(en)A transport vehicle having a refrigerated container and system of refrigeration is provided.

1.ApplicationNumber: US-201515509824-A
1.PublishNumber: US-2017292759-A1
2.Date Publish: 20171012
3.Inventor: AL-HALLAJ SAID
DHAR SUBHASH
BEREISA, JR. JONAS
TOWNSEND DENNIS

4.Inventor Harmonized: AL-HALLAJ SAID(US)
DHAR SUBHASH(US)
BEREISA JR JONAS(US)
TOWNSEND DENNIS(US)

5.Country: US
6.Claims:
(en)A transport vehicle having a refrigerated container and system of refrigeration is provided.

7.Description:
(en)FIELD OF THE INVENTION
The present invention relates to refrigerated container, refrigeration system and method. More specifically, the present invention relates to a more efficient refrigeration system for refrigerated containers (“reefers”), a refrigerated container transport vehicle and container, and method of using the same.
BACKGROUND
Companies in the refrigerated ground transportation vehicle industry provide long-distance refrigerated trucking services. Products moved by this industry range from meat and poultry to pharmaceuticals and cosmetics, among other goods that require a climate-controlled environment. Goods are typically transported from manufacturers to wholesalers and retailers throughout the country.
Refrigerated containers (“reefers”) used in intermodal freight transport, have an integral refrigeration unit but rely on external power still from electrical power points. Sometimes, if the route is short, they are powered by cryogenic cooling, which is suitable for short distances, but on a longer route, as the frozen gas evaporates, the ability to cool will also eventually disappear. These containers have solid carbon dioxide in a chamber and are temperature regulated via a thermostatically controlled electric fan. When these reefers are transported over land, they are often configured to be powered by diesel generators.
With fuel prices high, these costs drive pricing levels in the market as refrigerated ground transportation vehicles not only burn diesel to power their cab and tractor/trailers but also burn diesel to maintain the desired refrigerated temperatures as low as 0° C., and less: for instance, eggs are usually transported at −16° C. and frozen meat at −18° C., while fruit can travel at +12/14° C.
Therefore, a more efficient and adaptable system is necessary in the industry for refrigerated ground transportation vehicles to remain a viable option for transport of valuable refrigerated and frozen products.
SUMMARY OF THE INVENTION
A system for refrigerating a reefer is provided having reefer container with a plurality of compartments; an energy supply unit comprising a battery; a controller; a system of tubes configured to circulate refrigerant to and from the unit through the reefer, and configured to place the refrigerant to be in thermal communication with the compartments; and a refrigerant for the thermal energy exchange.
The reefer, refrigeration system and method of using the system, according to the principles of the present invention, overcomes a number of the shortcomings of the prior art by providing a hybrid refrigeration system coupling an electrical compressor and/or a heat pump, with a battery, and ultimately with cold energy storage technology.
The reefer, system and method according to the present invention is related to a more efficient system of refrigeration in terms of reduced operational costs by providing modularity dependent upon such factors including, but not limited to, the weight of the load, the size of the load, the nature of the load, conservation requirement, the weather, distance of the route, and terrain of the route.
The reefer, system, and method according to the present invention is related to a reefer, system and method having at least one energy supply unit, tubes of refrigerant, sensors and a controller
The reefer, system, and method according to the present invention is also related to a reefer, system, and method having a plurality of energy supply units each having a battery, an electric compressor along with a condenser and evaporator and/or a heat pump, a system of tubes carrying a refrigerant, a refrigerant, sensors and a controller, and potentially having an engine exhaust system generator and or a panel having a phase change material.
The reefer and vehicle is related to a reefer and vehicle that is fitted with space for at least one energy supply unit and at least one panel, to up to as many as are needed providing variability and flexibility which lead to cost savings and efficiency.
The panel of the invention is related to a structure for containing a phase change material, and is placed in a system in thermal communication with a refrigerant and a space to be cooled in a reefer.
The vehicle, system and method of the present invention is also related to a vehicle, system and method wherein the energy supply unit battery during mobile vehicle operation can be used for cooling, or a supplemental energy source such as an energy grid can be used when the vehicle is stationary to both keep the compartment(s) of the reefer cold and to recharge the battery.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution of the art may be better appreciated.
Numerous objects, features and advantages of the present invention will be readily apparent to those of ordinary skill in the art upon reading of the following detailed description of presently preferred, but nonetheless illustrative, embodiments of the present invention when taken in conjunction with the accompanying drawings. In this respect, before explaining the current embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts an intermodal refrigerated container transport vehicle in accordance with the present invention;
FIG. 2 depicts an embodiment of an energy supply unit of the system in accordance with the principles of the present invention;
FIG. 3 depicts an embodiment of a phase change material (“PCM”) panel in accordance with the principles of the present invention;
FIG. 4 illustrates an embodiment of the panel in accordance with the principles of the present invention;
FIG. 5 illustrates another embodiment of a PCM configuration which can be used in a panel in accordance with the principles of the present invention;
FIG. 6 illustrates an embodiment of an energy supply unit in accordance with the principles of the present invention;
FIG. 7 illustrates an embodiment of an energy supply unit in accordance with the principles of the present invention;
FIG. 8 illustrates a flow chart of the energy transfer in accordance with the principles of the present invention;
FIG. 9 illustrates a battery powered system in accordance with the principles of the present invention;
FIG. 10 illustrates a battery powered hybrid electric motor driven compressor and heat pump system in accordance with the principles of the present invention;
FIG. 11 illustrates a battery powered hybrid electric motor driven compressor and heat pump which is referenced to a PCM in a PCM panel in accordance with the principles of the present invention;
FIG. 12 illustrates an integrated battery and exhaust energy powered electric generator system in accordance with the principles of the present invention; and
FIG. 13 illustrates an integrated battery with exhaust energy powered refrigeration unit system in accordance with the principles of the present invention.



DETAILED DESCRIPTION OF THE DRAWINGS
The following detailed embodiments presented herein are for illustrative purposes. That is, these detailed embodiments are intended to be exemplary of the present invention for the purposes of providing and aiding a person skilled in the pertinent art to readily understand how to make and use of the present invention.
Accordingly, the detailed discussion herein of one or more embodiments is not intended, nor is to be construed, to limit the metes and bounds of the patent protection afforded the present invention, in which the scope of patent protection is intended to be defined by the claims and their equivalents thereof. Therefore, embodiments not specifically addressed herein, such as adaptations, variations, modifications, and equivalent arrangements, should be and are considered to be implicitly disclosed by the illustrative embodiments and claims described herein and therefore fall within the scope of the present invention.
Further, it should be understood that, although steps of various the claimed method may be shown and described as being in a sequence or temporal order, the steps of any such method are not limited to being carried out in any particular sequence or order, absent an indication otherwise. That is, the claimed method steps are to be considered to be capable of being carried out in any sequential combination or permutation order while still falling within the scope of the present invention.
Additionally, it is important to note that each term used herein refers to that which a person skilled in the relevant art would understand such term to mean based on the contextual use of such term herein. To the extent that the meaning of a term used herein, as understood by the person skilled in the relevant art based on the contextual use of such term, differs in any way from any particular dictionary definition of such term, it is intended that the meaning of the term as understood by the person skilled in the relevant art should prevail.
Furthermore, a person skilled in the art of reading claimed inventions should understand that “a” and “an” each generally denotes “at least one,” but does not exclude a plurality unless the contextual use dictates otherwise. And that the term “or” denotes “at least one of the items,” but does not exclude a plurality of items of the list.
Generally, the system 10 of the present invention provides a method for cooling a plurality of compartments of a reefer 102 , as in FIG. 1 . The reefer 102 could be an intermodal reefer container or equally a reefer unit fixed and mounted to a truck 100 . The system 10 can be of varying different embodiments, each including a plurality of energy supply units 104 . The system 10 can also be provided with a plurality of phase change material (“PCM”) panels 106 .
The units 104 can have different configurations depending on the energy needs of the system, also dictated by whether panels 106 are present, and if so, how many. The energy supply units 104 of the system 10 each at least includes a battery 103 , a condenser 128 and an evaporator 127 , and an electrically driven compressor 101 and/or a heat pump 140 . All of these components of the system 10 , and operational use, is discussed herein.
Also included in the system 10 is a system of tubes 12 for delivering cooled refrigerant 122 from a condenser 128 of the energy supply units 104 to the evaporator 127 , and then for circulating the warmed refrigerant 122 back to the compressor of both or either the electrical compressor 101 and/or the heat pump 140 , depending on the configuration of the system 10 , in order to re-cool the refrigerant 122 . The evaporator 127 of the unit(s) 104 can also be in the panel 106 , if the panel 106 includes a PCM 111 and a refrigerant coil 121 , in which case the coil 121 acts as the evaporator in thermal communication with the PCM. The system 10 is controlled by a controller 131 , which can act as a master controller, or can monitor different components via each component controller e.g. the batter controller 133 .
FIG. 1 illustrates components of the system 10 disposed in and on an intermodal transport vehicle 100 having a reefer 102 . The system 10 is not limited to an intermodal transport vehicle 100 , but can also be a reefer 102 having the system 10 fixed on a truck. Also provided is at least one energy supply unit 104 . It should be noted that the parts in an energy supply unit 104 , as will be discussed, such as a battery 103 , condenser 128 , evaporator 127 and an electrically driven condenser 101 and/or a heat pump 140 , are in operational communication, not necessarily physically stacked one upon another, or adjacent to one another.
FIG. 2 provides a closer look at an embodiment of the components of an energy supply unit 104 having an electric compressor 101 , a condenser 128 , an evaporator 127 , and a battery 103 .
Depending on the configuration and included components of the unit 104 , some components of a unit 104 in some embodiments can be removably engaged with the reefer 102 and possibly to the diesel engine propulsion system located in the front of the cab 110 and/or to the cab battery, in order to maintain a sufficient amount of energy supply. The engine can also take over the role of the battery in some cases. This system 10 may be useful for routes with less difference in temperature between the outside natural environmental conditions and the required refrigeration temperature in a reefer. Moreover, this embodiment of the unit 104 may be useful when the route temperature is relatively stable without huge shifts between high and low outside temperatures, for example, during the day and night, and/or along the length of the route.
If the configuration of a unit 104 allows, components of units 104 can be added to the system of refrigeration 10 as needed. For example, a unit 104 having a battery 103 and an electric compressor 101 could be arranged to be together, and the two components 101 , 103 together could be added or removed, so that multiple components of a unit 104 could be accommodated by the system 10 .
A portable unit 104 , therefore, wherein components are not permanently affixed to the reefer 102 and can be added and removed as needed, may have a grip 105 for ergonomically holding the component to be added and/or removed for ease of operator handling. The grip 105 can be any grip understood in the art for gripping and carrying a unit including, but not limited to, a handle, or a plurality of grips 105 (as is illustrated in FIG. 2 ).
Turning back to FIG. 1 , FIG. 1 further illustrates at least one energy supply unit 104 and a plurality of panels 106 . If portable, the number of portable unit 104 components and the number of PCM panels 106 that could be installed/removed depends on a number of factors, some of which include environmental conditions such as humidity, temperature, pressure, load, distance of the route, type of load and refrigeration needed, and the duration of the journey. Not all units 104 or components of the unit(s) will be easily attached/detached or be portable. The location of the energy supply unit(s) 104 and panel(s) 106 will depend upon the expected ease of installation and removal by the operator, the number of units 104 needed, cost requirements, and the terrain of the route. The difference between the external natural temperature and the internal required conservation temperature should be considered when determining the number and disposition of unit(s) 104 or components thereof and panel(s) 106 .
The unit(s) 104 can be located in any location for safe transport, ease of installation and efficient performance along the transport vehicle 100 , for example, and not limited to a space 108 between the cab 110 and the reefer 102 . Another example location could be a vertical disposition in the back of the cab 112 or in front of the reefer 114 . A further example location would be the roof 116 of the reefer 102 , and/or the side(s) 118 of the reefer 102 , and/or on the bottom 120 of the reefer 102 .
It is also contemplated that the different components of the unit(s) 104 can be located in different locations on the reefer 102 . For example, the electric compressor 101 could be located in the front of the reefer 102 while the battery 103 could be located underneath/at the bottom of the reefer 102 . In FIG. 1 , the unit(s) 104 is also thermofluid dynamically connected to PCM panel(s) 106 . Illustrated is the system of tubes 12 which is adapted to deliver cooled refrigerant 122 , in this configuration, from the unit(s) 104 to close to the PCM 111 such that the refrigerant 122 in the tubes is in thermal communication with the PCM 111 of the PCM panel 106 . The PCM panels 106 are removably affixed to the reefer 102 at a receiving portion 107 of the reefer 102 .
The tubes 12 of the system 10 should be covered with an insulating material known in the art to insulate from heat dissipation so that transfer of the refrigerant 122 between the various components of the system does not disperse thermal energy. Some examples of insulating material which could be used include, but are not limited to, polyurethane, fiberglass and polyethylene.
The reefer 102 can have a plurality of refrigerated or freezer compartments inside which in the walls, ceiling, and/or base a plurality of receiving portions 107 can receive the removable PCM panels 106 . The panel(s) 106 can be any shape, size, and/or material which can be removably affixed within the walls, ceiling, and/or floor of the reefer 102 , and without disturbing the integrity of the load to be carried within the compartment in the reefer 102 .
A PCM panel 106 of the system 10 includes a PCM 111 , or in another embodiment can include a PCM along with a refrigerant coil 121 . FIG. 3 is a cross section of an embodiment of the panel 106 , wherein there is both a PCM 111 disposed in thermal communication with the refrigerant coil 121 . The panel 106 has a frame 119 which hosts a refrigerant coil 121 which carries the cooled refrigerant 122 . The refrigerant 122 can be any known refrigerant that operates in conjunction with a refrigerated compressor, heat pump system and any electric-driven motor, and is commonly used in the art to run through HVAC systems, for example, but not limited to, water, Freon™ (halo-carbon product or hydro fluoro-carbons), propylene glycol or any combination thereof.
The configuration and location of the PCMs 111 can vary. For example, the PCMs 111 can be wrapped around the refrigerant coil 121 at a particular distance along the length of the same, or the PCMs 111 can be provided in between parallel arms of the refrigerant coil 121 . These are merely examples, and the invention is not to be limited thereby. Rather, different configurations of PCM 111 within the panel 106 are dictated by the application and the best thermal energy transfer contemplated.
The refrigerant coil 121 could be disposed in the panel 106 in any shape that provides effective thermal transfer between the refrigerant 122 in the coil 121 and the PCM 111 in panel 106 , for example, but not limited to, a serpentine shape through the panel. The refrigerant coil 121 in the panel 106 can be in any suitable arrangement, including for example, in parallel and/or in series.
The panels 106 themselves can have many different configurations depending on the various factors. The first factor could possibly be the shape of the receiving portion 107 of the reefer 102 that accommodates the panel 106 . A panel 106 could, for example, be provided with a lip or groove for being accommodated into the lip located on the reefer 102 , or vice versa. The driver could thereby slide the panel 106 into place by pushing a handle (not shown) situated on the panel 106 and then lock the panel 106 into place by any known mechanism understood to keep the panel in place, such as, but not limited to a latch. The handle of the panel 106 could be any ergonomic handle. The invention is not intended to be limited by this configuration, and those skilled in the art would understand that other methods of retaining a panel 106 on the reefer 102 wall are also included in the present invention.
In use, the panel 106 , as in FIG. 3 , provided with a charged/cooled PCM 111 and a refrigerant coil 121 , is both in thermodynamic communication with the internal compartment of the reefer 102 and the refrigerant coil 121 through which the refrigerant 122 runs.
If a panel 106 such as in FIG. 3 , is used in the system 10 , the operator would have to add the panel(s) 106 to the system 10 . The number of panels added would depend on various factors including the duration, length and geographic location of the route, and the type of goods to be kept cool or cold. Therefore, in order to use a panel 106 as in FIG. 3 , at a first end, the refrigerant coil 121 has an inlet 123 , and at a second end an outlet 124 . The inlet 123 and the outlet 124 , upon installation of the panel 106 are securely removably adjoined to an inlet adaptor 125 and an outlet adaptor 126 (seen in FIG. 1 ) which are revealed by removing a tube portion of the system of tubes 12 flanked on either side by the inlet adaptor 125 and the outlet adaptor 126 . In this way, refrigerant 122 is not lost or leaked during installation and use of the system 10 . However, if a panel 106 is not to be used, the tubing portion remains in place.
The panel 106 does not necessarily have to have a refrigerant coil 121 . In an embodiment, the panel 106 only has a PCM 111 . Such a PCMs 111 in the panel 106 could be cooled/charged externally prior to the vehicle 100 being mobile. The receiving portion 107 could be located at any part of the reefer which allows the PCMs 111 in the panel 106 to be in thermodynamic communication with a compartment of the reefer 102 .
However, in this embodiment, the PCMs 111 upon warming up/ discharging, would have to be removed to be recharged. Therefore, either this type of panel 106 could be accommodated in a reefer 102 which is to travel shorter distances, have very constant external environmental temperatures, or colder external environmental temperatures. This type of panel could be exchanged with charged PCM panels 106 which could be conveniently kept by the operator in the cab of the vehicle 100 in a refrigerator or freezer depending on the type of PCM that needs charging, and the temperature desired both for the PCM as well as for the internal compartment. This type of panel 106 could be added to currently existing reefers 102 , and could be added to reefers 102 which have a unit 104 which utilizes an evaporator 127 to cool the internal space of the reefer 102 .
In the latter embodiment of the system 10 , the energy supply unit 104 could be used only when the internal temperature of the compartment is determined to be out of the range necessary for refrigeration due to the discharge of the PCM 111 . The energy supply unit 104 could be triggered (manually or automatically) to cool the refrigerant 122 through the unit 104 and thus to an evaporator (see e.g. FIG. 8 evaporators 722 , 724 ), by which a fan 129 could be placed to circulate the air in the compartment(s) and also across the evaporator 127 such that the temperature of the compartment could be reduced to an acceptable range. After this, the panel(s) 106 could be removed and replaced with charged/cooled panels 106 by which the compartment is cooled and maintained until again the PCMs 111 of the panel 106 are discharged and the unit(s) 104 is required to refrigerate the compartment.
The temperature of the system 10 could be gauged by a plurality of temperature sensors 130 in thermal communication with the PCM 111 and/or the reefer compartment (see e.g. FIGS. 4 and 9 ). The sensor(s) 130 can be operationally connected with the controller 131 (also shown in FIG. 9 ) to provide information about the temperature of the PCM 111 and/or the compartment. For instance, when the PCM 111 temperature reaches an established threshold, the controller 131 could start the energy supply unit(s) 104 to keep the compartment cool via an evaporator 127 located in thermodynamic communication with the air of the compartment.
In yet another embodiment of the system, the panel 106 without a refrigerant coil 121 could be placed thermodynamically close to the evaporator 127 of the unit 104 . In this way, the PCM 111 would be recharged/cooled while the unit(s) 104 are active and cold refrigerant 122 is provided to the evaporator 127 to keep the compartment cool. The unit 104 could be turned off by the controller 131 when the PCM 111 is determined by the sensor(s) to be at the appropriate temperature for keeping the compartment cool.
The use of PCM panel(s) 104 in a system 10 for refrigerating reefers 102 , provides efficiency and better use of energy by allowing the PCM 111 to cool the internal compartment(s) when charged, thereby giving the battery and other components of the unit(s) 104 a rest.
PCMs 111 can be any organic material, inorganic materials like salt hydrates, bio-based materials like fatty acids derived from plant and animal sources. Organic PCMs 111 can include paraffins and fatty acids, and low temperature waxes. The use of PCMs 111 is advantageous even over eutectics because the PCMs 111 volumetric storage density is lower than that of eutectics. PCMs 111 continue to absorb energy subsequent to a phase change from liquid to solid and may store thermal energy or release over a prolonged period of time thereby making a more efficient and potentially cheaper system to keep a reefer cool, in accordance with the principles of the present invention.
PCMs 111 absorb heat from the adjacent reefer space during their discharge phase and transfer the extracted cold thermal energy from the refrigerant 122 stored in the refrigerant coil 121 to the surrounding environment. This cooling of the space continues while phase change occurs. PCMs 111 are “charged” when they completely solidified and cooled to the desired temperature, and the solid phase is adopted by the PCM 111 . Depending on the temperature and quantity and speed of refrigerant 122 flowing by the PCM 111 , the system 10 presents fast charging rates and is able to maintain constant temperatures more easily than systems that have slower charging rates. In a panel 106 wherein the PCM 111 is water encapsulated in a hydrogel or is a low temperature wax, the panel 106 itself could be used to contain and provide support for the PCM 111 . In an embodiment of the panel 106 wherein a PCM 111 is used along with a refrigerant coil 121 , various different types of PCM could be used including a PCM composite (“PCC”) (to be discussed later) which provides both support and structure for the PCM 111 .
A PCM 111 that can also be used in this invention is a low temperature wax. Low temperature waxes are reliable, non-corrosive and chemically inert below 500° C. The use of a low temperature wax instead of water/ice is much more efficient because of a much higher volumetric energy density (under some conditions more than 32 Wh/Lit compared to the 22 Wh/Lit) which translates into being able to store a much larger amount of heat than water/ice energy storage solutions.
An important property presented by low temperature waxes is negligible “super cooling”, which is the possibility of lowering the temperature of a material below its freezing point without it becoming a solid. Without solidifying, the PCM 111 cannot store thermal energy. Therefore, the use of low temperature waxes in the PCM 111 is advantageous because it experiences negligible super cooling and can thus freeze and store thermal energy. Though, a PCM 111 encapsulated in a hydrogel is also an embodiment of a PCM 111 used in this invention, using a low temperature wax or a PCM 111 encapsulated in a hydrogel contains and may require structural support from the panel 106 .
Another type of PCM 111 which can be used in the panel 106 is a PCM composite (“PCC”) including low temperature waxes and support material like expanded graphite, providing faster cooling of the PCM due to a high thermal conductivity of graphite. FIG. 4 illustrates yet another embodiment of the PCM 111 , wherein the PCM 111 is in the form of a composite slabs. The shape of the panel 106 , the receiving portion 107 and the location of the adaptor sections 125 , 126 of the system of tubes 12 , will dictate the exact size and shape of the PCM 111 composite such that the frame 119 of the panel 106 can accommodate the PCM 111 , and can fit into the receiving portion 107 on the reefer 102 . For more demanding loads, a plurality of slabs or other configurations could be accommodated into a single panel in series or parallel.
In one embodiment, the refrigerant coil 121 can be made of copper and can exist in the PCM 111 in a serpentine coil disposition (as is shown in the FIG. 3 cross section). The refrigerant 122 exits the refrigerant coil 121 from the outlet 124 . The refrigerant coil 121 can also be any other material which is conducive to the thermal transfer of energy from the refrigerant 122 to the PCM 111 and vice versa.
Aluminum oxide or other conductive metals can be added to the composite in order to further enhance thermal conductivity, which signifies faster charge times. A PCC can be characterized by a wide range of melting points. By increasing the number of atoms of carbon in the PCC it is possible to increase the melting point and vice versa. Using different percentages of low temperature wax and graphite, and potentially other materials in the PCC, allows the system 10 to operate at different efficiencies due to the different melting points of the materials involved. Therefore, the system 10 can be used in different applications and for different operative needs by customizing the composite in the PCC and therefore providing appropriate melting points.
A PCC uses expanded graphite as a supporting porous matrix to hold the phase change material (low temperature waxes) together, therefore dispensing with the need for structural support from the panel 106 , as may be the case for water encapsulated in a hydrogel and even a low temperature wax alone. Commercially available expanded graphite (EG) is formed by an intercalation reaction with various acids and subsequent heat treatment. Commercial EG is uni-axially compacted using a pneumatic press, or any commercially available press. Examples of pressing pressures range at between about 10 to about 30 psi pressure, and until bulky density of between about 170-about 200 Kg/m 3 is achieved. Different pressures can be applied to achieve different densities. Afterwards, the compressed EG is submerged in a bath of molten PCM (low temperature waxes), kept at a temperature of between about 5-10° C., higher than its melting temperature, and left to soak until the PCM has reached its maximum absorption into the graphite matrix.
EG density increases with the compaction pressure applied and it can be varied in order to reach higher thermal conductivity. Therefore, thermal conductivity increases with EG density, whereas the PCM latent heat of fusion reduces with EG density (lower EG mass involved).
The PCC composition can for example be, but is not limited to, between about 60-85% PCM, and between about 15-40% EG. These percentages are not meant to be limiting, and the percentages can vary according to the application and operative mode desired. Other materials can also be used to replace EG in a PCC including, for example, but not limited to graphite powder, carbon fibers, graphite/carbon nano-powders/nano-fibers, copper, aluminum powder and conductive foam such as carbon, graphite, copper and aluminum. Other additives such as polymer can also be added to improve the mechanical properties.
Varying the percentages of graphite and other conductive materials along with the low temperature wax, in the PCC leads to varying thermal conductivity, providing the system of the invention with more versatility and the panels 106 comprising the PCM 111 can be customizable to many different applications and configurations.
For instance, with refrigerant 122 transferring cold energy to the PCC at a pace of 1.86 GPH (gallons per hour), PCC slabs can be cooled and store cold thermal energy in about 1 hour. At 4.5 GPH, a PCC can be expected to charge in 20 to 30 minutes, while at 12 GPH the PCC can fully charge in approximately 10 to 20 minutes. In this way, when the reefer 102 and vehicle 100 are in a stationary condition, it is contemplated that the panels 106 could be externally charged and the time would be very little in order to keep the operator on a schedule. The cooled/charged panels 106 of PCM 111 would be quickly ready to load onto the reefer 102 . Moreover, a PCM composite composed of low temperature wax and other additives in different combinations has quite a long operative life, possibly of more than 15 years.
FIG. 5 is another embodiment of a PCC 111 that could be used for example with an insulated compartment, wherein the a PCC 111 is in a stacked slabs configuration providing ample thermal energy transfer for the entire compartment for the duration of a journey, can be added to any compartment for a journey by connecting the inlet 123 and the outlet 124 with the system of tubes 12 . Upon arriving at a destination, the entire unit could be removed and placed at an outside source for recharging. By utilizing such an embodiment, panels 106 would not be necessary as the entire system would revolve around this configuration of the PCM. Any number of, in this embodiment, slabs can be used. If using a PCM 111 in a composite, which has twenty eight (28) PCM 111 composite (“PCC”) slabs ( 14 - 72 ) of comparable dimensions, arranged in a pile and the refrigerant coil 121 running between the slabs. The embodiment shown in FIG. 4 can be enclosed in the frame 119 of the panel 106 . The refrigerant 122 , after running through the system of tubes 12 pours into the refrigerant coil 121 from the inlet 123 . 14 is the first slab from the bottom, 26 is the fifth slab from the bottom, 36 is the tenth slab from the bottom and so on; 72 is slab on top of the pile. As shown in the FIG. 4 , after the inlet 123 , the refrigerant coil 121 penetrates between the PCC slabs 111 from the left side of the front section, splitting into 3 conduit tubes that run from the front section to the rear section in parallel, one over the other, between slabs 72 and 70 , between slabs 70 and 68 and between slabs 68 and 66 . After exiting the PCC slabs 111 from the rear section the parallel tubes of the refrigerant coil 121 go back towards the center of the rear section between the same slabs and exit from the front section. Again the parallel tubes go back to the rear section and come back to the front section. In total, after splitting into 3 tubes, the refrigerant coil 121 runs through each couple of PCC slabs 111 with 4 tubes segments, maximizing the thermal communication between the PCM 111 in the composite and the refrigerant 122 .
The 3 parallel tubes exiting one last time from the PCC slabs 111 from the front section on its right side curve towards the lower layers of slabs and penetrate in parallel between slabs 66 and 64 , 64 and 62 , 62 and 60 on the right side of the front section. Again, the conduit tubes run back and forth from the front to the rear and from the rear to the front section in parallel between the same slabs twice and exit the front section on its left side before moving to the lower slabs (between 60 and 58 , between 56 and 54 and between 54 and 52 ) and repeating the same procedure until reaching the last 4 slabs placed at the bottom of the PCC slabs 111 . The 3 parallel tubes run through the PCC slabs 111 between slabs 26 and 18 , slabs 18 and 16 and slabs 16 and 14 from left to right back and forth 4 times and merge in a single tube of the refrigerant coil 121 in the bottom-right area of the front section of the PCC slabs 111 pile. The refrigerant 122 exits the refrigerant coil 121 at the outlet 124 . From the outlet 124 , the refrigerant 122 flows into the system of tubes 12 and back to be cooled by the energy supply unit 104 .
In one cooling experiment, 28 slabs were piled one over the other with the PCC composite 111 and the refrigerant coil 121 together comprising 74% PCC and 11.5% copper tubing for the refrigerant coil 121 . The remaining percentage is the sensor(s) for gauging the temperature of the PCM in the PCC, and the frame 119 of the panel 106 . Other characterizing features of this embodiment could be, but are not limited to, a thermal capacity of about 4.2 kWh, PCC's energy density of about 54 Wh/Kg, PCC and copper refrigerant coil 121 energy density of about 46 Wh/Kg and system energy density of about 40 Wh/Kg.
Several discharge experiments have been conducted at different refrigerant 122 flow rates. For example, at 1.6 L/min a total cooling time of more than 6 hours was achieved with cold refrigerant 122 reaching the refrigerant coil 121 for the whole period, while the refrigerant 122 flowing through the different slabs was heating up at different rates: less than 1 hour for the refrigerant at the inlet (slab 72 to 66 ), 3 to 4 hours at slabs 46 and 54 , 24 , to 26 hours at slab 62 , 5 to 6 hours at slab 30 and 6.25 hours from slabs 24 to 14 .
Currently existing refrigeration systems 10 of reefers 102 do not utilize a system of tubes 12 to deliver refrigerant 122 through the system 10 and cool the internal compartments, let alone with the possible addition of a PCM in various possible embodiments.
For those panels 106 which have a refrigerant coil 121 , and need to be appended to the reefer 102 , the inlet 123 would be accommodated by the inlet adaptor 125 at a location on a tube of the system of tubes 12 close to the receiving portion 107 of the reefer 102 that accommodates the panel 106 . The outlet 124 would be accommodated by the outlet adaptor 126 found on the side opposing the inlet adaptor 125 at the area of the receiving portion 107 .
The adaptor sections 125 , 126 could be provided with a refrigerant flow control valve 117 . This refrigerant flow control valve 117 would be open when refrigerant 122 is flowing through the system 10 and could be closed when the panel(s) 106 is/are to be removed from the reefer 102 , to avoid loss of refrigerant 122 . Some examples of a refrigerant flow control valve 117 could be, but are not limited to, any valve commonly used or known in the art to stop or allow the flow of refrigerant when in an open or closed position, for example a check valve such as a solenoid valve or a ball valve could be used to prevent and open the flow of a liquid in such a tube as can carry a refrigerant.
The inlet 123 and the outlet 124 are also configured to accommodate a refrigerant flow control valve 117 in order to prevent leaking of the refrigerant 122 when the panel 106 is removed from or accommodated by the reefer. The opening and closing of the refrigerant flow control valve 117 could be manually controlled by the operator with, for example, a switch or a button. Or in the alternative could be automatically or electrically controlled by the controller 131 . Moreover, the attachment of the inlet 123 to the inlet adaptor 125 and the outlet 124 to the outlet adaptor 126 could be manually, automatically, or electrically accomplished. If automatically set, then the closing could be triggered, for example, when the vehicle stops, and could be opened again when the panel is locked into place.
As mentioned above, the units 104 always include at least one compressor and evaporator to function correctly. In fact, when the PCM panel 106 is used, it is the refrigerant coil 121 in the PCM panel 106 which acts as the evaporator.
FIG. 6 illustrates another embodiment of the energy supply unit 104 a battery 103 (potentially reduced size) and a heat pump 140 (other components including the evaporator and condenser are not shown). In this embodiment is provided another solution to efficiently refrigerate items in a reefer. The heat pump 140 of the system 10 operates as any other heat pump is known in the art to operate. The heat pump 140 is able to capture heat energy from either the outside natural environment, but more preferably from the heat energy from the diesel engine exhaust. The unit 104 in FIG. 6 can provide refrigeration to a compartment in the reefer 102 via an evaporator 127 . In the alternative, a PCM panel 106 can be charged by the refrigerant 122 exiting the heat pump 140 , thereby utilizing the heat to provide the PCM(s) in a panel 106 with the required cold energy for refrigeration. Or both could be used wherein the PCM 111 is charged and thereafter the evaporator is also used to further cool the compartment. Sometimes the use of a heat pump can be desirable because the amount of energy consumed by a heat pump is often a quarter the amount of thermal energy output. As previously provided, adding PCM panels 106 into the system lends even more efficiency to the system 10 .
FIG. 7 illustrates yet another embodiment of the unit 104 having an electric compressor 101 , a battery 103 , and a heat pump 140 (for simplicity, evaporator 127 and condenser 128 are not shown). By having a hybrid unit such as that of FIG. 7 , the unit 104 can interchangeably utilize the heat pump 140 and the electric compressor 101 . The electric compressor 101 could run alternatively to the heat pump's compressor 140 . This unit 104 is thought to be able to accommodate large variations between the outside natural environmental temperature and the desired refrigeration temperature inside the reefer, by switching to using the electric compressor 101 . The battery 103 of the unit 104 can be smaller than the battery 103 of FIG. 2 due to potentially smaller energy requirements. The unit 104 of FIG. 6 can accommodate the following control mechanisms to enable switching between the electrically driven compressor 101 and the heat pump 140 , including but not limited, to a manual or an automated switch. The manual switch can be operated by for instance the operator when perceived temperature differences so require. The automated switch can be configured to be activated when threshold temperature levels are reached thereby switching between the compressor 101 and the heat pump 140 .
The battery 103 of the unit(s) 104 can be charged either while connected to the engine of the cab; and/or via an external power source before, during or after a journey. The battery 103 of the unit 104 can also be charged via an exhaust system to be discussed later.
FIG. 8 provides an energy transfer flow chart 600 . In use, energy is provided from energy supply unit(s) 104 and possibly the cab engine 150 . Some examples of the unit(s) 104 can be, but are not limited to, a battery 103 and an electric compressor 101 (as in FIG. 2 ), and/or the unit(s) 104 can have a battery 103 and a heat pump 140 (as in FIG. 6 ), and/or the unit(s) 104 can have a battery 103 , an electric compressor 101 , and a heat pump 140 (as in FIG. 7 ). In one embodiment, when incorporating the PCM panel(s) 106 and thus the PCMs 111 , the unit(s) 104 move a refrigerant 122 through a system of tubes 12 into the refrigerant coil 121 , or at least close to the PCM 111 via the evaporator 127 , in a panel 106 , as is illustrated in FIG. 1 and FIG. 3 , which are in thermal communication with the inside of the reefer.
These tubes 12 are configured to deliver refrigerant 122 in a location such that it is in thermal communication with the PCMs 111 (configuration illustrated in, but not limited to, for example FIG. 3 ) thereby allowing the PCMs 111 to exchange heat already absorbed from the adjacent space of the reefer 160 , thereby cooling the PCMs 111 to the desired temperature for maintaining the desired refrigeration temperature in the reefer 102 . The PCMs 111 store or release energy by the changing of their aggregate state (phase) at a relatively constant temperature, such as melting and solidifying. In use, once the desired energy level in the PCMs 111 is reached, as may be determined by a temperature sensor 130 , the unit 104 operation may be reduced or turned off in order to gain energy efficiencies.
The system 10 of the invention may also be automatically controlled through a controller 131 over a distributed network intelligence. The controller can monitor the system 10 functions and performance including for example, but not limited to, outside temperatures, internal temperatures of the reefer, the temperature of the PCM 111 , the temperature of the refrigerant 122 in communication with the PCM 111 , the flow rate of the refrigerant 122 through the system of tubes 12 and the refrigerant coil 121 , and whether the components are running properly. The controller 131 could also be provided with automated starting and stopping of each unit 104 , be configured to adjust the flow rate of the refrigerant 122 , provide alerts as to the optimal functioning of the system 10 , and provide alerts when the system 10 is outside acceptable ranges or malfunctions. The controller 131 can also provide information to a computer in order to pre-set energy emission over time, override a standard procedure, a schedule or a program of cooling in emergency.
It is also anticipated that a reefer 102 is provided with different compartments which may need to be at different temperatures, and therefore, in an embodiment that uses a panel in thermal communication with each of the different compartments of the reefer, the controller 131 could maintain heterogeneous temperature and/or phase state of the PCMs 111 for each compartment accordingly. The controller 131 could also receive input from an electric compressor controller 132 and/or a battery controller 133 and adjust/maintain each electric compressor 101 and/or battery 103 of the system 10 in order to run efficiently.
Another embodiment of the system 10 is illustrated in FIG. 9 showing a battery powered mobile refrigeration system 10 without PCM. As mentioned above, the reefer 102 can be provided with compartments that are to be maintained at different temperatures. In this embodiment is provided a refrigerated compartment 161 and a freezer compartment 162 , further provided with a refrigerator compartment evaporator 722 and a freezer compartment evaporator 724 , respectively, and a fan 129 for circulating the air past the evaporator 722 . The reefer 102 of FIG. 8 has an energy supply unit 104 . In this embodiment, however, the energy supply unit 104 is provided with an electric compressor 101 operationally coupled to a battery 103 , wherein the electric compressor 101 is located at the front of the reefer 114 and the battery 103 is located at the bottom of the reefer 120 . Also provided are a compressor controller 132 and a battery controller 133 . A charger 134 is also provided which can be connected on one end to an energy grid and on the other end to the battery 103 in order to charge the same. For example, when the system 10 is stationary, the charger may provide sufficient power to chill the system 10 down during cargo loading and/or can fully recharge the battery 103 . Also shown in the reefer 102 of FIG. 9 is a three-phase inverter/controller 135 , which provides three-phase variable voltage, current, and frequency power to the compressor 101 .
In use, the battery 103 of the reefer 102 of FIG. 9 is charged via the charger 134 when the reefer 102 is stationary. The connection between the energy grid and the battery 103 may also provide enough power to chill the reefer 102 during stationary cargo loading. During mobile operation, however, the battery 103 in this embodiment is anticipated to provide enough energy to the compressor 101 , which in turn maintains the freezer 162 and refrigerated compartment 161 temperatures by coupling the compressor 101 to the freezer compartment evaporator 724 and the refrigerator compartment evaporator 722 . The compressor controller 132 corrects for the temperature. The battery controller 133 corrects for the charging and cell-to-cell balancing. Also provided on the reefer 102 is a controller 131 for remote control and management of for example location, temperatures, system status, and diagnostics.
Another embodiment of the system 10 of the invention is illustrated in FIG. 10 , also without a PCM, but showing a battery powered hybrid electric compressor and heat pump refrigeration system 10 with a reduced size battery, which is possible due to the accommodation of a heat pump 140 . In FIG. 10 is shown a reefer 102 having both a freezer compartment 162 and a refrigerated compartment 161 , and a temperature sensor 130 for gauging the temperature in the compartment 161 , and is operationally connected to the controller 131 . The freezer compartment 162 has a freezer compartment evaporator 824 and the refrigerated compartment 161 has a refrigerated compartment evaporator 822 . The reefer 102 has an electric motor compressor 101 , along with an electric compressor controller 132 on the front of the reefer 114 , operationally coupled to a battery 103 , a three-phase inverter/controller 135 , and a heat pump 140 on the bottom of the reefer 120 . The electric motor driven compressor 101 has a compressor controller 132 coupled thereto and the battery 103 again has a battery controller 133 coupled thereto. Also shown is the charger 134 which can be used when the vehicle is stationary. The heat pump 140 is also provided with a heat pump controller 141 . An ambient air reference condenser 142 is also seen located in operational communication with the heat pump 140 and the heat pump controller 141 . In use, the heat pump 140 is referenced to the ambient air via the ambient air reference condenser 142 .
In this embodiment, the freezer compartment 162 of the system 10 is kept cold by the electric motor driven compressor 101 while the refrigerated compartment 161 is kept cold by the heat pump 140 operation. As mentioned before, using a heat pump 140 , as in this embodiment of the system 10 , allows for the battery 103 to be smaller in size and also reduces the battery provided energy requirement. During mobile operation, energy from the battery 103 maintains the freezer 162 and refrigerated compartment 161 temperatures, and the compressor controller 132 and the heat pump controller 141 control these temperatures, respectively.
As mentioned, the system 10 as shown in FIGS. 9 and 10 does not also include a PCM panel.
Turning now to FIG. 11 , provided is a system 10 utilizing a battery powered hybrid compressor (electric compressor and heat pump) and heat pump referenced to a PCM. The reefer 102 is provided with a refrigerated compartment 161 and a freezer compartment 162 , along with a refrigerated compartment evaporator 922 and a freezer compartment evaporator 924 , respectively. In this embodiment, the freezer compartment 162 is temperature controlled via the electric motor driven compressor 101 along with the compressor controller 132 while the refrigerated compartment 161 is temperature controlled by the heat pump 140 along with the heat pump controller 141 . A three-phase inverter/controller 135 is again operationally coupled to the system 10 to ensure proper operation.
Also provided is a charger 134 which when connected to an energy grid, in stationary mode, provides sufficient power to chill the system 10 and cargo, recharge the battery 103 , and also to chill PCM 111 in a PCM panel 106 . In this embodiment, the heat pump controller 141 is operationally coupled to the PCM panel 106 so that the heat pump 140 is referenced to the chilled PCM 111 in the PCM panel 106 . The heat pump 140 reduces the need for battery energy and size, and also the stored thermal energy of the PCM 111 in a PCM panel 106 further reduces the battery energy requirements and size.
During mobile operations, the battery 103 energy and the stored PCM energy in the PCM panel 106 maintain the freezer 162 and refrigerator 161 compartment temperature. In the event that the PCM in the panel does not fully refrigerate the compartment 161 , the refrigerant 122 can run to the evaporator 922 after charging the PCM to further cool the compartment 161 as needed. The three-phase inverter/controller 135 provides power to the compressors ( 101 , 140 ).
FIG. 12 shows the system 10 of a reefer 102 wherein the battery 103 requirements are reduced due to the use of an exhaust energy powered electric generator system 145 . Provided therefore is an electric compressor 101 , a freezer 162 and a refrigerated 161 compartment, having an evaporator each ( 1024 , 1022 , respectively). Also provided are the compressor controller 132 , a battery 103 along with its battery controller 133 , and a three-phase inverter/controller 135 . In this system 10 , the compressor controller 132 controls the system 10 . Also provided is an alternating current electricity generator 145 , which could be any cycle technology electricity generator, for example thermoelectric or turbine, to convert engine exhaust 146 (exhaust energy) to electrical energy. During mobile operation, the battery 103 is recharged by the exhaust energy driven electric generator 145 , therefore, during mobile stationary operation, the recharged battery 103 is able to provide the energy to the system 10 in order to maintain the freezer 162 and refrigerated 161 compartments at the correct temperature.
It is also contemplated that in another embodiment illustrated in FIG. 13 , that an exhaust heat driven refrigeration cycle unit, maintains the exhaust energy driven electric generator 145 and maintains both the compartment ( 161 , 162 ) temperatures via supplemental evaporators 1140 , while the battery 103 does the same during mobile stationary operation.
Of note is that any and all of the embodiments can be remotely monitored and/or controlled by a controller 131 form any fixed fleet or business operations location, and the compartments of the reefer 102 can be one or more compartments of unique temperature to that particular compartment. Controller 131 also has the capability to record system temperatures and reefer operational status over time.
It should be noted that another embodiment of the invention includes the same systems as are described throughout the specification, and also illustrated in FIGS. 9 through 13 , in a fixed mounted reefer unit on a truck. Therefore, the same reefer 102 can be used with a fixed mounted reefer or an intermodal reefer container.
As with all reefers whether fixedly mounted on a truck, or an intermodal reefer container, the systems of the present invention provide a way to transport goods in extreme cold weather operations. A refrigerated compartment can be monitored and kept at a particular temperature by varying the different features of the system 10 , including, for example, reversing the heat pump 140 , including electrical heaters, by exhaust heat transfer, or with different compositions of PCM 111 as discussed above, or any combination of the same. In this way, a refrigerated compartment of a reefer can continue to be maintained at a particular temperature due to the versatility of the system 10 .
As to the manner of usage and operation of the present invention, the same should be apparent from the above description. Accordingly, no further discussion relating to the manner of usage and operation will be provided.
While a preferred embodiment of the system 10 has been described in detail, it should be apparent that modifications and variations thereto are possible, all of which fall within the true spirit and scope of the invention. With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.
Throughout this specification, unless the context requires otherwise, the word “comprise” or variations such as “comprises” or “comprising” or the term “includes” or variations, thereof, or the term “having” or variations, thereof will be understood to imply the inclusion of a stated element or integer or group of elements or integers but not the exclusion of any other element or integer or group of elements or integers. In this regard, in construing the claim scope, an embodiment where one or more features is added to any of the claims is to be regarded as within the scope of the invention given that the essential features of the invention as claimed are included in such an embodiment.
Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is to be understood that the invention includes all such variations and modification that fall within its spirit and scope. The invention also includes all of the steps, features, compositions and compounds referred to or indicated in this specification, individually or collectively, and any and all combinations of any two or more of said steps or features.
Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.