U.S. patent application number 14/241770 was filed with the patent office on 2014-08-07 for vehicle for the refrigeration transport of products the energy consumption of which is improved by incorporating a phase-change material into the walls of the vehicle body.
The applicant listed for this patent is Thierry Dubreuil, Mohammed Youbi-Idrissi. Invention is credited to Thierry Dubreuil, Mohammed Youbi-Idrissi.
Application Number | 20140216101 14/241770 |
Document ID | / |
Family ID | 46724529 |
Filed Date | 2014-08-07 |
United States Patent
Application |
20140216101 |
Kind Code |
A1 |
Dubreuil; Thierry ; et
al. |
August 7, 2014 |
Vehicle for the Refrigeration Transport of Products the Energy
Consumption of which is Improved by Incorporating a Phase-Change
Material into the Walls of the Vehicle Body
Abstract
A vehicle for the refrigerated transport of products comprising
at least one products storage chamber, characterized in that:--one
or more panels made from a material of so-called "phase-change"
type have been incorporated into the structure of all or part of
the walls of at least one of the storage chambers of the
lorry;--the phase-change material has a melting point that is just
a few degrees higher than the target datum temperature for the
chamber in question, preferably 2 to 10.degree. C. higher than said
datum temperature and more preferably still 3 to 5.degree. C.
higher than said datum temperature.
Inventors: |
Dubreuil; Thierry;
(Boissets, FR) ; Youbi-Idrissi; Mohammed; (Massy,
FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Dubreuil; Thierry
Youbi-Idrissi; Mohammed |
Boissets
Massy |
|
FR
FR |
|
|
Family ID: |
46724529 |
Appl. No.: |
14/241770 |
Filed: |
August 2, 2012 |
PCT Filed: |
August 2, 2012 |
PCT NO: |
PCT/FR2012/051824 |
371 Date: |
February 27, 2014 |
Current U.S.
Class: |
62/457.2 |
Current CPC
Class: |
F25D 2303/0831 20130101;
B62D 33/048 20130101; F25D 3/105 20130101; F25D 3/06 20130101 |
Class at
Publication: |
62/457.2 |
International
Class: |
F25D 3/10 20060101
F25D003/10 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 30, 2011 |
FR |
1157655 |
Claims
1-2. (canceled)
3. A vehicle for the refrigerated transport of products comprising
at least one chamber for storing products, of the type where the
cooling system used by the vehicle is cryogenic, by means of the
direct or indirect injection of a cryogenic fluid into the said at
least one storage chamber, characterized in that: one or more
panels made from a phase-change material are incorporated into the
structure of all or a portion of the walls of at least one of the
storage chambers of the lorry; and the phase-change material has a
melting point that is 2 to 10.degree. C. higher than an intended
set point temperature in the chamber in question.
4. The vehicle of claim 3, wherein, the phase-change material has a
melting point that is 3 to 5 .degree. C. higher than said set point
temperature.
5. The vehicle of claim 3, wherein the phase-change material is
incorporated into at least half of the wall located on the storage
chamber side.
6. The vehicle of claim 3, wherein the phase-change material is
incorporated into at least one third of the wall located on the
storage chamber side.
Description
[0001] The present invention relates to the area of transport and
the distribution of thermosensitive products, such as
pharmaceutical products and foodstuffs.
[0002] Transporting products at a controlled and regulated
temperature has become a major issue with regard to cold chain
distribution, which is essential for maintaining the quality and
viability of organic products, whether they are foodstuffs or
drugs, vaccines, bio-samples, etc. Typically, perishable foodstuffs
are transported chilled or frozen (at a positive or negative
temperature), whereas drugs and vaccines are transported chilled
(at a positive temperature). The transportation generally takes
place between the place of production, storage or distribution
sites and places of sale and/or consumption.
[0003] Chilled or frozen products are transported in refrigerated
lorries. This transport is essentially dependent on "mechanical"
methods of generating cold. It is also possible to use "cryogenic"
solutions based on the use of liquid nitrogen or CO.sub.2 as cold
sources for maintaining positive (chilled) or negative (frozen)
temperatures.
[0004] The advantages of cryogenic solutions, which consist of
"direct" injections into the interior of the chamber or chambers
for storing the products (spray) or "indirect" injections (where
cryogenic fluid is channelled from a cryogenic reservoir stored on
the refrigerated lorry (generally underneath the lorry) to one or
more heat exchangers located on the inside of the cold chamber or
chambers of the lorry), are well known, but their penetration onto
the market has been held back by the associated economic cost.
[0005] One factor that has a significant influence on the cost is
of course the quantity of cryogen (nitrogen or CO.sub.2) required
to chill to the desired temperatures.
[0006] A physical analysis of heat exchanger mechanisms shows
clearly that the thermal inertia of the walls of the storage
chamber or chambers plays a significant part in the energy balance.
It could, in itself, in some configurations be responsible for 50%
of the overall consumption of cryogen.
[0007] The present invention therefore proposes a solution which
makes it possible to recover at least a portion of the cold
transferred to the walls for subsequent reuse during the
operational phase of the lorry.
[0008] It is known that in refrigerated lorries the insulating
walls used currently are most commonly made of polyurethane with a
plastic coating on the outside and a conducting material on the
inside (the "cold" side being in contact with the chamber). The
cooling of this structure is very time-consuming and uses a lot of
primary energy.
[0009] As explained in more detail below the present invention
proposes a new wall structure that can be summarised as follows:
[0010] one or more panels made from a "less energy consuming"
material is or are incorporated into the structure of all or a
portion of the walls of at least one of the storage chambers of the
lorry, said material is known as a "phase change" material; [0011]
this incorporation preferably covers all or a portion of half of
the wall on the side of the cold source (side of the storage
chamber, which comprises the injectors in a "direct" injection or
exchangers in an "indirect" injection method); [0012] by way of
example according to one exemplary embodiment of the invention the
succession of layers from the interior of the box would be: a
conducting layer, a layer of phase change material, a layer of
polyurethane and a layer of plastic material, the conducting layer
on the inner side of the box acting as a thermal transmission sheet
towards the phase-change material; [0013] the phase-change material
is selected in order to obtain a sufficient melting point according
to the type of application intended (chilled, or frozen transport)
and the range of temperatures needed (very specific temperature
ranges for some organic products for example). For reasons that
will be explained in more detail below, preferably according to the
invention a phase-change material is used with a melting
temperature which is only a few degrees higher than the intended
set point temperature in the chamber in question: preferably 2 to
10.degree. C. higher than the set point temperature and more
preferably 3 to 5.degree. C. higher.
[0014] As an example of the set point temperatures usually used in
the transport industry it would be possible to have a set point
temperature of 0 to 4.degree. C. for the transport of chilled
products, whereas set point temperatures of -20.degree. C. are used
for the transport of frozen products, both of these set point
temperatures can be used in two adjacent chambers of the same
lorry.
[0015] By way of example, according to the invention a material is
selected with a melting temperature of +8.degree. C. for chilled
transport and a melting temperature of -10.degree. C. for frozen
transport.
[0016] It is also possible to select these materials from a range
of organic materials including waxes, oils, fatty acids and
polyglycols or even from a range of capsules filled with salt
hydrates.
[0017] The advantage of including such a material in the wall of
the box is associated with its ability to store cold at the time of
cooling the lorry (when starting up, or even after opening the door
. . . ), and then restore it when the temperature of the box is
higher than the melting temperature.
[0018] The latent melting/solidification heat then makes it
possible to save a significant amount of primary energy (nitrogen
or CO2 in the case of cryogenic solutions) and thus reduce the
consumption thereof.
[0019] Thus the present invention relates to a vehicle for the
refrigerated transport of products, comprising at least one chamber
for storing products, of the type where the cooling system used by
the vehicle is cryogenic, by means of the direct or indirect
injection of a cryogenic fluid into said at least one storage
chamber, characterised in that: [0020] one or more panels made from
a so-called "phase-change" type of material are incorporated into
the structure of all or a portion of the walls of at least one of
the storage chambers of the lorry; [0021] the phase-change material
has a melting point that is only a few degrees higher than the
intended set point temperature in the chamber in question,
preferably 2 to 10.degree. C. higher than said set point
temperature and even more preferably 3 to 5.degree. C. higher than
said set point temperature.
[0022] According to one of the preferred embodiments of the
invention the phase-change material is incorporated into all or a
portion of half of the wall located on the side of the cold source
(storage chamber side) and even more preferably into all or a
portion of a third of the wall located on the side of the cold
source.
[0023] The attached FIG. 1 illustrates in cross section in its two
views a) and b): [0024] in a) a wall structure that is found in
some current lorries, with a sequence from the inside of the box of
a conducting layer 1, a polyurethane layer 2 and layer of plastic
material 3; [0025] in b) an exemplary embodiment of the invention,
where a layer 4 of phase-change material is incorporated into the
preceding structure, it should be noted that this layer 4 is
incorporated substantially into the half of the wall which is on
the chamber side of the assembly.
[0026] In the following an example of the behaviour of the wall is
explained during an operational phase of the lorry.
[0027] For a refrigerated lorry designed for transporting chilled
products, the start-up of the cooling system (either the direct or
indirect injection of cryogenic fluid) makes it possible to lower
the temperature of the air inside the chamber to the set point
temperature, then to maintain this temperature enabling the
regulation of the system. In a manner known to a person skilled in
the art the existing solutions for controlling the temperature of
the internal air in the box storing the transported products use
algorithms for controlling the opening/closing of valves supplying
the injectors or the internal exchangers in the box with
cryogen.
[0028] After each delivery of one or more pallets the doors are
open to the outside air and the temperature of the air inside the
lorry rises and the cooling system has to supply the necessary
refrigerating power to restore the set point temperature as quickly
as possible to maintain the chain of cold.
[0029] The time necessary to reach the set point temperature when
first starting up and after each opening of the door depends on
several parameters, principally the maximum refrigeration power
that the cooling system can supply but also the removal of the
inner/outer temperature and the thermo-physical properties (in
particular the conductivity) of the materials forming the walls of
the lorry.
[0030] Although the air reaches its set point temperature after a
period defined by the functioning parameters mentioned above, the
walls of the lorry continue to absorb energy as their thermal
inertia is much greater than air. Consequently, they only achieve
equilibrium after several hours of lowering the temperature of the
internal air in the lorry (this time is known in the industry as
"pull down").
[0031] In the case of a refrigeration lorry according to the
invention which is formed integrally or partially by walls
containing phase-change materials, during the lowering of the air
temperature when starting up or after opening the door the
temperature in the walls also falls, in particular in the layer
containing the phase-change material which will drop in temperature
until it reaches its solidification temperature. Then the phase of
storing energy is initiated in this material which is going to
solidify progressively.
[0032] More precisely, at the start of a tour or after a prolonged
opening of the door, cryogen is introduced to lower the internal
temperature of the chamber for storing products to the level of a
required set point temperature (for example from 20-25.degree. C.
to a set point temperature of +4.degree. C. for chilled products),
either by means of a direct injection technique (spray) or an
indirect injection technique (exchangers). Following the
introduction of cryogen the temperature in the walls lowers,
particularly in the layer containing the phase-change material
which will drop in temperature until it reaches its solidification
temperature.
[0033] Then the phase of storing energy is initiated in this
material which is going to solidify progressively.
[0034] On the basis of the material selected the storage of energy
in the material will start before the set point temperature of the
internal air in the chamber has been reached, and the partial or
complete solidification of the material before the set point
temperature of the internal air in the chamber has been reached is
going to depend on different parameters, essentially on its
thermo-physical properties (conductivity, specific heat) and the
quantity of material used (mass), but it is preferable to select
the correct amount of a suitable material so that the material is
completely or almost completely solidified when the temperature has
reached the internal set point temperature in the box.
[0035] When the door has been opened for a significant time during
the tour and the temperature of the internal air has risen, the
return to the set point temperature of the interior of the box will
be more rapid as the phase-change material will restore to the air
a portion of the energy that it has stored thus saving energy.
[0036] Thus at each point in the route of the vehicle: [0037] if
the internal temperature of the chamber is very slightly above the
required set point temperature (1 K for example), the material will
transfer a little energy (variation of sensible heat) contributing
to the air returning to its temperature, it serves as a kind of
buffer in order to even out the variation in temperature more
effectively, [0038] if the internal temperature in the chamber
increases by several degrees following the opening of the door(s)
for several minutes for example, the material transfers a
significant portion of its energy up to the point of partly melting
(variation of its latent heat) and facilitates the rapid return of
the air to its set point temperature, requiring the addition of
less primary cryogen: the system for controlling the temperature in
such vehicles, by controlling the opening/closing of the valves
supplying the injectors or the internal exchangers of the box with
cryogen as a function of taking the internal temperature, takes
into account (takes advantage) of the supply of energy coming from
the panels of phase-change material.
[0039] And the choice in this respect of a phase-change material
with a slightly higher melting temperature than the set point
temperature of the desired air is very advantageous, since in
contrast a material with melting temperature lower than the set
point temperature would continue to store the energy during the
maintenance phase (a useless process) and moreover, with each
return to the set point temperature it would continue to consume
energy as it would have the tendency to want to solidify
naturally.
* * * * *