EP2724097B1

EP2724097B1 - A cooling device preventing freezing of foodstuffs placed in the fresh food compartment

Info

Publication number: EP2724097B1
Application number: EP12729659.8A
Authority: EP
Inventors: Tugba SARICAY; Turgay Ercan; Ridvan BERBEROGLU
Original assignee: Arcelik AS
Current assignee: Arcelik AS
Priority date: 2011-06-27
Filing date: 2012-06-27
Publication date: 2015-08-26
Anticipated expiration: 2032-06-27
Also published as: WO2013000969A3; EP2724097A2; RU2556716C1; TR201106333A2; CN103635769A; CN103635769B; WO2013000969A2; PL2724097T3

Description

The present invention relates to a cooling device that prevents freezing of foodstuffs placed in the fresh food compartment.
In cooling devices, particularly in refrigerators, foodstuffs like vegetables, fruits and beverages are generally placed into the fresh food compartment and these foodstuffs are not desired to be frozen. In cases when the ambient temperature is low, for example when lower than 0°C, the temperature of the fresh food compartment decreases towards minus values even if the compressor, providing the cooling of the fresh food compartment, does not operate and causes the foodstuffs therein to be frozen. In order to solve this problem, heaters are used that are generally disposed at the rear side of the fresh food compartment. But in very low ambient temperatures (for example at -15°C') even though the regions around the heater are raised to desired temperature values, a homogeneous heat distribution within the fresh food compartment cannot be provided and minus temperature values are encountered in some places. When the power of the heater is increased, the place around the heater is overheated and rises to high temperature values. Therefore, cooling devices are being developed that use two heaters at the same time inside the fresh food compartment.
In the state of the art Chinese Patent Application No. CN101922837 , a cooling device is described that comprises two heaters, one on the refrigerating chamber evaporator, the other disposed on the water discharge outlet of the refrigerating chamber. The power of the heater disposed on the refrigerating chamber evaporator is higher than the heater disposed on the water discharge outlet. When the temperature of the refrigerating chamber falls below a predetermined value, both of the heaters are activated and when the temperature of the refrigerating chamber rises above a predetermined value then both heaters are deactivated. By means of the heaters, the compressor that operates in order to cool the freezing chamber is prevented from lowering the temperature of the refrigerating chamber below a predetermined threshold temperature.
In the state of the art Japanese Patent Document No. JP2010230223 a cooling device with adjacent doors is described. There are two heaters in the cooling device, one at the defrost exit, the other on the side wall, both operating together. When the outside air temperature is very low, the microprocessor detects the temperature difference between the freezing chamber and the refrigerating chamber and adjusts the power of the heaters. Document US5842 355A discloses a cooling device according to the preamble of claim 1.
The aim of the present invention is the realization of a cooling device wherein the fresh food compartment is cooled effectively even at very low ambient temperatures and the foodstuffs placed therein are prevented from freezing.
In the cooling device realized in order to attain the aim of the present invention, explicated in the first claim and the respective claims thereof, at least one fresh food compartment, a compressor, at least one evaporator, an evaporator temperature sensor, a fresh food compartment temperature sensor, a control unit and a first heater and a second heater, both positioned to heat the interior of the fresh food compartment are disposed. The first heater is disposed on the evaporator and the second heater at the bottom of the fresh food compartment.
When the evaporator temperature sensor reaches a threshold evaporator value predetermined by the producer, the control unit controls the temperature detected by the fresh food compartment temperature sensor in order to activate the compressor. The compressor is activated or deactivated depending on the temperature value detected by the fresh food compartment temperature sensor.
When the ambient temperature is very low, the temperature detected by the fresh food compartment temperature sensor continues to decrease even though the compressor is deactivated and upon reaching the first heater cut-in temperature, the control unit cuts in the first heater. Thus, the temperature detected by the fresh food compartment temperature sensor falling below zero and the freezing of the foodstuffs in the fresh food compartment are prevented.
In the case the temperature detected by the fresh food compartment temperature sensor rises upon operation of the first heater, the control unit cuts out the first heater when the temperature detected by the fresh food compartment temperature sensor reaches the cut-out temperature of the heaters. Since the cut-out temperature of the heaters is lower than the compressor cut-in temperature, the first heater can be operated again before the compressor is activated depending on the ambient temperature.
In the case the temperature detected by the fresh food compartment temperature sensor decreases even when the first heater operates, the second heater is activated when the temperature detected by the fresh food compartment temperature sensor reaches the second heater cut-in temperature predetermined by the producer. Thus, a more effective heating is provided in the fresh food compartment and freezing is prevented.
Depending on the ambient temperature, the temperature detected by the fresh food compartment temperature sensor is fixed between the second heater cut-in temperature predetermined by the producer and the cut-out temperature of the heaters while the first heater is operating. In this embodiment, the second heater is activated at the end of the threshold time predetermined by the producer in order to prevent the first heater from operating for a long time. As the second heater operates, the temperature detected by the fresh food compartment temperature sensor rises, reaching the cut-out temperature of the heaters and both of the heaters are deactivated.
When the temperature detected by the fresh food compartment temperature sensor reaches the cut-out temperature of the heaters while the first heater and/or the second heater operates, both of the heaters are deactivated.
In an embodiment of the present invention, the first heater is disposed at the lower side of the evaporator. In this embodiment, the first heater is almost aligned with the center of the fresh food compartment. Thus, the heat radiated from the heater is dissipated homogeneously inside the fresh food compartment. In a version of this embodiment, the collection container is disposed at the front side of the first heater. The frost around the evaporator is collected in the collection container and melts when the first heater is operated.
In these embodiments, the second heater is positioned at a place near the lower side of the fresh food compartment. A homogeneous heat distribution is maintained while the two heaters operate together since the first heater is disposed at the center of the fresh food compartment and the second heater at the lower part of the fresh food compartment. Consequently, while some portion of the fresh food compartment has temperature values above zero, another portion is prevented from falling below zero.
In another embodiment of the present invention, a fan is disposed in the cooling device which blows air into the fresh food compartment. The fan is preferably disposed on the evaporator at a place near the first heater. Thus, the fan propels the cold air while the compressor operates, propels the hot air while the first heater operates and in both cases provides the heat in the fresh food compartment to be distributed homogeneously.
In another embodiment of the present invention, besides the fresh food compartment, a freezing compartment is present wherein the food stuffs desired to be frozen are placed. A freezing compartment evaporator that provides cooling is disposed at the rear side of the freezing compartment. In this embodiment, preferably a first heater is situated on both of the evaporators and a second heater is placed so as to heat only the interior of the fresh food compartment.
By means of the present invention, the foodstuffs placed in the fresh food compartment are provided not to freeze even at very low ambient temperatures and an effective cooling is maintained. Furthermore, energy saving is provided by optimizing the operation times of the heaters and the compressor.
The cooling device realized in order to attain the aim of the present invention is illustrated in the attached figures, where:

Figure 1 - is the schematic view of the cooling device of the present invention.
Figure 2 - is the schematic view of the cooling device related to an embodiment of the present invention.

The elements illustrated in the figures are numbered as follows:

1. Cooling device
2. Fresh food compartment
3. Compressor
4. Evaporator
5. Fresh food compartment temperature sensor
6. Evaporator temperature sensor
7. First heater
8. Second heater
9. Control unit
10. Collection container
11. Fan
12. Freezing compartment
13. Freezing compartment evaporator

The following symbols are used for explicating the cooling device (1) of the present invention:

T_R: is the temperature detected by the fresh food compartment temperature sensor (5)
T_Rcut-in : is the compressor (3) cut-in temperature
T_Rcut-out : is the compressor (3) cut-out temperature
T_EVA: is the temperature detected by the evaporator temperature sensor (6)
T_EVAcr : is the evaporator (4) threshold temperature predetermined by the producer
T_1cut-in : is the first heater (7) cut-in temperature
T_2cut-in : is the second heater (8) cut-in temperature
T_1,2cut-out is the cut-out temperature of the heaters (7, 8)
t: is the threshold time predetermined by the producer

The cooling device (1) comprises at least one fresh food compartment (2) wherein foodstuffs to be cooled are placed, a compressor (3) that compresses and circulates the refrigerant fluid in the refrigeration cycle, at least one evaporator (4) that provides the cooling of the interior volume of the fresh food compartment (2) by absorbing the thermal energy, a fresh food compartment temperature sensor (5) that measures the temperature in the fresh food compartment (2), an evaporator temperature sensor (6) that measures the temperature on the evaporator (4), a first heater (7) disposed on the evaporator (4), a second heater (8) disposed at the rear side of the fresh food compartment (2) so as to heat the fresh food compartment (2) and a control unit (9) (Figure 1).
The control unit (9),

compares the temperature (T_EVA) detected by the evaporator temperature sensor (6) with the evaporator (4) threshold temperature (T _EVAcr) predetermined by the producer while the compressor (3) is not activated and checks the temperature (T_R) detected by the fresh food compartment sensor (5) when the temperature (T_EVA) detected by the evaporator temperature sensor (6) reaches the evaporator (4) threshold temperature (T_EVAcr) predetermined by the producer,
compares the temperature (T_R) detected by the fresh food compartment temperature sensor (5) with the compressor (3) cut-in temperature (T R_cut-in) predetermined by the producer and cuts in the compressor (3) when the temperature (T_R) detected by the fresh food compartment temperature sensor (5) is equal to or greater than the compressor (3) cut-in temperature (T_Rcut-in) predetermined by the producer,
if the temperature (T_R) detected by the fresh food compartment temperature sensor (5) is smaller than the compressor (3) cut-in temperature (T_Rcut-in) predetermined by the producer, waits for the temperature (T_R) detected by the fresh food compartment temperature sensor (5) to reach the compressor (3) cut-in temperature (T_Rcut-in) predetermined by the producer and cuts in the compressor (3) when the temperature (T_R) detected by the fresh food compartment temperature sensor (5) reaches the compressor (3) cut-in temperature (T_Rcut-in) predetermined by the producer and
while the compressor (3) is activated, compares the temperature (T_R) detected by the fresh food compartment temperature sensor (5) with the compressor (3) cut-out temperature (T_Rcut-out) predetermined by the producer and cuts out the compressor (3) when the temperature (T_R) detected by the fresh food compartment temperature sensor (5) reaches the compressor (3) cut-out temperature (T_Rcut-out) predetermined by the producer.

The evaporator (4) threshold temperature (T_EVAcr) predetermined by the producer is preferably +4°C approximately whereat the frost around the evaporator (4) is almost entirely eliminated. The compressor (3) cut-in temperature (T_Rcut-in) is +5.5°C and the compressor (3) cut-out temperature (T_Rcut-out) is +4.5°C.
In the cooling device (1) of the present invention, after the compressor (3) is deactivated, the control unit (9) compares the temperature (T_R) detected by the fresh food compartment temperature sensor (5) with the first heater (7) cut-in temperature (T_1cut-in) predetermined by the producer and cuts in the first heater (7) when the temperature (T_R) detected by the fresh food compartment temperature sensor (5) reaches the first heater (7) cut-in temperature (T_1cut-in) predetermined by the producer. Thus, when the ambient temperature is low, the temperature (T_R) detected by the fresh food compartment temperature sensor (5) is prevented from reaching minus values and the foodstuffs placed in the fresh food compartment (2) is prevented from freezing. In this embodiment, the first heater (7) cut-in temperature (T_1cut-in) is lower than the compressor (3) cut-out temperature (T_Rcut-out). The first heater (7) cut-in temperature (T_1cut-in) is preferably +4 °C.
In an embodiment of the present invention, while the first heater (7) is activated, the control unit (9) compares the temperature (T_R) detected by the fresh food compartment temperature sensor (5) with the cut-out temperature (T_1,2cut-out) of the heaters (7, 8) predetermined by the producer and cuts out the first heater (7) when the temperature (T_R) detected by the fresh food compartment temperature sensor (5) reaches the cut-out temperature (T_1,2cut-out) of the heaters (7, 8) predetermined by the producer. Thus, the first heater (7) is prevented from operating when not required and energy saving is provided. In the preferred version of this embodiment, the cut-out temperature (T_1,2cut-out) of the heaters (7, 8) is lower than the compressor (3) cut-in temperature (T_Rcut-in). Consequently, the compressor (3) is prevented from operating when not required.
In another embodiment of the present invention, while the first heater (7) is activated, the control unit (9) compares the temperature (T_R) detected by the fresh food compartment temperature sensor (5) with the second heater (8) cut-in temperature (T_2cut-in) predetermined by the producer and cuts in the second heater (8) when the temperature (T_R) detected by the fresh food compartment temperature sensor (5) reaches the second heater (8) cut-in temperature (T_2cut-in) predetermined by the producer. Thus, in very low ambient temperature conditions, for example around -15°C whereat the first heater (7) cannot prevent the foodstuffs in the fresh food compartment (2) from freezing, the second heater (8) is activated and provides the temperature (T_R) detected by the fresh food compartment temperature sensor (5) to remain at the level of preventing the foodstuffs placed in the fresh food compartment (2) from freezing. The second heater (8) cut-in temperature (T_2cut-in) is preferably +2°C.
In another embodiment of the present invention, when the first heater (7) operates alone as long as the threshold time (t) predetermined by the producer, the control unit (9) cuts in the second heater (8) even if the temperature (T_R) detected by the fresh food compartment temperature sensor (5) does not reach the second heater (8) cut-in temperature (T _2cut-in). When the temperature (T_R) detected by the fresh food compartment temperature sensor (5) is balanced between the second heater (8) cut-in temperature (T_2cut-in) and the cut-out temperature (T _1,2cut-out) of the heaters (7, 8), the second heater (8) is activated at the end of the threshold time (t) predetermined by the producer and the heaters (7, 8) are deactivated by bringing the temperature (T_R) detected by the fresh food compartment temperature sensor (5) to the cut-out temperature (T_1,2cut-out) of the heaters (7, 8) and thus energy saving is provided.
In another embodiment of the present invention, while the first heater (7) and the second heater (8) are activated, the control unit (9) compares the temperature (T_R) detected by the fresh food compartment temperature sensor (5) with the cut-out temperature (T_1,2cut-out) of the heaters (7,8) predetermined by the producer and cuts out the heaters (7, 8) when the temperature (T_R) detected by the fresh food compartment temperature sensor (5) reaches the cut-out temperature (T_1,2cut-out) of the heaters (7, 8) predetermined by the producer. In this embodiment, the heaters (7, 8) are deactivated before the compressor (3) is activated. Thus, the compressor (3) is prevented from operating unnecessarily and energy saving is maintained.
In another embodiment of the present invention, the first heater (7) is disposed at the lower side of the evaporator (4) so as to align almost with the center of the rear wall of the fresh food compartment (2). In this embodiment, the evaporator (4) extends from the upper side of the fresh food compartment (2) towards the center behind the rear wall of the fresh food compartment (2). Accordingly, both the frost on the evaporator (4) is eliminated and also the interior of the fresh food compartment (2) is heated.
In another embodiment of the present invention, the cooling device (1) comprises at least one collection container (10) wherein the frost accumulating around the evaporator (4) fall and the first heater (7) located behind the collection container (10). In this embodiment, the frost around the evaporator (4) falls off and is collected in the collection container (10) during the defrosting process. When the first heater (7) is operated, the frost in the collection container (10) melts and provides completion of the defrosting process.
In another embodiment of the present invention, the second heater (8) is placed so as to align with the lower part of the rear wall of the fresh food compartment (2). The first heater (7) and the second heater (8) have preferably the same power. In this embodiment, since the first heater (7) is aligned with the central part of the fresh food compartment (2), when the heaters (7, 8) operate together, the interior of the fresh food compartment (2) is heated homogeneously and the effectiveness of the cooling device (1) is increased.
In another embodiment of the present invention, the cooling device (1) comprises at least one fan (11) that provides the air in the fresh food compartment (2) to be propelled. Thus, a homogeneous heat distribution is achieved inside the fresh food compartment (2). The fan (11) can operate simultaneously with the heaters (7,8) and the compressor (3).
In another embodiment of the present invention, the cooling device (1) comprises a freezing compartment (12) wherein the foodstuffs are placed for freezing, kept at lower temperatures then the fresh food compartment (2) and a freezing compartment evaporator (13) that provides the cooling of the interior volume of the freezing compartment (12) by absorbing the thermal energy. In this embodiment, the refrigerant pumped from the compressor (3) circulates through both evaporators (4, 13) (Figure 2).
By means of the present invention, the foodstuffs in the fresh food compartment (2) can be stored without freezing even in very low ambient temperatures. Furthermore, both cooling effectiveness is increased and also energy saving is provided by utilizing the first heater (7), the second heater (8) and the compressor (3) in a controlled manner.
It is to be understood that the present invention is not limited to the embodiments disclosed above and a person skilled in the art can easily introduce different embodiments. These should be considered within the scope of the protection postulated by the claims of the present invention.

Claims

A cooling device (1) comprising at least one fresh food compartment (2)
wherein foodstuffs to be cooled are placed, a compressor (3) that compresses and circulates the refrigerant fluid in the refrigeration cycle, at least one evaporator (4) that provides the cooling of the interior volume of the fresh food compartment (2) by absorbing the thermal energy, a fresh food compartment temperature sensor (5) that measures the temperature in the fresh food compartment (2), an evaporator temperature sensor (6) that measures the temperature on the evaporator (4), a first heater (7) disposed on the evaporator (4), a second heater (8) and a control unit (9) that
- compares the temperature (T_EVA) detected by the evaporator temperature sensor (6) with the evaporator (4) threshold temperature (T_EVAcr) predetermined by the producer while the compressor (3) is not activated and checks the temperature (T_R) detected by the fresh food compartment sensor (5) when the temperature (T_EVA) detected by the evaporator temperature sensor (6) reaches the evaporator (4) threshold temperature (T_EVAcr) predetermined by the producer,

- compares the temperature (T_R) detected by the fresh food compartment temperature sensor (5) with the compressor (3) cut-in temperature (T_Rcut-in) predetermined by the producer and cuts in the compressor (3) when the temperature (T_R) detected by the fresh food compartment temperature sensor (5) is equal to or greater than the compressor (3) cut-in temperature (T_Rcut-in) predetermined by the producer,

- if the temperature (T_R) detected by the fresh food compartment temperature sensor (5) is smaller than the compressor (3) cut-in temperature (T_Rcut-in) predetermined by the producer, waits for the temperature (T_R) detected by the fresh food compartment temperature sensor (5) to reach the compressor (3) cut-in temperature (T_Rcut-in) predetermined by the producer and cuts in the compressor (3) when the temperature (T_R) detected by the fresh food compartment temperature sensor (5) reaches the compressor (3) cut-in temperature (T_Rcut-in) predetermined by the producer and

- while the compressor (3) is activated compares the temperature (T_R) detected by the fresh food compartment temperature sensor (5) with the compressor (3) cut-out temperature (T_Rcut-out) predetermined by the producer and cuts out the compressor (3) when the temperature (T_R) detected by the fresh food compartment temperature sensor (5) reaches the compressor (3) cut-out temperature (T_Rcut-out) predetermined by the producer.
characterized in that the second heater is disposed at the rear side of the fresh food compartment (2) so as to heat the fresh food compartment (2) and in that the control unit (9) compares the temperature (T_R) detected by the fresh food compartment temperature sensor (5) with the first heater (7) cut-in temperature (T_1cut-in) predetermined by the producer after the compressor (3) is deactivated and cuts in the first heater (7) when the temperature (T_R) detected by the fresh food compartment temperature sensor (5) reaches the first heater (7) cut-in temperature (T_1cut-in) predetermined by the producer.
A cooling device (1) as in Claim 1, characterized in that the control unit (9) compares the temperature (T_R) detected by the fresh food compartment temperature sensor (5) with the cut-out temperature (T_1,2cut-out) of the heaters (7, 8) predetermined by the producer while the first heater (7) is activated and cuts out the first heater (7) when the temperature (T_R) detected by the fresh food compartment temperature sensor (5) reaches the cut-out temperature (T _1,2cut-out) of the heaters (7, 8) predetermined by the producer.
A cooling device (1) as in Claim 1 or 2, characterized in that the control unit (9) compares the temperature (T_R) detected by the fresh food compartment temperature sensor (5) with the second heater (8) cut-in temperature (T_2cut-in) predetermined by the producer while the first heater (7) is activated and cuts in the second heater (8) when the temperature (T_R) detected by the fresh food compartment temperature sensor (5) reaches the second heater (8) cut-in temperature (T_2cut-in) predetermined by the producer.
A cooling device (1) as in any one of the above Claims, characterized in that the control unit (9) cuts in the second heater (8) when the first heater (7) operates alone as long as the threshold time (t) predetermined by the producer, even if the temperature (T_R) detected by the fresh food compartment temperature sensor (5) does not reach the second heater (8) cut-in temperature (T_2cut-in).
A cooling device (1) as in any one of the above Claims, characterized in that the control unit (9) that compares the temperature (T_R) detected by the fresh food compartment temperature sensor (5) with the cut-out temperature (T_1,2cut-out) of the heaters (7, 8) predetermined by the producer while the first heater (7) and the second heater (8) are activated and cuts out the heaters (7, 8) when the temperature (T_R) detected by the fresh food compartment temperature sensor (5) reaches the cut-out temperature (T_1,2cut-out) of the heaters (7, 8) predetermined by the producer.
A cooling device (1) as in any one of the above Claims, characterized in that the first heater (7) is disposed at the lower side of the evaporator (4) so as to align almost with the center of the rear wall of the fresh food compartment (2).
A cooling device (1) as in any one of the above Claims, characterized by at least one collection container (10) wherein the frost accumulating around the evaporator (4) falls and the first heater (7) that is located behind the collection container (10).
A cooling device (1) as in any one of the above Claims, characterized in that the second heater (8) is disposed so as to align with the lower part of the rear wall of the fresh food compartment (2).
A cooling device (1) as in any one of the above Claims, characterized by at least one fan (11) that provides the air in the fresh food compartment (2) to be propelled.
A cooling device (1) as in any one of the above Claims, characterized by a freezing compartment (12) wherein the foodstuffs are placed for freezing, kept at lower temperatures than the fresh food compartment (2) and a freezing compartment evaporator (13) that provides the cooling of the interior volume of the freezing compartment (12) by absorbing the thermal energy.