EP2025802A2 - Hybrid household drying device - Google Patents

Abstract

The appliance (1) has a treatment chamber (3) for accommodating articles (2) e.g. laundry, where processing air flow is guideable through the chamber by a processing air duct. Heat pump circuits e.g. evaporator (12) and liquefier (14) are integrated into the air duct. The liquefier liquefies working fluid under heating the processing air flow blowing against the chamber. A compressor (13) e.g. rotation compressor, of the air duct is provided for receiving power between 200 watts and 500 watts, and a heater is designed for a thermal power between 300 watts and 3500 watts.

Description

The invention relates to a domestic appliance for drying articles, comprising a treatment chamber for receiving the objects and a process air duct, through which a process air flow through the treatment chamber is feasible, and which a fan, a heater for heating the process air flow in front of the treatment chamber, an air-air Wherein the heat pump cycle comprises a closed working fluid circuit in which a working fluid is circulated and in which an evaporator, a compressor, a condenser and a throttle are arranged, wherein the evaporator for evaporating the working fluid while cooling the of Treatment chamber flowed stream of process air and the condenser for liquefying the working fluid are integrated into the process air duct while heating the process air stream flowing to the treatment chamber.

Such a household appliance is apparent from the DE 42 16 106 A1 , There, a tumble dryer is described, in which a process air stream, which dries the objects, is guided in a substantially closed circuit, so that the tumble dryer is configured as a condensation dryer. Arranged in this closed circuit are a conventional electric heater and a conventional air-to-air heat exchanger, as well as a heat pump circuit. Therefore, this clothes dryer may also be referred to as a "hybrid dryer" or "hybrid condensation dryer".

Reference should be made to the prior art relating to domestic appliances for drying with heat pump circuits on the EP 0 467 188 B1 and the WO 2006/029953 A1 ; the former document relates to the application of a heat pump cycle in a tumble dryer, the second-mentioned document such an application in a dishwasher.

Attention is also drawn to the documents EP 1 672 294 A2 and EP 1 672 294 A2 which relate to air conditioners with heat pump circuits. Such a heat pump cycle is particularly similar in terms of the temperatures that occur during normal operation in him, a heat pump cycle, as described above as a component in a domestic appliance for drying objects.

From the WO 2007/141166 A1 is a household appliance in the form of a device for drying laundry, which has, inter alia, a heat pump cycle. The heat pump cycle is in particular a thermoelectric heat pump. In addition, the device includes a conventional heater and a conventional air-to-air heat exchanger. For the heat pump circuit and the heater and the air-to-air heat exchanger information on preferred operating power output or power consumption are mentioned.

From the document "Application of Danfoss Hermetic Compressors", which was published on July 26, 2007 by the following Internet address
htt p : // com p ressors.danfoss.com/service su pp ort / service su pp ort index.htm downloadable information about compressors that can be used in heat pump circuits of the type defined at the beginning or refrigerators, freezers or air conditioning systems are, forth. Thus, a given compressor has a characteristic relating to the temperature range or pressure range in which the evaporation of the working fluid which the compressor has to compress as part of its application. Thus, the parameter for a compressor for a low evaporation temperature freezer is "LBP" (low back pressure), for a compressor for a refrigeration system "MBP"("medium back pressure") and for a compressor for an air conditioner or heat pump " HBP "(" high back pressure ").

So far, a successful marketing of a hybrid household appliance of the type defined initially unsuccessful because such a domestic appliance has a rather complicated structure and compared to a simple, especially without heat pump circuit or with heat pump cycle, but without a heat exchanger built device is at a disadvantage.

The present invention is therefore based inter alia on the task of further developing a generic hybrid household appliance in such a way that it can be marketed despite a generally increased outlay with a good chance of success.

To solve this problem, a domestic appliance for drying objects, comprising a treatment chamber for receiving the objects and a process air duct, through which a process air flow through the Treatment chamber is feasible, and which has a fan, a heater for heating the process air flow in front of the treatment chamber, an air-air heat exchanger and a heat pump circuit, wherein the heat pump cycle comprises a closed working fluid circuit in which a working fluid is circulated and in which an evaporator, a compressor, a condenser and a throttle are arranged, wherein the evaporator for evaporating the working fluid while cooling the effluent from the treatment chamber process air flow and the condenser for liquefying the working fluid while heating the treatment chamber inflowing process air flow are integrated into the process air duct, in which domestic appliance the Compressor for power between 200 W and 500 W and the heater designed for thermal power between 300 W and 3500 W, and for which domestic appliance the compressor is designed for use in a house advises to freeze objects or in an air conditioner.

The compressor in the domestic appliance according to the invention is designed for use in a domestic appliance for freezing objects or an air conditioning system. In particular, such a compressor is a compressor with the above-mentioned characteristic "LBP", which implies the determination for a freezing application, whereas the application of the invention has the characteristic "HBP" - this because of the usually well above 0 ° C. lying evaporation temperature of the working fluid in the household appliance according to the invention. This opens up the use of a mass product in the household appliance according to the invention; It should be noted that, according to the invention, other components of the heat pump circuit, in particular the condenser, besides the compressor are also suitable for implementation with low-cost mass-produced products for refrigeration, freezing or air-conditioning applications.

The invention is based on the recognition that the energy balance of a conventional condensation dryer without heat pump system already by the addition of a small heat pump cycle, which recovers as intended only a portion of the total applied to dry the items heat from the effluent from the objects, laden with moisture process air, so far that the resulting hybrid dryer can be allocated to the best energy consumption class known in Western Europe, Class A, and thus Compared to a conventional dryer without heat pump circuit receives a market relevant and recognizable to end users advantage. The invention further proceeds from the recognition that such a small heat pump cycle can be composed of components which are customary for heat pump circuits in refrigeration, in particular freezer, and air conditioning systems and which are cheap available as mass products. It therefore eliminates both development and design effort for a correspondingly efficient heat pump cycle, which would be required for a dryer operating essentially only with the heat pump cycle, and also a cost disadvantage, which would be acceptable for corresponding specially developed components away from the usual supply of mass products , Thus, it is possible to use in the construction of the hybrid household appliance according to the invention cost advantages through the use of commercially available components and pass it on to the end user.

In a preferred embodiment of the domestic appliance according to the invention, the heater is designed for a thermal power between 500 W and 2500 W. As a result, the heater is flexible in operation; it can be used to quickly heat up the process air duct when the home appliance is put into service, thus overcoming a fundamental drawback of a conventional dryer with heat pump circuit, and can be back-steered in its performance to accommodate the recirculation of heat into the process air duct by the heat pump circuit ,

A likewise preferred development of the domestic appliance according to the invention is characterized in that the compressor is designed to accommodate a power between 300 W and 400 W. This sets a standard for a contribution that the heat pump cycle provides to the application of heat in the domestic appliance, which contribution is appropriate for obtaining the energy consumption class A.

The compressor in the domestic appliance according to the invention is preferably a rotary compressor. Rotary compressors are known in various designs, especially as rotary valves, gate valves and turbo compressors. All of these types are characterized in particular by low-noise and low-vibration running and high efficiency.

It is also particularly preferred that in the household appliance according to the invention, the heat pump cycle has a pumping factor between 1.5 and 2.

A further embodiment of the domestic appliance according to the invention provides that the working medium circuit contains a working medium which has a critical temperature between 60 ° C and 100 ° C and a heat of vaporization at the boiling point under normal pressure of at least 220 kJ / kg. As such working medium are customary "refrigerants" in question, in particular those designated as corresponding ASHRAE and DIN standards compounds or mixtures R22, R290, R134a, R407C and R410A - wherein the use of both chlorine and fluorine-containing R22 in aspects of Environmental protection and use of the R290, namely propane, may be problematic under aspects of fire safety.

Within the scope of another embodiment of the domestic appliance according to the invention, the heat exchanger is designed to remove a thermal power of between 1000 W and 2000 W and preferably to extract a thermal power of approximately 1500 W from the process air flow.

Particularly preferred is also an embodiment in which the domestic appliance according to the invention is a tumble dryer.

An embodiment of the invention is described below with reference to the drawing. The drawing shows the various channels and components of the household appliance in a schematic manner. For further information on the realization of such a domestic appliance reference is made to the cited documents of the prior art.

The sole figure of the drawing shows a domestic appliance 1, which is a tumble dryer 1 concrete. The household appliance is intended for drying articles 2, in the present case wet laundry items 2. These articles 2 are located in a treatment chamber 3, which is a rotatable drum and which loosens and drops the objects 2 to be dried as they move flows around a process air stream which is driven in a process air duct 4 by means of a blower 5 in a substantially closed circuit becomes. "Essentially closed" here means that there is no significant difference in pressure between the process air duct 4 and an environment of the domestic appliance 1, although nevertheless no exchange of air between the process air duct 4 and the environment of the domestic appliance 1 takes place to a significant extent. In addition to the fan 5, a heater 6 and an air-to-air heat exchanger 7 are arranged in the process air duct 4. The heater 6 is used to heat the process air stream before it flows through the treatment chamber 3, and the air-to-air heat exchanger 7 for cooling the process air stream after it has flowed away from the treatment chamber 3. The heat exchanger 7 is part of both the process air duct 4 and a cooling air duct 8, in which a second fan 9 sucks air from the environment of the domestic appliance 1 and drives through the heat exchanger 7 and back into the environment of the domestic appliance 1. When cooling the process air stream in the heat exchanger 7, moisture condenses out of the process air stream, which has absorbed it from the objects 2 in the treatment chamber 3. This moisture is reflected in the heat exchanger 7 and flows through a correspondingly provided gradient and / or supported by a (not shown) condensate pump to a condensate collector 10 if necessary. From there, the collected moisture can be disposed of after completion of the drying process.

In addition to the heater 6 and the heat exchanger 7, the process air duct 4 is coupled to a heat pump circuit 11, 12, 13, 14, 15. This heat pump cycle 11, 12, 13, 14, 15 comprises a closed working fluid circuit 11, in which a working fluid is circulated. It further comprises an evaporator 12, in which the working fluid is vaporized by absorbing heat from the process air duct 4, a compressor 13, which promotes the vaporized working fluid from the evaporator 12 to a condenser 14 and compresses it, and a throttle 15 in the form of a Control valve, a diaphragm or a capillary, which reduces the pressure of the liquefied working fluid so that it can evaporate again in the evaporator 12, which it flows behind the throttle 15. The condenser 14 is intended for liquefying the compressed working fluid while heating the circulating in the process air duct 4 process air flow before it reaches the treatment chamber 3. Since the process air stream is cooled again in the evaporator 12, moisture also condenses in the evaporator 12 from the process air stream. This moisture also flows through a suitably provided natural gradient and / or supported by said, not shown condensate pump, the condensate collector 10 for later disposal.

Not shown are means for catching lint, which entrains the process air stream the laundry items 2 and carries in the process air duct 4. Corresponding means, in particular lint filters, are generally known and must be provided in the tumble dryer 1 in order to avoid harmful contamination of the heat exchanger 7 and / or of the evaporator 12. These two components are particularly at risk because they produce moisture, which binds the lint in a wet film, which covers the components and hinders the heat exchange with the cooling air or the working fluid. For the present explanation, however, a lint filter is not required and was therefore not shown for the sake of clarity.

Of importance in the present case, the distribution of the heating and cooling capacity between the heater 6 and the heat exchanger 7 on the one hand and the heat pump circuit 11 to 15 on the other. Accordingly, it is provided that the compressor 13, which essentially determines the thermal performance data of the heat pump circuit 11 to 15, is designed to absorb a power of between 200 watts and 500 watts, in particular between 300 watts and 400 watts. Likewise, the heater 6 is designed for thermal power between 300 watts and 3500 watts, preferably between 500 watts and 2500 watts. The heat exchanger 7, however, is designed to extract a thermal power between 1000 watts and 2000 watts, preferably about 1500 watts, from the process air stream. The heat pump cycle 11 to 15 in this case has a pumping factor between 1.5 and 2. As a working medium esp. Such a working medium into consideration, which is a critical temperature between 60 ° C and 100 ° C, and a heat of vaporization at the boiling point under atmospheric pressure of at least 220 kJ per kg.

With this performance data, the domestic appliance 1 can achieve a specific energy consumption in the drying process, which is low enough to allocate the domestic appliance 1 to the energy consumption class A. In addition, as the compressor 13, a type may be used which is adapted for use in a domestic appliance for freezing articles or in an air conditioner, and is preferably a rotary compressor. Such types are for use in freezers and Air conditioning systems as mass-produced cheap available, which is why the domestic appliance 1 described herein can be manufactured and marketed despite a relatively high construction cost at a low price.

Thus, the invention described herein provides a highly advantageous compromise between lowest possible power consumption and lowest cost, and thus provides a particularly inexpensive home appliance.

Claims (9)

Domestic appliance (1) for drying articles (2), comprising a treatment chamber (3) for receiving the articles (2) and a process air duct (4) through which a process air flow through the treatment chamber (3) can be guided, and which a blower ( 5), a heater (6) for heating the process air flow upstream of the treatment chamber (3), an air-air heat exchanger (7) and a heat pump circuit (11, 12, 13, 14, 15), wherein the heat pump cycle (11, 12, 13, 14, 15) comprises a closed working medium circuit (11) in which a working medium is circulated and in which an evaporator (12), a compressor (13), a condenser (14) and a throttle (15) are arranged wherein the evaporator (12) for evaporating the working fluid while cooling the process air flow discharged from the treatment chamber (3) and the condenser (14) for liquefying the working fluid while heating the process air flow flowing to the treatment chamber (3) in the process air duct (4) are integrated, characterized in that the compressor (13) for receiving a power between 200 W and 500 W and the heater (6) for a thermal power between 300 W and 3500 W is designed, and that the Compressor (13) is adapted for use in a domestic appliance for freezing objects or in an air conditioner. Domestic appliance (1) according to claim 1, wherein the heater (6) is designed for a thermal power between 500 W and 2500 W. Domestic appliance (1) according to one of the preceding claims, wherein the compressor (13) is designed to receive a power between 300 W and 400 W. Domestic appliance (1) according to one of the preceding claims, in which the compressor (13) is a rotary compressor (13). Domestic appliance (1) according to one of the preceding claims, wherein the heat pump circuit (11, 12, 13, 14, 15) has a pumping factor between 1.5 and 2. Domestic appliance (1) according to claim 5, wherein the working medium circuit (11) contains a working medium which has a critical temperature between 60 ° C and 100 ° C and a heat of vaporization at the boiling point under normal pressure of at least 220 kJ / kg. Domestic appliance (1) according to one of the preceding claims, wherein the heat exchanger (7) is designed for extracting a thermal power between 1000W and 2000W from the process air stream. Domestic appliance (1) according to claim 7, wherein the heat exchanger (7) is designed to extract a thermal power of about 1500 W from the process air stream. Domestic appliance (1) according to one of the preceding claims, which is a tumble dryer (1).

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