FIELD OF THE INVENTION
[0001] The present invention relates to a eutectic refrigeration unit intended to refrigerate
foodstuffs or other perishable products transported in vehicles powered by electricity,
diesel, petrol, gas, methane or some other source.
STATE OF THE ART
[0002] Many different types of perishable goods are transported every day, for example from
the place of production to the place of distribution. Most of these are foodstuffs,
such as fruit, vegetables, meat, fish, milk, dairy products, frozen foods, all products
that are sensitive to ambient temperature, at which they undergo changes that cause
them to deteriorate.
[0003] In addition to foodstuffs, pharmaceuticals, ornamental plants and flowers, and others,
are also types of merchandise that deteriorate as a result of thermal shocks and the
temperature of the external environment.
[0004] In order to be able to transport perishable goods properly, i.e. to ensure that they
also do not deteriorate during transport, there is therefore a need to use suitable
vans and vehicles that are able to maintain the temperature required for their proper
storage, depending on the type of goods being transported to their destination.
[0005] Insulated vehicles in which thermal insulation for the products transported is ensured
by an insulated chamber installed inside the load compartment are therefore commercially
available. The insulated compartment avoids the exchange of temperature between the
outside and inside, and the structure thus provided makes the van specifically intended
for the transport of perishable goods that must be kept at a certain temperature,
such as fruit, vegetables, milk and its derivatives, eggs and ornamental plants.
[0006] There are also refrigerated vans, in which a refrigeration system is added to keep
the temperature inside the load compartment not only controlled but also constant,
for foodstuffs such as meat, fish products or fresh pasta.
[0007] The provision of a refrigeration system on board a van certainly improves the quality
of temperature maintenance suitable for the transport of perishable goods, but it
requires an expensive and cumbersome accessory consisting of the condenser-compressor
refrigeration system, which is either connected to the vehicle's engine or independently
driven. Furthermore, in electric vehicles, use of some of the electric charge stored
in the batteries to refrigerate the load compartment has an adverse effect on the
vehicle's range, a problem that is very much felt in vehicles of this type that depend
on the availability of recharging equipment along the route.
Italian patent application 102020000032666 from the same applicant as the present application describes a system based on the
use of a eutectic fluid. The system in
Italian application 102020000032666 offers advantages through its ease of construction, but there is still room for improvement
as regards the efficiency of the system for exchange of cold between the eutectic
fluid and the load compartment.
OBJECT OF THE INVENTION
[0008] The object of the present invention is to provide a eutectic refrigeration unit that
at least partly overcomes the disadvantages of systems in the known art.
SUMMARY OF THE INVENTION
[0009] According to the present invention there is provided a eutectic refrigerating unit
for refrigerating foodstuffs or other perishable products transported in motor vehicles,
that is intended to be placed inside the insulated load compartment of a vehicle and
is characterised in that it comprises a set of closed hollow elements in fluid communication
with one another in series, the closed hollow elements being intended to contain and
circulate a eutectic fluid within them; a plurality of open hollow elements adapted
to let air passing through them, each of the plurality of open hollow elements being
associated with and adjacent to at least one of the set of closed hollow elements;
a box-shaped enclosure within which is enclosed the set of closed hollow elements
and the open hollow elements so as to maintain the cold generated by the cooled eutectic
fluid, the box-shaped element being provided with slits (or louvres or slots) for
the passage of air in and out; ventilation means associated with said box-shaped enclosure
and controllable by a microprocessor associated with means for sensing the temperature
within said load compartment, in which the ventilation means are intended to be operated
and controlled by the microprocessor so as to draw air from the load compartment into
the box-shaped element through the inlet slits, causing air to circulate in the open
hollow elements and air to be discharged from the box-shaped element into the load
compartment through the outlet slits, thereby controlling the temperature in the load
compartment.
[0010] In a preferred embodiment of the present invention, the tubular circuit is a coil
flowing through the closed hollow elements. The coil can be connected to a refrigeration
device for extracting heat from said eutectic fluid and bringing it to a low temperature,
the refrigeration device comprising a condenser - compressor - external filter assembly
located outside the vehicle, to which the tubular coil circuit can be connected by
means of pipes having quick couplings. The eutectic fluid is preferably cooled to
a temperature of -33°C.
[0011] In one possible embodiment the ventilation means may consist of one or more fans
associated with the box-shaped enclosure and operating cooperatively with the inlet
and exit slits, the temperature sensing means may consist of a digital thermostat
located for example in the driver's cab of the vehicle and connected to sensors located
within said insulated load compartment.
[0012] In a preferred embodiment, the box-shaped enclosure is made of a plastics material,
for example ABS, and comprises an upper casing, a front closure panel, two side closure
panels, two rear uprights for wall mounting of the unit, four corner uprights and
a lower water collection tank. Two thermally insulating panels, an upper and a lower
respectively, with said upper thermally insulating panel pierced by slits, two thermally
insulating panels, a front and rear respectively, with said front thermally insulating
panel having slits at the top and openings at the bottom, and two thermally insulating
panels at the sides may be located between said box-shaped enclosure and said plurality
of closed hollow elements (103). The thermally insulating panels may, for example,
be made of polyurethane.
[0013] In a possible alternative embodiment, the entry and exit slits may be fitted with
adjustable, microprocessor-controlled opening/closing systems.
[0014] According to another aspect of the present invention, there is provided a method
of using the eutectic refrigeration unit described above, the refrigeration unit being
installed in a vehicle, the method comprising the steps of: refrigerating the eutectic
fluid prior to use of the vehicle; and controlling the temperature within the load
compartment by means of the microprocessor. The step of completely defrosting the
system before it is periodically refrigerated may also be envisaged, so that the unit
also has optimum efficiency when subsequently used.
[0015] According to a further aspect of the present invention, there is provided a vehicle
for transporting perishable goods comprising the refrigeration unit described above.
[0016] One of the advantages of the eutectic refrigeration unit according to the present
invention is that it is not cumbersome and does not require complex devices for its
operation in the van, such as plug-in connectors/disconnectors to the engine, independent
drive systems, etc.
[0017] Furthermore, the eutectic refrigeration unit according to the present invention is
practical and simple to use, but makes it possible to maintain temperatures suitable
for the storage of perishable products within the insulated vehicle compartment.
BRIEF DESCRIPTION OF THE FIGURES
[0018] An embodiment will in particular be described below with specific but not limiting
reference to the plate of drawings in which
Figure 1 depicts a preferred embodiment of the eutectic refrigeration unit which is
the subject of the present invention;
Figures 2a-2c show details of the unit in Figure 1;
Figure 3 shows the assembly in the previous figures installed in a van with an insulated
load compartment;
Figure 4 diagrammatically illustrates a refrigeration device that can be connected
to the eutectic refrigeration unit in the previous figures.
DETAILED DESCRIPTION
[0019] With reference to the attached set of drawings, Figure 1 shows eutectic refrigeration
unit 100 suitable for refrigerating foodstuffs or other perishable products transported
by vehicles powered by electricity, diesel, petrol, gas, methane or some other source.
[0020] Eutectic refrigeration unit 100 is intended to be installed inside the insulated
load compartment V of a vehicle 300 (see Figure 3).
[0021] According to a preferred embodiment of the present invention, unit 100 comprises
assembly 101, shown in Figure 2a, comprising a set of hollow elements 103 held together
substantially in parallel by means, for example, of interlocking guides formed in
the hollow elements themselves. Hollow elements 103 are closed so as to contain a
eutectic fluid (for example a refrigerant fluid). Pipes, preferably made of copper
or aluminium, run inside them in fluid communication with each other, in series with
each other, through tubular fittings 107 (shown in Figure 2b) which depart from one
end of an element 103 and connect to the end of a subsequent element 103. A gas (for
example freon or nitrogen) at a very low temperature may be caused to flow through
these pipes, which are essentially joined into an uninterrupted coil (serpentine),
to cool the eutectic fluid. This cooling operation is carried out when the vehicle
is stationary (for example overnight) by connecting the coil to an external machine.
[0022] Hollow elements 103 preferably have a parallelepiped shape, which allows for easy
arrangement in series (side by side), but other shapes are possible.
[0023] Each of the hollow elements 103 is associated with an open hollow element 105 which
functions as an air channel. In a preferred embodiment, there is one-to-one correspondence
between the closed hollow elements and the open hollow elements, i.e. each closed
element has its own open element with which it shares a wall of the parallelepiped
(through which the heat exchange takes place), but the possibility of other configurations
is not ruled out, with for example one open hollow element being associated and exchanging
heat with two or more closed hollow elements; conversely, several open elements may
be in contact with a single closed element.
[0024] Assembly 101 of elements 103/105 is then enclosed within a box-shaped enclosure (104),
as shown in Figure 1, which enables it to be installed and substantially operate,
as will become clear below.
[0025] According to a preferred embodiment of the present invention, the eutectic evaporating
unit (also called the refrigerating unit) comprising the assembly 101 and the box-shaped
enclosure is suitable for refrigerating foodstuffs or other perishable products transported
in electric, diesel, petrol, gas, methane or otherwise powered vehicles. The refrigeration
unit is intended to be installed inside the load compartment of insulated vehicles
(see Figure 3). According to a preferred embodiment of the present invention, assembly
101 comprises a set of 8 hollow elements 103, preferably of drawn aluminium alloy
or plastics or stainless steel materials. The number of hollow elements 103 may of
course be different and be adapted to the different needs and dimensions of the load
compartment. Preferably, as already mentioned, each hollow element 103 has a corresponding
open hollow element 105, but other configurations are possible and the number of hollow
elements 103 and open hollow elements 105 may also be different. In a preferred embodiment,
each pair comprising a hollow element 103 and an open hollow element 105 will be made
using a die, where the two parts - one that will contain the eutectic fluid/fluid
and one that will remain empty and open to allow the passage of air - are made by
extrusion. The set of pairs of closed hollow elements 103 and open hollow elements
105 are coupled together with closed elements 103 housing the eutectic refrigerant
fluid, with the latter being located in the upper part and open elements 105 in the
lower part. Air circulates in open elements 105.
[0026] When the system is in operation, the suitably cooled (for example to -33°C) refrigerant
liquid or fluid (eutectic fluid) transfers the frigories previously accumulated, for
example during overnight charging, to the metal walls (made of aluminium, for example)
which in turn transmit them to the air circulating in the open hollow elements; the
air then forced to circulate in the load compartment/refrigeration chamber cools its
temperature. More specifically, the air that is forced through hollow elements 105
is cooled by the refrigerant fluid. The box-shaped enclosure is provided with inlet
vents or slits 111 and outlet vents or slits 109: the air is circulated by means of
one or more fans that draw it from the load compartment into open hollow elements
105, where it cools in contact with the wall that divides open hollow element 105
from the corresponding closed hollow element 103 (with the refrigerant fluid) and
is then fed into the load compartment through outlet vents/ slits 109. Once in the
load compartment, the cooling power is transmitted from the cooled air to the environment
of the load compartment. In a preferred embodiment of the present invention, the fans
are placed inside the box-shaped element, but this does not rule out the fans being
external and connected to the inlet slits (the fans are not shown in the figures).
[0027] Within the chambers where the eutectic refrigerant fluid is located there is the
refrigerant circuitry, made, for example, of copper or aluminium; a refrigerant gas
can circulate in the circuitry within the assembly 101 of closed hollow elements 103,
passing from one closed hollow element 103 to the next by means of connecting pipe
107. Normally, the coil circuitry is kept closed and empty. During pre-use cooling
operations, it is connected to external machinery through the nozzle of the first
coil assembly and the nozzle of the last coil assembly. The machinery, shown in Figure
4, causes a gas (for example Freon R504) to flow at a very low temperature that cools
the eutectic fluid.
[0028] In the lower part where the cold air circulates, there are the resistances for defrosting
the system after hours of operation (the detail of the resistances is not shown in
the figures). During the daily use of refrigerated vehicles the doors are opened and
closed several times. Moisture entering the cell can create frost in the air passages.
The heating elements are used to defrost the air passages before recharging at night.
[0029] The refrigerating unit includes an ABS cover. The vacuum or injection-moulded enclosure
may be fitted with a condensate drain hole at the rear. Thermal insulation panels
(for example 4 in number) may be provided to ensure effective thermal insulation of
the aluminium tubes. The thermal insulation panels may be made of polyurethane or
any other thermally insulating material. In a preferred embodiment of the present
invention, a digital thermostat placed in the driver's cab determines the desired
temperature in the insulated chamber or insulated vehicle based on the output of sensors
fitted in the refrigerated compartment. An external assembly with hoses and quick
couplings is connected to cool the eutectic fluid contained in the extruded piping.
Connection is for example brought about through the use of a lever system using known
quick-release couplings that allow rapid connection and disconnection of assembly
100 and the recharge device, ensuring a gastight seal even when disconnected. The
recharging device comprises a condenser, a compressor, a fan, a filter and various
accessories for defrosting assembly 100 and cooling it.
[0030] The box-shaped enclosure is preferably made of plastics, although other materials
cannot be ruled out; in a preferred embodiment of the present invention the box-shaped
enclosure is made of ABS.
[0031] Figure 2c shows a cross-section of cooling unit 100 and a pair of elements 103/105,
showing the coil inside closed hollow element 103.
[0032] In a preferred embodiment of the present invention, thermally insulating panels are
located between the box-shaped enclosure and assembly 101 at the top and bottom respectively,
with two thermally insulating panels at the front and rear respectively, and two thermally
insulating panels at the sides, in order to ensure effective thermal insulation of
assembly 101 of closed hollow elements 103 and open hollow elements 105.
[0033] In a possible embodiment of the present invention, insulating panels are located
all around the evaporating assembly, on its four sides.
[0034] By way of non-limiting example, the thermally insulating panels may be made of, for
example, polyurethane. It is understood that any other effectively thermally insulating
material may be used as a substitute.
[0035] The thickness of the thermally insulating material used will be decisive for a longer
service life of the cooling function of unit 100.
[0036] Associated with the box-shaped enclosure are ventilation means consisting of one
or more fans. The fans cause a flow of air through the box-shaped enclosure. Air enters
the enclosure through a series of slits 111; the air exits via exit slits 109. Figure
1 shows air exit slits 109, while Figure 2c shows the inlet slits through which the
cooled air is fed back into the cargo area. For ease of description we have indicated
the inlet slits as 111 and the exit slits as 109, but it is obvious that the direction
of air flow may be different and the inlet slits may act as the exit and vice versa.
[0037] The temperature sensing means may for example consist of a thermostat, for example
of the digital type, which may be located in the driver's cab of the vehicle and be
connected to sensors located in insulated load compartment V, in suitable positions
appropriate for optimally detecting the temperature of the load compartment.
[0038] For cooling the eutectic fluid contained in assembly 101 of closed hollow cylinders
103, the assembly can be connected to a cooling device 400 (Figure 4) without removing
assembly 100 from the vehicle.
[0039] Connection may be made through a pair of hoses using known quick-connect couplings,
which allow quick connection and disconnection of the unit 100 to (and from) refrigeration
unit 400.
[0040] Refrigeration device 400 comprises, for example, a condenser - compressor - external
filter unit, all of a known type and therefore not described in further detail.
[0041] The operation and mode of application of eutectic refrigeration unit 100 is now described
according to a preferred embodiment of the present invention, by way of example and
without limitation. Refrigeration device 400 is independent and is put into operation
when the vehicle is stationary, to cool the eutectic fluid, for example overnight,
so that it can then release the frigories during vehicle movements. In one possible
configuration, refrigeration unit 400 remains on the ground, for example in the garage
after the vehicle is parked, but there is nothing to prevent it from being transported
by the vehicle itself, perhaps incorporated into the body of the vehicle, for example
on the roof of the load compartment; in this way, in the case of long journeys, perhaps
of several days, refrigeration unit 400 can be put into operation when the vehicle
is stationary during stops, for example by connecting it to an external power source.
[0042] First of all it is necessary to specify the following: according to the definition
in the Treccani dictionary, a frigorie is defined as the amount of heat that must
be withdrawn from a kilogram of water in order to decrease its temperature by 1°C;
in other words, to give a body one frigorie is to subtract one calorie from it. More
generally, however, calories are used in the context of both the generation and the
absorption of heat. Frigories, on the other hand, are only used in relation to refrigeration.
Thus, while it can be said that a refrigerating appliance produces
n frigories or that it absorbs
n calories, it is not normal to say that a heating appliance absorbs
n frigories: instead, it is said that it produces
n calories.
[0043] In the present case, for the sake of clarity, the term "frigories" (units of refrigeration)
conventionally "provided" to unit 100 will be used to actually indicate the calories
withdrawn from the eutectic fluid. For the same reason, the term "accumulation" of
frigories in unit 100 will be improperly used in order to simplify and clarify the
description.
[0044] Initially provision is made for total defrosting of the system before it is periodically
refrigerated, so that unit 100 will also be satisfactorily efficient in subsequent
use.
[0045] Eutectic refrigeration unit 100 is then connected to refrigeration device 400 using
the connection pipes and quick couplings, without removing it from vehicle 300. The
refrigerant gas will then be fed into the coils running inside hollow elements 103,
causing the eutectic fluid to cool within the hollow elements.
[0046] In a preferred embodiment of the present invention, by activating refrigeration device
400, the eutectic fluid is cooled to a temperature of -33°C. This temperature is the
one which, from tests carried out, has provided optimum results, but this value should
not be understood to be limiting and other temperatures may instead be set and reached.
[0047] Once the eutectic fluid has cooled down, unit 100 is disconnected from unit 400 and
vehicle 300 can be used to transport foodstuffs, such as fruit, vegetables, meat,
fish, milk, dairy products, frozen foods, and other products that are sensitive to
ambient temperature at which they can undergo changes that cause deterioration, such
as pharmaceutical products, ornamental plants and flowers.
[0048] A box-shaped enclosure, made for example of steel, aluminium, ABS or other materials,
allows the eutectic fluid's accumulated frigories to be stored over time and used
only when necessary, as described below.
[0049] The digital thermostat in the driver's cab of vehicle 300 allows the temperature
in load compartment V to be checked where the sensors are positioned. This thermostat
is equipped with processing capabilities and includes a microprocessor that receives
the data detected by sensors located inside load compartment V and controls operation
of the ventilation means inside the box-shaped enclosure.
[0050] When the temperature in load compartment V needs to be restored to the necessary
values pre-set on the thermostat, the thermostat's microprocessor activates the ventilation
means (comprising one or more fans) which, drawing air from the environment of load
compartment V through the slits 111, pass it through the open hollow elements 105,
cooling it and then feeding it back into load compartment V through exit slits 109.
[0051] This system makes it possible to maintain a constant low temperature in load compartment
V of vehicle 300 without having an active refrigeration unit on the vehicle.
[0052] In a further embodiment, inlet slits (111) and exit slits (109) may be equipped with
closing means, also operable and adjustable by the thermostat's microprocessor, so
that when the ventilation means are not in operation the frigories generated by the
cooling system are kept longer.
[0053] The advantage of adopting the eutectic refrigeration unit according to the present
invention is obvious.
[0054] In vehicles powered by an internal combustion engine there is no need for compressors
connected to the engine, with complex ducting arrangements to bring the refrigerating
fluid into the load compartment.
[0055] The advantage is particularly obvious when the eutectic refrigeration unit according
to the present invention is fitted to vehicles with electric or hybrid drive. In this
case there is in fact a need to provide an electric motor to drive the active refrigerating
unit, a motor which takes the electrical energy required for traction away from the
batteries.
[0056] This energy drain therefore leads to a substantial reduction in the range and performance
of electric or hybrid drive vehicles.
[0057] By contrast, this drain does not occur when the eutectic refrigerating unit according
to the present invention is adopted, although proper preservation of the transported
products, at least for the time required for their distribution, is still ensured.
[0058] A further advantage of the present invention is that it provides a device that is
well suited to the design of insulated load compartments and that is able to withstand
the operating conditions resulting from the low temperatures produced inside them.
[0059] In addition, the device according to the present invention may be installed and made
operational in all vehicles with insulated load compartments, both those newly manufactured
and those already in operation, which can thus be easily equipped with a system that
solves the problems described above.
[0060] Finally, another advantage of the present invention is that the device can be constructed
as a simple but efficient form of construction, which is cost-effective to build and
fit to insulated load compartments.
1. Eutectic refrigerating unit (100) for refrigerating foodstuffs or other perishable
products transported in motor vehicles, intended to be placed inside the insulated
load compartment (V) of a vehicle (10) and
characterised in that it comprises:
a plurality of closed hollow elements (103) adapted to contain a eutectic fluid;
a plurality of open hollow elements (105), adapted to let air passing through them,
each of the plurality of open hollow elements (105) being associated with and adjacent
to at least one of the plurality of closed hollow elements (103) and each of the plurality
of closed hollow elements (103) being associated with and adjacent to at least one
of the plurality of open hollow elements (105);
at least one part of the closed hollow elements having inside it a tubular circuit
adapted to contain a refrigerant gas and let it flowing, the circuit comprising an
inlet terminal and an outlet terminal, the inlet and outlet terminals adapted to be
connected to an external device for the introduction of a refrigerant gas;
a box-shaped enclosure (104) within which the plurality of closed hollow elements
(103) and open hollow elements (105) are enclosed, so as to maintain the frigories
generated by the eutectic fluid, the box-shaped enclosure being provided with a plurality
of inlet slits and a plurality of exit slits;
ventilation means associated with said box-shaped enclosure, the ventilation means
being controllable by a microprocessor associated with temperature sensing means within
said load compartment (V), in which the ventilation means are arranged to be operated
and controlled by the microprocessor so as to draw air from the load compartment into
the box-shaped enclosure through the inlet slits to circulate air in the open hollow
elements (105) and exhaust air from the box-shaped enclosure to the load compartment
through the outlet slits, thereby regulating the temperature in the load compartment.
2. Eutectic refrigeration unit according to claim 1, wherein the tubular circuit is a
coil running through closed hollow elements (103).
3. Eutectic refrigeration unit according to claim 2, comprising a refrigeration device
(400) which may be connected to said tubular coil circuit for extracting heat from
said eutectic fluid and bringing it to a low temperature, the refrigeration device
(400) comprising a condenser - compressor - external filter unit located outside the
vehicle, to which the tubular coil circuit can be connected by means of pipes equipped
with quick couplings.
4. Eutectic refrigeration unit according to any one of the preceding claims, in which
the ventilation means comprise one or more fans associated with the box-shaped enclosure
and operate in cooperation with the inlet and exit slits (109 and 111), the temperature
sensing means comprising a digital thermostat located in the driver's cab of the vehicle
and being connected to sensors located within said insulated load compartment (V).
5. Eutectic refrigeration unit according to any one of the preceding claims, in which
said eutectic fluid is cooled to a temperature of -33°C.
6. Eutectic refrigeration unit according to any one of the preceding claims, in which
said box-shaped enclosure is made of a plastics material, for example ABS, and comprises
an upper casing, a front closing panel, two side closing casings, two rear uprights
for wall mounting of the unit, four corner uprights and a lower water collection tank.
7. Eutectic refrigeration unit according to any one of the preceding claims, wherein
between said box-shaped enclosure and said plurality of closed hollow elements (103)
there are arranged two thermally insulating panels at the top and bottom respectively,
with said top thermally insulating panel crossed by slits two thermally insulating
panels at the front and rear respectively, with said front thermally insulating panel
bearing slits at the top and openings at the bottom, and two thermally insulating
panels at the sides.
8. Eutectic refrigeration unit according to claim 7, in which said thermally insulating
panels are made of polyurethane.
9. Eutectic refrigeration unit according to any one of the preceding claims, in which
the inlet and exit slits are provided with microprocessor-controllable, adjustable
closing/opening systems.
10. Method of using the eutectic refrigeration unit according to any one of the preceding
claims, the refrigeration unit being installed in a vehicle, comprising the steps
of:
- refrigerating the eutectic fluid before using the vehicle;
- controlling the temperature inside the load compartment by means of the microprocessor.
11. Method according to claim 10, in which the system is completely defrosted before it
is periodically refrigerated, so that the unit is always optimally efficient even
in subsequent uses.
12. Vehicle for the transport of perishable goods comprising a refrigerating unit according
to any one of claims 1-9.