Patent Publication Number: US-2021188036-A1

Title: Power takeoff-driven refrigeration

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. Non-Provisional application Ser. No. 17/086,692 filed on Nov. 2, 2020, and further claims the benefit of U.S. Provisional Application Ser. No. 62/951,505, filed on Dec. 20, 2019, both of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to semi-trailer refrigeration. More particularly, the present disclosure relates to power takeoff-driven refrigeration to control temperature on a semi-trailer. 
     BACKGROUND 
     Freight companies commonly use semi-trailer trucks (more commonly referred to as “semi-trucks” or simply “semis”) to transport freight. Often, semi-trucks are used to transport freight under temperature-controlled conditions (e.g., to avoid spoilation). For example, semi-trucks may pull one or more semi-trailers with refrigeration units mounted thereon. 
     Conventional semi-trailer refrigeration units suffer from numerous drawbacks. For example, conventional semi-trailer refrigeration units are powered by a dedicated diesel engine, necessitating engine maintenance (e.g., coolant monitoring, cleaning, fuel/air filter changing, oil changing, etc.) for an additional diesel engine that is independent of the diesel engine of the semi-truck. Diesel engine maintenance and breakdowns result in semi-trailer refrigeration unit downtime, which increases costs for freight companies. 
     Furthermore, conventional semi-trailer refrigeration units cause substantial diesel fuel consumption, adding costs and resulting in significant emissions in addition to the emissions already caused by semi-trucks. In addition, conventional semi-trailer refrigeration units require monitoring of additional diesel fuel reservoirs (e.g., the reservoir of the refrigeration unit as well as the reservoir of the semi-truck). When operated independently of a semi-truck (e.g., when operated while not in transit and/or when disconnected from the semi-truck), semi-trailer refrigeration units must still be carefully monitored and/or refueled to preserve freight disposed therein. The excessive maintenance, monitoring, and care required to operate conventional semi-trailer refrigeration units make them prone to user errors that may cause additional breakdowns and/or reduce the lifespan of the units, thereby further increasing costs for freight companies. 
     Accordingly, there are a number of disadvantages with semi-trailer refrigeration units that can be addressed. 
     The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced. 
     SUMMARY OF EXAMPLE EMBODIMENTS 
     Implements of the present disclosure solve one or more of the foregoing or other problems in the art with semi-trailer refrigeration units. In particular, one or more implementations can include a generator that is configured to be mechanically connected to a power takeoff (PTO) and a converter that is configured to receive AC power from the generator and is operable to convert the AC power to DC power. In some instances, the generator is connected to a charge controller that is connected to an energy storage element (e.g., one or more batteries). The energy storage element is, in some implementations, connected to a controller configured to receive DC power provided by the converter (e.g., through the energy storage element) and provide AC power to a motor. The motor may be mechanically connectable to a refrigeration system. 
     In some embodiments, the energy storage element is further configured to receive power from a second charge controller that receives power via a 220V AC power input. In some embodiments, the energy storage element may receive power from one or more solar panels coupled to a solar charge controller. 
     This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an indication of the scope of the claimed subject matter. 
     Additional features and advantages of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the disclosure. The features and advantages of the disclosure may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features of the present disclosure will become more fully apparent from the following description and appended claims or may be learned by the practice of the disclosure as set forth hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to describe the manner in which the above recited and other advantages and features of the disclosure can be obtained, a more particular description of the disclosure briefly described above will be rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the disclosure and are not therefore to be considered to be limiting of its scope. 
       The disclosure will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
         FIG. 1  illustrates a conceptual representation of semi-truck-mounted components of a system for power takeoff (PTO) driven refrigeration; 
         FIG. 2  illustrates a conceptual representation of a semi-trailer and refrigeration unit of a system for PTO-driven refrigeration; 
         FIG. 3  illustrates a conceptual representation of semi-trailer-mounted components of a system for PTO-driven refrigeration; 
         FIG. 4  illustrates a conceptual representation of semi-trailer-mounted components of a system for PTO-driven refrigeration; 
         FIG. 5  illustrates a schematic representation of a PTO air shift assembly in a disengaged configuration; 
         FIG. 6  illustrates a schematic representation of a PTO air shift assembly in an engaged configuration; 
         FIG. 7  illustrates a schematic representation of a PTO air shift assembly modified to be locked into an engaged configuration 
         FIG. 8  illustrates a schematic representation of a computing system; 
         FIG. 9  illustrates a flowchart of temperature regulation of a system for PTO-driven refrigeration; and 
         FIG. 10  illustrates a flowchart of battery regulation of a system for PTO-driven refrigeration. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS 
     The following descriptions depict only example embodiments and are not to be considered limiting in scope. Any reference herein to “the invention” is not intended to restrict or limit the invention to exact features or steps of any one or more of the exemplary embodiments disclosed in the present specification. References to “one embodiment,” “an embodiment,” “various embodiments,” and the like, may indicate that the embodiment(s) so described may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes the particular feature, structure, or characteristic. Further, repeated use of the phrase “in one embodiment,” or “in an embodiment,” do not necessarily refer to the same embodiment, although they may. 
     Reference to the drawings is done throughout the disclosure using various numbers. The numbers used are for the convenience of the drafter only and the absence of numbers in an apparent sequence should not be considered limiting and does not imply that additional parts of that particular embodiment exist. Numbering patterns from one embodiment to the other need not imply that each embodiment has similar parts, although it may. 
     Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention, which is to be given the full breadth of the appended claims and any and all equivalents thereof. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. Unless otherwise expressly defined herein, such terms are intended to be given their broad, ordinary, and customary meaning not inconsistent with that applicable in the relevant industry and without restriction to any specific embodiment hereinafter described. As used herein, the article “a” is intended to include one or more items. When used herein to join a list of items, the term “or” denotes at least one of the items, but does not exclude a plurality of items of the list. For exemplary methods or processes, the sequence and/or arrangement of steps described herein are illustrative and not restrictive. 
     It should be understood that the steps of any such processes or methods are not limited to being carried out in any particular sequence, arrangement, or with any particular graphics or interface. Indeed, the steps of the disclosed processes or methods generally may be carried out in various sequences and arrangements while still falling within the scope of the present invention. 
     The term “coupled” may mean that two or more elements are in direct physical contact. However, “coupled” may also mean that two or more elements are not in direct contact with each other, but yet still cooperate or interact with each other. 
     The terms “comprising,” “including,” “having,” and the like, as used with respect to embodiments, are synonymous, and 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.). 
     Before describing various embodiments of the present disclosure in detail, it is to be understood that this disclosure is not limited to the parameters of the particularly exemplified systems, methods, apparatus, products, processes, and/or kits, which may, of course, vary. Thus, while certain embodiments of the present disclosure will be described in detail, with reference to specific configurations, parameters, components, elements, etc., the descriptions are illustrative and are not to be construed as limiting the scope of the claimed invention. In addition, any headings used herein are for organizational purposes only, and the terminology used herein is for the purpose of describing the embodiments. Neither are not meant to be used to limit the scope of the description or the claims. 
     Disclosed embodiments are directed to systems and methods for PTO-driven refrigeration. Some embodiments include a generator that is configured to be mechanically connected to a power takeoff (PTO) and a converter that is configured to receive AC power from the generator and is operable to convert the AC power to DC power. In some instances, the generator is connected to a charge controller that is connected to an energy storage element (e.g., one or more batteries). The energy storage element is, in some implementations, connected to a controller configured to receive DC power provided by the converter (e.g., through the energy storage element) and provide AC power to a motor. The motor may be mechanically connectable to a refrigeration system. 
     In some embodiments, the energy storage element is further configured to receive power from a second charge controller that receives power via a 220V AC power input. In an alternate embodiment, the energy storage element is configured to receive power from a solar panel coupled to the semi-trailer. 
     Those skilled in the art will recognize that the disclosed embodiments may address many of the problems associated with semi-trailer refrigeration systems. For instance, disclosed embodiments eliminate the need to use an independent diesel engine to power semi-trailer refrigeration units, thereby avoiding the maintenance, breakdowns, downtime, fuel level monitoring and refilling, and/or emissions associated with using a dedicated diesel engine (e.g., in addition to a diesel engine of a semi-truck). Disclosed embodiments may also avoid problems that typically arise from users failing to exercise due care in maintaining, monitoring, and/or using diesel-powered refrigeration units. 
     Furthermore, conveniently, at least some disclosed embodiments provide for semi-trailer refrigeration units that may operate independently of a semi-truck by connecting the refrigeration unit to a 220V power input (e.g., when the unit resides in a warehouse). Alternatively, the semi-trailer refrigeration unit may operate independently by connecting the refrigeration unit to a solar panel coupled to the semi-trailer. 
     In view of the foregoing, the disclosed embodiments may allow freight companies to avoid considerable costs associated with maintaining and operating diesel-driven semi-trailer refrigeration units. 
     Having just described some of the various benefits and high-level attributes of the disclosed embodiments, additional detail will be provided with reference to  FIGS. 1-10 , which show various examples, schematics, conceptualizations, and/or supporting illustrations associated with the disclosed embodiments. 
       FIG. 1  illustrates a conceptual representation of semi-truck-mounted components of a system for power takeoff (PTO) driven refrigeration  100 . In particular, as shown in  FIG. 1 , the system for PTO-driven refrigeration  100  includes a generator  102  that is mechanically connected to a PTO  104 . The PTO  104  may be in mechanical communication with the transmission of a semi-truck  106 , such that a drive shaft of the PTO  104  is actuated by running the engine of the semi-truck  106 . As will be described in more detail hereinafter, the drive shaft of the PTO  104  may be in constant mechanical communication with a PTO driver gear of the transmission of the semi-truck  106  such that the PTO is constantly engaged and rotating whenever the truck runs (e.g., by omitting a shift mechanism). 
     The generator  102  may be driven by the PTO  104  to generate AC power. It should briefly be noted that the generator  102  may be implemented as an electronic motor that is reversibly operable to receive rotational force to generate AC power or receive AC power to generate rotational force. In some embodiments, the generator  102  is implemented as a three-phase, water-cooled, permanent magnet motor operated as a generator for generating three-phase AC power (e.g., to maintain a high peak voltage). However, other motors/generators may be used. For instance, the generator  102  may be embodied as a brushless DC motor (BLDC motor) operated as a generator. 
     The generator  102  provides AC power to a converter  108  (e.g., Rectifier/Controller), which converts the AC power into DC power. As suggested by the labeling in  FIG. 1 , in some implementations, the converter  108  is implemented as a rectifier or another controller/circuit/system suitable for converting AC power into DC power (e.g., motor-generator, rotary converter). As such, the rectifier/controller  108  may provide DC power to other components of the PTO-driven refrigeration system  100 . The converter  108  may provide DC power to a refrigeration unit  110  comprising the semi-trailer mounted components of the system for PTO-driven refrigeration  100 . 
       FIG. 2-4  illustrate a conceptual representation of semi-trailer-mounted components of the system for PTO-driven refrigeration  100 . The rectifier/controller  108  described with reference to  FIG. 1  may provide DC power to a charge controller  112 , (e.g., a DC regulator) via a wire  114  (shown in  FIG. 1  extending toward the semi-trailer). In this manner, in some embodiments, the rectifier/controller  108  provides DC power to an energy storage element, such as a bank of batteries  116  ( FIG. 2 ), through the charge controller  112 . Those skilled in the art will recognize that the depiction of a battery bank  116  in  FIG. 2  is illustrative only, and non-limiting. For example, the energy storage element  116  may be implemented as one or more lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, lithium-ion polymer batteries, flow batteries, capacitors (e.g., supercapacitors, lithium-ion capacitors), and/or even superconducting magnetics. 
     The rectifier/controller  108  ( FIG. 1 ) may provide DC power to the energy storage element  116  (e.g., battery bank) via a charge controller  112  (e.g., DC regulator). Being charged by the rectifier/controller  108  and DC regulator  112 , the battery bank  116  may then provide DC power to a controller  118  via battery wires  119  ( FIG. 4 ). In some embodiments, the controller  118  is configured to invert the received DC power into AC power and provide the AC power to a motor  120 . The controller  118  may be implemented as any suitable circuit/system for inverting DC power into AC power (e.g., power inverter, motor-generator, rotary converter). 
     As mentioned earlier with reference to  FIG. 1 , the generator  102  may be implemented as an electronic motor that is reversibly operable to receive rotational force to generate AC power or receive AC power to generate rotational force. In this regard, the motor  120  and the generator  102  (shown in  FIG. 1 ) may be identical motors operated in reverse fashion with respect to one another. Specifically, the motor  120  receives AC power from the energy storage element  116  (via the controller  118 ) and generates rotational force to control a compressor  122 , whereas the generator  102  receives rotational force from the PTO  104  and generates AC power. 
     The motor  120  may be mechanically connected to a refrigeration element/system  121  (e.g., a mechanical-compression refrigeration system). In some implementations, the motor  120  is mechanically connected to a compressor  122  of a refrigeration system such that the motor  120  drives the compressor  122  (e.g., A/C Compressor). It will be appreciated that any type of compressor  122  is within the scope of this disclosure, such as, but not limited to, reciprocating compressors, open drive compressors, scroll compressors, rotary-screw compressors, centrifugal compressors, dual-piston, etc. 
     Thus, in at least some of the disclosed embodiments, the generator  102  mechanically connected to the rotating PTO  104  generates AC power, which is converted by the converter  108  into DC power and provided to the energy storage element  116  (e.g., to the battery bank via the DC regulator or charge controller  112 ). The energy storage element  116  then provides stored DC power to the controller  118  that inverts the DC power into AC power. The AC power is sent via controller wires  124  to drive the motor  120  that drives the compressor  122  of the refrigeration unit  110 . The compressor  122  may operate within a mechanical-compression refrigeration system/unit to regulate the temperature (e.g., maintain a desired low temperature) within a semi-trailer  126  (or other cavity) to which the refrigeration system/unit  110  is mounted. 
     In this regard, at least some disclosed embodiments provide a system for PTO-driven refrigeration wherein the refrigeration system on the semi-trailer  126  is powered by the PTO  104  of the semi-truck  106 , thereby eliminating the need to power the refrigeration system with an independent diesel engine and eliminating all maintenance, breakdown, monitoring, and/or emissions and fuel consumption problems associated with the use of an independent diesel engine to power the semi-trailer refrigeration unit  110 . 
     Further advantageously, in some implementations, the battery bank  116  (or other energy storage element(s)) is further configured to receive power from a separate charge controller (e.g., separate from the DC regulator). This may allow the refrigeration systems of the present disclosure to be versatilely connectable to different charge sources to be driven thereby, in addition to being chargeable/drivable by the PTO  104 . In some instances, the functionality of being chargeable/drivable by different power sources allows the presently disclosed refrigeration systems to be operated when disconnected from a semi-truck or other vehicle (such as when temporarily stored in a warehouse), without requiring diesel fuel monitoring or refilling for the refrigeration systems. For example, referring to  FIG. 3 , the battery bank  116  (as appreciated from comparing  FIGS. 2-3 , the location of the battery bank  116  may vary without departing herefrom) may be configured to receive power from a solar panel  128  coupled to the semi-trailer  126 . In some embodiments, the solar panel  128  may be non-flexible and may be UV epoxy coated to achieve greater efficiency, although any solar panels may be used. Accordingly, the battery bank  116  may be charged to provide DC power to the controller  118  to drive the motor  120  and the A/C compressor  122  via the solar panels  128  even when the semi-truck  106  is disconnected from the semi-trailer  126 . 
     As represented in  FIG. 3 , the battery bank  116  may further be configured to receive power from a 220V AC power input  130  (or other AC charge controller). In some embodiments, the 220V AC power input  130  bypasses the DC regulator  112  when a 220V power source is connected to the 220V power input  130 . In this manner, the battery bank  116  may be charged via the 220V power input  130  to provide DC power to the controller  118  to drive the motor  120  and the A/C compressor  122  even when the semi-truck  106  is disconnected from the semi-trailer  126  and/or when the rectifier/controller  108  (or other converter described with reference to  FIG. 1 ) is disconnected from the battery bank  116 . Those skilled in the art will recognize that providing the functionality of powering a semi-trailer refrigeration system by simply connecting a 220V (or other) power source to the semi-trailer refrigeration battery bank  116  may eliminate significant costs associated with conventional diesel-driven semi-trailer refrigeration systems (e.g., emissions, refueling, fuel monitoring, etc.). 
       FIGS. 1-4  have shown certain components of the presently disclosed systems for PTO-driven refrigeration  100  as mounted on either the semi-truck  106  or the semi-trailer  126 . However, it will be appreciated that the arrangements depicted in  FIGS. 1-4  are illustrative only, and non-limiting. For example, the DC regulator  112  (or other charge controller) may be mounted on a semi-truck  105  (or other vehicle) proximate to the rectifier/controller  108  (or other converter), or, alternatively, the rectifier/controller  108  may be mounted on the semi-trailer  126  proximate to the DC regulator  112  and the battery bank  116  (or other energy storage element). Further, the battery bank  116  may be mounted on the semi-trailer  126  below the refrigeration unit  110  ( FIG. 2 ), mounted within the refrigeration unit  110  ( FIG. 3 ), or mounted in other locations on the semi-trailer  126 . 
     Additionally, it will be appreciated that  FIGS. 1-4  show conceptual representations of the components of the presently disclosed systems for PTO-driven refrigeration  100 , and, therefore, any depicted positioning/placement of components on the semi-trailer  126  or semi-truck  106  are illustrative only and non-limiting. For instance, although  FIG. 1  shows a rectifier/controller  108  mounted underneath the semi-truck  106  proximate to the generator  102 , it will be recognized that the rectifier/controller  108  may be mounted on the catwalk of the semi-truck  106 , within the cab thereof, or even on the semi-trailer  126  as mentioned above. 
     It should also be noted that the presently disclosed systems for PTO-driven refrigeration  100  may include components not explicitly shown in  FIGS. 1-4 . For example, as will be described in more detail hereinafter, the system for PTO-driven refrigeration  100  may include or be in communication with one or more computing systems and/or sensors to facilitate the operation and/or monitoring of the system and/or components thereof. In another example, the system for PTO-driven refrigeration  100  may include one or more cooling systems for cooling the generator  102  and/or the motor  120 , such a semi-truck-mounted radiator and fan system in fluid communication with the generator  102  and a semi-trailer-mounted radiator and fan system in fluid communication with the motor  120  that drives the A/C compressor  122 . 
     Those skilled in the art will recognize that certain aspects and/or components of the system for PTO-driven refrigeration  100  shown and described with reference to  FIGS. 1-4  may be omitted and/or replaced in some implementations. For instance, in some embodiments, the battery bank  116  and/or charge controller  112  is omitted from the system such that the rectifier/controller  108  converts the AC power received from the generator  102  into DC power and is directly coupled to the controller  118  that receives the DC power and inverts it into AC power to provide to the A/C compressor  122 . In some embodiments, the rectifier/controller  108  may be directly coupled to the generator  102 . 
     As briefly noted hereinabove, the drive shaft of the PTO  104  may be in constant mechanical communication with a PTO driver gear of the transmission to which the PTO  104  is attached/affixed (e.g., the transmission of a semi-truck). For example, in some embodiments, the PTO  104  may be constantly engaged by using an electric disconnect (e.g., a solenoid) and a wet clutch (or other suitable clutch system). In one embodiment, the solenoid may be internal to the wet clutch. By using an electronically controlled clutch (e.g., the solenoid), the PTO  104  can be engaged/disengaged electronically via user input or when a set of parameters has been met (e.g., insufficient power remaining in batteries, insufficient sun for solar, etc.). In such a scenario, the solenoid engages the wet clutch to generate power from the PTO to the generator  102 . According to at least some of the presently disclosed embodiments, the PTO  104  is not utilized to mechanically drive a hydraulic pump (e.g., in a conventional wet kit for use with tanker trucks) but rather to drive the generator  102  to generate AC power for conversion into DC power to provide to the charge controller  112  with electricity to charge the battery bank  116 . As such, running the PTO  104  at a high rate does not carry the risk of causing mechanical damage to a hydraulic pump, components thereof, or any other mechanical elements. Therefore, advantageously, the PTO  104  may be constantly engaged without risking damage to the components driven thereby, according to the present embodiments. 
       FIG. 5  illustrates a schematic representation of a PTO air (or other fluid) shift assembly  132  in a disengaged configuration, while  FIG. 6  illustrates the air shift assembly  132  in an engaged configuration. As shown, the air shift assembly  132  includes a shifter shaft  134  connected to a shifter fork  136 . The shifter fork  136  is sized to fit around a sliding gear (not shown) of the PTO  104  such that the sliding gear of the PTO  104  will translate along with the shifter fork  136  between a disengaged position (as represented in  FIG. 5 ) and an engaged position (as represented in  FIG. 6 , wherein the sliding gear becomes mechanically driven by a driver gear of a transmission). 
     As shown in  FIGS. 5 and 6 , the air shift assembly  132  includes a return spring  138  and an air valve  140  connected to an air chamber  142 . In some instances, a switch (e.g., located within the cab of a semi-truck) triggers the opening of the air valve  140  to fill the air chamber  142 , pushing the shifter shaft  134  (e.g., via a piston) against the return spring  138  (compressing the return spring) and translating the shifter fork  136  into the engaged position (as illustrated in  FIG. 6 ). The process may be reversed (e.g., in response to disengaging the switch) to open the air valve  140  to release the air from the air chamber  142  and allow the return spring  138  to push the shifter shaft  134  and shifter fork  136  into the disengaged position (illustrated in  FIG. 5 ). 
     Those skilled in the art will recognize that the principles disclosed herein may be practiced utilizing the PTO  104  that utilizes any type of shift assembly (e.g., hydraulic shift, wire shift, other mechanical linkage, clutch shift, etc.), recognizing that the PTO  104  must be engaged to power the generator  102  to ultimately drive the system for PTO-driven refrigeration  100 . However, as noted above, a system for PTO-driven refrigeration may operate with a PTO that omits a shift mechanism for shifting between engaged and disengaged positions. Such PTOs may be specially or specifically manufactured without a shift mechanism and with gears positioned and sized such that the drive shaft of the PTO is in constant mechanical communication with the PTO driver gear of the transmission when the PTO is mounted to the transmission. In other instances, an existing PTO shift mechanism may be modified to lock the shift mechanism into an engaged position. 
       FIG. 7  illustrates an example of a shift assembly  200  that has been modified to be locked into an engaged configuration. As shown, the shift assembly  200  omits the air valve  140  or intake channel, and the shift assembly  200  includes a lock  202  (e.g., block, pin, solid member, etc.) inserted and secured within the air chamber  142  keeping the shifter shaft  134  and the shifter fork  136  into the engaged configuration. As shown, the air shift assembly  200  also omits a return spring. Accordingly, as modified in the manner shown in  FIG. 7 , when the air shift assembly  200  is affixed to the PTO  104 , the shift assembly  200  is locked in an engaged configuration, causing a sliding gear to which the shifter fork  136  is connected to persist in an engaged state and causing a drive shaft of the PTO  104  to be in constant mechanical communication with a PTO driver gear of a transmission when the PTO  104  is mounted to the transmission. This may allow the semi-trailer system for PTO-driven refrigeration  100  to run whenever the semi-trailer  126  is connected to the semi-truck  106  (or other ground transportation vehicle) with a constantly engaged PTO (e.g., as shown and/or described with reference to  FIG. 7 ), thereby eliminating the possibility of inadvertently disengaging the PTO  104  while operating the semi-truck  106  and causing the temperature within the semi-trailer  126  to reach unacceptable levels. 
     Although  FIG. 7  focuses on modifications that one could make to an air shift assembly to lock a sliding gear into an engaged position, those skilled in the art will recognize that any modifications to a PTO shift assembly (e.g., a wire shift, clutch shift, mechanical linkage, or other shift assembly) that cause a sliding gear or collar of the PTO to persist in an engaged configuration are within the scope of this disclosure. For example, in place of air or a block, a PTO shift assembly may utilize a solenoid switch, engaging and disengaging the generator from the PTO via an electric switch within the cab of the truck or using controllers or a computing system (described later herein) using predetermined parameters (e.g., temperature, battery status, solar status, etc.). 
     As mentioned, the systems for PTO-driven refrigeration  100  disclosed herein provide DC power at various points, such as from the rectifier/controller  108  (or another converter) that converts AC power received from the generator  102  into DC power, or from the battery bank  116  (or other energy storage element). Accordingly, as previously noted, the presently disclosed systems for PTO-driven refrigeration  100  may provide power to one or more computing systems (e.g., electronic control modules (ECMs)) that are implemented as part of the systems for PTO-driven refrigeration  100  or are in communication with the same. For example, the one or more computing systems may receive DC power from the converter  108  (e.g., rectifier/controller) directly or the battery bank  116 . The computing system(s) may provide input, monitoring, communication, sensing, notification, and/or safety functionalities that may protect the system components and/or increase control by administrators (e.g., fleet commanders, freight companies). In some instances, one or more computing systems are implemented into the rectifier/controller  108  that converts the AC power from the generator  102  into DC power and/or into the controller  118  that receives DC power from the battery bank  116 . As will be described in more detail hereinafter, the one or more computing systems may be in communication with one another and/or with outside computing systems, devices, or components. 
       FIG. 8  illustrates a schematic representation of a computing system  300 . The computing system  300  may take various forms, such as electronic control modules (ECMs) personal computers, desktop computers, laptop computers, tablets, handheld devices (e.g., mobile phones, PDAs, pagers), microprocessor-based or programmable consumer electronics, minicomputers, mainframe computers, multi-processor systems, network PCs, distributed computing systems, datacenters, message centers, routers, switches, and even devices that conventionally have not been considered a computing system, such as wearables (e.g., glasses, head-mounted displays). 
     As noted, the computing system  300  may also be a distributed system that includes one or more connected computing components/devices that are in communication. Accordingly, the computing system  300  may be embodied in any form and is not limited to any particular embodiment explicitly shown herein. 
     In its most basic configuration, the computing system  300  includes various components. For example,  FIG. 8  shows that computing system  300  includes at least one hardware processing unit  302  (a “processor”), input/output (I/O) interfaces  304 , and storage  306 . 
     The storage  306  may be physical system memory, which may be volatile, non-volatile, or some combination of the two. The term “memory” may also be used herein to refer to non-volatile mass storage such as physical storage media. If the computing system  300  is distributed, the processing, memory, and/or storage capability may be distributed as well. As used herein, the term “executable module,” “executable component,” or even “component” can refer to software objects, routines, or methods that may be executed on the computing system  300 . The different components, modules, engines, and services described herein may be implemented as objects or processors that execute on the computing system  300  (e.g., as separate threads). 
     Computer storage media are hardware storage devices, such as RAM, ROM, EEPROM, CD-ROM, solid state drives (SSDs) that are based on RAM, Flash memory, phase-change memory (PCM), or other types of memory, or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code means in the form of computer-executable instructions, data, or data structures and that can be accessed by a general-purpose or special-purpose computer. 
     The disclosed embodiments may comprise or utilize a special-purpose or general-purpose computer including computer hardware, such as, for example, one or more processors (such as the hardware processing unit  302 , which may include one or more central processing units (CPUs), graphics processing units (GPUs) or other processing units) and system memory (such as storage  306 ). Such components may also be combined into a single unit (e.g., microcontroller). Embodiments also include physical and other computer-readable media for carrying or storing computer-executable instructions and/or data structures. Such computer-readable media can be any available media that can be accessed by a general-purpose or special-purpose computer system. Computer-readable media that store computer-executable instructions in the form of data are physical computer storage media. Computer-readable media that carry computer-executable instructions are transmission media. Thus, by way of example and not limitation, the current embodiments can comprise at least two distinctly different kinds of computer-readable media: computer storage media and transmission media. 
     A “network,” like the network  308  shown in  FIG. 8 , is defined as one or more data links and/or data switches that enable the transport of electronic data between computer systems, modules, and/or other electronic devices. When information is transferred, or provided, over a network (either hardwired, wireless, or a combination of hardwired and wireless) to a computer, the computer properly views the connection as a transmission medium. The computing system  300  will include one or more communication channels that are used to communicate with the network  308 . Transmissions media include a network that can be used to carry data or desired program code means in the form of computer-executable instructions or in the form of data structures. Further, these computer-executable instructions can be accessed by a general-purpose or special-purpose computer. Combinations of the above should also be included within the scope of computer-readable media. 
     Upon reaching various computer system components, program code means in the form of computer-executable instructions or data structures can be transferred automatically from transmission media to computer storage media (or vice versa). For example, computer-executable instructions or data structures received over a network or data link can be buffered in RAM within a network interface module (e.g., a network interface card or “NIC”) and then eventually transferred to computer system RAM and/or to less volatile computer storage media at a computer system. Thus, it should be understood that computer storage media can be included in computer system components that also (or even primarily) utilize transmission media. 
     Computer-executable (or computer-interpretable) instructions comprise, for example, instructions that cause a general-purpose computer, special-purpose computer, or special-purpose processing device to perform a certain function or group of functions. The computer-executable instructions may be, for example, binaries, intermediate format instructions such as assembly language, or even source code. 
     While not all computing systems require a user interface, in some embodiments, a computing system  300  includes, as part of the I/O interfaces  304 , a user interface for use in communicating information to/from a user. The user interface may include output mechanisms as well as input mechanisms. The principles described herein are not limited to the precise output mechanisms or input mechanisms as such will depend on the nature of the device. However, output mechanisms might include, for instance, speakers, displays, tactile output, projections, holograms, and so forth. Examples of input mechanisms might include, for instance, microphones, touchscreens, controllers, projections, holograms, cameras, keyboards, stylus, mouse, or other pointer input, sensors of any type, and so forth. The computing system  300  may perform certain functions in response to detecting certain user input. 
     The computing system  300  may also be connected (via a wired or wireless connection) to external sensors  310  (e.g., a temperature sensor associated with the generator, motor, or refrigeration unit, or internal temperature of the trailer, an RPM sensor, a pressure sensor, battery sensors, or other sensors). It will be appreciated that the external sensors  310  may regulate the temperature of the semi-trailer  126 . For example, the external sensors  310  may communicate with the computing system  300 , when the temperature exceeds a predetermined threshold, to start the motor  120  and the compressor  122 . Additionally, the external sensors  310  may communicate with the computing system  300  to determine the state of charge of the battery bank  116 . For example, if the battery bank has a low state of charge, the external sensors  310  may communicate with the computing system  300 . The computing system  300  may then communicate with the systems for PTO-driven refrigeration  100  to retrieve power from the PTO  104 , 220V power input, or the solar panel  128 . It will be appreciated that the external sensors may include sensor systems known in the art rather than solely individual sensor apparatuses. 
     Further, the computing system  300  may also include communication channels allowing the computing system  300  to be in wireless (e.g., Bluetooth, Wi-Fi, satellite, infrared, etc.) or wired communication with any number or combination of sensors  310 , networks  308 , and/or other remote systems/devices  312 . Remote systems/devices  312  may be configured to perform any of the processing described with regard to computing system  300 . By way of example, a remote system may include an administrative system that receives sensor readings from the sensors  310 . 
     Those skilled in the art will appreciate that the embodiments may be practiced in network computing environments with many types of computer system configurations. The embodiments may also be practiced in distributed system environments where local and remote computer systems that are linked (either by hardwired data links, wireless data links, or by a combination of hardwired and wireless data links) through a network each perform tasks (e.g., cloud computing, cloud services and the like). In a distributed system environment, program modules may be located in both local and remote memory storage devices. 
     Those skilled in the art will also appreciate that the disclosed methods may be practiced in a cloud computing environment. Cloud computing environments may be distributed, although this is not required. When distributed, cloud computing environments may be distributed internationally within an organization and/or have components possessed across multiple organizations. In this description and the following claims, “cloud computing” is defined as a model for enabling on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services). The definition of “cloud computing” is not limited to any of the other numerous advantages that can be obtained from such a model when properly deployed. 
     A cloud-computing model can be composed of various characteristics, such as on-demand self-service, broad network access, resource pooling, rapid elasticity, measured service, and so forth. A cloud-computing model may also come in the form of various service models such as, for example, Software as a Service (“SaaS”), Platform as a Service (“PaaS”), and Infrastructure as a Service (“IaaS”). The cloud-computing model may also be deployed using different deployment models such as private cloud, community cloud, public cloud, hybrid cloud, and so forth. 
     Additionally, or alternatively, the functionality described herein can be performed, at least in part, by one or more hardware logic components (e.g., the hardware processing unit  302 ). For example, and without limitation, illustrative types of hardware logic components that can be used include Field-Programmable Gate Arrays (FPGAs), Application-Specific or Application-Specific Integrated Circuits (ASICs), Application-Specific Standard Products (ASSPs), System-On-A-Chip Systems (SOCs), Complex Programmable Logic Devices (CPLDs), Central Processing Units (CPUs), and other types of programmable hardware. 
     Having described exemplary components and configurations of a computing system  300 , the following describes various functionalities that may be facilitated by the computing system  300  or a remote system/device  312  of a system for PTO-driven refrigeration of the present disclosure. 
     In some embodiments, the computing system  300  includes computer-executable instructions (e.g., stored on storage  306 ) that enable the computing system  300  (e.g., by one or more processors  302  executing the computer-executable instructions) to selectively activate or deactivate any portion of the system for PTO-driven refrigeration  100 , such as the generator  102 , the motor  120 , the compressor  122 , etc. 
     In some instances, the computing system  300  selectively activates or deactivates one or more components of the system for PTO-driven refrigeration  100  in response to a triggering event, such as receiving user input (e.g., locally or from an administrative computing system) or detecting a sensor reading that meets or exceeds a predetermined threshold or is outside of a predefined acceptable range. In implementations where the computing system  300  includes or is in communication with a user interface (e.g., whether directly as an I/O interface  304  or as part of a remote system/device  312 , such as a mobile device of a semi-truck driver or fleet administrator), the computing system  300  may receive triggering input (e.g., from an I/O interface  310  or a remote system/device  312 ) that causes the computing system  300  to selectively activate or deactivate one or more components of the system for PTO-driven refrigeration  100  (e.g., the motor  120 , the generator  102 , the A/C compressor  122 ). 
     Furthermore, a computing system  300  may cause sensor values detected by the various sensors  310  in communication with the computing system  300  to be displayed on a user display or user interface (e.g., an I/O interface  304  and/or a display of a remote system/device  312 ). For example, the computing system  300  may cause display of representations of sensor readings associated with detected state of charge, DC draw amperage, and/or amp hours associated with the battery bank, load amps of the motor, temperature of the motor, generator, and/or refrigerated semi-trailer (or other cavity), etc. Displaying combinations of sensor readings to a user/administrator may enable a user/administrator to ensure that the system for PTO-driven refrigeration  100  is operated with due care, so as to avoid damage to the system or other damages caused by improper operation thereof. 
     In some instances, the computing system  300  is configured to provide a notification on a user/administrator interface in response to detecting that a sensor reading of one or more sensors of the system for PTO-driven refrigeration  100  has met or exceeded a predetermined threshold value (e.g., an unacceptably high temperature of the motor  120 , generator  102 , and/or refrigerated area). The notification can take on various forms, such as a visual notification on a screen, a sound, etc. 
     It should be noted that a user or an administrator may define threshold values that may trigger the display of a notification (or even trigger selective deactivation of one or more system components). For instance, the administrator or user may define a maximum operational temperature for the generator  102  or motor  120 , a minimum state of charge for the battery bank  116 , a maximum draw from the battery bank  116 , and/or a maximum starting load for the motor  120 . In this way, freight company administrators and/or fleet commanders may ensure optimal operation of systems for PTO-driven refrigeration  100  to extend the economic life of such systems. 
       FIGS. 9 and 10  illustrate example flow charts of a computing system  400  used for monitoring temperature and battery state of charge. As shown in  FIG. 9 , at step  402 , the computing system starts. Then the computing system receives information from temperature sensors at step  404 . After the information is received, at step  406 , the temperature is analyzed to determine if it is above a predetermined threshold. If it is not above the threshold, then the system returns to step  404 . If the temperature for the semi-trailer is above a predetermined threshold, then at step  408  the computing system starts the motor and compressor to cool the semi-trailer. The system may then return to step  404  while also proceeding to step  410 . At step  410 , the system checks whether the temperature of the generator, motor, or compressor is above a predetermined threshold. If the temperature is not above the threshold, the system returns to step  404 . If the temperature is above the threshold at  410 , then at step  412  the computing system stops the generator, motor, or compressor to prevent damage to those components. The system then returns to step  404 . Additionally, using the computing system and network hereinabove described, a notification may be sent to a user at any step in the flow. For example, if a component is stopped in  412 , a notification may be sent to a user, allowing them to take appropriate measures to ensure that the cargo in the trailer is not spoiled as a result of increasing temperatures due to mechanical failures. 
     Referring to  FIG. 10 , at step  414 , the system starts. The computing system then checks the state of charge of the battery bank at step  416 . Once the state of charge is checked, at step  418 , the system determines whether the battery bank state of charge is below the preset minimum state of charge. If it is not below the preset minimum, then the system returns to step  416 . If it is below the preset minimum charge, then at step  420  the battery bank is charged by the PTO, 220V power input, and/or the solar panel  420 . 
     Additionally, although the foregoing disclosure has focused on semi-truck/semi-trailer refrigeration unit implementations, those skilled in the art will recognize that the principles described may be applied to any ground transportation vehicles/trailers, and even to subject areas that do not include refrigeration. For example, a system may include a PTO-driven generator that provides AC power to a converter that converts the received AC power into DC power and provides the DC power to an inverter that inverts the DC power back into AC power and provides the AC power to a motor that drives/operates a dump truck/trailer, aerial lift, pump, vacuum, plow, excavator, or other device. 
     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure pertains. 
     Various alterations and/or modifications of the inventive features illustrated herein, and additional applications of the principles illustrated herein, which would occur to one skilled in the relevant art and having possession of this disclosure, can be made to the illustrated embodiments without departing from the spirit and scope of the invention as defined by the claims, and are to be considered within the scope of this disclosure. Thus, while various aspects and embodiments have been disclosed herein, other aspects and embodiments are contemplated. While a number of methods and components similar or equivalent to those described herein can be used to practice embodiments of the present disclosure, only certain components and methods are described herein. 
     It will also be appreciated that systems and methods according to certain embodiments of the present disclosure may include, incorporate, or otherwise comprise properties or features (e.g., components, members, elements, parts, and/or portions) described in other embodiments. Accordingly, the various features of certain embodiments can be compatible with, combined with, included in, and/or incorporated into other embodiments of the present disclosure. Thus, disclosure of certain features relative to a specific embodiment of the present disclosure should not be construed as limiting application or inclusion of said features to the specific embodiment unless so stated. Rather, it will be appreciated that other embodiments can also include said features, members, elements, parts, and/or portions without necessarily departing from the scope of the present disclosure. 
     Moreover, unless a feature is described as requiring another feature in combination therewith, any feature herein may be combined with any other feature of a same or different embodiment disclosed herein. Furthermore, various well-known aspects of illustrative systems, methods, apparatus, and the like are not described herein in particular detail in order to avoid obscuring aspects of the example embodiments. Such aspects are, however, also contemplated herein. 
     The present disclosure may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. While certain embodiments and details have been included herein and in the attached disclosure for purposes of illustrating embodiments of the present disclosure, it will be apparent to those skilled in the art that various changes in the methods, products, devices, and apparatus disclosed herein may be made without departing from the scope of the disclosure or of the invention, which is defined in the appended claims. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. 
     While the forgoing examples are illustrative of the principles of the present invention in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage, and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the invention. 
     Exemplary embodiments are described above. No element, act, or instruction used in this description should be construed as important, necessary, critical, or essential unless explicitly described as such. Although only a few of the exemplary embodiments have been described in detail herein, those skilled in the art will readily appreciate that many modifications are possible in these exemplary embodiments without materially departing from the novel teachings and advantages herein. Accordingly, all such modifications are intended to be included within the scope of this invention.