[001] The present invention relates to a cooling device where temperature control of the compartment interiors is accomplished by a small amount of energy consumption and a cooling method thereof.

[002] In cooling devices having one or more compartments where food and beverages are stored, cooling is accomplished by a refrigerant fluid circulated in a circuit which generally comprises a condenser transferring the heat outside, a capillary tube reducing the pressure, an evaporator absorbing the heat and a compressor. The compartments are brought to the desired temperature by sucking the air from the interior by the help of preferably one or more fans and/or channels, and by bringing the air into contact with the evaporator surfaces. In the compartments, there are one or more thermostats for measuring the interior temperature values, and one or more dampers for controlling the cool air circulating in the channels in order to reach the temperature values measured by the thermostats. In state-of-the-art various mechanical or electronically controlled dampers are utilized.

[003] In state-of-the-art, in dampers run by motors, the motor activates a shaft with a command from the control card and allows the damper to be opened. When the damper is fully opened, it sends a signal to the control card and the power is turned off. In a similar fashion, a command is sent from the control card for closing and the damper is closed with the help of a spring. When the damper is closed, it sends a signal to the control card and the power is turned off. However, in this embodiment, the spring aiding the damper to be closed can be frozen due to the effects of humidity or low temperature, and can prevent the damper from closing. This in turn results in overcooling or not cooling at all. Furthermore, since the damper has to give feedback to the control card during opening and closing, the possibility of a malfunction increases due to the number of components used.

[004] In state-of-the-art German Patent Document no. DE4017382 a thermo-actuator for cooling devices is described which controls the damper and controls the temperature inside the compartments according to the values received from the thermostat.

[005] The aim of the present invention is to realise a cooling device where the temperature control of the compartment interiors is accomplished by means of a thermo-actuator, by consuming a small amount of energy, and a cooling method thereof.

[006] The cooling device and the cooling method designed to fulfill the objectives of the present invention is shown in the annexed drawings, where:

[007] Figure 1 - is the schematic view of a cooling device.

[008] Figure 2 - is the top schematic view of a damper for keeping more than one channel openings in the closed position and a thermo-actuator which moves the damper.

[009] Figure 3 - is the top schematic view of a damper for keeping more than one channel openings in the open position and a thermo-actuator which moves the damper.

[010] Figure 4 - is the flow chart of a cooling method.

[011] Figure 5 - is the compressor operation status - temperature graph.

[012] Figure 6 - is the damper operation status - temperature graph.

[013] Figure 7 - is the current applied on the damper - time graph within a specified temperature range.

[014] Elements shown in the figures are numbered as follows:

1. Cooling device

2. Channel

3. Thermo-actuator

4. Damper

5. Stopper

6. Passage hole

7. Control card

8. Evaporator

9. Compressor

10. Compartment

11. Fan

12. Thermostat

[015] The cooling device (1) comprises a compressor (9) which provides the circulation of the refrigerant fluid utilized for cooling purposes, an evaporator (8) which absorbs the ambient heat for cooling the surroundings, one or more compartments (10) where food like vegetables, fruit or beverages are stored, one or more fans (11) providing air flow to the compartments (10), one or more channels (2) that guide the air flow provided by the fan (11), one or more dampers (4) which provide the control of air flow into the compartment (10), one or more thermostats (12) for measuring the temperature values, one or more passage holes (6) that are opened/closed by the damper (4) allowing the air from the channel (2) to flow into the compartment (10), a stopper (5) that limits the movement of the damper (4), at least one control card (7) which provides the control of the damper (4) and thus the interior temperature of the compartment (10) according to the values measured by the thermostat (12), and a thermo-actuator (3) which actuates the damper (4).

[016] In the preferred embodiment of the present invention, a thermo-actuator is utilized comprising a heater, a special oil, for example wax, and a shaft that provides the actuation of the damper (4) that it is connected to.

[017] The durations of operation and stopping of the compressor (9) are determined by the control card (7), so that the compartment (10) is kept between the desired temperatures (T1-T2) according to the temperature values measured by the thermostat (12). In the preferred embodiment, the compressor (9) is started at one temperature value (Tcut-in) and stopped at another temperature value (Tcut-out).

[018] In the embodiment subject to the present invention, a thermo-actuator (3) is utilized which provides the actuation of the damper (4) and keeps it at the desired position by the current applied intermittently at time intervals determined by the producer (ti; i=l,2,..,n ; i= interval index) via the help of the control card (7) so that the compartment (10) is kept within the desired temperature range (Tl - T2). Consequently continuous current is not applied to the thermo-actuator (3) so that the compartment (10) is kept within the desired temperature range (Tl - T2), current is switched on and off at consecutive time intervals determined by the producer, providing for a small amount of energy consumption. During this time the thermo-actuator (3) cannot respond instantaneously due to its material composition and the damper (4) keeps its former position during the response duration of the thermo-actuator (3). Since the damper (4) can be kept perpetually at the desired position, preferably open, the desired cooling can be achieved by a small amount of energy. Current is applied to the thermo- actuator (3) when the compartment (10) temperature reaches the starting value (Tl), and the current is switched off when the control value (T2) is reached. Between the starting and control values (Tl - T2), the current is switched on and off periodically.

[019] In the method of the present invention, when the starting value (Tl) is reached, current is applied to the thermo-actuator (3), and the current is applied intermittently at application durations (ti) determined by the producer until the ambient temperature value (T) reaches the control value (T2), and when the control value (T2) is reached, the current is switched off.

[020] The producer decides on which of the Tcut-in and Tcut-out temperature values will be set as the starting value (Tl) for the method, or the control value (T2) according to the position of the damper (4) when energy is not supplied and according to the average duration of the damper (4) staying in the open position and in the closed position. For example, it is decided that Tl= Tcut-in and T2= Tcut-out when a damper (4) is employed which is in the open position when current is not applied to the thermo-actuator (3), or that Tl= Tcut-out and T2= Tcut-in while a damper (4) is employed which is in the closed position when current is not applied to the thermo- actuator (3). An embodiment of the present invention according to these alternatives comprises the following steps (Figure 4):

[021] Start (105),

- Resetting the operation interval index (i) (109),

- Comparing the ambient temperature value (T) with the starting value (Tl) (110), and continuing until the ambient temperature value (T) reaches the starting value (Tl),

When the starting value (Tl) is reached, operating the thermo-actuator (3)

(112),

Increasing the operation interval index (i) by one and selecting the application duration (ti) for this index which is determined by the producer (111),

Controlling whether or not the application duration (ti) is completed (113), and continuing to control until the elapsed time reaches a greater value than the application duration (ti),

- Controlling whether or not the operation interval index (i) is the end value (n) determined by the producer (114),

- At the step of controlling whether or not the operation interval index (i) is the end value (n) determined by the producer (114), if the operation interval index (i) is the end value (n) determined by the producer, controlling (120) whether or not the ambient temperature value (T) has reached the control value (T2),

- At the step of controlling (120) whether or not the ambient temperature value (T) has reached the control value (T2), if not reached then determining the operation interval index (i) as (n-1) (118),

After determining the operation interval index (i) as (n-1) (118), switching off the thermo-actuator (3) (115),

- At the step of controlling whether or not the operation interval index (i) is the end value (n) determined by the producer (114), if the operation interval index (i) is not the end value (n) determined by the producer, switching off the thermo-actuator (3) (115),

- Increasing the operation interval index (i) by one and selecting the application duration (ti) for this index (i) determined by the producer (116),

- Controlling whether or not the application duration (ti) is completed (117) and continuing to control until the elapsed time reaches a greater value than the application duration (ti),

In the step of controlling whether or not the application duration (ti) is completed (117), when the elapsed time reaches a greater value than the determined application duration (ti), controlling whether or not the ambient temperature value (T) has reached the control value (T2) (119), At the step of comparing the ambient temperature value (T) with the control value (T2) (119), if the control value (T2) is reached, then switching off (121) the thermo-actuator (3)

- If the control value (T2) is not reached, then returning back to the step before

the thermo-actuator (3) is switched on (112),

If the control value (T2) is reached, then switching off the thermo-actuator (3)

(121),

After the step of switching off the thermo-actuator (3) (121), going back to the step of resetting the operation interval index (i) (109) and applying the subsequent steps.

[022] In the cooling device (1) of the present invention, if the average time duration that the damper (4) is open is greater than the closed time duration, then by using an open damper (4) when current is not applied to the thermo-actuator (3), opening of the passage hole (6) by the damper (4) is provided when the current is not applied. And when the current is applied, the passage hole (6) is closed. In this cooling device (1), the method of the present invention is started by taking the temperature value as Tl= Tcut-in.

[023] In this embodiment, if the compartment (10) interior temperature (T) is greater than the value of Tcut-in determined by the producer, then the control card (7) provides the energy (network current) to be applied to the thermo-actuator (3) during the time interval of ti (i=l; tl). The heater inside the thermo-actuator (3) heats up with the given energy and transfers the heat to the special oil (wax) inside a closed cylinder. The expanded oil pushes the shaft, and the shaft pushes the upper surface of the damper (4). The upper surface of the damper (4) opens until it rests on the stopper (5) on the lower surface of the damper (4), opening so as to allow the air to flow. Later on, in order to keep the damper (4) open perpetually on the one hand and conserve energy on the other, the energy is cut off for the duration of ti (i=i+l ; t2) and is applied for the duration of ti (i=i+l; t3). During this cycle, the interior temperature (T) of the cooling device (1) is constantly controlled and if it is less than the Tcut-out, the energy of the thermo-actuator (3) is turned off. When the energy is turned off, the special oil inside cools down, its volume decreases, and the damper (4) closes with the help of the spring inside. The damper (4) remains closed until the temperature is greater than the Tcut-out value, and the above explained cooling method cycle is repeated when the temperature (T) rises.

[024] In the cooling device (1) of the present invention, if the average time duration that the damper (4) stays open is less than its staying closed, the damper (4) provides to close the passage hole (6) when current is not applied, by utilizing a damper (4) in the closed position when the current is not applied to the thermo-actuator (3). And when the current is applied, the passage hole (6) is opened. In this cooling device (1) the method of the present invention is started by taking Tl= Tcut-out as the temperature value. In this manner the energy consumption duration of the damper (4) is shortened.

[025] In a preferred embodiment of the present invention, if the temperature value (T) is

less than the Tcut-out temperature value which is determined by the manufacturer, the control card (7) provides energy (network power) to the thermo-actuator (3) for the duration of ti (i=l; tl). The heater inside the thermo-actuator (3) heats up with the given energy and transfers the heat to the special oil (wax) inside a closed cylinder. The expanded oil pushes the shaft, and the shaft pushes the upper surface of the damper (4). The upper surface of the damper (4) closes until it rests on the stopper (5) on the lower surface of the damper (4), so as to block the passage of the air. Later on, in order to keep the damper (4) closed perpetually while at the same time conserving energy, the energy is cut off for the duration of ti (i=i+l ; t2) and is given again for the duration of ti (i=i+l; t3) (t2>t3). During this cycle, the temperature (T) is constantly controlled and if it is greater than the Tcut-out, the energy of the thermo-actuator (3) is turned off. When the energy is turned off, the special oil cools down, and the damper (4) opens with the help of the spring inside, allowing the passage of air. The damper (4) remains open until the temperature is less than the Tcut-out, and when the temperature (T) decreases, the above explained cycle is repeated. Thanks to the embodiment of the present invention, the risk of frozen spring that can be encountered in motor dampers is overcome by the thermo-actuator. Since the application is simple, its control is also simple, it takes up less volume and can be produced inexpensively.