WO2016071051A1

WO2016071051A1 - A cooling device with improved refrigeration performance

Info

Publication number: WO2016071051A1
Application number: PCT/EP2015/072413
Authority: WO
Inventors: Egemen TINAR; Tolga Nurettin AYNUR; Emre Oguz; Vasi Kadir Ertis; Tolga APAYDIN; Gokmen PEKER
Original assignee: Arcelik Anonim Sirketi
Priority date: 2014-11-04
Filing date: 2015-09-29
Publication date: 2016-05-12

Abstract

Cooling device (1) comprising a body (2), a compressor (3), a condenser (4) that enables the refrigerant fluid leaving the compressor (3) as superheated vapor to change into liquid phase by condensing, an evaporator (8) through which the refrigerant fluid passes and providing the cooling of the environment where the evaporator (8) is located, an expansion unit (7), at least one temperature sensor (9) that is disposed on the body (2) and that detects the ambient temperature, and a heater (10) that is situated on the refrigerant tube (5) of the condenser (4). The refrigeration performance is improved by increasing the condenser capacity in low environment temperatures.

Description

A COOLING DEVICE WITH IMPROVED REFRIGERATION PERFORMANCE

The present invention relates to a cooling device the refrigeration performance of which is improved.

In cooling devices, the refrigerant fluid in the refrigeration cycle is in superheated vapor phase while leaving the compressor and the refrigerant fluid leaving the compressor in vapor phase changes first to liquid – vapor phase in the condenser and then to liquid phase in the region near the expansion unit. Along the expansion unit, the fluid starts changing from liquid phase to liquid – vapor phase as the pressure decreases and reaches the evaporator in liquid – vapor phase with low dryness rate. The refrigerant fluid changing to vapor phase while leaving the evaporator due to absorption of heat from the environment reaches the compressor again.

In situations where the temperature of the environment is low, more heat is discharged by the refrigerant fluid passing through the condenser. Therefore, the temperature and pressure of the refrigerant fluid abruptly decrease, resistance increases at the inlet of the expansion unit due to excessive liquid refrigerant fluid and passing of the refrigerant fluid from the expansion unit to the evaporator becomes difficult. In this case, the refrigeration cycle performance of the cooling device decreases.

In the state of the art, there are embodiments wherein the flow rate of the air blown by the fan over the condenser is changed depending on the temperature of the environment in order to adjust the condenser capacity.

In the state of the art Japanese Patent Application No. JPH0674641A, the flow rate of the air passing over the condenser is changed depending on the temperature of the outside environment.

The aim of the present invention is the realization of a cooling device of which the refrigeration performance is improved by increasing the condenser capacity in low environment temperatures.

The cooling device realized in order to attain the aim of the present invention, explicated in the first claim and the respective claims thereof, comprises a body; a compressor that provides the compression of the refrigerant fluid; a condenser that is formed by bending a pipe in serpentine shape, that enables the refrigerant leaving the compressor as superheated vapor to change into liquid phase by condensing it; an evaporator through which the refrigerant fluid passes, providing the cooling of the environment wherein the evaporator is located; an expansion unit that provides the delivery of the refrigerant fluid leaving the condenser to the evaporator and at least one temperature sensor that is disposed on the body and that detects the ambient temperature.

The cooling device of the present invention comprises a control unit that controls the activation of the heater depending on the compressor operation rate (RT) when the ambient temperature (Tamb) detected by the temperature sensor falls below the minimum temperature value (Tlim) determined by the manufacturer. If the ambient temperature value (Tamb) is lower than the predetermined minimum temperature value (Tlim), the heater is activated and the refrigerant fluid passing through the condenser is enabled to be heated. Thus, the passage of the refrigerant fluid leaving the condenser to the evaporator is facilitated and the performance of the refrigeration cycle is improved.

In an embodiment of the present invention, the cooling device comprises the control unit that provides the activation of the heater when the ambient temperature (Tamb) detected by the temperature sensor falls below the minimum temperature value (Tlim) determined by the manufacturer. The minimum temperature value (Tlim) determined by the manufactureris the temperature limit at which the refrigerant fluid in the condenser starts to overcool due to low ambient temperature and thus the passage of the refrigerant fluid from the expansion unit to the evaporator becomes difficult. In the situation wherein the ambient temperature value (Tamb) is lower than the minimum temperature value (Tlim), the performance of the refrigeration cycle decreases since sufficient amount of refrigerant fluid cannot be delivered to the evaporator.

In another embodiment of the present invention, the cooling device comprises the control unit that provides the activation of the heater if the compressor operation ratio (RT) measured by the control unit is smaller than the minimum operation ratio (RTlim) determined by the manufacturer. The ambient temperature of the environment wherein the cooling device is located may increase/decrease momentarily due to opening of a window or cooking of food. In the case the heater is frequently operated and stopped depending only on the data received from the temperature sensor, the energy consumption of the cooling device increases and the life span of the heater decreases due to frequent usage. In momentary changes occurring in the environment, the change in the compressor operation ratio (RT) is very low hence the control unit is enabled to make a more accurate evaluation. If the compressor operation ratio (RT) is smaller than the minimum operation ratio (RTlim) determined by the manufacturer, it is determined that the temperature of the refrigerant fluid in the condenser is excessively low and hence sufficient amount of refrigerant fluid cannot be delivered to the evaporator. In this situation, the control unit activates the heater and enables the refrigerant fluid to be heated by the heater while passing through the condenser. Thus, the refrigerant fluid changes to the liquid -vapor phase before being entirely condensed in the condenser and changes to the liquid phase in the region close to the inlet of the expansion unit. Thus, the amount of the refrigerant fluid delivered to the evaporator is increased and the refrigeration performance is improved.

In another embodiment of the present invention, the cooling device comprises the control unit that controls whether or not the compressor is operating when the ambient temperature (Tamb) detected by the temperature sensor falls below the predetermined minimum temperature value (Tlim) and if the compressor is operating, provides the activation of the heater. When the compressor does not operate, refrigerant fluid cannot be delivered to the condenser. Activating the heater when refrigerant fluid is not present in the condenser causes the refrigerant tube to overheat and the energy consumption of the cooling device to increase.

In another embodiment of the present invention, the cooling device comprises the control unit that controls whether or not the compressor is operating while the heater is activated and if the compressor is not operating, then deactivates the heater. The heater is operated as long as the compressor operates and is deactivated when the compressor does not operate. Thus, the heater is operated only if the refrigerant fluid passes through the condenser and when there is no refrigerant fluid passage, the heater is prevented from operating unnecessarily.

In another embodiment of the present invention, the cooling device comprises a carrier apparatus that is mounted detachably on the refrigerant tube and whereon the heater is disposed. By means of the detachable carrier apparatus, the heater is enabled to be detached in hot environment conditions when the use of the heater is not required.

In another embodiment of the present invention, the carrier apparatus comprises a gripper that enables the carrier apparatus to be mounted on the refrigerant tube. By means of the flexible configuration of the gripper, the carrier apparatus can be attached/detached to/from the refrigerant tube. The gripper has a half-circular shape so as to at least partially surround the refrigerant tube and is snap-fitted on the refrigerant tube. Thus, the carrier apparatus is prevented from moving on the refrigerant tube and falling down.

In another embodiment of the present invention, the carrier apparatus comprises a protector plate that covers the heater such that there is a space therebetween. In the cooling devices that are generally located in kitchens, in situations where containers filled with liquid and placed on the body overturn, the liquid spilled on the body flows over the body and contacts the electrical components of the compressor. Furthermore, contact of the flowing liquid with the heater may cause the heater to malfunction. The carrier apparatus is placed on the condenser in alignment with the compressor, thus the protector plate prevents the liquids flowing over the body from reaching the heater and the electric components of the compressor.

In another embodiment of the present invention, the carrier apparatus comprises a stopper that is placed on the protector plate. During the installation of the cooling device, the user cannot properly see the rear side of the body and therefore the condenser may bump into a hard surface while being installed. Furthermore, a distance predetermined by the manufacturershould be left at the rear side of the cooling device so that the refrigeration cycle can be realized with the desired performance. The stopper placed on the protector plate prevents the condenser from contacting a hard surface and also provides that the minimum distance predetermined by the manufactureris left at the rear of the cooling device. The stopper placed on the protector plate by means of a hinge rotates around the hinge while the cooling device is transported and packaged and comes to a position on the protector plate, thus prevented from occupying space in situations where the cooling device does not operate.

By means of the present invention, by placing the heater on the condenser the refrigerant fluid passing through the condenser is prevented from condensing by overcooling in cold ambient temperature conditions. The heater is mounted on the condenser by means of a detachable carrier apparatus, thus enabling the carrier apparatus to be detached in warm ambient conditions when the heater is not required.

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 a cooling device in the prior art.

Figure 2 – is the schematic view of a refrigeration circuit.

Figure 3 – is the perspective view of the carrier apparatus in an embodiment of the present invention.

Figure 4 – is the schematic view of the cooling device when the carrying apparatus is mounted to the condenser in an embodiment of the present invention.

The elements illustrated in the figures are numbered as follows:

Cooling device
Body
Compressor
Condenser
Refrigerant tube
Heat transfer means
Expansion unit
Evaporator
Temperature sensor
Heater
Control unit
Carrier apparatus
Protector plate
Stopper
Gripper

The cooling device (1) comprises a body (2), a compressor (3) providing the compression of the refrigerant fluid and a condenser (4)

that enables the refrigerant fluid leaving the compressor (3) as superheated vapor to change into liquid phase by condensing and
that has a refrigerant tube (5) formed by bending a tube in serpentine shape
more than one heat transfer means (6), in wire or fin shape, contacting the refrigerant tube (5),

an evaporator (8) through which the refrigerant fluid passes, providing the cooling of the environment wherein the evaporator (8) is located, an expansion unit (7) providing the delivery of the refrigerant fluid leaving the condenser (4) to the evaporator (8) and at least one temperature sensor (9) that is disposed on the body (2) and that detects the ambient temperature (Figure 1 and 2).

The cooling device (1) of the present invention comprises

a heater (10) that is situated on the refrigerant tube (5) and
a control unit (11) that provides the activation or deactivation of the heater (10) depending on the changes in the ambient temperature (Tamb).

In another embodiment of the present invention the cooling device (1) comprises the control unit (11) that provides the activation of the heater (10) when the ambient temperature (Tamb) detected by the temperature sensor (9) falls below the minimum temperature value (Tlim) determined by the manufacturer. When the ambient temperature (Tamb) falls below the minimum temperature value (Tlim) predetermined, the temperature of the refrigerant fluid passing through the condenser (4) falls very quickly and the control unit (11) activates the heater (10), thus enabling the temperature of the refrigerant fluid to be increased while passing through the refrigerant tube (5). Thus, resistance that may occur in the expansion unit (7) is prevented, passage of the refrigerant fluid to the evaporator (8) is facilitated and hence performance of the refrigeration cycle is improved.

In another embodiment of the present invention, the cooling device (1) comprises the control unit (11) that provides the activation of the heater (10) if the compressor (3) operation ratio (RT) measured by the control unit (11) is smaller than the minimum operation ratio (RTlim) determined by the manufacturer. The ambient temperature value (Tamb) detected by the temperature sensor (9) may show rapid changes instantaneously. Therefore, making evaluations depending only on the ambient temperature value (Tamb) may cause the heater (10) to be activated when not required. In this situation, energy loss is encountered. The compressor (3) operation ratio (RT) is the ratio of the operation duration of the compressor (3) to the total durations of operation and non-operation of the compressor (3). In low ambient temperatures, the time period the compressor (3) operates is shorter and hence the compressor (3) operation ratio (RT) is lower. The compressor (3) operation ratio (RT) is not affected by the instantaneous temperature changes, thus a more accurate evaluation can be made for the activation of the heater (10). When the measured compressor (3) operation ratio (RT) is smaller than the minimum operation ratio (RTlim) determined by the manufacturer, the control unit (11) decides that the temperature of the refrigerant fluid passing through the condenser (4) has decreased excessively and activates the heater (10), thereby increasing the temperature of the refrigerant fluid and improving performance of the refrigeration cycle.

In another embodiment of the present invention, the cooling device (1) comprises the control unit (11) that controls whether or not the compressor (3) is operating and if the compressor (3) is operating, provides the activation of the heater (10) when the ambient temperature (Tamb) detected by the temperature sensor (9) falls below the predetermined minimum temperature value (Tlim). While operating, the compressor (3) delivers high temperature refrigerant fluid in gas phase to the condenser (4). When the compressor (3) is not operating, the refrigerant fluid is not delivered to the condenser (4). Therefore, the heater (3) is activated only when the compressor (3) is operating for heating the refrigerant fluid in the condenser (4).

In another embodiment of the present invention, the cooling device (1) comprises the control unit (11) that controls whether or not the compressor (3) is operating while the heater (10) is activated and if the compressor(3) is not operating then, provides the deactivation of the heater (10). When the compressor (3) is not operating, refrigerant fluid does not pass through the condenser (4). Therefore, the control unit (11) controls whether or not the compressor (3) is operating while the heater (10) is activated, and if the compressor (3) is not operating then deactivates the heater (10). Thus, the heater (10) is prevented from operating when the refrigerant fluid is not present in the condenser (4). The energy loss that the heater (10) may cause is avoided by preventing the heater (10) from operating when the compressor (3) is not operating.

In another embodiment of the present invention, the cooling device (1) comprises a carrier apparatus (12) that is mounted detachably on the refrigerant tube (5) and whereon the heater (10) is disposed. When the carrier apparatus (12) is placed on the refrigerant tube (5), heat transfer from the heater (10) to the condenser (4) is provided. In high ambient temperatures where the heater (10) is not required, the heater (10) is enabled to be detached together with the carrier apparatus (12) (Figure 3 and 4).

In another embodiment of the present invention, the carrier apparatus (12) comprises a gripper (15) that provides the carrier apparatus (12) to be mounted on the refrigerant tube (5). The gripper (15) is configured in half circular shape so as to surround the refrigerant tube (5) at least partially. By means of the flexible configuration of the gripper (15), the carrier apparatus (12) can be attached/detached to/from the refrigerant tube (5). In this embodiment, the heater (10) is placed on the gripper (15) and the losses that may occur in heat transfer are decreased by means of the contact of the heater (10) with the refrigerant tube (5) (Figure 3 and 4).

In another embodiment of the present invention, the carrier apparatus (12) comprises a protector plate (13) that covers the heater (10) such that there is a space between the protector plate (13) and the heater (10). The protector plate (13) prevents liquids that may flow over the body (2) from contacting the heater (10). In this embodiment, the carrier apparatus (12) is placed on the condenser (3) so as to be aligned with the compressor (3), thus the protector plate (13) prevents the liquids that may flow over the body (2) from contacting the electric components of the compressor (3) and possible malfunctions are avoided (Figure 3).

In another embodiment of the present invention, the carrier apparatus (12) comprises a stopper (14) that is placed on the protector plate (13). The stopper (14), one end of which is connected to the protector plate (13) and the other end extending outwards from the body (2), provides that the minimum distance determined by the manufactureris kept behind the cooling device (1), between the condenser (4) and the wall. Thus, the carrier apparatus (12) carries the stopper (14) as well as the heater (10) (Figure 3).

In the cooling device (1) of the present invention, by placing a heater (10) over the condenser (4), excessive decrease in the temperature and pressure of the refrigerant fluid passing through the condenser (4) is prevented in low ambient temperatures, resistance in the expansion unit (7) is avoided, delivery of the refrigerant fluid to the evaporator (8) is facilitated and hence the performance of the refrigeration cycle is increased.

Claims

A cooling device (1) comprising a body (2), a compressor (3) which provides the compression of the refrigerant fluid, a condenser (4)

- that enables the refrigerant fluid leaving the compressor (3) as superheated vapor to change into liquid phase by condensing and

- that has a refrigerant tube (5) formed by bending a tube in serpentine shape

- more than one heat transfer means (6), in wire or fin shape, contacting the refrigerant tube (5),

an evaporator (8) through which the refrigerant fluid passes, providing the cooling of the environment wherein the evaporator (8) is located, an expansion unit (7) providing the delivery of the refrigerant fluid leaving the condenser (4) to the evaporator (8) and at least one temperature sensor (9) that is disposed on the body (2) and that detects the ambient temperature characterized by

- a heater (10) that is situated on the refrigerant tube (5) and

- a control unit (11) that provides the activation or deactivation of the heater (10) depending on the changes in the ambient temperature (Tamb).
A cooling device (1) as in Claim 1, characterized by the control unit (11) that provides the activation of the heater (10) when the ambient temperature (Tamb) detected by the temperature sensor (9) falls below the minimum temperature value (Tlim) determined by the manufacturer.
A cooling device (1) as in Claim 2, characterized by the control unit (11) that provides the activation of the heater (10) if the compressor (3) operation ratio (RT) measured by the control unit (11) is smaller than the minimum operation ratio (RTlim) determined by the manufacturer.
A cooling device (1) as in Claim 2 or 3, characterized by the control unit (11) that controls whether or not the compressor (3) is operating and if the compressor (3) is operating, provides the activation of the heater (10) when the ambient temperature (Tamb) detected by the temperature sensor (9) falls below the predetermined minimum temperature value (Tlim).
A cooling device (1) as in any one of the above claims, characterized by the control unit (11) that controls whether or not the compressor (3) is operating while the heater (10) is activated and if the compressor (3) is not operating then provides the deactivation of the heater (10).
A cooling device (1) as in any one of the above claims, characterized by a carrier apparatus (12) that is mounted detachably on the refrigerant tube (5) and whereon the heater (10) is disposed.
A cooling device (1) as in Claim 6, characterized by the carrier apparatus (12) comprising a gripper (15) that provides the carrier apparatus (12) to be mounted on the refrigerant tube (5).
A cooling device (1) as in Claim 6 or 7, characterized by the carrier apparatus (12) comprising a protector plate (13) that covers the heater (10) such that there is a space between the protector plate (13) and the heater (10).
A cooling device (1) as in Claim 8, characterized by the carrier apparatus (12) comprising a stopper (14) disposed on the protector plate (13).