EP4086537A1 - Refrigeration plant using a cryogenic fluid as cold source - Google Patents

Refrigeration plant using a cryogenic fluid as cold source Download PDF

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Publication number
EP4086537A1
EP4086537A1 EP22172081.6A EP22172081A EP4086537A1 EP 4086537 A1 EP4086537 A1 EP 4086537A1 EP 22172081 A EP22172081 A EP 22172081A EP 4086537 A1 EP4086537 A1 EP 4086537A1
Authority
EP
European Patent Office
Prior art keywords
evaporator
box
fluid
temperature
liquid
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.)
Pending
Application number
EP22172081.6A
Other languages
German (de)
English (en)
French (fr)
Inventor
Mattia ZOCCOLI
Angelo ZENONI
Alessandro BERTULETTI
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SIAD Societa Italiana Acetilene e Derivati SpA
Original Assignee
SIAD Societa Italiana Acetilene e Derivati SpA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by SIAD Societa Italiana Acetilene e Derivati SpA filed Critical SIAD Societa Italiana Acetilene e Derivati SpA
Publication of EP4086537A1 publication Critical patent/EP4086537A1/en
Pending legal-status Critical Current

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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
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B19/00—Machines, plants or systems, using evaporation of a refrigerant but without recovery of the vapour
    • F25B19/005—Machines, plants or systems, using evaporation of a refrigerant but without recovery of the vapour the refrigerant being a liquefied gas
    • 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
    • F25D3/00—Devices using other cold materials; Devices using cold-storage bodies
    • F25D3/10—Devices using other cold materials; Devices using cold-storage bodies using liquefied gases, e.g. liquid air
    • F25D3/105—Movable containers
    • 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
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/19—Pressures
    • F25B2700/197—Pressures of the evaporator
    • 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
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2117—Temperatures of an evaporator
    • 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
    • F25D2700/00—Means for sensing or measuring; Sensors therefor
    • F25D2700/02—Sensors detecting door opening
    • 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
    • F25D2700/00—Means for sensing or measuring; Sensors therefor
    • F25D2700/10—Sensors measuring the temperature of the evaporator

Definitions

  • the present invention relates to a refrigeration system, in particular a mobile refrigeration system that uses a cryogenic fluid as cold source.
  • Perishable goods are transported by road using temperature-controlled vehicles, i.e. equipped with isothermal boxes fitted with refrigeration units.
  • the purpose of the isothermal box is to thermally insulate the inside environment from the outside environment.
  • the refrigeration unit on the other hand, has the capacity to release frigories and thus counteract the heat incoming from the walls of the isothermal box by effectively controlling the temperature.
  • the change of state from liquid to gas takes place in an evaporator and involves a release of frigories by the fluid that causes cooling of the air circulating inside the isothermal box.
  • cryogenic fluids can represent a solution to all the points listed above.
  • Refrigeration systems that can be mounted on vehicles are described in US 2019135159 , US 2017234583 , US 2019086145 and DE 10 2011014746 .
  • the systems described are not suitable for the use of carbon dioxide as a refrigerant gas and approval by transport regulatory authorities is difficult.
  • the present invention is therefore based on this latter type of solution to which it brings several system and functional innovations in order to:
  • the refrigeration system of an isothermal box having at least one isothermal compartment comprising:
  • the refrigeration system thus includes
  • the system according to the invention has no motor or compressor. It has no moving parts with the exception of the blades of the fan.
  • Two temperature sensors inside the isothermal box control the temperature of the air in input and in output from the evaporator.
  • the control system When the temperature measured by the sensor in input rises above the predetermined setpoint, the control system appropriately opens the regulation valve, which makes the refrigerant flow through the evaporator or the evaporators.
  • Actuation of the fans is modulated as a function of the DeltaT detected between the evaporator inlet and outlet, so that the quantity of air is commensurate with the availability of 'cold' and therefore maximum heat exchange efficiency is preserved and refrigerant fluid consumption is saved.
  • Evaporators are heat exchangers with copper coils and aluminum fins for maximum heat transfer. They are equipped with fans so that the air movement provides an even temperature throughout the compartment.
  • the circulation fans and control system are powered by solar panels and/or a dedicated battery that recharges thanks to the vehicle's battery when in motion, enabling functioning thereof even when the vehicle is switched off. Thanks to the small number of components, electricity consumption is low, allowing significant autonomy even when the vehicle is switched off.
  • the system can be either mono-temperature (and therefore mono isothermal compartment) or multi-temperature (and therefore multi isothermal compartment).
  • Each compartment contains a dedicated evaporator with respect to the volume to be refrigerated and to the refrigeration temperature. As a means of making the refrigeration system more efficient, the output of one compartment represents the supply for the next compartment.
  • the refrigeration circuit of the various compartments is made in series, optimising the ventilation as a function of the temperature of the input fluid, so as to exploit any residual frigories thereof, in addition to the DeltaT of the output temperature already mentioned previously.
  • carbon dioxide will be considered as a refrigerant fluid in that it requires additional precautions with respect to other cryogenic fluids. It will therefore be possible to fully describe all the functions of the technology in its most complex use, including in fact functioning in the case of fluids whose management is less articulated (such as nitrogen, argon, air, etc.).
  • liquid carbon dioxide is stored in a tank 1, in equilibrium with its gas phase, at a pressure indicatively comprised between 10 - 16 bar.
  • the cryogenic tank is thermally insulated from the outside thanks to a double wall with a vacuum cavity filled with insulating material.
  • the tank 1 is connected to the evaporator 2 via piping 3 capable of withstanding high pressures and low temperatures.
  • valve 4 is preliminarily opened so as to deliver cryogenic fluid in the gaseous state and bring the pressure of the system to operating pressure.
  • valve 4 closes and cryogenic fluid can be delivered in the liquid state by opening of the solenoid valve 5.
  • valve 4 is always closed and valve 5 is always open.
  • the heat exchange takes place in the evaporator 2, placed inside the isothermal box 6 and capable of releasing frigories in the load compartment 7 thanks to the liquid - gas phase transition of the cryogenic fluid during which a large quantity of heat is absorbed from the surrounding environment.
  • the principle is that of providing a high surface area of heat exchange, obtained thanks to the structure of the evaporator 2 made up of a finned tube bundle, in which the passage of air is forced through the use of fans 8.
  • the fans are actuated consequentially according to the temperature difference recorded on the air side by the pair of temperature transmitters placed at the inlet 9 and outlet 10 of the evaporator 2, respectively.
  • the air flow is partialized according to the cooling that it undergoes when traversing evaporator 2, thus guaranteeing maximum efficiency. If in fact the temperature difference on the air side is greater than a certain set point, other air will be forced through by turning on an additional fan so as to cool a larger quantity of air, and vice versa.
  • the aim is to maintain a certain temperature difference value on the air side constant so as to always exploit the maximum cooling capacity in relation to the quantity of recirculated air.
  • the exhaust gas meets regulation valve 11, which is the heart of the system.
  • the valve in fact, modulates its opening to manage the flow of refrigerant circulating through the entire system.
  • Pressure and temperature transmitters 12a and 12b measure the pressure and temperature of the fluid in the liquid state while pressure and temperature transmitters 13a and 13b measure the pressure and temperature in the gaseous state.
  • the combination of these parameters translates into a specific percentage of opening of regulation valve 11. This is due to the fact that the phase transition, which takes place in evaporator 2, causes an expansion of the fluid with a consequent back-pressure effect for which it is necessary to modulate the opening of the valve according to the extent of the phenomenon.
  • the PLC of the system which manages the control logic, (not shown) continuously processes the input data to return the correct opening of the regulation valve 11 on time.
  • the temperature transmitter 10 defines whether there is the need to cool or otherwise the air in the load compartment 7 by actuating or not actuating the regulation valve 11 and, when actuated, the pressure and temperature transmitters 12a and 12b provide information on the fluid input conditions in the system while the pressure and temperature transmitters 13a and 13b on the output conditions, which define the exact percentage of opening thereof.
  • Figs. 3 and 4 a multi-temperature system is described, using the same reference numerals to denote elements described in the embodiment of Figs. 1 and 2 , even if differently arranged.
  • Temperature-controlled distribution may also require the simultaneous transport of products to be handled at different temperatures. It becomes necessary to have several isothermal compartments in which to store fresh (tends to be at 0-4°C) and/or frozen (tends to be at -20°C) and/or dry (tends to be at room temperature) goods separately. For each compartment, a special heat exchanger is installed to ensure the necessary heat exchange.
  • the multi-temperature system in turn, can be understood as an extension of the features already described with reference to.1 and.2, therefore only the emblematic aspects of this configuration will be highlighted in detail.
  • Liquid carbon dioxide is stored in tank 1 which is connected to the first evaporator 2 via piping 3.
  • cryogenic fluid traverses the various exchangers in series, from the isothermal compartment with lowest temperature to the one with highest temperature. In this way, the refrigerant leaving the first exchanger still has frigories for cooling the next isothermal compartment, which requires a higher temperature than the previous one, and so on. It must be remembered that, thermodynamically, the fluid cannot leave the isothermal compartment at a higher temperature than that of the compartment itself.
  • Two solenoid valves 4 and 5 are installed on tank 1, capable of delivering cryogenic fluid in the gas phase or liquid phase to the system and isolating the tank from the rest of the system.
  • the heat exchange takes place through the use of fans 8, in the evaporator 2, placed inside the isothermal box 6 and capable of releasing frigories in the load compartment 7 thanks to the liquid - gas phase transition of the cryogenic fluid during which a large quantity of heat is absorbed from the surrounding environment.
  • the fans 8 are actuated on the basis of the signals recorded by the temperature transmitters 9 and 10.
  • the cryogenic fluid In output from the first evaporator 2, the cryogenic fluid enters the second evaporator 15 mounted in the isothermal compartment 16, which requires a higher temperature than that of the isothermal compartment 2.
  • the heat exchange takes place through the use of fans 17 exploiting the latent heat of the liquid/gas phase transition of the cryogenic fluid, in the case wherein the fans 8 have remained switched off during the supply of liquid through the evaporator 2, or by exploiting the sensible heat from the heating of the cold gas, in the opposite case.
  • An optional bypass 18 can be implemented in order to selectively deliver liquid to the various evaporators 2, 15.
  • the fans 17 are activated on the basis of the signals recorded by the temperature transmitters 19, 20 according to the operating logic already described for the fans 8.
  • the exhausted gas meets the regulation valve 11 which modulates its opening to manage the flow of refrigerant circulating through the whole system.
  • both the temperature transmitter 10 placed on the air in output from the first evaporator 2, and the temperature transmitter 20 placed on the air in output from the second evaporator 15, independently define whether or not there is the need to cool the air in the load compartment 7 and/or in the load compartment 16, respectively, with actuation of the regulation valve 11 and the respective fans 8, 17.
  • the percentage of opening is defined by the signals of the pressure and temperature transmitters 13a and 13b, as described previously.
  • the result is a regulation valve 11 with the capacity for delivering a constant and specific flow of refrigerant fluid as all other parameters vary, selectively refrigerating several isothermal compartments.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Devices That Are Associated With Refrigeration Equipment (AREA)
  • Separation By Low-Temperature Treatments (AREA)
EP22172081.6A 2021-05-07 2022-05-06 Refrigeration plant using a cryogenic fluid as cold source Pending EP4086537A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT102021000011702A IT202100011702A1 (it) 2021-05-07 2021-05-07 Impianto di refrigerazione utilizzante un fluido criogenico come sorgente di freddo

Publications (1)

Publication Number Publication Date
EP4086537A1 true EP4086537A1 (en) 2022-11-09

Family

ID=77022039

Family Applications (1)

Application Number Title Priority Date Filing Date
EP22172081.6A Pending EP4086537A1 (en) 2021-05-07 2022-05-06 Refrigeration plant using a cryogenic fluid as cold source

Country Status (2)

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EP (1) EP4086537A1 (it)
IT (1) IT202100011702A1 (it)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1369648A2 (en) * 2002-06-04 2003-12-10 Sanyo Electric Co., Ltd. Supercritical refrigerant cycle system
DE102011014746A1 (de) 2011-03-22 2012-09-27 Air Liquide Deutschland Gmbh Vorrichtung und Verfahren zum Betrieb eines Kühlsystems mit zwei oder mehr Kühlkammern
US20170234583A1 (en) 2009-05-12 2017-08-17 Reflect Scientific, Inc Self-powered, long-term, low-temperature, controlled shipping unit
US20190086145A1 (en) 2017-09-19 2019-03-21 Bao Tran Freezer with remote management
US20190135159A1 (en) 2017-11-07 2019-05-09 Chin Te Jan Co., Ltd. Cooling apparatus and a vehicle including the same
US10634395B2 (en) 2017-09-19 2020-04-28 Reflect Scientific, Inc. Transport refrigeration unit with vented cryogenic cooling

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1369648A2 (en) * 2002-06-04 2003-12-10 Sanyo Electric Co., Ltd. Supercritical refrigerant cycle system
US20170234583A1 (en) 2009-05-12 2017-08-17 Reflect Scientific, Inc Self-powered, long-term, low-temperature, controlled shipping unit
DE102011014746A1 (de) 2011-03-22 2012-09-27 Air Liquide Deutschland Gmbh Vorrichtung und Verfahren zum Betrieb eines Kühlsystems mit zwei oder mehr Kühlkammern
US20190086145A1 (en) 2017-09-19 2019-03-21 Bao Tran Freezer with remote management
US10634395B2 (en) 2017-09-19 2020-04-28 Reflect Scientific, Inc. Transport refrigeration unit with vented cryogenic cooling
US20190135159A1 (en) 2017-11-07 2019-05-09 Chin Te Jan Co., Ltd. Cooling apparatus and a vehicle including the same

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Publication number Publication date
IT202100011702A1 (it) 2022-11-07

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