EP2006622A2 - Machine de réfrigération avec unité de décongélation - Google Patents

Machine de réfrigération avec unité de décongélation Download PDF

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Publication number
EP2006622A2
EP2006622A2 EP08158472A EP08158472A EP2006622A2 EP 2006622 A2 EP2006622 A2 EP 2006622A2 EP 08158472 A EP08158472 A EP 08158472A EP 08158472 A EP08158472 A EP 08158472A EP 2006622 A2 EP2006622 A2 EP 2006622A2
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EP
European Patent Office
Prior art keywords
refrigerating machine
machine according
defrosting
thermoelectric
subchamber
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP08158472A
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German (de)
English (en)
Other versions
EP2006622A3 (fr
Inventor
Niccolo' Gaggelli
Alessandro Rosi
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Individual
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Individual
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Publication date
Application filed by Individual filed Critical Individual
Publication of EP2006622A2 publication Critical patent/EP2006622A2/fr
Publication of EP2006622A3 publication Critical patent/EP2006622A3/fr
Withdrawn legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
    • F25D21/00—Defrosting; Preventing frosting; Removing condensed or defrost water
    • F25D21/06—Removing frost
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B21/00—Machines, plants or systems, using electric or magnetic effects
    • F25B21/02—Machines, plants or systems, using electric or magnetic effects using Peltier effect; using Nernst-Ettinghausen effect
    • F25B21/04—Machines, plants or systems, using electric or magnetic effects using Peltier effect; using Nernst-Ettinghausen effect reversible

Definitions

  • the invention relates to a refrigerating machine with defrosting unit, aimed at preserving products and adapted to cool a volume to temperatures even below 0°C, provided with a device by means of which the formation of frost in its useful cooled volume is hindered.
  • Refrigerating machines are known which are used to contain products, particularly food products, to be preserved at a temperature which is lower than the ambient temperature, comprising temperatures below 0°C.
  • Direct Cooling comprises a chamber, which is optionally divided into several parts and is delimited by one or more heat-conducting surfaces which act as heat exchangers, and therefore are in contact on one side with the evaporator assembly of the refrigeration system and are in contact on the other side with the air of the volume to be cooled, from which they remove heat.
  • Another known refrigerating machine which operates according to a different technical method, normally known as "no frost", comprises a volume which is divided into two chambers, of which the first one is designed to generate cold and has the heat exchangers concentrated therein, and the second one is designed to contain the products to be cooled and does not contain heat exchangers.
  • a suitable fan generates a stream of air, which passes through the two chambers: in the first one, it is cooled by contact with the heat exchange surfaces, which are cooled by the refrigeration system; in the second one, it flows over the products to be preserved and removes heat from them until they are brought to the programmed temperature.
  • the circulating air releases its moisture, in the form of frost, to the heat exchangers that are present only in the first chamber, while the surfaces of the second chamber are preserved from frosting.
  • the first chamber is also provided with a heating assembly, usually an electric resistor, to be activated periodically, when the refrigeration system is deactivated, in order to perform defrosting.
  • Such machine for an equal overall volume, has a smaller useful volume, is relatively complicated and therefore more expensive, and entails a higher energy expenditure; moreover, the temperature in the second chamber, despite not being affected by the frost, nonetheless increases during defrosting intervals even in this machine, and therefore the products therein may risk damage.
  • the aim of the present invention is to provide a refrigerating machine which is constructively simple and in which the moisture of the air gathers in the form of frost in a very small space within the cooled volume, so that the overall refrigeration heat exchange and the temperature inside the machine remain substantially constant over time.
  • an object of the invention is to provide a refrigerating machine in which defrosting can be performed without altering significantly the temperature in the refrigerated chamber and therefore without requiring, during this step, the extraction of the products accommodated therein from said chamber or the shutdown of the refrigerating machine.
  • Another object of the invention is to provide a refrigerating machine in which defrosting can be automated and/or programmed by the user.
  • a refrigerating machine with defrosting unit comprising a chamber to be refrigerated and a subchamber, characterized in that the chamber to be refrigerated is delimited at least in one part by the heat exchange surface which is thermally connected to the evaporator assembly, in that the subchamber has a much smaller volume than the chamber to be refrigerated and contains a thermoelectric Peltier-effect refrigerating device, which on one side is connected to the evaporator assembly and on the other side is connected to the freezing-defrosting surface, a fan and a thawing liquid collector, said subchamber comprising a switching assembly with which at least the polarities of the power source of the thermoelectric refrigerating device are exchanged.
  • Such machine is particularly advantageous, because it is easy to provide and because the introduction of the defrosting assembly does not alter significantly its structure and useful volume.
  • the machine as a refrigeration system, operates continuously and does not require its shutdown in time intervals in which defrosting is performed.
  • frost forms only on a limited surface inside the machine and thus the heat efficiency of such machine remains substantially constant over time.
  • defrosting can be activated with a programmed circuit, in which the defrosting intervals are set and adjusted by the user.
  • the invention consists of a refrigerating machine, such as for example a refrigerator or freezer of the type for family use or for shops or points of sale of products to be preserved at a temperature which is in any case lower than the ambient temperature, including the temperature around the dew point in which the defrosting operation, i.e., the removal of the frost that has formed inside it by condensation of the moisture of the air that is present in the refrigerated chamber, occurs automatically or under the command of the operator.
  • a refrigerating machine such as for example a refrigerator or freezer of the type for family use or for shops or points of sale of products to be preserved at a temperature which is in any case lower than the ambient temperature, including the temperature around the dew point in which the defrosting operation, i.e., the removal of the frost that has formed inside it by condensation of the moisture of the air that is present in the refrigerated chamber, occurs automatically or under the command of the operator.
  • the machine comprises a chamber 1 to be refrigerated, a small subchamber 2, within which the formation of frost, i.e., the freezing of the moisture that is present in the air that has entered such chamber to be refrigerated during its opening and introduction of the products to be kept at the chosen temperature, which is lower than the ambient temperature.
  • frost i.e., the freezing of the moisture that is present in the air that has entered such chamber to be refrigerated during its opening and introduction of the products to be kept at the chosen temperature, which is lower than the ambient temperature.
  • Both the chamber 1 to be refrigerated and the subchamber 2 have heat exchange surfaces which are connected, directly or by means of a eutectic fluid, to an evaporator assembly 10 of the refrigeration system with which the machine is equipped.
  • the subchamber 2 whose volume is normally much smaller than the volume of the chamber 1 to be refrigerated, on the order of one hundredth or even less than the volume of the chamber 1 to be refrigerated, contains a Peltier-effect thermoelectric refrigerating device 4, which on one side is connected directly to the evaporator assembly 10 or connected thereto by means of a eutectic mass, in the vicinity of its initial portion, where the temperature is substantially constant, and on the other side is combined with a freezing-defrosting surface 6.
  • a suitable small fan 3 conveys thereon a stream of air which is drawn from the chamber 1 to be refrigerated, where it is then returned after skimming the surface 6 associated with the thermoelectric refrigerating device 4.
  • a collector 7 for defrosting liquids which is provided with a duct 9 by means of which they are conveyed outside.
  • the Peltier effect is the thermoelectric phenomenon by which an electric current that flows between two different metals or semiconductors arranged in contact (Peltier junction) produces a transfer of heat, i.e., the opposite of the better-known Seebeck effect.
  • the Peltier cell therefore should be considered as a solid-state heat pump, having the appearance of a thermoelectric circuit which has a pair of electrodes, a "warm” electrode and a “cold” electrode, which are mutually connected by a pair of laminas: one lamina absorbs heat, while the heat is emitted by the other lamina.
  • the direction in which the heat is transferred depends on the direction of the applied current.
  • thermoelectric refrigerator 4 comprises a circuit which is constituted by two bars made of different semiconductors, for example antimony and bismuth, which are welded at their ends.
  • a generator is inserted between the two semiconductors, which are connected by means of a pair of copper laminas which are mutually parallel, so that such current can circulate.
  • a pair of electrodes is formed which are referenced as “warm” and “cold” because if a positive voltage is applied to one electrode and a negative voltage is applied to the other electrode, the result is that one lamina becomes cool and the other one becomes warm.
  • thermoelectric refrigerating device 4 is therefore, on the side that is normally warm, in thermal contact with a portion, preferably the initial portion at a substantially constant temperature, of the evaporator assembly 10 of the refrigeration system, or with a eutectic mass which is refrigerated by the evaporator assembly 10, with which the machine is equipped, which drives and keeps substantially constant its operating temperature.
  • the other side of the thermoelectric refrigerating device 4, the one that is normally cold, is instead connected to the heat exchanger with the large surface 6, acting as a condensation surface during the freezing step and as a liquefaction surface in the defrosting step.
  • This heat exchanger is normally a structure made of metal or otherwise a material which has a high thermal conductivity.
  • thermoelectric refrigerator 4 normally has a finned configuration with a surface which is suitable for the frost to be collected therein during normal operation and is designed to be skimmed by the air stream that is pushed into the subchamber 2 by the fan 3.
  • the warm side of the thermoelectric refrigerator 4 is therefore substantially at the temperature of the initial portion of the evaporator assembly 10 with which it is in contact. Its cold side, and the freezing surface 6 with it, is at a temperature which is approximately 10°C and lower than the warm side and is in any case lower than the dew point.
  • frost 8 The moisture that is present in the air that skims it undergoes a sudden cooling and freezes therein in the form of frost 8.
  • the average moisture diffused in the air inside the chamber 1 to be refrigerated of the machine is thus reduced, hindering or in any case reducing in this manner the formation of frost outside the subchamber 2, even if the temperature of the surfaces outside the subchamber 2, at least part of which act as refrigerating surfaces, reaches temperatures lower than the dew point.
  • thermoelectric refrigerator 4 is combined with its own electric power supply. Its input electric terminals, during normal operation, have the polarity that gives its inner side, i.e., the side in thermal contact with the evaporator assembly 10 of the machine, a "warm” temperature. It is further combined with a switching-adjustment assembly A-C 5, by means of which the polarity of the electric source that supplies it is switched, so that once such switching has been performed its inner side becomes the "cold” one and therefore its outer side becomes the "warm” one, i.e., reaches a temperature higher than 0°C and in any case sufficient to thaw the frost 8 in contact with the surface 6, which in this step acts as a defrosting surface.
  • the temperature of the surface 6 is changed by means of a suitable adjustment of the absorbed electric current, such current being adjusted as a function of the refrigerating machine in which the invention is applied.
  • the heating of the surface 6 in the defrosting steps is achieved by combining such surface with an electrical resistor which is activated, and therefore heated, in the intervals in which defrosting is performed.
  • such heating of the defrosting surface 6 is achieved by the combined effect of an electric resistor which is crossed by a current and by the reversal of the current in the thermoelectric refrigerator 4.
  • the frost 8 at least the frost in direct contact with the surface 6 which, when heated, becomes the defrosting surface, thaws and slides into the defrosting liquid collector 7 and at least its liquid part is conveyed outside the machine through the suitable duct 9.
  • the switching assembly 5 can have manual activation or can be combined with a programmed timing assembly, which is adapted to drive for a definite time and at programmed intervals the reversal of the polarity of the power supply of the thermoelectric refrigerating device 4 in defrosting intervals.
  • thermoelectric refrigerating device 4 Normally, reversal of the polarities of the power supply source of the thermoelectric refrigerating device 4 also causes an interruption in the power supply of the fan 3, so that in the defrosting steps in the subchamber 2 the air is stationary, thus facilitating such defrosting.
  • the surface 6 is normally of the type with fins, so that for an equal occupied volume it is large and therefore, in the freezing step, facilitates contact with the air to be dehumidified.
  • This set of fins, or in any case its contour, when heated, therefore in the defrosting step, is further such as to also facilitate the sliding of the frost and of the drops toward the collector 7.
  • the liquid produced in the defrosting step is guided outward and normally conveyed into an open container 11, which is arranged above a compressor assembly 12, from which it receives heat to facilitate the evaporation of such liquid, so that it is made to mix with the air of the enclosed space in which the refrigerating machine is accommodated.
  • the subchamber 2 can have a constant temperature which can be adjusted by the user.
  • thermoelectric control circuit by means of which the temperature of the subchamber 2 is adjusted by controlling the current that is sent to the Peltier cell of the thermoelectric refrigerating device 4, such control being performed by means of a device for measuring the temperature of the subchamber 2 and a current regulator.
  • thermoelectric control circuit is programmed to vary the current that passes through the Peltier module (and therefore the delta T between the two faces of such module), depending on the measurements of the temperature measurement device.
  • a container for liquids for example an ice holder tray
  • the "cold" electrode at the temperature for liquid-solid state transition (or below) and the "warm” electrode at the temperature provided in the chamber 1, it is in fact always possible to generate ice even when the chamber 1 is adjusted to operate at temperatures above zero and in the refrigerating machine there is no separate freezing compartment or freezer.
  • such defrosting unit is shaped like a container for liquid.
  • thermoelectric refrigerating device 4 at least one more Peltier cell, which is accommodated within the subchamber 2, so as to obtain, by adding each thermal delta of each Peltier cell, an important high temperature gradient between the subchamber 2 and the chamber 1.
  • Each one of these cells must have both electrodes connected to a power supply provided with adjustment and reversal means for the electric current in order to obtain the freezing or defrosting effects.
EP08158472A 2007-06-19 2008-06-18 Machine de réfrigération avec unité de décongélation Withdrawn EP2006622A3 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
ITAR20070030 ITAR20070030A1 (it) 2007-06-19 2007-06-19 Macchina frigorigena con sbrinatore

Publications (2)

Publication Number Publication Date
EP2006622A2 true EP2006622A2 (fr) 2008-12-24
EP2006622A3 EP2006622A3 (fr) 2009-08-19

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EP08158472A Withdrawn EP2006622A3 (fr) 2007-06-19 2008-06-18 Machine de réfrigération avec unité de décongélation

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EP (1) EP2006622A3 (fr)
IT (1) ITAR20070030A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2746701A1 (fr) * 2012-12-20 2014-06-25 Whirlpool Corporation Réfrigérateur avec un congélateur sans givre
US20140345306A1 (en) * 2013-05-23 2014-11-27 Michael L. Bakker, Jr. Anti-Icing System and Method for a Refrigeration Cooling Apparatus
DE102015006559A1 (de) * 2015-01-29 2016-08-04 Liebherr-Hausgeräte Lienz Gmbh Wärmeisoliertes Behältnis
CN113865154A (zh) * 2021-10-12 2021-12-31 珠海格力电器股份有限公司 翅片式蒸发器及其化霜控制方法、装置和制冷设备

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4764193A (en) 1987-10-07 1988-08-16 Raytheon Company Thermoelectric frost collector for freezers

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10153370A (ja) * 1996-11-21 1998-06-09 Sanyo Electric Co Ltd 冷却貯蔵庫
JP2000097546A (ja) * 1998-09-24 2000-04-04 Sanyo Electric Co Ltd 冷却貯蔵庫
JP2004176952A (ja) * 2002-11-25 2004-06-24 Twinbird Corp 冷却庫
CA2618570A1 (fr) * 2005-08-12 2007-02-22 Carrier Corporation Systeme de degivrage thermoelectrique

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4764193A (en) 1987-10-07 1988-08-16 Raytheon Company Thermoelectric frost collector for freezers

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2746701A1 (fr) * 2012-12-20 2014-06-25 Whirlpool Corporation Réfrigérateur avec un congélateur sans givre
US20140345306A1 (en) * 2013-05-23 2014-11-27 Michael L. Bakker, Jr. Anti-Icing System and Method for a Refrigeration Cooling Apparatus
DE102015006559A1 (de) * 2015-01-29 2016-08-04 Liebherr-Hausgeräte Lienz Gmbh Wärmeisoliertes Behältnis
CN113865154A (zh) * 2021-10-12 2021-12-31 珠海格力电器股份有限公司 翅片式蒸发器及其化霜控制方法、装置和制冷设备
CN113865154B (zh) * 2021-10-12 2022-05-31 珠海格力电器股份有限公司 翅片式蒸发器及其化霜控制方法、装置和制冷设备

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Publication number Publication date
ITAR20070030A1 (it) 2008-12-20
EP2006622A3 (fr) 2009-08-19

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