of the heat pump system, for example
of the refrigerant temperature. For example, if a fixed temperature threshold value
would be used for all drying operations, it may occur in high ambient temperature
condition (e.g. above 30°C), that the refrigerant temperature is lower than the fixed
compressor switch-off threshold (i.e. the compressor is kept ON), while the safety
device intervenes by switching the compressor OFF. This is mainly due to the refrigerant
circuit and safety device having different thermal inertia and due to that a temperature
sensor for detecting the temperature signal (e.g. of the refrigerant) and the safety
device are placed at different locations within the treatment apparatus. Therefore
the temperature sensor and the safety device are subject to different temperatures.
[0016] To prevent an emergency switch-off by means of a safety device, the above described
at least one temperature threshold value is set, such that the compressor may be switched-off
before the safety device intervenes or is activated. For example, when the detected
first temperature signal is low, the at least one selected temperature threshold value
may be set at a higher level, when compared to threshold value(s) selected in case
of a high first temperature signal. A high value of the detected first temperature
signal may result from a previous drying operation or from a high ambient temperature.
In this case the treatment apparatus, in particular the compressor, reaches a critical
(temperature) condition faster than in comparison to the case when detecting a low
level of the first temperature signal. A low first temperature signal may be detected
when the treatment apparatus has not been operated for some time, such that the treatment
apparatus had time to cool down, and/or the ambient temperature is low or normal (e.g.
below 30°C).
[0017] As described above, preferably a pair of temperature threshold values are selected
in dependency of the at least one detected first temperature signal: (i) a switch-OFF
temperature threshold value for switching the compressor OFF, and (ii) a switch-ON
temperature threshold value for switching the compressor ON, wherein the switch-OFF
temperature threshold value and the switch-ON temperature threshold value are different
of each other (resulting in a hysteresis effect in the temperature profile). In particular
the switch-ON threshold value may be lower than the switch-OFF threshold value to
provide that the heat pump system is safely out of a critical condition. Thus it is
prevented that the heat pump system repeatedly reaches a critical condition in short
intervals, i.e. it is prevented that the compressor has to be switched-off repeatedly.
[0018] Preferably the at least one detected first temperature signal is indicative of an
ambient or environment temperature of the laundry treatment apparatus. At least one
detected first temperature signal may be provided by a temperature sensor capable
of detecting the environment or ambient temperature at least under a predefined operation
condition. As described above it may be determined whether the apparatus is located
in a high temperature environment or an environment where removal of heat from a drying
cycle is hindered (e.g. due to the apparatus being located in a wall recess or the
like). Thereby corresponding temperature threshold value(s) may be selected to prevent
e.g. emergency switch offs of the compressor due to overheating as described above.
[0019] For example the temperature sensor may be a real ambient temperature sensor, i.e.
a sensor arranged outside the apparatus housing or a sensor arranged in a cooling
air passage for cooling air sucked in from the outside of the apparatus housing. Or
the temperature sensor may be arranged within the apparatus cabinet and is best adapted
to detect a temperature corresponding to the ambient temperature (see below).
[0020] Preferably the at least one detected temperature signal is provided by at least one
temperature sensor which is capable of detecting the environment or ambient temperature
at least under a predefined operation condition. A predefined operation condition
may be that the laundry apparatus was non-operative for a while. For example such
that a component where the temperature sensor(s) is(are) placed is cooled down for
a while by blowing ambient air to the component and/or sensor. For example a sensor
detecting the temperature of a refrigerant or of an electronic board or of compressor
motor. Then the temperature sensor detects ambient temperature only if at the location
of the sensor the apparatus component or operating fluid has cooled down (equilibrated)
to ambient temperature. For example when the sensor is in contact with the heat pump
system or heat pump fluid that is cooled down to ambient temperature.
[0021] According to an embodiment, temperature signals of several temperature sensors arranged
at different locations within and/or outside the apparatus may be received by the
control unit, wherein the control unit makes a plausibility check or evaluation of
the temperature signals to conclude on an ambient temperature having high likelihood.
For example, in case of several temperature sensors, the sensor signal indicating
the correct or close ambient temperature is selected. For example the temperature
sensor with the lowest temperature signal may indicate the ambient temperature which
is true for sensors except under some conditions when a sensor is placed in contact
with the second heat exchanger (evaporator) or expansion device.
[0022] Preferably the laundry treatment apparatus comprises a control unit having an associated
memory, wherein at least one, at least two or more than two predetermined temperature
threshold values are stored in the memory for being selectively retrieved by the control
unit upon selection in dependency of the at least one detected temperature signal
as described above and below.
[0023] Preferably the selection of the at least one predetermined temperature threshold
value is made among
- (i) a first predetermined temperature threshold value or a first pair of predetermined
threshold values to be selected for a first temperature or a first temperature range
of the detected temperature signal, and
- (ii) at least one second predetermined temperature threshold value or at least one
second pair of predetermined threshold values to be selected for a second temperature
or a second temperature range of the detected temperature signal, wherein the first
and second threshold values or first and second pairs of threshold values are different
of each other, and wherein the first and second temperature and/or the first and second
temperature ranges are different of each other. For example, if the detected first
temperature signal is less than or equal to 28°C the compressor switch-OFF threshold
may be set to 70°C and the compressor switch-ON threshold may be set to 60°C. In case
the detected temperature signal is greater than 28°C the compressor switch-OFF threshold
may be set to 65°C and compressor switch-ON threshold may be set to 50°C.
[0024] Preferably the higher the value of the detected first temperature signal or temperature
range, the lower the value of the selected temperature threshold value or the selected
pair of temperature threshold values.
[0025] Preferably detecting comprises detecting the at least one first temperature signal
before starting a drying cycle and/or before starting to operate the compressor. For
example the first temperature signal is detected shortly after a 'button' for activating
the drying cycle is pushed. Alternatively or additionally the temperature signal is
detected after about 1 min. after starting a drying cycle or program but while the
compressor is still switched-off. For example after starting a drying cycle a process
air fan (which may be connected to the drum motor) and/or an optional cooling air
blower (e.g. for cooling the compressor) already operates, whereby the detected temperature
may be stabilized or equalized before detecting the first temperature signal.
[0026] According to an embodiment, the first temperature signal may be detected repeatedly
or permanently during a drying operation to continuously adapt the temperature threshold
value(s) or pair(s) of threshold values to the present condition or state of the treatment
apparatus (or heat pump system) throughout the apparatus operation. In other words
the threshold value(s) may change in dependency of permanent or repeated detection
of operation conditions (for example by constantly monitoring the first temperature
signal). For example when the ambient temperature (i.e. the corresponding temperature
signal) is in a normal range (for example 15-30°C) a first predetermined temperature
threshold value or a pair of predetermined threshold values is selected or set. When
the ambient temperature is in a low range (for example below 15 °C) a second temperature
threshold value or a pair of predetermined threshold values. When the ambient temperature
is in a hot range (for example above or 30°C) a third temperature threshold value
or a pair of predetermined threshold values is set or selected.
[0027] Preferably the method further comprises (i) selecting in dependency of the at least
one detected temperature signal a predetermined switch-OFF time for the compressor,
and (ii) switching OFF the compressor for a predetermined switch-OFF time when the
selected temperature threshold value is exceeded. For example a selected predetermined
time may be 5 min. Preferably the duration of the switch-OFF time depends on the detected
first temperature signal. For example the higher the detected first temperature signal
(e.g. the higher the ambient temperature), the longer the selected switch-OFF time.
Thereby it is provided that the apparatus (or heat pump system) has sufficient time
to cool down during compressor switch-off.
[0028] Preferably at least one, at least two or more than two predetermined switch-OFF time(s)
are stored in an associated memory of the control unit for being selectively retrieved
by the control unit upon selection in dependency of the at least one detected temperature
signal as described above and below. For example the selection of the at least one
predetermined switch-OFF time is made among
(i) a first predetermined switch-OFF time to be selected for a first temperature or
a temperature range of the detected first temperature signal, and
(i) at least one second predetermined switch-OFF time to be selected for a second
temperature or a temperature range of the detected first temperature signal, wherein
the first and second switch-OFF times are different of each other, and wherein the
first and second temperature and/or the first and second temperature ranges are different
of each other. For example, if the detected first temperature signal is less than
or equal to 28°C the compressor switch-OFF time may be set to 5 min. In case the detected
first temperature signal exceeds 28°C the compressor switch-OFF time may be set to
7 min.
[0029] After switching-off the compressor, preferably (i) a second temperature signal or
the first temperature signal (in dependency of which the compressor is switched-on/off)
is detected after the predetermined switch OFF time, and (ii) when a selected temperature
threshold value is undershoot, the compressor is switched-on. In case that after the
predetermined switch OFF time the selected (switch-on) threshold value is not undershoot
(underrun), the compressor is not switched-on, i.e. the compressor is kept switched-off.
In this case the temperature signal may be detected again after the predetermined
switch OFF time as described above in steps (i) and (ii). Alternatively (after the
predetermined switch-off time has elapsed once) the temperature signal is detected
continuously or permanently until the selected temperature threshold value is undershoot,
whereupon the compressor is switched-on. Thus the duration of the (overall) compressor
switch-off time is minimized.
[0030] According to an embodiment, the method comprises repeatedly detecting the at least
one first temperature signal before starting to operate the compressor to determine
a first temperature gradient of the at least one first temperature signal. Alternatively
the method comprises detecting at least two temperatures of at least two spaced apart
positions in the cabinet of the apparatus to determine a second temperature gradient
between the at least two positions. If the (first or second) temperature gradient
exceeds a predetermined gradient, a predetermined temperature threshold value or a
pair of predetermined threshold values is selected. A high temperature gradient may
occur due to a malfunction of the temperature sensor(s) used for receiving the temperature
signal(s). Thus, when a temperature gradient threshold is exceeded, this may indicate
e.g. a broken temperature sensor.
[0031] For example, if the detected temperature signal is indicative of an ambient temperature,
the exceeded (first or second) temperature gradient may indicate that the detected
ambient temperature signal is not the real ambient temperature. In this case the selected
temperature threshold value(s) for switching the compressor on/off may correspond
to the threshold value(s) selected for a "cold" or "normal" temperature environment
(e.g. below 28°C). Alternatively the selected threshold value(s) may be between the
selected threshold value(s) for a "cold/normal" environment and a "hot" environment.
Thus a middle threshold value setting may be used which takes into account the possibility
of both environment conditions ("normal", "hot").
[0032] To determine whether a high (initial) first temperature signal (i.e. a temperature
detected in the hot range, e.g. above 30 °C) results from a previous drying cycle
or from a hot environment, the method preferably comprises: repeatedly detecting the
at least one first temperature signal before starting to operate the compressor to
determine a first temperature gradient of the at least one first temperature signal.
When the first temperature gradient exceeds a predetermined gradient, a predetermined
first temperature threshold value or a first pair of predetermined threshold values
is selected. When the first temperature gradient is below the predetermined gradient,
at least one predetermined second temperature threshold value or at least one second
pair of predetermined threshold values is selected. The first and second temperature
threshold value(s) may be different of each other.
[0033] For example, the first temperature signal may be detected at least two times, for
example before and after starting a drying cycle (wherein a process air fan already
starts operating) but before the compressor is operated, such that the ventilation
of the blower (e.g. process air blower and/or cooling air blower) balances the temperature
of the location where temperature is detected. When the initial signal is higher than
the subsequently detected signal, i.e. the temperature gradient is negative, the temperature
signals indicate that the treatment apparatus is located in an environment that is
colder than the detected temperature, such that the above described temperature threshold
values(s) for a cold/normal environment are selected. Preferably the threshold values
are chosen by the control unit, among a plurality of predetermined threshold values,
upon estimation of actual environment (ambient) temperature based on temperature signals
and/or temperature signals difference and time elapsed between two subsequent temperature
measurements by an appropriate algorithm. If a small temperature difference between
the successively detected first temperature signals is detected, i.e. the corresponding
gradient is almost zero, a hot or high temperature environment is indicated. Consequently
temperature threshold value(s) for a hot environment are selected.
[0034] An alternative or additional method for determining whether high (initial) first
temperature signal (i.e. a temperature detected in the hot range, e.g. above 30°C)
results from a previous drying cycle or from a hot environment is provided as described
below. At least two temperature signals of at least two spaced apart positions in
the cabinet of the apparatus are detected to determine a second temperature gradient
between the at least two positions. When the second temperature gradient exceeds a
predetermined gradient a first temperature threshold value or a first pair of predetermined
threshold values is selected among a plurality of predetermined threshold values.
A second temperature threshold value or a second pair of predetermined threshold values,
further selected among a plurality of predetermined threshold values, is selected
when the second temperature gradient is below the predetermined gradient. E.g. if
the detected (first) temperature signals are almost the same, i.e. the temperature
gradient is almost zero, an initial high temperature signal results from a hot environment,
such that a hot cycle is executed. In turn when at least one of the detected temperature
signals is higher than the other temperature signals, a cold environment may be indicated.
For example the initial high temperature of e.g. a sensor arranged at the heat pump
system results from a previous drying cycle but but not from a high temperature environment.
[0035] Preferably the value or level of at least one of the first temperature signal(s),
the first temperature gradient and the second temperature gradient is depending on
one or more of the following: an operation state of the laundry treatment apparatus,
an operation state of the heat pump system, a program cycle, a selected program for
laundry treatment, and a user input or selection input by a user of the laundry treatment
apparatus.
[0036] The at least one or the at least two detected first temperature signals may correspond
to a temperature detected at one of the following positions in the heat pump system
or within the cabinet of the laundry treatment apparatus: a refrigerant fluid outlet
position at the first or second heat exchanger, an electronic board or inverter position
of an electronic board or inverter controlling a component of the heat pump system,
an electronic board or inverter position of an electronic board or inverter controlling
a motor for driving the laundry treatment chamber being a drum, a refrigerant fluid
outlet position at the compressor, the compressor, the expansion device, a position
in a cooling air flow path (where e.g. the cooling air blown by a cooling air blower
flows), or a position in the air flow of the process air. Additionally at least one
temperature sensor may be arranged outside the treatment apparatus cabinet to detect
an ambient or environment temperature instantly. Further, a (second) temperature signal
which is compared to the selected threshold value(s), i.e. to determine whether the
compressor is to be switched-off/-on, may correspond to a temperature detected at
any of the above described positions.
[0037] According to an embodiment the at least one detected first temperature signal (Tx)
is provided by combining temperature signals that are detected at different locations
at or in the laundry treatment apparatus, and/or temperature signals that are detected
at different time points. Preferably all combined temperature signals are detected
for combining before starting the heat pump system or during or before a starting
phase of a laundry treatment sequence using the heat pump system.
[0038] A laundry treatment apparatus, in particular heat pump tumble dryer or washing machine
having a drying function is provided, wherein the apparatus comprises a heat pump
system, a control unit adapted to control the operation of the heat pump system and
a laundry treatment chamber for treating laundry using process air. The heat pump
system comprises a first heat exchanger for cooling a refrigerant fluid, a second
heat exchanger for heating the refrigerant fluid, an expansion device, a refrigerant
loop, in which the refrigerant fluid is circulated through the first and second heat
exchangers and the expansion device, a compressor for circulating the refrigerant
fluid through the refrigerant loop, and at least one temperature sensor for detecting
the temperature signal, wherein the control unit is adapted to implement a method
according to any of the above and below described embodiments.
[0039] Any of the above described features and elements of the methods of operating a treatment
apparatus may be combined in any arbitrary combination and may be implemented in a
heat pump laundry dryer or heat pump washing machine having drying function as described
above.
[0040] Reference is made in detail to preferred embodiments of the invention, examples of
which are illustrated in the accompanying figures, which show:
- Fig. 1
- a schematic view of a laundry treatment apparatus having a heat pump system,
- Fig. 2
- a schematic block diagram of controlling components of the apparatus of Fig. 1,
- Fig. 3
- an exemplary flow chart showing how predetermined temperature threshold values are
selected according to a first embodiment,
- Fig. 4
- an exemplary flow chart showing how predetermined temperature threshold values are
selected according to a second embodiment,
- Fig. 5
- an exemplary flow chart showing the selection of predetermined temperature threshold
values and the application of the temperature threshold values during an operation
of the laundry treatment apparatus, and
- Figs. 6a-b
- flow charts illustrating how to evaluate whether a high detected temperature signal
is due to ambient conditions or to what the heat pump system has performed before
the temperature detection.
[0041] Fig. 1 depicts a schematic representation of a laundry treatment apparatus 2 which
in this embodiment is a heat pump tumble dryer. The tumble dryer having a cabinet
3 or housing comprises a heat pump system 4, including in a closed refrigerant loop
6 in this order of refrigerant flow B: a first heat exchanger 10 acting as evaporator
for evaporating the refrigerant R and cooling process air, a compressor 14, a second
heat exchanger 12 acting as condenser for cooling the refrigerant R and heating the
process air, and an expansion device 16 from where the refrigerant R is returned to
the first heat exchanger 10. Together with the refrigerant pipes connecting the components
of the heat pump system 4 in series, the heat pump system 4 forms a refrigerant loop
6 through which the refrigerant R is circulated by the compressor 14 as indicated
by arrow B. If the refrigerant R in the heat pump system 4 is operated in the transcritical
or totally supercritical state, the first and second heat exchanger 10, 12 can act
as gas heater and gas cooler, respectively.
[0042] The expansion device 16 is a controllable valve that operates under the control of
a control unit 30 (Fig. 2) to adapt the flow resistance for the refrigerant R in dependency
of operating states of the heat pump system 4. In an embodiment the expansion device
16 may be a fixed, non-controllable device like a capillary tube.
[0043] The process air flow within the treatment apparatus 2 is guided through a compartment
18 of the treatment apparatus 2.The compartment 18 for receiving articles to be treated
may be a drum 18. The articles to be treated are textiles, laundry 19, clothes, shoes
or the like. In the embodiments here these are preferably textiles, laundry or clothes.
The process air flow is indicated by arrows A in Fig. 1 and is driven by a process
air blower 8 or fan. The process air channel 20 guides the process air flow A outside
the drum 18 and includes different sections, including the section forming the battery
channel 20a in which the first and second heat exchangers 10, 12 are arranged. The
process air exiting the second heat exchanger 12 flows into a rear channel 20b in
which the process air blower 8 is arranged. The air conveyed by blower 8 is guided
upward in a rising channel 20c to the backside of the drum 18. The air exiting the
drum 18 through the drum outlet (which is the loading opening of the drum) is filtered
by a fluff filter 22 arranged close to the drum outlet in or at the channel 20.
[0044] When the heat pump system 4 is operating, the first heat exchanger 10 transfers heat
from process air A to the refrigerant R. By cooling the process air to lower temperatures,
humidity from the process air condenses at the first heat exchanger 10, is collected
there and drained to a condensate collector 26. The process air which is cooled and
dehumidified after passing the first heat exchanger 10 passes subsequently through
the second heat exchanger 12 where heat is transferred from the refrigerant R to the
process air. The process air is sucked from exchanger 12 by the blower 8 and is driven
into the drum 18 where it heats up the laundry 19 and receives the humidity therefrom.
The process air exits the drum 18 and is guided in front channel 20d back to the first
heat exchanger 10. The main components of the heat pump system 4 are arranged in a
base section 5 or basement of the dryer 2.
[0045] An optional cooling air blower 24 or fan unit is arranged close to the compressor
14 to remove heat from the from the heat pump system 4 during a drying operation.-
Here as an example the cooling air flow C is taking heat from (the surface of) the
compressor 14. The air blower 24 comprises a blower or fan 36 which is driven by a
fan motor 34 controlled by the control unit 30 of the dryer 2. As indicated in Fig.
1, the cooling air C is sucked in at the bottom of the cabinet 3 and conveyed towards
the compressor 14 for compressor cooling. The cooling air (at least partially passed
over the compressor) exits the cabinet 3 through openings at the cabinet bottom and/or
rear wall of the cabinet 3. By transferring heat from the compressor 14, during operation
of the heat pump system 4, the refrigerant is shifted to optimized thermodynamic conditions
for the heat exchanges processes between the closed loops of the process air loop
and the refrigerant loop 6. Alternatively no fan unit 24 is provided.
[0046] The dryer 2 comprises a temperature sensor 28 for monitoring or detecting a temperature
of the refrigerant R (or of a temperature dependent on the refrigerant temperature)
at the compressor output to provide a temperature signal for the control unit 30.
In this embodiment the dryer 2 comprises an additional temperature sensor 27 preferably
arranged inside the cabinet 3 designed to detect the ambient temperature. The 'ambient'
temperature is a measure for the temperature of the environment where the dryer 2
is placed. For example when the dyer is placed indoor, the ambient temperature is
indoor temperature or when the dryer is placed outdoor (e.g. in a garage or a veranda)
the temperature is or is close to outside temperature. Sensor 27 may be placed external
to the cabinet 3, but is preferably internal to it and arranged at a position such
that at least at specific conditions the ambient temperature or a temperature that
is close to the real outside ambient temperature can be detected. As indicated in
Fig. 1, sensor 27 may be placed in an upper region of dryer, for example at or close
to the input panel 38. This position is distant to the heat sources or heated components
(where the process air flows) and measures a temperature close to the external temperature.
Alternatively, sensor 27 is placed in the bottom of the cabinet 3, for example in
the air path of the cooling air C sucked in by the blower 24 such that (at least after
operating the blower 24 for a short time) the detected ambient temperature is directly
related to the 'outside' ambient temperature.
[0047] As shown in Fig. 2 a further temperature sensor 29 is provided to monitor or detect
the temperature of an electronic board of the control unit 30, which provides a further
temperature signal for the control unit 30. Alternatively only one temperature sensor
is provided, e.g. sensor 28.
[0048] Examples for locations for temperature sensors are: a refrigerant fluid outlet of
the first or second heat exchanger 10, 12, an electronic board or inverter position
of an electronic board or inverter controlling a component of the heat pump system
4, an electronic board or inverter position of an electronic board or inverter controlling
the drum motor 32, a refrigerant fluid outlet position at the compressor 14, the compressor
14, the expansion device 16 or a position in the air flow A of the process air. Preferably
one or more temperature sensors are positioned such that an operating state of the
heat pump system 4 and/or ambient conditions and/or starting conditions for the heat
pump system 4 may be derived or deduced from the detected temperature or from a combination
of temperature signals of two or more temperature sensors. In the following temperature
detection is described in more detail as an example.
[0049] Fig. 2 shows a schematic block diagram of components of the dryer of Fig. 1 illustrating
the control of the dryer components. The control unit 30 is adapted to control the
operation of the components of the dryer 2, for example the drum motor 32, the compressor
14, the valve 16 (optionally) and the fan motor 34, according to the selected program.
Via an input panel 38 a user may select a drying program or cycle, e.g. FAST, ECONOMY,
IRON-AID. Optionally further inputs may be made, e.g. residue humidity, laundry amount
and/or laundry type. Further, the control unit 30 is adapted to control the air blower
24 and the compressor 14 such that during the heat pump 4 warm-up period and the following
normal operation period the operation conditions of the heat pump system 4 can be
optimized in view of one or more of: energy consumption / drying duration / drying
result / component's lifetime.
[0050] Fig. 3 shows a flow chart illustrating an exemplary method for operating a treatment
apparatus 2 as described above. Before starting to operate the compressor 14, a first
temperature signal Tx is detected, e.g. from temperature sensor 28 at the compressor
exit. When the heat pump system 4 is in a 'cold' state, the detected temperature signal
corresponds to the ambient temperature where the treatment apparatus is placed, or
the detected temperature signal is at least indicative of the ambient temperature.
When the temperature signal is higher than a predetermined upper limit, e.g. 28°C,
the dryer 2 or the heat pump system 4 is considered to be in a "hot" state or condition.
Depending on the level of the detected first temperature signal Tx, respective predetermined
temperature threshold values are selected. The respective predetermined temperature
threshold values to be selected may be stored in a memory of the control unit 30 which
may be adapted to select the threshold values as described above and below.
[0051] In the exemplary embodiment depicted, if Tx > 28°C, "hot" temperature threshold values
are selected and applied to the compressor control provided by the control unit 30.
If the detected first temperature signal Tx is below the upper limit, e.g. 28°C, the
dryer or heat pump system 4 is considered to be in a "normal" state or condition.
Then the predetermined "normal" temperature threshold values are selected and applied
in the control routines to control the compressor 14 via control unit 30. Self-evident
that the predefined 'hot' temperature threshold values are different to the predefined
'normal' temperature threshold values. (For the embodiments below the 'hot' temperature
threshold values, the 'normal' temperature threshold values and the 'cold' temperature
threshold values are mutually different to each other). The 'values' may be one 'value'
and can also be denoted or understood as parameter or parameters used in compressor
or heat pump system control routines.
[0052] As shown in Fig. 3, preferably at least two different temperature threshold value(s)
or two pairs of temperature threshold values for switching the compressor on and/or
off are provided. The respective threshold value(s) are selected depending on the
temperature range (below or above 28°C) in which the detected first temperature signal
Tx lies. For example for each temperature range (below or above 28°C) (i) one predetermined
temperature threshold value or (ii) one pair of predetermined temperature threshold
values may be provided.
[0053] Depending on a repeatedly or permanently detected (second) temperature signal (e.g.
of sensor 27, sensor 28 and/or sensor 29) the compressor is switched-off when the
temperature signal reaches or exceeds the selected compressor switch-off temperature
threshold value and is switched-on when the selected switch-on temperature threshold
value is undershoot. Alternatively the compressor is switched-on and/or -off depending
on the repeatedly or permanently detected first temperature signal Tx. For example
only one temperature threshold value may be selected for determining when the compressor
has to be switched-off and switched-on. Alternatively a pair of temperature threshold
values are selected, preferably one switch-off threshold value (T_off) and a further
switch-on threshold value (T_on) different from the switch-off value.
[0054] The above and below described methods provide that compressor switch-off/-on threshold
values are adapted to the current/present (temperature) condition of the treatment
apparatus. Thereby compressor operation is adapted to the current condition or state
of the dryer 2. For example, if a "hot" environment is detected, a switch-off temperature
threshold value is selected which is lower than a switch-off temperature threshold
value for a "normal" environment. In a "hot" environment the capacity of the heat
pump system (or treatment apparatus) to convey/discharge heat is reduced as compared
to a "normal" or "cold" temperature environment. By reducing the switch-off threshold
value for a detected "hot" condition it is provided that the compressor is safely
switched-off in critical (temperature) conditions. Thus it is provided that the compressor
14 is safely operated during a drying operation.
[0055] The above method provides additionally that emergency switch-offs of the compressor
14 by means of a safety device (not shown) like a thermoprotector are prevented. For
example the dryer 2 may comprise a safety device to switch-off the compressor 14 to
prevent damage of the compressor 14 in a critical (temperature) condition. The duration
of an emergency switch-off by means of a safety device is generally long and not well
controllable. Thus a drying operation is suspended unnecessarily long when an emergency
switch-off of the compressor 14 occurs. In general, a compressor safety device intervenes
for a combined effect of compressor temperature and current absorbed by the compressor.
Thus the safety device is not controlled by a temperature signal indicating the condition
of the heat pump system, for example of the refrigerant temperature. For example,
if a fixed temperature threshold value would be used for all drying operations, it
may occur in high ambient temperature condition (e.g. above 30°C), that the refrigerant
temperature is lower than the fixed compressor switch-off threshold (i.e. the compressor
is kept ON), while the safety device intervenes by switching the compressor OFF. This
is mainly due to the refrigerant circuit and safety device having different thermal
inertia. For example this difference is due to the situation that a temperature sensor
(e.g. sensor 28) for detecting the temperature signal (e.g. of the refrigerant) and
the safety device are placed at different locations within the treatment apparatus.
Therefore the temperature sensor 28 and the safety device are subject to different
temperatures.
[0056] To prevent an emergency switch-off by means of a safety device, the above described
at least one predetermined temperature threshold value is selected, such that the
compressor 14 may be switched-off before the safety device intervenes or is activated.
When the detected first temperature signal Tx is low ('ambient' temperature low),
the at least one selected temperature threshold value may be set at a higher level,
as compared to threshold value(s) for a detected high value of the first temperature
signal Tx. A detected high value of the first temperature signal Tx may result from
a previous drying operation and/or from a high ambient temperature. In this case the
dryer 2 or (the components of) the heat pump system 4 reaches a critical (temperature)
condition faster as compared to the case when a low value of the first temperature
signal Tx is detected. The first temperature signal Tx may have a low value when the
dryer 2 has not been operated for some time, such that the dryer 2 is cooled down,
and/or the ambient temperature is low or normal (e.g. below 28°C).
[0057] Fig. 4 shows a flow chart depicting an alternative method for operating a dryer 2.
In contrast to the method shown in Fig. 3, this method provides a selection of at
least three predetermined pairs of temperature threshold values T_off1..3, T_on1..3.
As in the above embodiment, the respective pair of temperature threshold values T_off1..3,
T_on1..3 is selected in dependency of a detected first temperature signal Tx. If the
detected first temperature signal Tx is between two limiting temperature values (e.g.
15°C and 28°C) the dryer or heat pump system is considered to be in a normal state
or condition, i.e. corresponding temperature threshold values T_off2/T_on2 are selected.
In the control unit memory there may be provided one, two, three (as depicted in Fig.
4) or more predefined pairs of temperature threshold values for specific temperature
ranges or values of the detected first temperature signal Tx. In the embodiment of
Fig. 4 the pair T_off1, T_on1 is for the range Tx < 15°C, the pair T_off2, T_on2 is
for the range 15°C ≤ Tx < 28°C, and the pair T_off3, T_on3 is for the range Tx > 28°C.
[0058] Fig. 5 shows a flow chart illustrating an exemplary course of selecting predetermined
temperature threshold values and applying the selected temperature threshold values
during a laundry treatment apparatus operation. The steps for selecting the temperature
threshold values T_off1..2, T_on1..2 for switching the compressor 14 on and off correspond
to the method described above in Fig. 3. Alternatively the selection of the predetermined
temperature threshold values may be executed as described with respect to Fig. 4 or
any other way described above and below.
[0059] According to the control sequence shown in Fig. 5, after selecting the respective
threshold values T off1..2, T_on1..2 the control unit 30 is adapted to start a drying
operation. During the drying operation a second temperature signal T is detected (permanently
or repeatedly) and the control unit 30 is adapted to control whether the second temperature
signal T is equal to or exceeds the selected compressor switch-off threshold value
T_off1..2. The detected second temperature signal T may be the same as the above described
first temperature signal Tx. Alternatively the second temperature signal T may be
a temperature signal different from the above first temperature signal Tx used for
selecting the threshold values T off1..2, T_on1..2. In the following the term "second
temperature signal" is used to distinguish the first temperature signal Tx detected
for determining the switch-on/-off threshold values for the compressor 14 from the
detected (first or second) temperature signal T during an operation of the dryer 2.
T and Tx may but must not be different signals.
[0060] When the detected second temperature signal T is below the respective selected switch-off
threshold T off1..2, the drying operation is continued. When the detected second temperature
signal T is above the selected switch-off threshold T_off1..2 the compressor 14 is
switched-off (and the drying operation suspended). After a predetermined switch-off
time (e.g. 5 min.) the second temperature signal T is detected once more. When the
second temperature signal T is below the selected compressor switch-on threshold value
T_on1..2, the compressor 14 is switched-on and the drying operation is continued.
[0061] If (after the predetermined switch-off time) the second temperature signal T is higher
than the selected switch-on threshold T_on1..2, the compressor is kept switched-off
once more for the predetermined switch-off time (e.g. 5 min.). After the switch-off
time has elapsed, the second temperature signal T is detected once more to determine
whether the switch-on threshold value T_on1..2 is undershot as described above.
[0062] Alternatively, after the switch-off time is expired once and the second temperature
signal T is not below the selected switch-on threshold T_on1..2, the second temperature
signal T may be detected permanently, such that the compressor 14 may be switched
on immediately when the switch-on threshold value is undershot. Thereby the overall
switch-off time of the compressor 14 is minimized.
[0063] Before starting dryer operation (here start of heat pump system), a predetermined
switch-off time may be selected in dependency of the detected at least one first temperature
signal Tx. For example, the higher the value of the first temperature signal (e.g.
the higher the ambient temperature) the longer the duration of the predetermined switch-off
time. Thereby it is provided that after switching of the compressor the dryer 2 has
sufficient time to cool down. Exemplary predetermined temperature threshold values
and switch-off times selected in dependency of the detected first temperature signal
Tx are shown in the following table.
|
Tx < 15°C |
15°C ≤ Tx ≤ 30°C |
Tx > 30°C |
switch-OFF value (T_off) |
75°C |
70°C |
65°C |
switch-ON value (T_on) |
65°C |
60°C |
50°C |
compressor switch-OFF time |
4 min. |
5 min. |
6 min. |
[0064] Figs. 6a-b show flow charts of two different embodiments for evaluating whether a
high detected temperature Tx (i.e. a temperature detected in the hot range, for example
a temperature detected above 30 °C) is due to ambient conditions or is due to operating
conditions of the heat pump system 4 which were applied before the current temperature
detection and resulted in the detection of the high temperature (e.g. starting a drying
program immediately or shortly after a previous drying process).
[0065] As shown in Fig. 6a, an initial (high) value of the first temperature signal Tx is
T1 which is measured or detected just when the machine is switched on or a drying
program is selected (at that time none of the treatment apparatus components like
compressor 14 or blower 8 is activated). The first temperature signal Tx may be measured
by an NTC (Negative Temperature Coefficient Thermistor) or temperature sensor installed
in or at the heat pump system 4 (for example sensor 28 at the compressor outlet),
wherein any temperature sensor placed at other places of the apparatus 2 could be
used for the same purpose. Another example would be one or more temperature sensors
mounted on electronic boards, e.g. a power board and a compressor control board.
[0066] Subsequent to determining Tx the first time, the drying cycle is started which in
this cycle means that the drum motor 32 rotates the drum 18 and the connected process
air fan 8 for circulating air A. After a predetermined time from the start of the
drying cycle (e.g. 1 min) the compressor 14 is still switched off and the temperature
measurement is repeated to obtain a second temperature signal Tx = T2.
[0067] Then the two temperatures T1, T2 are compared. When the initially detected (high)
temperature signal T1 is higher than the subsequently detected temperature signal
T2, the treatment apparatus 2 is located in an environment that is colder than the
detected temperatures T1, T2. The ventilation effect of the fan 8 leveled the initial
high temperature signal T1 to the lower temperature level T2 of the apparatus environment.
For example the high temperature signal T1 results from a previous drying operation
of the apparatus 2, but not from a generally high temperature (ambient) environment
of the dryer 2. The actual (ambient) environment may be estimated from detected temperatures
T1, T2 and/or temperature difference T1-T2 and time elapsed between two subsequent
temperature measurements by an appropriate algorithm. The control unit 30 selects
the predetermined temperature threshold value(s) based on the (ambient) environment
temperature estimated by such algorithm as described above.
[0068] When the initially detected temperature signal T1 is the same or less than the subsequently
detected temperature signal T2, the dryer 2 is located at a high temperature environment.
Alternatively the dryer 2 is located in an environment which does not allow sufficient
removal of heat from the dryer, e.g. the dryer 2 is located in a small compartment,
niche or room. Here it is determined that e.g. the ventilation effect due to the fan
8 gave no results in term of temperature decrease after a sufficiently long period
of fan operation. The control unit selects the predetermined temperature threshold
value(s) as described above based on the detected temperature value T1 or T2.
[0069] As shown in Fig. 6b three temperature sensors are available to detect three temperature
signals Ta, Tb, Tc (at the same time) at three different positions. For example temperature
sensor 28 at the refrigerant circuit, temperature sensor 27 at the upper or lower
region of the cabinet 3 (see above), and a temperature sensor on the compressor control
board. Sensor 28 may be in the machine basement 5, and the compressor control board
is in a region over the basement 5.
[0070] The detected temperature signals Ta, Tb, Tc are compared to determine whether they
are essentially the same, i.e. whether the temperature values vary within a predetermined
range ΔT ≤ ΔT1
threshold. If the detected (high) temperature signals Ta, Tb, Tc are essentially the same,
the high temperature is due to the high temperature ambient condition. If one or more
of the temperature sensors (in particular sensor 28) detects a completely different
temperature, i.e. ΔT > ΔT1
threshold then the initial high temperature probably results from a previous drying cycle.
In this case the ambient temperature may be normal (e.g. in the range of 15 to 30°C)
or cold (e.g. below 15°C). In particular it is checked whether the temperature difference
ΔT is below a further predetermined threshold ΔT2
threshold > ΔT1
threshold such that it is concluded that there is a normal environment (normal range of ambient
temperature). Otherwise (ΔT > ΔT2
threshold) it is a cold ambient temperature. The control unit 30 selects the appropriate predetermined
temperature threshold value(s) as described above. The difference temperature ΔT may
be a complex or simple function of the temperature signals Ta, Tb, Tc (ΔT = f(Ta,
Tb, Tc) or only a function of two of the temperature signals.
[0071] Figs. 6a and 6b are examples of combining temperature signals measured at differently
positioned temperature sensors (27, 28, 29) and/or measured at different time points
and which are combined in a way by the control logic of the control unit for determining
(here on a plausibility scheme) the 'external' conditions (hot/normal/cold environment)
and/or 'internal' conditions (cold/warm/hot state of the heat pump system) for optimizing
the control of the heat pump system operation. In the above embodiment the temperature-dependent
configuration of the control parameters (temperature thresholds) results in avoiding
exceptional operation interrupts by prioritized controls (compressor shut-down).
Reference Numeral List
2 |
heat pump tumble dryer |
26 |
condensate collector |
3 |
cabinet/housing |
27 |
external temperature sensor |
4 |
heat pump system |
28 |
temperature sensor |
5 |
base section |
|
(compressor exit) |
6 |
refrigerant loop |
29 |
temperature sensor |
8 |
blower |
|
(electronic board) |
10 |
first heat exchanger (evaporator) |
30 |
control unit |
|
|
32 |
drum motor |
12 |
second heat exchanger (condenser) |
34 |
fan motor |
|
|
36 |
fan |
14 |
compressor |
38 |
input panel |
16 |
expansion device |
A |
process air flow |
18 |
drum (laundry compartment) |
B |
refrigerant flow |
19 |
laundry |
C |
cooling air (flow) |
20 |
process air channel |
R |
refrigerant |
20a |
battery channel |
T, Tx |
detected temperature signal |
20b |
rear channel |
T_off1..2 |
compressor switch-off |
20c |
rising channel |
|
temperature threshold value |
20d |
front channel |
T_on1..2 |
compressor switch-on |
22 |
fluff filter |
|
temperature threshold value |
24 |
cooling air blower |
|
|
1. Method for operating laundry treatment apparatus, in particular a heat pump dryer
or washing machine having dryer function, wherein the apparatus (2) comprises a heat
pump system (4) and a laundry treatment chamber (18) for treating laundry using process
air (A), and wherein the heat pump system comprises:
a first heat exchanger (10) for heating a refrigerant fluid (R),
a second heat exchanger (12) for cooling the refrigerant fluid (R),
an expansion device (16),
a refrigerant loop (6), in which the refrigerant fluid is circulated through the first
and second heat exchangers and the expansion device, and
a compressor (14) for circulating the refrigerant fluid (R) through the refrigerant
loop (6),
the method comprising detecting at least one first temperature signal (Tx), characterized by
in dependency of the at least one detected first temperature signal (Tx), selecting
at least one predetermined temperature threshold value (T_off1..3, T_on1..3) for switching
the compressor (14) ON and/or OFF, such as to prevent an overheating of the compressor
(14).
2. Method according to claim 1, wherein the method comprises selecting in dependency
of the at least one detected first temperature signal a pair of temperature threshold
values:
(i) a switch-OFF temperature threshold value (T_off1..3) for switching OFF the compressor,
and
(ii) a switch-ON temperature threshold value (T_on1..3) for switching ON the compressor,
wherein the switch-OFF temperature threshold value and the switch-ON temperature threshold
value are different of each other.
3. Method according to claim 1 or 2, wherein the at least one detected first temperature
signal is indicative of an ambient or environment temperature of the laundry treatment
apparatus.
4. Method according to claim 1, 2 or 3, wherein the at least one detected first temperature
signal is provided by at least one temperature sensor (27, 28) capable of detecting
the environment or ambient temperature at least under a predefined operation condition.
5. Method according to any of the previous claims, wherein the laundry treatment apparatus
(2) comprises a control unit (30) having an associated memory, wherein at least one,
at least two or more than two predetermined temperature threshold values (T_off1..3,
T_on1..3) are stored in the memory for being selectively retrieved by the control
unit upon selection in dependency of the at least one detected first temperature signal
(Tx).
6. Method according to any of the previous claims, wherein the selection of the at least
one predetermined temperature threshold value is made among
a first predetermined temperature threshold value or a first pair of predetermined
threshold values (T_off1..3, T_on1..3) to be selected for a first temperature or a
temperature range of the detected first temperature signal (Tx),
at least one second predetermined temperature threshold value or at least one second
pair of predetermined threshold values (T_off1..3, T_on1..3) to be selected for a
second temperature or a temperature range of the detected first temperature signal
(Tx),
wherein the first and second threshold values or first and second pairs of threshold
values (T_off1..3, T_on1..3) are different of each other, and
wherein the first and second temperature and/or the first and second temperature ranges
are different of each other.
7. Method according to any of the previous claims, wherein the higher the detected first
temperature signal or temperature range, the lower the value of the selected temperature
threshold value or the selected pair of temperature threshold values (T_offl..3, T_on1..3).
8. Method according to any of the previous claims, wherein the method further comprises:
selecting in dependency of the at least one detected first temperature signal (Tx)
a predetermined switch-OFF time for the compressor (14), and
switching OFF the compressor (14) for a predetermined switch-OFF time, when the selected
temperature threshold value (T_off1..3) is exceeded.
9. Method according to any of the previous claims, wherein the compressor (14) is switched
OFF in dependency of the detected first temperature signal (Tx) or at least one detected
second temperature signal (T).
10. Method according to any of the previous claims, wherein the method further comprises:
detecting the at least one first or second temperature signal (T, Tx) after the predetermined
switch OFF time, and
switching ON the compressor (14) when a selected temperature threshold value (T_on1..3)
is undershoot.
11. Method according to any of the previous claims, wherein the method comprises:
repeatedly detecting the at least one first temperature signal (Tx) before starting
to operate the compressor to determine a first temperature gradient of the at least
one first temperature signal, or
detecting at least two temperatures of at least two spaced apart positions in the
cabinet of the apparatus to determine a second temperature gradient between the at
least two positions,
wherein the method further comprises selecting a predetermined temperature threshold
value or a pair of predetermined threshold values when the first or second temperature
gradient exceeds a predetermined gradient.
12. Method according to claim 11, wherein the selected temperature threshold value or
pair of temperature threshold values correspond to values selected for a low temperature
signal.
13. Method according to claim 11,
wherein the selected temperature threshold value lies between threshold values selected
for a low temperature signal and a high temperature signal, or
wherein the values of the selected pair of threshold values lie between the corresponding
values selected for a low temperature signal and a high temperature signal.
14. Method according to any of claims 1 to 10, wherein the method comprises:
repeatedly detecting the at least one first temperature signal (Tx) before starting
to operate the compressor (14) to determine a first temperature gradient of the at
least one first temperature signal (Tx),
selecting a predetermined first temperature threshold value or a first pair of predetermined
threshold values when the first temperature gradient exceeds a predetermined gradient,
and
selecting at least one predetermined second temperature threshold value or at least
one second pair of predetermined threshold values when the first temperature gradient
is below the predetermined gradient.
15. Method according to any of claims 11 to 14, wherein the method further comprises:
detecting at least two temperatures of at least two spaced apart positions in the
cabinet of the apparatus to determine a second temperature gradient between the at
least two positions,
selecting a predetermined first temperature threshold value or a first pair of predetermined
threshold values when the second temperature gradient exceeds a predetermined gradient,
and
selecting at least one predetermined second temperature threshold value or at least
one second pair of predetermined threshold values when the second temperature gradient
is below the predetermined gradient.
16. Method according to any of the previous claims, wherein the at least one or the at
least two detected first temperature signals (Tx) or the at least one second temperature
signal (T) correspond to a temperature detected at one of the following positions
in the heat pump system (4) or within the cabinet of the laundry treatment apparatus
(2):
a refrigerant fluid outlet position at the first or second heat exchanger (10, 12),
an electronic board or inverter position of an electronic board or inverter controlling
a component of the heat pump system (4),
an electronic board or inverter position of an electronic board or inverter controlling
a motor for driving the laundry treatment chamber being a drum,
a refrigerant fluid outlet position at the compressor (14),
the compressor (14),
the expansion device (16), or
a position in the air flow (A) of the process air.
17. Method according to any of the previous claims, wherein the at least one detected
first temperature signal (Tx) is provided by combining
- temperature signals that are detected at different locations at or in the laundry
treatment apparatus,
- temperature signals that are detected at different time points, or
- temperature signals that are detected at different locations at or in the laundry
treatment apparatus and temperature signals that are detected at different time points.
18. Laundry treatment apparatus, in particular heat pump tumble dryer or washing machine
having a drying function, wherein the apparatus comprises a heat pump system (4),
a control unit (30) adapted to control the operation of the heat pump system and a
laundry treatment chamber (18) for treating laundry using process air, and wherein
the heat pump system (4) comprises:
a first heat exchanger (10) for cooling a refrigerant fluid (R),
a second heat exchanger (12) for heating the refrigerant fluid (R),
an expansion device (16),
a refrigerant loop (6), in which the refrigerant fluid is circulated through the first
and second heat exchangers and the expansion device,
a compressor (14) for circulating the refrigerant fluid through the refrigerant loop
(6); and
at least one temperature sensor for detecting a temperature signal;
wherein the control unit (30) is adapted to implement a method according to any of
the previous claims.
1. Verfahren zum Betreiben einer Wäschebehandlungsvorrichtung, insbesondere eines Wärmepumpentrockners
oder einer Waschmaschine, die eine Trocknerfunktion besitzt, wobei die Vorrichtung
(2) ein Wärmepumpensystem (4) und eine Wäschebehandlungskammer (18) zum Behandeln
von Wäsche unter Verwendung von Prozessluft (A) umfasst und wobei das Wärmepumpensystem
Folgendes umfasst:
einen ersten Wärmetauscher (10) zum Erhitzen eines Kühlfluids (R),
einen zweiten Wärmetauscher (12) zum Kühlen des Kühlfluids (R),
eine Ausdehnungsvorrichtung (16),
eine Kältemittelschleife (6), in der das Kühlfluid durch den ersten und den zweiten
Wärmetauscher und die Ausdehnungsvorrichtung umgewälzt wird, und
einen Kompressor (14) zum Umwälzen des Kühlfluids (R) durch die Kältemittelschleife
(6),
wobei
das Verfahren ein Detektieren mindestens eines ersten Temperatursignals (Tx) umfasst,
gekennzeichnet durch
Wählen in Abhängigkeit von dem mindestens einen detektierten ersten Temperatursignal
(Tx) mindestens eines ersten vorgegebenen Temperaturschwellenwerts (T_offl...3, T_onl...3)
zum Ein- und/oder Ausschalten des Kompressors (14), um ein Überhitzen des Kompressors
(14) zu verhindern.
2. Verfahren nach Anspruch 1, wobei das Verfahren ein Wählen in Abhängigkeit von dem
mindestens einen detektierten ersten Temperatursignal eines Paars Temperaturschwellenwerte
umfasst:
(i) eines Ausschalttemperaturschwellenwerts (T_offl...3) zum Ausschalten des Kompressors
und
(ii) eines Einschalttemperaturschwellenwerts (T_onl...3) zum Einschalten des Kompressors,
wobei
der Ausschalttemperaturschwellenwert und der Einschalttemperaturschwellenwert voneinander
verschieden sind.
3. Verfahren nach Anspruch 1 oder 2, wobei das mindestens eine detektierte erste Temperatursignal
eine Außen- oder Umgebungstemperatur der Wäschebehandlungsvorrichtung angibt.
4. Verfahren nach Anspruch 1, 2 oder 3, wobei das mindestens eine detektierte erste Temperatursignal
durch mindestens einen Temperatursensor (27, 28) geliefert wird, der die Außen- oder
Umgebungstemperatur mindestens unter einer im Voraus definierten Betriebsbedingung
detektieren kann.
5. Verfahren nach einem der vorhergehenden Ansprüche, wobei die Wäschebehandlungsvorrichtung
(2) eine Steuereinheit (30) umfasst, die einen zugeordneten Speicher besitzt, wobei
mindestens ein, mindestens zwei oder mehr als zwei vorgegebene Temperaturschwellenwerte
(T_offl...3, T_onl...3) im Speicher gespeichert sind, um durch die Steuereinheit nach
einer Auswahl in Abhängigkeit vom mindestens einen detektierten ersten Temperatursignal
(Tx) wahlweise abgerufen zu werden.
6. Verfahren nach einem der vorhergehenden Ansprüche, wobei die Auswahl des mindestens
einen vorgegebenen Temperaturschwellenwerts zwischen Folgendem vorgenommen wird:
einem ersten vorgegebenen Temperaturschwellenwert oder einem ersten Paar vorgegebener
Schwellenwerte (T_offl...3, T_onl...3), die für eine erste Temperatur oder einen Temperaturbereich
des detektierten ersten Temperatursignals (Tx) gewählt werden sollen, und
mindestens einem zweiten vorgegebenen Temperaturschwellenwert oder mindestens einem
zweiten Paar vorgegebener Schwellenwerte (T_offl...3, T_on1...3), die für eine zweite
Temperatur oder einen Temperaturbereich des detektierten ersten Temperatursignals
(Tx) gewählt werden sollen, wobei
der erste und der zweite Schwellenwert oder das erste und das zweite Paar Schwellenwerte
(T_offl...3, T_onl...3) voneinander verschieden sind und
die erste und die zweite Temperatur und/oder der erste und der zweite Temperaturbereich
voneinander verschieden sind.
7. Verfahren nach einem der vorhergehenden Ansprüche, wobei der Wert des gewählten Temperaturschwellenwerts
oder des gewählten Paars Temperaturschwellenwerte (T_offl...3, T_onl...3) umso niedriger
ist, je höher das detektierte erste Temperatursignal oder der detektierte erste Temperaturbereich
ist.
8. Verfahren nach einem der vorhergehenden Ansprüche, wobei das Verfahren ferner Folgendes
umfasst:
Wählen in Abhängigkeit vom mindestens einen detektierten ersten Temperatursignal (Tx)
einer vorgegebenen Ausschaltzeit für den Kompressor (14) und
Ausschalten des Kompressors (14) für eine vorgegebene Ausschaltzeit, wenn der gewählte
Temperaturschwellenwert (T_offl...3) überschritten wird.
9. Verfahren nach einem der vorhergehenden Ansprüche, wobei der Kompressor (14) in Abhängigkeit
vom detektierten ersten Temperatursignal (Tx) oder mindestens einem detektierten zweiten
Temperatursignal (T) ausgeschaltet wird.
10. Verfahren nach einem der vorhergehenden Ansprüche, wobei das Verfahren ferner Folgendes
umfasst:
Detektieren des mindestens einen ersten oder zweiten Temperatursignals (T, Tx) nach
der vorgegebenen Ausschaltzeit und
Einschalten des Kompressors (14), wenn ein gewählter Temperaturschwellenwert (T_onl...3)
unterschritten wird.
11. Verfahren nach einem der vorhergehenden Ansprüche, wobei das Verfahren Folgendes umfasst:
wiederholtes Detektieren des mindestens einen ersten Temperatursignals (Tx) vor dem
Starten des Betriebs des Kompressors, um einen ersten Temperaturgradienten des mindestens
einen ersten Temperatursignals zu bestimmen, oder
Detektieren von mindestens zwei Temperaturen von mindestens zwei beabstandeten Positionen
im Gehäuse der Vorrichtung, um einen zweiten Temperaturgradienten zwischen den mindestens
zwei Positionen zu bestimmen, wobei
das Verfahren ferner ein Wählen eines vorgegebenen Temperaturschwellenwerts oder eines
Paars vorgegebener Schwellenwerte umfasst, wenn der erste oder der zweite Temperaturgradient
einen vorgegebenen Gradienten überschreitet.
12. Verfahren nach Anspruch 11, wobei der gewählte Temperaturschwellenwert oder das Paar
Temperaturschwellenwerte Werten entsprechen, die für ein Niedrigtemperatursignal gewählt
wurden.
13. Verfahren nach Anspruch 11, wobei
der gewählte Temperaturschwellenwert zwischen Schwellenwerten liegt, die für ein Niedrigtemperatursignal
und ein Hochtemperatursignal gewählt wurden, oder
die Werte des gewählten Paars von Schwellenwerten zwischen den entsprechenden Werten,
die für ein Niedrigtemperatursignal und ein Hochtemperatursignal gewählt wurden, liegen.
14. Verfahren nach einem der Ansprüche 1 bis 10, wobei das Verfahren Folgendes umfasst:
wiederholtes Detektieren des mindestens einen ersten Temperatursignals (Tx) vor dem
Starten des Betriebs des Kompressors (14), um einen ersten Temperaturgradienten des
mindestens einen ersten Temperatursignals (Tx) zu bestimmen,
Wählen eines vorgegebenen ersten Temperaturschwellenwerts oder eines ersten Paars
vorgegebener Schwellenwerte, wenn der erste Temperaturgradient einen vorgegebenen
Gradienten überschreitet, und
Wählen mindestens eines vorgegebenen zweiten Temperaturschwellenwerts oder mindestens
eines zweiten Paars vorgegebener Schwellenwerte, wenn der erste Temperaturgradient
unter dem vorgegebenen Gradienten liegt.
15. Verfahren nach einem der Ansprüche 11 bis 14, wobei das Verfahren ferner Folgendes
umfasst:
Detektieren von mindestens zwei Temperaturen an mindestens zwei beabstandeten Positionen
im Gehäuse der Vorrichtung, um einen zweiten Temperaturgradienten zwischen den mindestens
zwei Positionen zu bestimmen,
Wählen eines vorgegebenen ersten Temperaturschwellenwerts oder eines ersten Paars
vorgegebener Schwellenwerte, wenn der zweite Temperaturgradient einen vorgegebenen
Gradienten überschreitet, und
Wählen mindestens eines vorgegebenen zweiten Temperaturschwellenwerts oder mindestens
eines zweiten Paars vorgegebener Schwellenwerte, wenn der zweite Temperaturgradient
unter dem vorgegebenen Gradienten liegt.
16. Verfahren nach einem der vorhergehenden Ansprüche, wobei das mindestens eine oder
die mindestens zwei detektierten ersten Temperatursignale (Tx) oder das mindestens
eine zweite Temperatursignal (T) einer Temperatur entsprechen, die bei einer der folgenden
Positionen im Wärmepumpensystem (4) oder im Gehäuse der Wäschebehandlungsvorrichtung
(2) detektiert wurde:
einer Kühlfluidauslassposition beim ersten oder beim zweiten Wärmetauscher (10, 12),
einer Position einer Elektronikplatine oder eines Wechselrichters einer Elektronikplatine
oder eines Wechselrichters, die bzw. der eine Komponente des Wärmepumpensystems (4)
steuert,
einer Position einer Elektronikplatine oder eines Wechselrichters einer Elektronikplatine
oder eines Wechselrichters, die bzw. der einen Motor zum Antreiben der Wäschebehandlungskammer,
die eine Trommel ist, steuert,
einer Kühlfluidauslassposition beim Kompressor (14),
dem Kompressor (14),
der Ausdehnungsvorrichtung (16) oder
einer Position im Luftstrom (A) der Prozessluft.
17. Verfahren nach einem der vorhergehenden Ansprüche, wobei das mindestens eine detektierte
erste Temperatursignal (Tx) durch Kombinieren von Folgendem bereitgestellt wird:
- Temperatursignalen, die bei verschiedenen Orten bei oder in der Wäschebehandlungsvorrichtung
detektiert werden,
- Temperatursignalen, die zu verschiedenen Zeitpunkten detektiert werden, oder
- Temperatursignalen, die bei verschiedenen Orten bei oder in der Wäschebehandlungsvorrichtung
detektiert werden, und Temperatursignalen, die zu verschiedenen Zeitpunkten detektiert
werden.
18. Wäschebehandlungsvorrichtung, insbesondere ein Wärmepumpentrockner oder eine Waschmaschine,
die eine Trocknerfunktion besitzt, wobei die Vorrichtung ein Wärmepumpensystem (4),
eine Steuereinheit (30), die ausgelegt ist, den Betrieb des Wärmepumpensystems zu
steuern, und eine Wäschebehandlungskammer (18) zum Behandeln von Wäsche unter Verwendung
von Prozessluft umfasst und wobei das Wärmepumpensystem (4) Folgendes umfasst:
einen ersten Wärmetauscher (10) zum Kühlen eines Kühlfluids (R),
einen zweiten Wärmetauscher (12) zum Erhitzen des Kühlfluids (R),
eine Ausdehnungsvorrichtung (16),
eine Kältemittelschleife (6), in der das Kühlfluid durch den ersten und den zweiten
Wärmetauscher und die Ausdehnungsvorrichtung umgewälzt wird,
einen Kompressor (14) zum Umwälzen des Kühlfluids (R) durch die Kältemittelschleife
(6); und
mindestens einen Temperatursensor zum Detektieren eines Temperatursignals; wobei
die Steuereinheit (30) ausgelegt ist, ein Verfahren nach einem der vorhergehenden
Ansprüche zu implementieren.
1. Procédé d'exploitation d'un appareil de traitement de linge, en particulier un sèche-linge
ou un lave-linge doté d'une fonction de sèche-linge avec pompe à chaleur, l'appareil
(2) comportant un système (4) de pompe à chaleur et une chambre (18) de traitement
de linge servant à traiter du linge en utilisant de l'air (A) de processus, et le
système de pompe à chaleur comportant :
un premier échangeur (10) de chaleur servant à chauffer un fluide frigorigène (R),
un deuxième échangeur (12) de chaleur servant à refroidir le fluide frigorigène (R),
un dispositif (16) de détente,
une boucle (6) de frigorigène, dans laquelle le fluide frigorigène est mis en circulation
à travers les premier et deuxième échangeurs de chaleur et le dispositif de détente,
et
un compresseur (14) servant à faire circuler le fluide frigorigène (R) à travers la
boucle (6) de frigorigène, le procédé comportant la détection d'au moins un premier
signal de température (Tx),
caractérisé par
la sélection, en fonction du ou des premiers signaux de température (Tx) détectés,
d'au moins une valeur seuil prédéterminée (T_offl..3, T_on1..3) de température servant
à ALLUMER et/ou à ETEINDRE le compresseur (14), notamment pour empêcher une surchauffe
du compresseur (14) .
2. Procédé selon la revendication 1, le procédé comportant la sélection, en fonction
du ou des premiers signaux de température détectés, une paire de valeurs seuils de
température :
(i) d'une valeur seuil (T_offl..3) de température d'EXTINCTION servant à ETEINDRE
le compresseur, et
(ii) d'une valeur seuil (T_on1..3) de température d'ALLUMAGE servant à ALLUMER le
compresseur,
la valeur seuil de température d'EXTINCTION et la valeur seuil de température d'ALLUMAGE
étant différentes l'une de l'autre.
3. Procédé selon la revendication 1 ou 2, le ou les premiers signaux de température détectés
étant indicatifs d'une température ambiante ou d'environnement de l'appareil de traitement
de linge.
4. Procédé selon la revendication 1, 2 ou 3, le ou les premiers signaux de température
détectés étant fournis par au moins un capteur (27, 28) de température capable de
détecter la température ambiante ou d'environnement au moins sous une condition de
fonctionnement prédéfinie.
5. Procédé selon l'une quelconque des revendications précédentes, l'appareil (2) de traitement
de linge comportant une unité (30) de commande à laquelle est associée une mémoire,
au moins une, au moins deux ou plus de deux valeurs seuils prédéterminées de température
(T_offl..3, T_onl..3) étant stockées dans la mémoire pour être sélectivement extraites
par l'unité de commande suite à une sélection en fonction du ou des premiers signaux
de température (Tx) détectés.
6. Procédé selon l'une quelconque des revendications précédentes, la sélection de la
ou des valeurs seuils prédéterminées de température étant effectuée parmi une première
valeur seuil prédéterminée de température ou une première paire de valeurs seuils
prédéterminées (T_offl..3, T_onl..3) à sélectionner pour une première température
ou une plage de température du premier signal de température (Tx) détecté,
au moins une deuxième valeur seuil prédéterminée de température ou au moins une deuxième
paire de valeurs seuils prédéterminées (T_offl..3, T_onl..3) à sélectionner pour une
deuxième température ou une plage de température du premier signal de température
(Tx) détecté,
les première et deuxième valeurs seuils ou les première et deuxième paires de valeurs
seuils (T_offl..3, T_onl..3) étant différentes l'une de l'autre, et
les première et deuxième températures et/ou les première et deuxième plages de température
étant différentes l'une de l'autre.
7. Procédé selon l'une quelconque des revendications précédentes, la valeur de la valeur
seuil de température sélectionnée ou la paire sélectionnée de valeurs seuils (T_offl..3,
T_onl..3) de température étant d'autant plus basse que le premier signal de température
détecté ou la plage de température sont élevés.
8. Procédé selon l'une quelconque des revendications précédentes, le procédé comportant
en outre les étapes consistant à :
Sélectionner, en fonction du ou des premiers signaux de température (Tx) détectés,
un temps d'EXTINCTION prédéterminé pour le compresseur (14), et
ETEINDRE le compresseur (14) pendant un temps d'EXTINCTION prédéterminé, lorsque la
valeur seuil (T_offl..3) de température sélectionnée est dépassée.
9. Procédé selon l'une quelconque des revendications précédentes, le compresseur (14)
étant ETEINT en fonction du premier signal de température (Tx) détecté ou d'au moins
un deuxième signal de température (T) détecté.
10. Procédé selon l'une quelconque des revendications précédentes, le procédé comportant
en outre les étapes consistant à :
détecter le ou les premiers ou deuxièmes signaux de température (T, Tx) après le temps
d'EXTINCTION prédéterminé, et
ALLUMER le compresseur (14) lorsqu'une valeur seuil (T_onl..3) sélectionnée de température
n'est pas atteinte.
11. Procédé selon l'une quelconque des revendications précédentes, le procédé comportant
les étapes consistant à :
détecter de façon répétée le ou les premiers signaux de température (Tx) avant de
commencer à faire fonctionner le compresseur pour déterminer un premier gradient de
température du ou des premiers signaux de température, ou
détecter au moins deux températures d'au moins deux positions espacées dans l'enceinte
de l'appareil pour déterminer un deuxième gradient de température entre lesdites au
moins deux positions,
le procédé comportant en outre la sélection d'une valeur seuil prédéterminée de température
ou d'une paire de valeurs seuils prédéterminées lorsque le premier ou deuxième gradient
de température dépasse un gradient prédéterminé.
12. Procédé selon la revendication 11, la valeur seuil de température ou la paire de valeurs
seuils de température sélectionnées correspondant à des valeurs sélectionnées pour
un signal de basse température.
13. Procédé selon la revendication 11,
la valeur seuil de température sélectionnée se situant entre des valeurs seuils sélectionnées
pour un signal de basse température et un signal de haute température, ou les valeurs
de la paire de valeurs seuils sélectionnée se situant entre les valeurs correspondantes
sélectionnées pour un signal de basse température et un signal de haute température.
14. Procédé selon l'une quelconque des revendications 1 à 10, le procédé comportant les
étapes consistant à :
détecter de façon répétée le ou les premiers signaux de température (Tx) avant de
commencer à faire fonctionner le compresseur (14) pour déterminer un premier gradient
de température du ou des premiers signaux de température (Tx),
sélectionner une première valeur seuil prédéterminée de température ou une première
paire de valeurs seuils prédéterminées lorsque le premier gradient de température
dépasse un gradient prédéterminé, et
sélectionner au moins une deuxième valeur seuil prédéterminée de température ou au
moins une deuxième paire de valeurs seuils prédéterminées lorsque le premier gradient
de température est inférieur au gradient prédéterminé.
15. Procédé selon l'une quelconque des revendications 11 à 14, le procédé comportant en
outre les étapes consistant à :
détecter au moins deux températures d'au moins deux positions espacées dans l'enceinte
de l'appareil pour déterminer un deuxième gradient de température entre lesdites au
moins deux positions,
sélectionner une première valeur seuil prédéterminée de température ou une première
paire de valeurs seuils prédéterminées lorsque le deuxième gradient de température
dépasse un gradient prédéterminé, et
sélectionner au moins une deuxième valeur seuil prédéterminée de température ou au
moins une deuxième paire de valeurs seuils prédéterminées lorsque le deuxième gradient
de température est inférieur au gradient prédéterminé.
16. Procédé selon l'une quelconque des revendications précédentes, le ou les ou lesdits
au moins deux premiers signaux de température (Tx) détectés ou le ou les deuxièmes
signaux de température (T) correspondant à une température détectée dans une des positions
suivantes dans le système (4) de pompe à chaleur ou à l'intérieur de l'enceinte de
l'appareil (2) de traitement de linge :
une position de sortie de fluide frigorigène au niveau du premier ou deuxième échangeur
(10, 12) de chaleur,
une carte électronique ou une position d'onduleur d'une carte électronique ou un onduleur
commandant un composant du système (4) de pompe à chaleur,
une carte électronique ou une position d'onduleur d'une carte électronique ou un onduleur
commandant un moteur servant à entraîner la chambre de traitement de linge qui est
un tambour,
une position de sortie de fluide frigorigène au niveau du compresseur (14),
le compresseur (14),
le dispositif (16) de détente, ou
une position dans l'écoulement d'air (A) de l'air de processus.
17. Procédé selon l'une quelconque des revendications précédentes, le ou les premiers
signaux de température (Tx) détectés étant fournis en combinant
- des signaux de température qui sont détectés à différents emplacements au niveau
ou dans l'appareil de traitement de linge,
- des signaux de température qui sont détectés à différents instants, ou
- des signaux de température qui sont détectés à différents emplacements au niveau
ou dans l'appareil de traitement de linge et signaux de température qui sont détectés
à différents instants.
18. Appareil de traitement de linge, en particulier sèche-linge ou lave-linge doté d'une
fonction de sèche-linge avec pompe à chaleur, l'appareil comportant un système (4)
de pompe à chaleur, une unité (30) de commande prévue pour commander le fonctionnement
du système de pompe à chaleur et une chambre (18) de traitement de linge servant à
traiter du linge en utilisant de l'air de processus, et le système (4) de pompe à
chaleur comportant :
un premier échangeur (10) de chaleur servant à chauffer un fluide frigorigène (R),
un deuxième échangeur (12) de chaleur servant à refroidir le fluide frigorigène (R),
un dispositif (16) de détente,
une boucle (6) de frigorigène, dans laquelle le fluide frigorigène est mis en circulation
à travers les premier et deuxième échangeurs de chaleur et le dispositif de détente,
un compresseur (14) servant à faire circuler le fluide frigorigène à travers la boucle
(6) de frigorigène ; et
au moins un capteur de température servant à détecter un signal de température ;
l'unité (30) de commande étant prévue pour mettre en œuvre un procédé selon l'une
quelconque des revendications précédentes.