WO2013045363A1

WO2013045363A1 - Heat pump laundry dryer

Info

Publication number: WO2013045363A1
Application number: PCT/EP2012/068651
Authority: WO
Inventors: Selcuk KARAGOZ; Dogan Demirhan; Arif Zafer Ozarslan; Can Sar
Original assignee: Arcelik Anonim Sirketi
Priority date: 2011-09-27
Filing date: 2012-09-21
Publication date: 2013-04-04
Also published as: PL2761078T3; EP2761078A1; EP2761078B1

Abstract

The present invention relates to a laundry dryer (1) comprising a drum (2) wherein the laundry to be dried is placed, an air duct (3) wherein the processing air cycle is realized, a fan (4) that provides the circulation of the processing air, a compressor (5) that realizes the refrigerant cycle, an evaporator (6) that provides the processing air in the air duct (3) to be dehumidified, a condenser (7) that provides the dehumidified processing air to be heated and a refrigerant pipe (8) that provides the refrigerant pressurized by the compressor (5) to pass through the condenser (7) and the evaporator (6) to be delivered to the compressor (5) again, and wherein the refrigerant in liquid phase is prevented from entering into the compressor (5).

Description

HEAT PUMP LAUNDRY DRYER

The present invention relates to a heat pump laundry dryer wherein the efficiency of the compressor is improved.

In laundry dryers, the heat pump used for drying the laundry is composed of flow ducts wherein the refrigerant flows, a compressor that provides circulation by pressurizing the refrigerant, an evaporator and a condenser, and the drying process is performed by passing the processing air over the laundry. The condenser disposed in the heat pump functions as a heater and the evaporator functions as a condenser. The processing air is heated while passing from the condenser, delivered onto the laundry and after dehumidifying the laundry, is condensed while passing over the evaporator. In the refrigerant cycle realized by means of the refrigerant pipes between the compressor, the evaporator and the condenser, the refrigerant sent from the compressor to the condenser with increased pressure and temperature in vapor phase passes through the capillary and enters into the evaporator in liquid phase, and afterwards the refrigerant is once more changed to the vapor phase.

In order to effectively condense the processing air, the refrigerant pipes passing through the evaporator must be colder than the processing air. With the effect of the high-temperature processing air, the refrigerant pipes in the evaporator sometimes overheat, and thus the dehumidification speed and the efficiency of the evaporator decrease. In the state of the art, in order to eliminate this problem, the amount of refrigerant circulated in the refrigerant pipes is increased and the temperature of the evaporator pipes is decreased; however, this solution causes another problem and as the efficiency of the evaporator increases, the efficiency of the compressor decreases. Since the amount of refrigerant is increased, the refrigerant does not entirely change to the vapor phase, and it is sent from the evaporator to the compressor in two phases, that is liquid and vapor. Since the compressor can only pressurize and send the refrigerant in vapor phase to the condenser, the refrigerant entering into the compressor must be entirely in vapor phase. In the state of the art, in order to prevent the refrigerant in liquid phase from entering into the compressor, an accumulator is used; however, the capacity of the accumulator may be insufficient, thus the refrigerant in liquid phase enters into the compressor, thus causing the efficiency of the compressor to fall.

In the state of the art Japanese Patent Applications No. JP2010220933 and JP2010069079, heat pump laundry washers/dryers are described, wherein the accumulator is used in order to prevent the refrigerant in liquid phase from entering into the compressor.

The aim of the present invention is the realization of a heat pump laundry dryer wherein the efficiency of the compressor is increased by preventing the refrigerant in liquid phase from entering into the compressor.

The heat pump laundry dryer realized in order to attain the aim of the present invention has a refrigerant pipe disposed among the compressor, the condenser and the evaporator, wherein the refrigerant circulates, and the part of the refrigerant pipe between the evaporator and the compressor is shaped so as to contact the outer casing of the compressor before being connected to the compressor. Thus, the refrigerant is heated before entering into the compressor and provided to change from the liquid + vapor phase to the vapor phase, and the refrigerant in liquid phase is prevented from entering into the compressor.

In an embodiment of the present invention, the refrigerant pipe wraps the outer casing of the compressor in coil form, an effective heat transfer is realized between the refrigerant pipe and the compressor and the need for cooling the compressor is also fulfilled.

In another embodiment of the present invention, the laundry dryer comprises an accumulator that provides the liquid phase and the vapor phase of the refrigerant moving from the evaporator to the compressor, to be separated and that provides only the refrigerant in vapor phase to enter into the compressor. The refrigerant pipe coming from the evaporator is wrapped around the compressor casing before being connected to the accumulator, then it is connected to the accumulator and to the compressor from the accumulator.

In the heat pump laundry dryer, the refrigerant sucked by the compressor at the part of the refrigerant pipe at the inlet of the compressor is heated and provided to change to the vapor phase, thus preventing the refrigerant in liquid phase from entering into the compressor. Moreover, the compressor casing is cooled by the refrigerant pipes wrapped around and usage of a cooling fan for cooling the compressor is not needed any more.

The laundry dryer 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 heat pump laundry dryer.

Figure 2 - is the perspective view of a compressor, an accumulator and refrigerant pipes used at the compressor region in a heat pump laundry dryer.

The elements illustrated in the figures are numbered as follows:

Laundry dryer
Drum
Air duct
Fan
Compressor
Evaporator
Condenser
Refrigerant pipe
Accumulator

The laundry dryer (1) comprises a drum (2) wherein the laundry to be dried is placed, an air duct (3) wherein the processing air cycle is realized, a fan (4) that provides the circulation of the processing air, a compressor (5) that realizes the refrigerant cycle, an evaporator (6) that provides the processing air in the air duct (3) to be dehumidified, a condenser (7) that provides the dehumidified processing air to be heated, a capillary or an expansion valve (K) that is disposed between the condenser (7) and the evaporator (6) and a refrigerant pipe (8) that provides the refrigerant pressurized by the compressor (5) to pass through the condenser (7) and the evaporator (6) to be delivered to the compressor (5) again.

In the laundry dryer (1) of the present invention, the part of the refrigerant pipe (8) between the evaporator (6) and the compressor (5) is shaped so as to contact the compressor (5) casing before being connected to the compressor inlet (G), and before entering into the compressor (5), the refrigerant is provided to be heated by the high-temperature compressor (5) casing (Figure 1, Figure 2).

At the part of the refrigerant pipe (8) between the evaporator (6) and the compressor (5), the compressor (5) realizes the suction of the refrigerant from the evaporator (6) in order to pressurize and send the refrigerant to the condenser (7). The temperature of the refrigerant flowing at this part of the refrigerant pipe (8) and hence the temperature of the outer surface of the refrigerant pipe (8) is lower with respect to the temperature of the compressor (5) casing. The refrigerant is vaporized in the evaporator (6); however, since it cannot be entirely changed to the vapor phase, the refrigerant leaves the evaporator (6) in two phases, that is liquid and vapor. The part of the refrigerant pipe (8) that extends from the evaporator (6) to the compressor (5) is made contact with the compressor (5), and thus the two-phase refrigerant moving through the refrigerant pipe (8) is heated before entering into the compressor (5) and is provided to change into the vapor phase so as to be pressurized by the compressor (5). The refrigerant in liquid phase is prevented from entering into the compressor (5).

In an embodiment of the present invention, the compressor (5) casing is cylindrical and the part of the refrigerant pipe (8) that contacts the compressor (5) is in coil form, and the refrigerant pipe (8) has helical windings (S) that wrap around the compressor (5) casing (Figure 2). The number of the windings (S) of the refrigerant pipe (8) wrapped around the compressor (5) may change due to the need for heating the refrigerant; moreover, in order to improve the heat transfer, refrigerant pipes (8) in various forms (D-shaped, having cylindrical or flat cross-section, in microchannel or grooved structure) can be used. The temperature of the helical windings (S) of the refrigerant pipe (8) wrapped around the compressor (5) casing is lower with respect to the temperature of the compressor (5) casing, and the compressor (5) casing is provided to be cooled by means of the helical refrigerant pipe (8). No additional cooling fan is needed for cooling the compressor (5).

In another embodiment of the present invention, the laundry dryer (1) comprises an accumulator (9) that provides the liquid phase and the vapor phase of the refrigerant moving from the evaporator (6) to the compressor (5) in the refrigerant pipe (8), to be separated and that provides the refrigerant in vapor phase to enter into the compressor (5), and the refrigerant pipe (8) that extends from the evaporator (6) to the compressor (5) is wrapped around the compressor (5) casing before being connected to the accumulator (9). The refrigerant pipe (8) is connected to the inlet of the accumulator (9) after being wrapped around the compressor (5) casing, and connected to the compressor inlet (G) from the accumulator (9) outlet. In this embodiment, before entering into the compressor (5), the two-phase refrigerant leaving the evaporator (6) passes through the refrigerant pipe (8) wrapped around the compressor (5) casing and heats up, and at this time cools the compressor (5) and enters into the accumulator (9). The refrigerant that is heated in the refrigerant pipe (8) wrapped around the compressor (5) casing and that is partially in liquid phase, is decomposed in the accumulator (9), and the refrigerant is provided to enter into the compressor (5) entirely in vapor phase.

In this embodiment, before being connected to the compressor (5) or the accumulator (9), the refrigerant pipe (8) disposed between the evaporator (6) and the compressor (5) is wrapped around the cylindrical compressor (5) casing in helical form, and the refrigerant in liquid phase is prevented from entering into the compressor (5), thus increasing the efficiency of the compressor (5). Moreover, the refrigerant pipe (8) wrapped around the compressor (5) casing cools the compressor (5), thus no additional cooling fan is needed for cooling the compressor (5).

It is to be understood that the present invention is not limited by 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 disclosed by the claims of the present invention.

Claims

A laundry dryer (1) comprising a drum (2) wherein the laundry to be dried, an air duct (3) wherein the processing air cycle is realized, a fan (4) that provides the circulation of the processing air, a compressor (5) that realizes the refrigerant cycle, an evaporator (6) that provides the processing air in the air duct (3) to be dehumidified, a condenser (7) that provides the dehumidified processing air to be heated and a refrigerant pipe (8) that provides the refrigerant pressurized by the compressor (5) to pass through the condenser (7) and the evaporator (6) to be delivered to the compressor (5) again, characterized in that the refrigerant pipe (8), of which the part between the evaporator (6) and the compressor (5) is shaped so as to touch the compressor (5) casing before being connected to the compressor inlet (G), and that provides the refrigerant to be heated before entering into the compressor (5).
A laundry dryer (1) as in Claim 1, characterized in that the refrigerant pipe (8) having helical windings (S) that wrap around the compressor (5) casing.
A laundry dryer (1) as in Claim 1 or 2, characterized in that an accumulator (9) that provides the liquid phase and the vapor phase of the refrigerant moving from the evaporator (6) to the compressor (5), to be separated and that provides the refrigerant in vapor phase to enter into the compressor (5), and the refrigerant pipe (8) that is wrapped around the compressor (5) casing prior to the accumulator (9).