Classifications

• • 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
  • F25D11/00—Self-contained movable devices, e.g. domestic refrigerators
• • 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
  • F25D23/00—General constructional features
  • F25D23/06—Walls
  • F25D23/061—Walls with conduit means
• • 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
  • F25B2500/00—Problems to be solved
  • F25B2500/01—Geometry problems, e.g. for reducing size
• • 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
  • F25B39/00—Evaporators; Condensers
  • F25B39/04—Condensers
• • 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
  • F25B40/00—Subcoolers, desuperheaters or superheaters
• • 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
  • F25D2500/00—Problems to be solved
  • F25D2500/02—Geometry problems

Definitions

• the present invention refers to a high-efficiency and high-performance positive temperature refrigerating apparatus.
• the prior art proposes refrigerating apparatuses equipped with a refrigerating plant that provides for the use of a condensating fan, since it is not possible to dispose of heat to the condenser with usual heat exchangers with natural convection, without obtaing a condensation pressure that cannot be supported by the compressor (usually with condensation temperatures greater than 55°C when operating and 65°C of peak).
• the compressors responsible for the necessary power of the compression systems currently used in this type of apparatuses are normally, but not only, of the type with medium/high evaporation pressure, since ventilated evaporators with winged pipe, usually but not exclusively used, take the normal working range to values greater than - 10°C, upper limit of the class of low-pressure compressors.
• the presence of the condensating fan creates an increase of costs of the refrigerating apparatus and a greater operating noise.
• the possible lack of operation or operation under anomalous conditions of the condensating fan can damage other apparatus components.
• the presence of the condensating fan generates a higher energy consumption of the apparatus and a higher global environmental impact, also linked to the construction of the fan itself.
• object of the present invention is solving the above prior art problems, by providing a refrigerating apparatus with positive temperature of the commercial type with high efficiency, characterised by a high refrigerating power and by its condensation without fans.
• Another object of the present invention is providing a refrigerating apparatus with positive temperature of the commercial type with high efficiency without condensating fan and equipped with a low-pressure compressor, though keeping refrigerating performances similar to those of prior art apparatuses.
• an object of the present invention is providing a refrigerating apparatus with positive temperature of the commercial type with high efficiency that, being free of condensating fan, is less noisy and less expensive with respect to prior art apparatuses.
• the present invention therefore refers to a high-efficiency positive temperature refrigerating apparatus equipped with a compression system advantageously comprising at least one compressor with low evaporation pressure as replacement of the compressor with medium/high evaporation pressure of prior art systems and a condensating system without any condensating fan.
• the Applicant has managed to obtain a refrigerating apparatus that, though keeping similar refrigerating performances as of comparable prior art apparatuses, through an inventive synergic optimisation of the various components, is free from the condensating fan and uses a compressor with low evaporation pressure: in fact, the low-pressure compressor, due to the reduced consumption in terms of electric power (it must be noted that the limit to low evaporation pressures implies, with the same compressor displacement, a lower refrigerating power in the working range, with respect to a medium/high power compressor, and therefore a lower electric consumption in the working range), manages to dispose, up to higher sizes with respect to medium/high pressure compressors, of the heat developed by the electric motor of the apparatus and the gas compression in a static environment, without obtaining, with this, excessively high thermal values of electric windings, that would risk to generate a decrease of the insulation capability of motor coil paints, or of gas delivery, that would risk to modify the characteristics of necessary oils for lubrifying
• the Applicant has then evaluated that the heat to be disposed of to the condenser is the sum of the refrigerating power and the compression power and, in order to reduce such value, has provided a refrigerating apparatus equipped with a compressor with low evaporation pressure characterised by a Coefficient of Performance (COP, defined as the ratio between the developed refrigerating power and the necessary electric power) that is better with respect to medium/high pressure compressors of prior art apparatuses, since the more advantageous COP values of currently known compressors are in fact those of low-pressure compressors for house environments, that join the lack of venting needs, inside the working range, to a reduced direct energy consumption.
• COP Coefficient of Performance
• the refrigerating apparatus according to the present invention can belong to any one of the two types of apparatuses for commercial refrigeration with positive temperature that follow:
• a thermostating percentage condition of 50% must be taken into account, for keeping the suitable margin to keep the required internal temperatures even under harder conditions (thermal load insertion, doors opening, higher external temperature). This takes to consider a necessary refrigerating power of 200 W at the evaporation temperature of -15°C. Under evaporation conditions, therefore, the condensation conditions are then defined; in case of static condensation, it is normal to obtain ⁇ Ts between 15 K and 25 K with respect to ambient temperature; therefore, 55°C can be take as limit worse condition.
• the rear wall of the refrigerating apparatus can be equipped with at least one condenser on a wall, for example of the type with pipes and wires, or any other dissipator with compatible surface to be placed in the above position and suitable for such purpose, taking then into account that, for these condensers with natural convection, in the version with pipe pitch of 50 mm, for a surface with about 0.6 m 2 with a 4.76-mm pipe, an exchange coefficient of about 10 kcal/hK is obtained, and such an exchange coefficient, for a value to be disposed of 264 kcal/h, implies a ⁇ T > 25 K.
• the lamination member of the refrigerating apparatus it must obviously be suitable to keep the correct pressures, concurring, together with the refrigerating gas charge, to reduce undercooling to a minimum (1 K), in such a way as to keep the condensation pressure as minimum as possible (maximum internal condensation volume), though allowing that the evaporation is performed till the end of the evaporator piping by correctly supplying it, such piping preferably baving an internal diameter substantially equal to 1.2 mm and a length substantially included between 3 m and 4 m with a regenerating exchanger having a length substantially equal to 1 m, in such a way as to keep the temperature of sucked gases at a value substantially equal to 32°C.
• such values can also be sized through suitable design evaluations.
• the refrigerating apparatus makes, for the above types and perfoming the tests required by EN23953 or EN441 standard, the M1 class (namely, tests performed with all test packs, simulating the refrigerated goods, of a weight of 0.5 kg equipped with thermocouple at their geometric centre, with the refrigerated volume suitably loaded with packs, at a temperature included between -1°C and +5°C), for a time length of 12 hours with an opened door followed by 12 hours with a closed door, at 30°C - 55% RU, namely class 4: what is stated above is the check of the capability of the refrigerating apparatus according to the present invention of keeping the most restrictive specification for storing goods at positive temperature, both next to 0°C and due to temperature uniformity in test packs.
• the M1 class namely, tests performed with all test packs, simulating the refrigerated goods, of a weight of 0.5 kg equipped with thermocouple at their geometric centre, with the refrigerated volume suitably loaded with packs, at a
• the proposed system in addition to exploiting high-efficiency electric components (internal fan and compressor), allows removing the condensation ventilation by eliminating an electric load, with a further energy saving, and the fan saving not only as regards costs, but also evaluating the life cycle (including maintenance).
• a suitable fan that would lower the condensation by about 15 K would imply a consumption reduction of about 13 W, value that, in order to be compensated, would have the need of a further high-efficiency fan.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Thermal Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Applications Or Details Of Rotary Compressors (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)

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Citations (3)

Family Cites Families (3)

• 2010
  • 2010-02-23 IT ITTO2010A000132A patent/IT1398991B1/it active
• 2011
  • 2011-02-17 EP EP11001282.0A patent/EP2362165A3/de not_active Withdrawn

Patent Citations (3)

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