EP2576888A1

EP2576888A1 - A thermoelectric heat pump laundry dryer

Info

Publication number: EP2576888A1
Application number: EP11723080.5A
Authority: EP
Inventors: Yavuz Sahin; Mehmet Kaya; Onur Hartoka; Serdar Kocaturk
Original assignee: Arcelik AS
Current assignee: Arcelik AS
Priority date: 2010-06-07
Filing date: 2011-06-06
Publication date: 2013-04-10
Anticipated expiration: 2031-06-06
Also published as: CN102918198B; CN102918198A; EP2576888B1; WO2011154336A1

Abstract

The present invention relates to a laundry dryer (1) comprising drum (2) wherein the laundry is placed, a drying duct (3) wherein the process air is circulated, a fan (4) providing the circulation of process air in the drying duct (3), a heater (5) that heats the process air, a condenser (6) providing the dehumidification of the process air and a thermoelectric heat pump (7) disposed in the drying duct (3), having a cold side (8), a hot side (9) that condenses by cooling and afterwards heats the process air passing thereover and an inlet opening (10) that provides entry of the process air into the hot side (9). A divider (11) is disposed in the drying duct (3) to divide the drying duct (3) into two, as the first drying duct (3') and the second drying duct (3"), whereby process air flowing in the first drying duct (3') is guided directly to the hot side (9).

Description

A THERMOELECTRIC HEAT PUMP LAUNDRY DRYER

The present invention relates to a laundry dryer comprising a thermoelectric heat pump.
In laundry dryers wherein the drying air is circulated within a closed cycle, the drying air activated by a fan removes the moisture of the laundry by being passed over the laundry and the water vapor in the air is condensed at the condenser. The drying air dehumidified at the condenser is later heated by being passed over the heater thus delivering hot and dry air unto the laundry. In laundry dryers generally air cooled type condensers are used. The air sucked by means of the cooling fan from the outer environment is delivered to the condenser and thus the drying air passing through the condenser is provided to be condensed by cooling. In the state of the art, furthermore thermoelectric heat pumps are used in laundry dryers in addition to the condenser and the heater. The thermoelectric heat pumps are also named as Peltier elements. The thermoelectric heat pumps have hot and cold sides and perform both the functions of condensing by cooling and also heating the drying air. While the hot side of the thermoelectric heat pumps used in laundry dryers assists the heater, the cold side assists the condenser. In the process of drying the laundry, the drying air is cooled by some amount while being passed over the condenser, afterwards is passed over the thermoelectric heat pump and thereby the dehumidification process of the drying air is accomplished in two stages. Similarly, the heating process is also in two stages. The drying air, which is almost completely dehumidified of the moisture contained therein by passing through the condenser and the cold side of the thermoelectric heat pump, is heated some amount by being passed over the hot side of the thermoelectric heat pump and afterwards the heating process is completed by the drying air being passed over the main heater. In the said laundry dryers wherein the heater, the condenser and the thermoelectric heat pump are used together, the problem of pressure loss arises due to the numerous paths and turns wherein the drying air circulates. The pressure of the drying air decreases while passing particularly from the heat sinks which provide heat transfer in the hot and cold sides of the thermoelectric heat pump and the volumetric flow and hence the speed of the drying air which is activated and delivered unto the laundry by the drying fan, decreases and the efficiency of drying is lowered. Furthermore, the low speed air passing over the thermoelectric heat pump decreases the operational efficiency thereof. When air with low volumetric flow and low speed passes from particularly the hot side of the thermoelectric heat pump, heat emission from the hot side to the outside becomes weaker. Decrease in the effectiveness of the thermoelectric heat pump hot side also results in decrease in the effectiveness of the cold side and hence the condensation efficiency is lowered.
In the German Patent Application No. DE102006005810, a Peltier element is disposed in the gap between two heat sinks. The sealing element is arranged between the Peltier element and the heat sinks.
In the German Patent Application No. DE102006016294, a laundry dryer comprising thermoelectric heat pump is explained. The drying process air is directed from the cold side of the thermoelectric heat pump to the hot side by means of an air guidance device.
In the German Patent Application No. DE102006026251, a laundry dryer is explained wherein the drying air is circulated in a closed channel system. The drying air is parallelly passed through the thermoelectric heat pump having cold side and hot side.
In the German Utility Model Application No DE20101641, the drying air leaving the drum in a laundry dryer enters the condenser after passing from the cold surface of the Peltier element and the air leaving the condenser is delivered to the drum after passing from the hot surface of the Peltier element and the heater.
The aim of the present invention is the realization of a laundry dryer which comprises the thermoelectric heat pump and wherein the pressure losses that occur in the drying cycle are decreased.
The laundry dryer realized in order to attain the aim of the present invention, explicated in the first claim and the respective claims thereof, comprises a thermoelectric heat pump (Peltier) having a hot side and a cold side, some portion of the process air activated by the fan continues its path in the drying duct after leaving the drum, passing from the condenser, the hot side, the cold side and the heater respectively and is delivered again to the drum in dehumidified and heated state. The other portion of the drying air is guided directly to the hot side of the thermoelectric heat pump by means of a divider disposed in the drying duct, without circulating through the condenser and the cold side of the thermoelectric heat pump and is again delivered to the drum over the main heater.
In an embodiment of the present invention, the end of the divider extending into the drying duct is in the form of a plate that extends in the reverse direction of the process air flow and vertically upwards in the drying duct.
In another embodiment of the present invention, the end of the divider extending to the inlet opening of the hot side, is in the form of a plate that bears against the sides of the inlet opening by extending in the horizontal direction to almost the center of the inlet opening.
In another embodiment of the present invention, a filter that extends into the second drying duct is integrated with the divider so as to form a barrier in front of the process air flow.
In the laundry dryer of the present invention, pressure losses are decreased by means of the divider, the effectiveness of both the hot side and the cold side of the thermoelectric heat pump are increased.
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 laundry dryer.
Figure 2 – is the schematic view of the drying duct, the condenser, the thermoelectric heat pump and the divider disposed in a laundry dryer.
The elements illustrated in the figures are numbered as follows:

Laundry dryer
Drum
3’, 3’’ Drying duct
Fan
Heater
Condenser
Thermoelectric heat pump
Cold side
Hot side
10’, 10’’ Inlet opening
Divider
Filter

The laundry dryer (1) comprises a body, a drum (2) wherein the laundry is placed, a drying duct (3) wherein the process air is circulated, a fan (4) providing the circulation of process air in the drying duct (3), a heater (5) that heats the process air, a condenser (6) providing the dehumidification of the process air and a thermoelectric heat pump (7) disposed after the condenser (6) in the drying duct (3), that condenses by cooling and afterwards heats the process air passing thereover.
The thermoelectric heat pump (7) comprises a cold side (8) that condenses the process air passing thereover by cooling, a hot side (9) that heats the process air passing thereover and an inlet opening (10) placed at the hot side (9) that provides entry of the process air into the hot side (9).
The laundry dryer (1) of the present invention comprises a divider (11) that,
- is disposed in the drying duct (3),
- one end of which extends into the drying duct (3) and dividing the drying duct (3) into two, as the first drying duct (3’) and the second drying duct (3’’),
-the other end of which extends to the inlet opening (10) and dividing the inlet opening (10) into two divisions as the upper inlet opening (10’) and the lower inlet opening (10’’),
-that guides the process air flowing in the first drying duct (3’) directly to the hot side (9) from the upper inlet opening (10’), without circulating the condenser (6) and the cold side (8) and
-that guides the process air flowing in the second drying duct (3’’) and circulating the condenser (6) and the cold side (8) to the hot side (9) from the lower inlet opening (10’’) (Figure1, Figure 2).
The thermoelectric heat pump (7) is positioned horizontally inside the body of the laundry dryer (1), the cold side (8) is situated below, and the hot side (9) above, and the condenser (6) is situated under the cold side (8), at the lowermost place inside the body of the laundry dryer (1). The said elements are arranged one above the other from the drum (2) towards the base as the hot side (9) – the cold side (8) – the condenser (6).
The divider (11) guides some portion of the process air leaving the drum (2) and flowing in the drying duct (3) to the first drying duct (3’), the other portion to the second drying duct (3’’). The first drying duct (3’) functions as the bypass duct for some portion of the process air, the process air flowing in the first drying duct (3’) is delivered directly to the hot side (9) of the thermoelectric heat pump (7) by being passed from the upper inlet opening (10’), without circulating the condenser (6) and the cold side (8), the process air leaving the hot side (9) is again delivered to the drum (2) by being passed over the heater (5). The process air flowing in the second drying duct (3’) is delivered to the hot side (9) of the thermoelectric heat pump (7) by being passed through the lower inlet opening (10’’) after circulating the condenser (6) and the cold side (8), mixes with the process air entering the hot side (9) from the upper inlet opening (10’) and enters the drum (2) again by passing from the heater (5).
The divider (11) provides at least some portion of the process air to be delivered directly to the hot side (9) by being passed through the first drying duct (3’) without losing pressure and without circulating the condenser (6) and the cold side (8) and from there to be delivered to the drum (2) again over the heater (5). The divider (11) provides the process air flowing through the first drying duct (3’) and the second drying duct (3’’) to enter the hot side (9) from the upper and lower inlet openings (10’, 10’’) by dividing the inlet opening (10) on the hot side (9) of the thermoelectric heat pump (7) into two and the hot air coming from both of the drying ducts (3’, 3’’) continues flowing onward by uniting at the hot side (9). Thus, the volumetric flow of the process air is increased, pressure losses are minimized and the thermoelectric heat pump (7) is provided to operate more effectively.
In an embodiment of the present invention, the end of the divider (11) inside the drying duct (3) is in the form of a plate that extends into the drying duct (3) vertically and in the reverse direction of the process air flow (Figure 2).
In another embodiment of the present invention, the end of the divider (11) on the side of the inlet opening (10), is in the form of a plate that bears against the sides of the inlet opening (10) by extending in the horizontal direction to almost the center of the inlet opening (10) (Figure 2).
In another embodiment of the present invention, the laundry dryer (1) comprises a filter (12) integrated with the divider (11) and disposed in the second drying duct (3’’) so as to form a barrier in front of the process air (Figure 1). The filter (12) only filters the process air flowing in the second drying duct (3''), the air flowing in the first drying duct (3') does not lose pressure since it is not filtered. Moreover, the filter (12), since being integrated with the divider (11), can be cleaned by being taken out of the laundry dryer (1) together with the divider (11) easily.
In the laundry dryer (1) of the present invention, the effectiveness of the thermoelectric heat pump (7) is increased by increasing volumetric flow of the process air passing from the hot side (9) of the thermoelectric heat pump (7) by means of the divider (11) and the pressure losses of the process air are decreased. Furthermore, the condensation effectiveness of the cold side (8) is increased by decreasing the volumetric flow of the process air passing from the cold side (8) of the thermoelectric heat pump (7).
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 postulated by the claims of the present invention.

Claims

A laundry dryer (1) comprising a drum (2) wherein the laundry is placed, a drying duct (3) wherein the process air is circulated, a fan (4) providing the circulation of process air in the drying duct (3), a heater (5) that heats the process air, a condenser (6) providing the dehumidification of the process air and a thermoelectric heat pump (7) disposed after the condenser (6) in the drying duct (3), having a cold side (8) that condenses the process air passing thereover by cooling, a hot side (9) that heats the process air passing thereover and an inlet opening (10) arranged at the hot side (9) that provides entry of the process air to the hot side (9), characterized by a divider (11) that - is disposed in the drying duct (3), - one end of which extends into the drying duct (3) and dividing the drying duct (3) into two, as the first drying duct (3’) and the second drying duct (3’’), - the other end of which extends to the inlet opening (10) and dividing the inlet opening (10) into two divisions as the upper inlet opening (10’) and the lower inlet opening (10’’), - that guides the process air flowing in the first drying duct (3’) directly to the hot side (9) from the upper inlet opening (10’), - that guides the process air flowing in the second drying duct (3’’) and circulating the condenser (6) and the cold side (8) to the hot side (9) from the lower inlet opening (10’’).
A laundry dryer (1) as in Claim 1, characterized by the divider (11) the end inside of the drying duct (3) of which is in the form of a plate that extends into the drying duct (3) vertically and in the reverse direction of the process air flow.
A laundry dryer (1) as in Claim 1 or 2, characterized by the divider (11) the end on the side of the inlet opening (10) of which is in the form of a plate that bears against the sides of the inlet opening (10) by extending in the horizontal direction to almost the center of the inlet opening (10).
A laundry dryer (1) as in any one of the above Claims, characterized by a filter (12) integrated with the divider (11) and disposed in the second drying duct (3’’).