DESC:TECHNICAL FIELD
[001] This disclosure relates generally to the field of vehicular refrigeration systems, and more specifically to a system and method for energy recovery based cooling system for improved cooling of reefer vehicles.
BACKGROUND
[002] Automotive vehicular containers are commonly equipped with GRP (Glass Reinforced Plastic) and PUF material layers installed over roof of a container of the vehicle in order to reduce a heat load of the sunlight. These layers is installed to prevent direct contact of the sunlight with roof of the container. However, with the installation of these layers, the heat absorption is excess and perishable goods become more prone to be spoiled.
[003] Currently, the refrigerated containers are installed with heat exchanger that utilize Vapor Compression Refrigeration System (VCRS) cycle for storage of chilled and frozen items. This system comprises of the evaporator, compressor, condenser, and an expansion valve, thus forming a closed loop system. The refrigerant used in such systems are generally not environment friendly as they are based on chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs) which pose a harmful impact on the ozone layer when released into air. Refrigerated transportation represents a critical phase in a cold chain due to its negative impact on energy consumption and greenhouse gas emissions. Approximately fifteen hundredth of global fossil fuel energy is estimated to be consumed by the refrigerator transport sector, rendering the cooling of perishable goods become an inefficient process.
[004] Therefore, there is a requirement to design an efficient cooling system on a rooftop of the refrigerated container to reduce a solar heat load and to provide appropriate insulation and cooling of the refrigerated container, thereby proactively increasing shelf life of the perishable goods.
SUMMARY
[005] In one embodiment, a system for energy recovery based cooling of a reefer vehicle is disclosed. The system may include a vehicular refrigerated container. The system may further include a heat exchanger configured within the vehicular refrigerated container to manage heat duty of the vehicular refrigerated container . In an embodiment, the heat exchanger may include a first flow control valve at an inlet of the heat exchanger and a second flow control valve at an outlet of the heat exchanger. The system may further include a duct installed on a roof of the vehicular refrigerated container, creating an air gap to allow passage of a cryogen gas for roof cooling. The system may further include a pipe with an opening in the duct, connected to the outlet of the heat exchanger, to direct the cryogen gas from the heat exchanger to the duct via the pipe. The system may further a controller to operate one or more of the first flow control valve and the second flow control valve to control a flow of the cryogen gas through the duct based on a temperature requirement of the vehicular refrigerated container and the duct. In yet another embodiment, a temperature of the cryogen gas at the outlet of the heat exchanger passing through the duct is set to be lower than a predefined temperature of the vehicular refrigerated container.
[006] In another embodiment, a method for energy recovery based cooling of a reefer vehicle is disclosed. The method may include receiving, by a controller and from a plurality of temperature sensors, a current temperature readings of each of a vehicular refrigerated container, an inlet, and an outlet of a heat exchanger. The method may further include determining, by the controller, a temperature requirement for the vehicular refrigerated container and a duct based on the current temperature readings. The method may further include controlling, by the controller, a flow of cryogen gas to pass through a duct by employing one or more of a first flow control valve and a second flow control valve based on the temperature requirement. In another embodiment, a temperature of the cryogen gas at the outlet of the heat exchanger passing through the duct is set to be lower than a predefined temperature of the vehicular refrigerated container.
[007] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[008] The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, serve to explain the disclosed principles.
[009] FIG. 1A illustrates a conventional roof configuration of a vehicular refrigerated container, in accordance with an exemplary embodiment of the present disclosure.
[010] FIG. 1B illustrates a proposed roof configuration of a vehicular refrigerated container, in accordance with an embodiment of the present disclosure.
[011] FIG. 2 illustrates a perspective view of an energy recovery based cooling system, in accordance with an embodiment of the present disclosure.
[012] FIG. 3 illustrates a top view of the vehicular refrigerated container depicting a plurality of guiding channels placed within a duct, in accordance with an embodiment of the present disclosure.
[013] FIG. 4 illustrates an exemplary configuration of a duct with an extended pipe arrangement having a plurality of holes, in accordance with an exemplary embodiment of the present disclosure.
[014] FIG. 5 illustrates an exemplary configuration of a duct without an extended pipe arrangement, in accordance with another exemplary embodiment of the present disclosure.
[015] FIG. 6 illustrates a circuit diagram for cooling of a driver cabin through waste energy from exit of cryogen gas of a vehicular refrigerated container, in accordance with an embodiment of the present disclosure.
[016] FIG. 7 illustrates a flow diagram of method for energy recovery based cooling of a reefer vehicle, in accordance with an exemplary embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE DRAWINGS
[017] The foregoing description has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which forms the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that the conception and specific embodiments disclosed may be readily utilized as a basis for modifying other devices, systems, assemblies, and mechanisms for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the scope of the disclosure as set forth in the appended claims. The novel features which are believed to be characteristics of the disclosure, to its device or system, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.
[018] The terms “including”, “comprises”, “comprising”, “comprising of” or any other variations thereof, are intended to cover a non-exclusive inclusions, such that a system or a device that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device. In other words, one or more elements in a system or apparatus proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.
[019] Reference will now be made to the exemplary embodiments of the disclosure, as illustrated in the accompanying drawings. Wherever possible, same numerals have been used to refer to the same or like parts. The following paragraphs describe the present disclosure with reference to FIGs. 1 - 7.
[020] Referring to FIG. 1A, a conventional roof configuration 100A of a vehicular refrigerated container 102 is illustrated, in accordance with an exemplary embodiment of the present disclosure. The conventional roof configuration 100A may typically include a 1.5mm-3.00 mm thick layer of a Glass Reinforced Plastic (GRP) installed over a roof of the vehicular refrigerated container 102. Further, a Polyurethane foam layer (PUF) with thickness 120-150 mm may be sandwiched between the GRP layers. The GRP may be made from strands of glass called fibers. These fibers may be extremely fine fibers that may be woven together to create a flexible fabric. The GRP may be a composite that incorporates aluminum oxide aggregate surface, which is diamond hard, and offers a high resistance to long-term wear. Further, the PUF layer may act as an insulating layer to reduce the heat load ‘Q’ transfer from a sunlight to the vehicular refrigerated container 102. The PUF sandwiched between the GRP layer may be industrially applicable.
[021] However, the conventional roof configuration 100A presents several shortcomings. For example, despite the use of GRP and PUF layers, this configuration may exhibit inefficiency in reducing the impact of the heat load ‘Q’ transferred from sunlight to the vehicular refrigerated container 102. The current may fall short in achieving the desired level of heat load reduction. The industrially applicable PUF sandwiched between the GRP layers may not provide the required level of cooling efficiency. This limitation compromises the overall performance of a refrigeration system. The inefficiency in mitigating the heat load ‘Q’ demands a more effective solution for cooling in the vehicular refrigerated container 102. There is a critical need for an improved cooling system that enhances efficiency, reduces heat load intensity, and ensures optimal conditions for the transportation of perishable goods.
[022] Referring to FIG. 1B, a proposed roof configuration 100B of a vehicular refrigerated container 102 is illustrated, in accordance with an embodiment of the present disclosure. The proposed roof configuration 100B addresses the aforementioned shortcomings and significantly improve the overall cooling performance of the vehicular refrigerated container 102 by installing an additional insulation layer i.e., a duct 104 below the GRP layer. As shown in present FIG. 1B, the installation of the duct 104 below the GRP layer aims to mitigate an impact of sunlight heat load from Q to Q'. It should be noted that the heat load Q in the conventional roof configuration 100A is greater than Q' of the proposed roof configuration 100B. The duct 104 may be capable of reducing the heat load Q’ from the sunlight due to the presence of a cryogenic gas 106, result in a 30-40% reduction in the cool-down time of the vehicular refrigerated container 102.
[023] The duct 104 may be made up of, for example, but may not be limited to, an aluminum. The materials like aluminum may be used in the duct 104 due to the properties such as, a low density, a non-toxicity, a high thermal conductivity, an excellent corrosion resistance, a non-magnetic and a non-sparking. The cryogenic gas 106 in fluid form may be a liquid nitrogen.
[024] The present disclosure eliminates the use of harmful CFC/HFC-based refrigerants, replacing them with environmentally friendly cryogenic fluid (e.g., liquid nitrogen). The gaseous form of this cryogenic fluid is subsequently repurposed for dynamic insulation on the vehicular refrigerated container 102, effectively reducing the heat loads Q' with rising temperatures. Consequently, the duct 104 contributes to improved insulation, significantly extending the shelf life of perishable items stored in the vehicular refrigerated container 102. The present disclosure focuses on enhancing cooling efficiency, reducing environmental impact, and improving overall performance in the transportation of perishable goods within the cold chain industry.
[025] Referring now to FIG. 2, a perspective view of an energy recovery based cooling system 200 is illustrated, in accordance with an embodiment of the present disclosure. The vehicular refrigerated container 102 may be equipped with a heat exchanger 202 that may include a fan assembly (not shown). Further, the fan assembly may be powered by an electric motor 204. The fan assembly circulates the air over the surface of the heat exchanger 202 that promotes the exchange of the heat between a cryogen liquid flowing within the heat exchanger 202. Accordingly, the heat exchanger 202 manages a heat duty of the vehicular refrigerate container 102 by circulating a cryogen fluid. In an embodiment, the cryogen fluid may correspond to a liquid nitrogen. The liquid nitrogen may be stored in a tank 206 and supplied to the heat exchanger 202, where it may undergo a phase change from liquid to gaseous nitrogen. Further, the heat exchanger 202 may include a first flow control valve installed at an inlet of the heat exchanger 202. Further, the heat exchanger 202 may include a second flow control valve installed at an outlet of the heat exchanger 202. The first flow control valve at the inlet to the heat exchanger 202 may regulate the flow of the liquid nitrogen entering the heat exchanger 202, while the second flow control valve may regulate the flow of the gaseous nitrogen exiting the heat exchanger 202based on set temperature and depending upon usage requirements.
[026] The cryogen gas exit from the heat exchanger 202 may be strategically released to the duct 104 installed on a roof of the vehicular refrigerated container 102 via a pipe 208 having an opening in the duct 104. The duct 104 may create an air gap to allow passage of the cryogen gas for roof cooling. In particular, the pipe 208 may establish a connection between the outlet of the heat exchanger 202 and the duct 104, to direct the cryogen gas from the heat exchanger 202 to the duct 104. This released cryogen gas to the duct 104 may act as an additional insulation layer, isolating the vehicular refrigerated container 102 from an external environment. This configuration significantly diminishes the heat load intensity within the vehicular refrigerated container 102, leading to a rapid cooling effect.
[027] Further, the system 100 may include a controller and a memory. In some embodiments, the controller may be an ECU (Electronic Control Unit) of the reefer vehicle. In an embodiment, the controller may be connected to the first flow control valve and the second flow control valve via a communication link. The communication link may be an intra vehicular communication network that may include, but may not be limited to, CAN (Controlled Area Network), CAN FD (Controlled Area Network Flexible Data-Rate), LIN (Local Interconnect Network), local area network (LAN), wide area network (WAN), Ethernet, and the like.
[028] The controller may further be connected to a Human-Machine Interface (HMI) that may be a dashboard or user interface to allow a user to adjust a temperature of the duct 102. The controller may operate one or more of the first flow control valve and the second flow control valve in order to control a flow of the cryogen gas through the duct 104 based on a temperature requirement of the vehicular refrigerated container 102 and the duct 104. This duct 104 may serve as a conduit for an excess cryogenic gas, which may otherwise be wasted during the cooling process. This configuration not only addresses environmental concerns by eliminating unused CFC/HFC-based refrigerants but also contributes to the reduction of high heat loads that may compromise the shelf life of perishable goods.
[029] Additionally, a low temperature cryogen gas exiting from the heat exchanger 202 may efficiently fills an air gap beneath the insulated roof, optimizing the cooling performance across the entire roof structure and effectively lowering the heat load Q'.
[030] In an embodiment, a temperature of the cryogen gas at the outlet of the heat exchanger 202 passing through the duct 102 may be set to be lower than a predefined temperature of the vehicular refrigerated container 102. In other words, the temperature of the exit cryogen gas may be 2 to 3 degrees Celsius cooler than the temperature inside the vehicular refrigerated container 102. For example, if temperature reading of the vehicular refrigerated container 102 is -22 degree Celsius, then the exit cryogen gas may be lower than or equal to -25 degree Celsius, which still has some energy. This energy may be utilized for dynamic insulation of the roof for additional cooling effect and reduction of the overall solar heat loads into the vehicular refrigerated container 102.
[031] Referring to FIG. 3, a top view 300 of a vehicular refrigerated container 102 depicting a plurality of guiding channels 304, in accordance with an embodiment of the present disclosure. The plurality of guiding channels 304 may be fitted within the duct 104 to guide the flow of the cryogen gas. This design not only allows for optimal residence time of the cryogen gas 106 but also ensures a semi-confined space, enabling the gas to spread over the entire roof, effectively covering the maximum area of the vehicular refrigerated container 102.
[032] In an embodiment, the pipe 208 with an opening 302 in the duct 104 and connected to the outlet of the heat exchanger 202, facilitates a controlled release of cryogen gas 106 into the duct 104. To ensure that the cryogen gas 106 covers a large possible area in an air gap of the duct 104 for more efficient cooling, an exit of the duct 104 may be arranged in a diagonal pattern. The bottom layer of the air gap in the duct 104 is composed of aluminium material which has a high thermal conductivity, contributes to achieving a faster cooling effect inside the vehicular refrigerated container 102.
[033] Additionally, to prevent gas pressure buildup within the duct 104, the cryogen gas 106 may be released out from the exit of the duct 104 into an external environment. In a more elaborative way, consider a scenario when the cryogen gas 106 may be supplied consistently to the duct 104 and the pressure starts to build due to accumulation of the cryogen gas 106. In such scenario, a pressure releasing valve 306 installed at the exit of the duct 104 may release the cryogen gas with excess pressure from the duct 104 to the external environment. This pressure releasing valve 306 may be actuated when the pressure exceeds a predefined threshold, effectively releasing excess pressure from the duct 104 to the external environment.
[034] Now Referring to FIG. 4, an exemplary configuration 400 of the duct 104 with an extended pipe arrangement having a plurality of holes is illustrated, in accordance with an exemplary embodiment of the present disclosure. The present Fig. 4 depicts an exemplary scenario where the cryogenic gas 106 may be supplied to the duct 104 through the pipe 208 having an extended length. In a more elaborative way, to supply the cryogenic gas 106 a section of the pipe 208 may be bent horizontally inside the duct 104 over a width of the vehicular refrigerated container 102 to cover a larger area. This bent section of the pipe 208 having the extended length may be referred to as an extended pipe arrangement 402. The extended pipe arrangement 402 may include a plurality of holes 404. The plurality of holes 404 may be designed for controlled bleeding of the cryogen gas 106 into duct 104. In other words, the plurality of holes 404 may facilitate the controlled spraying of the cryogen gas 106 into the duct 104 to cover a large surface area of the roof.
[035] The pipe 208 may further include a pipe connector 408. The pipe connector 408 may be configured to utilize the cryogen gas 106 from the heat exchanger 202. The pipe connector 408 may be a 3/4 way pipe connector that may serve multiple purpose for utilizing the energy of the cryogen gas exit from the heat exchanger 202. For instance, in some embodiments, the pipe connector 408 may be employed to reduce cool-down times, creating an inert atmosphere for perishable goods inside the vehicular refrigerated container 102 by regulating the flow of cryogen gas 106. In some embodiments, the pipe connector 408 may be utilized to direct the cryogen gas towards the duct 104, thereby reducing overall heat loads (Q') in the vehicular refrigerated container 102. In alternative embodiments, the pipe connector 408 may be utilized to redirect the cryogen gas exit from the heat exchanger 202 towards a driver cabin to enhance driving comfort.
[036] In order to provide energy recovery based cooling to the reefer vehicle, the cryogenic gas 106, initially in a liquid state such as liquid nitrogen stored in the tank 206, may be set to motion through a principle of pressure difference. In an embodiment, the pressure of liquid nitrogen in the tank 206 may be increased with an integrated pressure building unit in the tank 206. The integrated pressure building unit increases the desired pressure of the liquid nitrogen in order to be supplied to the heat exchanger 202. The heat exchanger 202, equipped with a fan assembly 406 and coiled tube (not shown), may facilitate a transformation of the liquid nitrogen into a gaseous state. The rotation of the fan assembly 406, driven by the electric motor 204, may alter the temperature of the liquid nitrogen within the coiled tube, ultimately maintaining the vehicular refrigerated container 102 at a low temperature.
[037] In an embodiment, a plurality of temperature sensors (e.g., a first temperature sensor, a second temperature sensor, and a third temperature sensor) may be installed at a body of the vehicular refrigerated container 102, the inlet of the heat exchanger 202, and the outlet of the heat exchanger 202, respectively. The first temperature sensor may be configured to monitor the temperature of the vehicular refrigerated container 102. The second temperature sensor may be configured to monitor a current operating temperature of the cryogen fluid at the inlet of the heat exchanger 202. Additionally, the third temperature sensor may be configured to monitor a current operating temperature of the cryogen gas at the outlet of the heat exchanger 202.
[038] In an embodiment, the inlet to the heat exchanger 202 may be installed with a first flow control valve that may regulate the flow of the cryogenic fluid to pass into the inlet of the heat exchanger 202. The outlet of the heat exchanger 202 may be installed with a second flow control valve that may regulate the flow of cryogenic gas exit from the heat exchanger 202 to pass through the duct 104. The first flow control valve and the second flow control valve may be controlled through a controller installed within the HMI of a dashboard of the reefer vehicle.
[039] The controller may be configured to operate at least one of the first flow control valve and the second flow control valve based on temperature readings from one or more of the first temperature sensor, the second temperature sensor, and the third temperature sensor. In particular, the first flow control valve may be in OFF state till the temperature of the vehicular refrigerated container 102 may rise to a desired set temperature. At this temperature, the first flow control valve may be in ON state to flow the cryogenic fluid to inlet of the heat exchanger 202 and releasing the cryogen gas inside the vehicular refrigerated container 102 to create inert atmosphere as per application specific requirement. The temperature of the cryogen gas at the outlet of the heat exchanger 202 passing through the duct 104 may be required to be set lower than the predefined temperature of the vehicular refrigerated container 102. Therefore, as soon as the third temperature sensor at the outlet of the heat exchanger 202 detects an operating temperature of the cryogen gas few degrees lower (for example, -2 degrees Celsius lower) than the set temperature inside the vehicular refrigerated container 102, the first flow control valve may be shut OFF and the second flow control valve may be shut ON. Based on the operation of the second flow control valve, the desired direction flow of the cryogen gas is set for re-utilization of the exit energy, thereby providing appropriate insulation on the roof and effective cooling to the vehicular refrigerated container 102.
[040] Now Referring to FIG. 5, an exemplary configuration 500 of the duct without the extended pipe arrangement 402 is illustrated, in accordance with another exemplary embodiment of the present disclosure. The present FIG. 5 depicts an exemplary scenario where the cryogenic gas 106 may be supplied directly to the duct 104 without any extended pipe arrangement 402.
[041] In a more elaborative way, the pipe connector 408 when directs the cryogen gas 106 towards the duct 104, the pipe 208 having an opening 502 may directly supply cryogen gas to the duct 104. This direct supply of cryogen gas contributes to providing an efficient cooling effect within the vehicular refrigerated container 102, thereby extending the shelf life of perishable goods stored inside. It should be noted that for both the scenario as discussed in conjunction with FIGs. 4 and 5, a process of roof cooling through the exit cryogen gas may be similar. The temperature of the exit cryogen gas may be a few degrees lower than the temperature within the vehicular refrigerated container 102 temperature. This may provide an additional cooling effect for dynamic insulation of the roof and reduction of the overall solar heat loads into the vehicular refrigerated container 102.
[042] Referring to FIG. 6, a circuit diagram 600 for cooling of a driver cabin through waste energy from exit of cryogen gas of vehicular refrigerated container 102 is illustrated, in accordance with an embodiment of the present disclosure. The present FIG. 6 depicts two scenarios for cooling the driver cabin 602. In first scenario, when cooling system of the vehicular refrigerated container 102 is operational, waste energy from the exit of cryogen gas is redirected to cool the driver cabin 602. The cooling effect is harnessed from the cryogen gas, utilizing it for additional purposes beyond the refrigeration process.
[043] Further, to manage the cooling of the driver cabin, the cooling process may be activated through a control logic (i.e., switching ON the heat exchanger 202). The user may open switch S1, allowing the first flow control valve to be switched ON. The pipe connector 408 may direct the supply of cryogenic gas 106 from the tank 206 via the heat exchanger 202 to the driver cabin 602. The temperature of the cryogen gas 106 may be adjusted based on the driver's requirement. If the temperature is below a required temperature, the pipe connector 408 may direct the supply of the exit cryogen gas 106 from the heat exchanger 202 to the driver cabin 602. Notably, the flowmeter V4 may be in a closed state. If the temperature of the driver cabin is within the set temperature, then valve V1 (i.e., the pipe connector 408) may supply the cryogen gas 106 to the duct 104 for providing heat insulation on the roof of the vehicular refrigerated container 102.
[044] Alternatively, in second scenario when the cooling system is turned off i.e., cooling in the vehicular refrigerated container 102 is not required, a cooling of the driver cabin 602 may be initiated independently. This activation involves opening a line from the tank 206, allowing the flow of liquid nitrogen into a cabin cooling unit. A third control valve V3 is incorporated in this line to regulate the rate of liquid flow into the driver cabin 602 based on temperature requirements, ensuring precise and controlled cooling for optimal comfort. In the OFF state of the cooling process, indicating the heat exchanger 202 and fan assembly 404 are inactive, the driver may initiate cabin cooling by pressing switch S1. In this scenario, the second control valve closes, and the valves V3 and V4 opens to supply cryogen gas 106 directly from the tank 206 to the driver cabin 602. The flowmeter valve V4 regulates the liquid flow rate into the cabin based on the driver’s temperature requirements.
[045] In an embodiment, the cryogen liquid flows from the tank 206 or from the pipe connector 408 to the cabin 602 to reduce the temperature of the cabin by recovering waste energy. The cryogen liquid may pass through an auxiliary heat exchanger 606 in order to transition the state of the cryogen liquid into the cryogen gas. The auxiliary heat exchanger 202 may be installed in the cabin 602. This transitioned cryogen gas may be utilized for providing the cooling effect to the user by reducing the temperature reading below the set temperature. If the cabin temperature is below the set temperature, the flowmeter valve V4 closes, indicating sufficient cooling has been achieved.
[046] In a more elaborative way, this may be the scenario when the vehicular refrigerated container 102 may be empty and there may be not needed to supply the cryogenic gas 106 to the heat exchanger 202. The heat exchanger 202 may be in OFF condition and then the cryogen gas 106 may be supplied directly from the tank 206 to the cabin 602 to provide the cooling effect to the driver by opening a third flow control valve V3. The third control flow valve V3 may be installed with the tank 206 that may regulate the flow of the cryogen liquid into the auxiliary heat exchanger 606. Further, the flowmeter valve 604 may be placed in connection with the third flow control valve V3 to regulate the rate of liquid flow into the cabin as per temperature requirements of the driver cabin 602.
[047] Referring now to FIG. 7, a flow diagram 700 of method for energy recovery based cooling of the reefer vehicle is illustrated, in accordance with an exemplary embodiment of the present disclosure. It should be noted that steps 702– 706 may be performed by the controller 706 to perform energy recovery-based cooling. At step 702, the controller may receive a current temperature readings of each of a vehicular refrigerated container 102, an inlet, and an outlet of a heat exchanger 202 in order to supply the cryogen gas into the duct 104. At step 704, the controller may determine a temperature requirement for the vehicular refrigerated container 102 and a duct 104 based on the current temperature readings. Further, the current temperature readings may be obtained from the first temp sensor installed, the second temperature sensor and the third temperature sensor. At step 706, the controller may determine the flow of cryogen gas to pass through the duct 104 by employing one or more of the first flow control valve and the second flow control valve based on the temperature requirement. It should be noted that the temperature of the cryogen gas at the outlet of the heat exchanger 202 passing through the duct may be set to be 2-3 degrees Celsius lower than the desired set temperature of the vehicular refrigerated container 102.
[048] In some embodiments, a first temperature sensor may monitor a current temperature of the vehicular refrigerated container (102). Further, a second temperature sensor may monitor a current operating temperature of cryogen fluid at the inlet of the heat exchanger (202). Additionally, a third temperature sensor may monitor a current operating temperature of cryogen gas (106) at the outlet of the heat exchanger (202).
[049] In some embodiments, the controller may operate at least one of the first flow control valve and the second flow control valve when a temperature difference between the cryogen gas (106) at the outlet of the heat exchanger (202) flowing to the duct (104) and the vehicular refrigerated container (102) is above a predefined threshold.
[050] Thus, the disclosed system try to reduce the need of harmful refrigerants in cooling of vehicle refrigerated container by enhancing efficiency. The cryogenic gas may be used such as liquid nitrogen in order to reduce the carbon footprint generated in cooling of the vehicle refrigerated container. The tank may be a source of the liquid nitrogen that may be supplied to the heat exchanger. Accordingly, the liquid nitrogen may be vaporized into gaseous form by exchanging energy with the air so that the set temperature may be achieved inside the vehicular refrigerated container 102. The cryogen gas may take exit from the heat exchanger to the pipe arrangement, that supplies the cryogen gas into the internal duct that may be installed over the roof to provide appropriate insulation and cooling effect to the perishable goods in the vehicular refrigerated container.
[051] As will be appreciated by those skilled in the art, the system described in various embodiment discussed above are not routine, or conventional or well understood in the art. The system discussed above may be capable of offering several advantages. Firstly, the plurality of guiding channels may be provided in order to increase the time of cryogen gas in the duct and ensure that the cooling effect from the cryogen gas may be distributed over the whole area of the vehicular refrigerated container.
[052] Secondly, the pressure may be regulated in the duct in case the pressure starts to develop due to accumulation of the cryogen gas. The pressure may be regulated by dispensing excess cryogen gas into the environment. Further, the system may provide the capability of providing the cooling effect to the cabin of the driver in case the cooling system may not be used in supplying the cryogen gas to the duct. Further, the supply of the cryogen gas may be taken from the coolant vessel in case the tank may be empty and heat exchanger may be in OFF state.
[053] Further, by utilizing the waste energy from the exit of cryogen gas, the system on the roof enhances overall cooling efficiency within the vehicular refrigerated container. This results in faster cool-down times and increased shelf life for perishable goods. The system on the roof effectively reduces the overall solar heat loads into the vehicular refrigerated container, further contributing to improved cooling performance and energy efficiency. The system on the roof results in a 30-40% reduction in the cool-down time of the vehicular refrigerated container.
[054] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
[055] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."
[056] In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.
[057] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
,CLAIMS:1. A system (100) for energy recovery based cooling of a reefer vehicle, comprising:
a vehicular refrigerated container (102);
a heat exchanger (202) within the vehicular refrigerated container (102) to manage heat duty of the vehicular refrigerated container (102), wherein the heat exchanger (202) comprises a first flow control valve at an inlet of the heat exchanger (202) and a second flow control valve at an outlet of the heat exchanger (202);
a duct (104) installed on a roof of the vehicular refrigerated container (102), creating an air gap to allow passage of a cryogen gas (106) for roof cooling;
a pipe (208) with an opening (502) in the duct (104), connected to the outlet of the heat exchanger (202), to direct the cryogen gas (106) from the heat exchanger (202) to the duct (104) via the pipe (208); and
a controller to operate one or more of the first flow control valve and the second flow control valve to control a flow of the cryogen gas (106) through the duct (104) based on a temperature requirement of the vehicular refrigerated container (102) and the duct (104), wherein a temperature of the cryogen gas (106) at the outlet of the heat exchanger (202) passing through the duct (104) is set to be lower than a predefined temperature of the vehicular refrigerated container (102).

2. The system (100) as claimed in claim 1, comprising a plurality of guiding channels (304) placed within the duct (104) to guide the flow of the cryogen gas (106), ensuring coverage over an entire surface area of the duct (104).

3. The system (100) as claimed in claim 1, comprises:
a first temperature sensor configured to monitor a temperature of the vehicular refrigerated container (102);
a second temperature sensor configured to monitor a current operating temperature of a cryogen fluid at the inlet of the heat exchanger (202); and
a third temperature sensor configured to monitor a current operating temperature of the cryogen gas (106) at the outlet of the heat exchanger (202).

4. The system (100) as claimed in claim 3, wherein the controller is configured to operate at least one of: the first flow control valve and the second flow control valve based on temperature readings from one or more of the first temperature sensor, the second temperature sensor, and the third temperature sensor installed at the inlet, the outlet of the heat exchanger (202) and a body of the vehicular refrigerated container (102), respectively.

5. The system (100) as claimed in claim 1, comprising a pressure releasing valve (306) installed at an exit of the duct (104) to release the cryogen gas (106) with excess pressure from the duct (104) to an environment.

6. The system (100) as claimed in claim 1, wherein the pipe (208) comprises:
a pipe connector (406); and
an extended pipe arrangement (402) having a plurality of holes (404), wherein the plurality of holes (404) facilitates spraying of the cryogen gas (106) into the duct (104) to cover a large surface area of the roof.

7. The system (100) as claimed in claim 1, comprising a tank (206) for storing cryogen fluid, wherein the cryogen fluid corresponds to a liquid nitrogen.

8. A method (700) for energy recovery based cooling of a reefer vehicle, comprising:
receiving (702), by a controller and from a plurality of temperature sensors, a current temperature readings of each of a vehicular refrigerated container (102), an inlet, and an outlet of a heat exchanger (202);
determining (704), by the controller, a temperature requirement for the vehicular refrigerated container (102) and a duct (104) based on the current temperature readings; and
controlling (706), by the controller, a flow of cryogen gas (106) to pass through a duct (104) by employing one or more of a first flow control valve and a second flow control valve based on the temperature requirement, wherein a temperature of the cryogen gas (106) at the outlet of the heat exchanger (202) passing through the duct (104) is set to be lower than a predefined temperature of the vehicular refrigerated container (102).

9. The method (700) as claimed in claim 8, comprising:
monitoring, by a first temperature sensor, a current temperature of the vehicular refrigerated container (102);
monitoring, by a second temperature sensor, a current operating temperature of cryogen fluid at the inlet of the heat exchanger (202); and
monitoring, by a third temperature sensor, a current operating temperature of cryogen gas (106) at the outlet of the heat exchanger (202).

10. The method (700) as claimed in claim 8, comprises operating, by the controller, at least one of the first flow control valve and the second flow control valve when a temperature difference between the cryogen gas (106) at the outlet of the heat exchanger (202) flowing to the duct (104) and the vehicular refrigerated container (102) is above a predefined threshold.