Patent Publication Number: US-2022228758-A1

Title: Systems and methods for reheat control of an hvac system

Description:
BACKGROUND 
     This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. 
     A heating, ventilation, and/or air conditioning (HVAC) system may be used to thermally regulate an environment, such as a space within a building, home, or other structure. The HVAC system generally includes a vapor compression system having heat exchangers, such as a condenser and an evaporator, which transfer thermal energy between the HVAC system and the environment. In some cases, the HVAC system also includes a reheat coil, which, together with the evaporator, is positioned along an air flow path of the HVAC system. The evaporator and the reheat coil may operate concurrently to facilitate dehumidification and temperature regulation of an air flow traveling along the air flow path and entering a building serviced by the HVAC system. Accordingly, the HVAC system may facilitate supply of a temperature regulated and dehumidified air flow to the building. 
     SUMMARY 
     The present disclosure relates to a heating, ventilation, and air conditioning (HVAC) system that includes a reheat valve configured to receive a refrigerant flow and regulate division of the refrigerant flow provided to a reheat coil and a condenser. The HVAC system also includes a condenser fan configured to draw a flow of outdoor air across the condenser and a controller communicatively coupled to the reheat valve and the condenser fan. The controller is configured to monitor a position of the reheat valve and control operation of the condenser fan based on a correspondence between the position of the reheat valve and a threshold degree of opening. 
     The present disclosure also relates to a reheat control system for a heating, ventilation, and air conditioning (HVAC) system. The reheat control system includes a reheat valve configured to receive a refrigerant flow and regulate division of the refrigerant flow provided to a reheat coil and a condenser. The reheat control system also includes a controller configured to adjust a position of the reheat valve based on feedback from one or more sensors to achieve an operational parameter, to monitor the position of the reheat valve, and to control operation of a condenser fan of the condenser based on the position of the reheat valve relative to a threshold degree of opening. 
     The present disclosure also relates to a method for operating a heating, ventilation, and air conditioning (HVAC) system. The method includes adjusting, with a controller, a position of a reheat valve based on feedback from one or more sensors to control division of a refrigerant flow between a reheat coil and a condenser. The method also includes monitoring, with the controller, the position of the reheat valve to determine a degree of opening of the reheat valve. The method also includes blocking, with the controller, operation of a condenser fan of the condenser in response to a determination that the degree of opening of the reheat valve reaches or exceeds a threshold degree of opening. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an embodiment of a building incorporating a heating, ventilation, and/or air conditioning (HVAC) system in a commercial setting, in accordance with an aspect of the present disclosure; 
         FIG. 2  is a perspective view of an embodiment of a packaged HVAC unit, in accordance with an aspect of the present disclosure; 
         FIG. 3  is a perspective view of an embodiment of a split, residential HVAC system, in accordance with an aspect of the present disclosure; 
         FIG. 4  is a schematic diagram of an embodiment of a vapor compression system used in an HVAC system, in accordance with an aspect of the present disclosure; 
         FIG. 5  is a schematic diagram of an embodiment of an HVAC system having a reheat coil, in accordance with an aspect of the present disclosure; and 
         FIG. 6  is a flow diagram of an embodiment of a process of operating an HVAC system having a reheat coil, in accordance with an aspect of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     One or more specific embodiments of the present disclosure will be described below. These described embodiments are only examples of the presently disclosed techniques. Additionally, in an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
     When introducing elements of various embodiments of the present disclosure, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. 
     As briefly discussed above, a heating, ventilation, and/or air conditioning (HVAC) system may be used to thermally regulate a space within a building, home, or other suitable structure. For example, the HVAC system may include a vapor compression system that transfers thermal energy between a working fluid, such as a refrigerant, and a fluid to be conditioned, such as air. The vapor compression system includes a condenser and an evaporator that are fluidly coupled to one another via one or more conduits of a refrigerant loop. A compressor may be used to circulate the refrigerant through the conduits and other components of the refrigerant loop (e.g., an expander), thus, enabling the transfer of thermal energy between components of the refrigerant loop (e.g., between the condenser and the evaporator via the refrigerant) and between the refrigerant loop and supply air. 
     The evaporator may be positioned within an enclosure or housing of the HVAC system that defines an air flow path of the HVAC system. As discussed in detail below, the air flow path permits the HVAC system to supply a flow of conditioned air (e.g., cooled air, heated air, dehumidified air) to one or more rooms, zones, or other suitable spaces within a building or other structure serviced by the HVAC system. For example, a fan or blower may be positioned in the air flow path and used to draw a flow of supply air into the air flow path. The supply air may include a flow of outdoor air drawn from an ambient environment surrounding the HVAC system, a flow of return air drawn from an interior of the building, or a mixture of both the outdoor air and the return air. In any case, the fan may direct the supply air across a heat exchange area of the evaporator to enable cooled refrigerant circulating through the evaporator to absorb thermal energy from the supply air. As such, the evaporator may reduce a temperature of the supply air and discharge the supply air as a flow of conditioned air (e.g., cooled air), which has a temperature that is less than a temperature of the supply air. 
     In certain cases, by cooling the supply air, the evaporator may also cause moisture suspended or contained within the supply air to condense. Specifically, moisture condensed from the flow of supply air may accumulate on a surface of the evaporator as condensate. The condensate may flow along the evaporator and drip into a drain pan that may be positioned beneath the evaporator (e.g., with respect to a direction of gravity). As such, a humidity level of the flow of conditioned air discharging from the evaporator may be less than a humidity level of the supply air received at the evaporator. The fan may direct the cooled, dehumidified air discharging from the evaporator along the flow path and into the building. In this manner, the HVAC system may be used to regulate a temperature and/or humidity level within an interior of the building. 
     In some cases, it may be desirable to reduce the humidity level within the building substantially without adjusting a current temperature within the building (e.g., without heating or cooling the interior of the building). For example, in certain cases, a temperature within the building (e.g., a temperature within one or more rooms, zones, or other spaces of the building) may be within a threshold range of a designated target temperature setpoint, while a humidity level within the building may exceed a designated target humidity level setpoint beyond an acceptable tolerance. In such situations, it may be desirable to operate the HVAC system in a dehumidification mode, in which the HVAC system may operate to dehumidify the building substantially without heating or cooling of the building. 
     To facilitate operation in the dehumidification mode, the HVAC system may include a reheat coil that is fluidly coupled to the vapor compression system and configured to reheat (e.g., increase a temperature of) the cooled, dehumidified air discharging from the evaporator before the air is directed into the building. For example, the reheat coil may be positioned within the air flow path and downstream of the evaporator, such that the reheat coil may receive the cooled, dehumidified air discharging from the evaporator. The compressor may be configured to receive, from the evaporator, a flow of heated refrigerant that has previously absorbed thermal energy from the supply air. The compressor may compress the refrigerant received from the evaporator, which adds more heat to the refrigerant, and direct the heated refrigerant toward and through a reheat valve (e.g., a three-way valve) that is positionable to direct at least a portion of the heated refrigerant to the reheat coil, while directing a remaining portion of the heated refrigerant toward the condenser. As such, the cooled, dehumidified air discharging from the evaporator and directed across the reheat coil may re-absorb thermal energy from the heated refrigerant circulating through the reheat coil. Accordingly, the reheat coil may increase a temperature of the cooled, dehumidified air discharging from the evaporator prior to delivery of the dehumidified air to the building. The refrigerant that has passed through the reheat coil may returned to the refrigerant loop up stream of the compressor and downstream of the condenser. 
     In typical HVAC systems, a condenser fan (or a plurality of condenser fans) of the condenser may be operational (e.g., on, active) while the HVAC system operates in the dehumidification mode. As such, the condenser fan may draw ambient air across the condenser to facilitate condensation of refrigerant within the condenser. In some cases, operation of the condenser fan may result in charge migration in the vapor compression system that reduces an operational efficiency of the reheat coil. For example, when the HVAC system operates in the dehumidification mode, operation of the condenser fan may cause relatively cool, low pressure refrigerant to condense and accumulate within the condenser and/or within refrigerant conduits adjacent to the condenser, thereby reducing a quantity of available refrigerant that the compressor may recirculate through a remainder of the vapor compression system, such as a reheat section of the vapor compression system that includes the reheat coil and the evaporator. As a result, the quantity of refrigerant remaining in the reheat section of the vapor compression system may be insufficient to enable adequate operation of the reheat coil. 
     For example, particularly in high-load periods of the reheat coil, the reduced quantity of refrigerant available in the reheat section of the vapor compression system may be such that, even when the reheat valve is adjusted to direct a majority of or substantially all of the heated refrigerant discharging from the compressor to the reheat coil, an amount of refrigerant arriving at the reheat coil is inadequate to enable the reheat coil to sufficiently reheat the cooled, dehumidified air to output a flow of neutral air. For clarity, as used herein, “neutral air” may refer to air that is output by the reheat coil and supplied to the building by the HVAC system at a temperature that is substantially matching (e.g., within a threshold temperature range of) a current temperature within the building or a set point temperature for the building, and has a humidity level that is less than a humidity level of return air extracted from the building. 
     Accordingly, embodiments of the present disclosure relate to a reheat control system that is configured to eliminate or substantially mitigate undesired charge migration within the vapor compression system that would otherwise reduce an operational efficiency of the reheat coil. Specifically, as discussed in detail herein, the reheat control system may adjust operation of the condenser fan based on a position of the reheat valve to ensure that sufficient refrigerant is available in the reheat section of the vapor compression system to satisfy a refrigerant demand of the reheat coil. In this manner, the reheat control system may facilitate supply and delivery of neutral air having a temperature that substantially matches (e.g., is within 2 degrees Fahrenheit of) an air temperature (set point or actual) within an interior of the building or other structure serviced by the HVAC system and has a humidity level that is less than a humidity level of a return air flow extracted from the building or structure. In this way, the HVAC system is operable to facilitate dehumidification within the building substantially without heating or cooling of an interior of the building beyond a desired or established temperature. 
     For example, the reheat control system may include a controller that is configured to facilitate performance of some of or all of the techniques disclosed herein. The controller may be configured to monitor a temperature of outdoor air surrounding the HVAC system via feedback acquired by the one or more temperature sensors. The controller may adjust operation of the condenser fan based on the acquired sensor feedback. For example, as discussed herein, the controller may be configured to retain the condenser fan in a non-operational (e.g., inactive) state upon determining that the temperate of the outdoor air is below a threshold value, and may be configured to activate and operate the condenser fan upon determining that the temperature of the outdoor air reaches or exceeds the threshold value. 
     The controller may monitor a position of the reheat valve throughout operation of the HVAC system in the dehumidification mode. The reheat valve may be configured to transition between a fully open position, a fully closed position, and a plurality of intermediate positions that are between the fully open and fully closed positions. In the fully open position, the reheat valve may divert all of or substantially all of (e.g., 80 percent or more) of the heated refrigerant discharging from the compressor to the reheat coil, while diverting none of or a minimal portion of (e.g., 20 percent or less) of the heated refrigerant discharging from the compressor to the condenser. In the fully closed position, the reheat valve may block flow of the heated refrigerant from the compressor to the reheat coil, such that all of the heated refrigerant output by compressor is directed toward the condenser. 
     Accordingly, a degree of opening of the reheat valve may affect diversion of refrigerant between the reheat coil and the condenser. As user herein, the “degree of opening” of the reheat valve may refer to a current position of the reheat valve (e.g., at a particular instance in time) with respect to the fully closed position of the reheat valve. Accordingly, while the reheat valve has a relatively low degree of opening (e.g., less than 50 percent of a total permitted valve opening), the reheat valve may bias refrigerant distribution from the compressor to the condenser. Conversely, while the reheat valve has a relatively high degree of opening (e.g., equal to or greater than 50 percent of the total permitted valve opening), the reheat valve may bias refrigerant distribution from the compressor to the reheat coil. As discussed in detail herein, the controller may adjust the degree of opening of the reheat valve (e.g., modulate a position of the reheat valve) based on one or more monitored operational parameters of the HVAC system to provide a desired quantity (e.g., flow rate) of heated refrigerant to the reheat coil. 
     Upon receiving feedback indicating that a degree of opening of the reheat valve remains less than a threshold degree of opening (e.g., a threshold opening setpoint, a position less than 80 percent of the total permitted valve opening) during operation of the HVAC system in dehumidification mode, the controller may adjust operation of the condenser fan based on the temperature of the outdoor air surrounding the HVAC system, as set forth above. In response to determining that the degree of opening of the reheat valve reaches or exceeds the threshold degree of opening, the controller may deactivate the condenser fan, regardless of the current outdoor temperature. As a result, by substantially reducing air flow across the condenser, the controller may reduce or substantially inhibit condensation of refrigerant within the condenser and, instead, enable the refrigerant to absorb thermal energy from the surrounding environment. Heating of the refrigerant within the condenser may cause a pressure within the condenser to increase and, thus, force refrigerant from the condenser and adjacent conduits into the reheat section of the vapor compression system. As such, the controller may substantially eliminate refrigerant accumulation within and near the condenser to ensure that, particularly while the reheat valve is substantially open (e.g., opened beyond the threshold degree of opening), such as when a refrigerant demand of the reheat coil is relatively high, sufficient refrigerant is available in the reheat portion of the vapor compression system to satisfy the refrigerant demand of the reheat coil. The controller may continue to keep the condenser fan in the non-operational state at least until the degree of opening of the reheat valve returns back below the threshold degree of opening. These and other features will be described below with reference to the drawings. 
     Turning now to the drawings,  FIG. 1  illustrates an embodiment of a heating, ventilation, and/or air conditioning (HVAC) system for environmental management that employs one or more HVAC units in accordance with the present disclosure. As used herein, an HVAC system includes any number of components configured to enable regulation of parameters related to climate characteristics, such as temperature, humidity, air flow, pressure, air quality, and so forth. For example, an “HVAC system” as used herein is defined as conventionally understood and as further described herein. Components or parts of an “HVAC system” may include, but are not limited to, all, some of, or individual parts such as a heat exchanger, a heater, an air flow control device, such as a fan, a sensor configured to detect a climate characteristic or operating parameter, a filter, a control device configured to regulate operation of an HVAC system component, a component configured to enable regulation of climate characteristics, or a combination thereof. An “HVAC system” is a system configured to provide such functions as heating, cooling, ventilation, dehumidification, pressurization, refrigeration, filtration, or any combination thereof. The embodiments described herein may be utilized in a variety of applications to control climate characteristics, such as residential, commercial, industrial, transportation, or other applications where climate control is desired. 
     In the illustrated embodiment, a building  10  is air conditioned by a system that includes an HVAC unit  12  with a reheat system in accordance with present embodiments. The building  10  may be a commercial structure or a residential structure. As shown, the HVAC unit  12  is disposed on the roof of the building  10 ; however, the HVAC unit  12  may be located in other equipment rooms or areas adjacent the building  10 . The HVAC unit  12  may be a single package unit containing other equipment, such as a blower, integrated air handler, and/or auxiliary heating unit. In other embodiments, the HVAC unit  12  may be part of a split HVAC system, such as the system shown in  FIG. 3 , which includes an outdoor HVAC unit  58  and an indoor HVAC unit  56 . 
     The HVAC unit  12  is an air cooled device that implements a refrigeration cycle to provide conditioned air to the building  10 . Specifically, the HVAC unit  12  may include one or more heat exchangers across which an air flow is passed to condition the air flow before the air flow is supplied to the building. In the illustrated embodiment, the HVAC unit  12  is a rooftop unit (RTU) that conditions a supply air stream, such as environmental air and/or a return air flow from the building  10 . After the HVAC unit  12  conditions the air, the air is supplied to the building  10  via ductwork  14  extending throughout the building  10  from the HVAC unit  12 . For example, the ductwork  14  may extend to various individual floors or other sections of the building  10 . In certain embodiments, the HVAC unit  12  may be a heat pump that provides both heating and cooling to the building with one refrigeration circuit configured to operate in different modes. In other embodiments, the HVAC unit  12  may include one or more refrigeration circuits for cooling an air stream and a furnace for heating the air stream. 
     A control device  16 , one type of which may be a thermostat, may be used to designate the temperature of the conditioned air. The control device  16  also may be used to control the flow of air through the ductwork  14 . For example, the control device  16  may be used to regulate operation of one or more components of the HVAC unit  12  or other components, such as dampers and fans, within the building  10  that may control flow of air through and/or from the ductwork  14 . In some embodiments, other devices may be included in the system, such as pressure and/or temperature transducers or switches that sense the temperatures and pressures of the supply air, return air, and so forth. Moreover, the control device  16  may include computer systems that are integrated with or separate from other building control or monitoring systems, and even systems that are remote from the building  10 . 
       FIG. 2  is a perspective view of an embodiment of the HVAC unit  12 . In the illustrated embodiment, the HVAC unit  12  is a single package unit that may include one or more independent refrigeration circuits and components that are tested, charged, wired, piped, and ready for installation. The HVAC unit  12  may provide a variety of heating and/or cooling functions, such as cooling only, heating only, cooling with electric heat, cooling with dehumidification, cooling with gas heat, or cooling with a heat pump. As described above, the HVAC unit  12  may directly cool and/or heat an air stream provided to the building  10  to condition a space in the building  10 . 
     As shown in the illustrated embodiment of  FIG. 2 , a cabinet  24  encloses the HVAC unit  12  and provides structural support and protection to the internal components from environmental and other contaminants. In some embodiments, the cabinet  24  may be constructed of galvanized steel and insulated with aluminum foil faced insulation. Rails  26  may be joined to the bottom perimeter of the cabinet  24  and provide a foundation for the HVAC unit  12 . In certain embodiments, the rails  26  may provide access for a forklift and/or overhead rigging to facilitate installation and/or removal of the HVAC unit  12 . In some embodiments, the rails  26  may fit into “curbs” on the roof to enable the HVAC unit  12  to provide air to the ductwork  14  from the bottom of the HVAC unit  12  while blocking elements such as rain from leaking into the building  10 . 
     The HVAC unit  12  includes heat exchangers  28  and  30  in fluid communication with one or more refrigeration circuits. Tubes within the heat exchangers  28  and  30  may circulate refrigerant, such as R-410A, through the heat exchangers  28  and  30 . The tubes may be of various types, such as multichannel tubes, conventional copper or aluminum tubing, and so forth. Together, the heat exchangers  28  and  30  may implement a thermal cycle in which the refrigerant undergoes phase changes and/or temperature changes as it flows through the heat exchangers  28  and  30  to produce heated and/or cooled air. For example, the heat exchanger  28  may function as a condenser where heat is released from the refrigerant to ambient air, and the heat exchanger  30  may function as an evaporator where the refrigerant absorbs heat to cool an air stream. In other embodiments, the HVAC unit  12  may operate in a heat pump mode where the roles of the heat exchangers  28  and  30  may be reversed. That is, the heat exchanger  28  may function as an evaporator and the heat exchanger  30  may function as a condenser. In further embodiments, the HVAC unit  12  may include a furnace for heating the air stream that is supplied to the building  10 . While the illustrated embodiment of  FIG. 2  shows the HVAC unit  12  having two of the heat exchangers  28  and  30 , in other embodiments, the HVAC unit  12  may include one heat exchanger or more than two heat exchangers. 
     The heat exchanger  30  is located within a compartment  31  that separates the heat exchanger  30  from the heat exchanger  28 . Fans  32  draw air from the environment through the heat exchanger  28 . Air may be heated and/or cooled as the air flows through the heat exchanger  28  before being released back to the environment surrounding the HVAC unit  12 . A blower assembly  34 , powered by a motor  36 , draws air through the heat exchanger  30  to heat or cool the air. The heated or cooled air may be directed to the building  10  by the ductwork  14 , which may be connected to the HVAC unit  12 . Before flowing through the heat exchanger  30 , the conditioned air flows through one or more filters  38  that may remove particulates and contaminants from the air. In certain embodiments, the filters  38  may be disposed on the air intake side of the heat exchanger  30  to prevent contaminants from contacting the heat exchanger  30 . 
     The HVAC unit  12  also may include other equipment for implementing the thermal cycle. Compressors  42  increase the pressure and temperature of the refrigerant before the refrigerant enters the heat exchanger  28 . The compressors  42  may be any suitable type of compressors, such as scroll compressors, rotary compressors, screw compressors, or reciprocating compressors. In some embodiments, the compressors  42  may include a pair of hermetic direct drive compressors arranged in a dual stage configuration  44 . However, in other embodiments, any number of the compressors  42  may be provided to achieve various stages of heating and/or cooling. As may be appreciated, additional equipment and devices may be included in the HVAC unit  12 , such as a solid-core filter drier, a drain pan, a disconnect switch, an economizer, pressure switches, phase monitors, and humidity sensors, among other things. 
     The HVAC unit  12  may receive power through a terminal block  46 . For example, a high voltage power source may be connected to the terminal block  46  to power the equipment. The operation of the HVAC unit  12  may be governed or regulated by a control board  48 . The control board  48  may include control circuitry connected to a thermostat, sensors, and alarms. One or more of these components may be referred to herein separately or collectively as the control device  16 . The control circuitry may be configured to control operation of the equipment, provide alarms, and monitor safety switches. Wiring  49  may connect the control board  48  and the terminal block  46  to the equipment of the HVAC unit  12 . 
       FIG. 3  illustrates a residential heating and cooling system  50 , also in accordance with present techniques. The residential heating and cooling system  50  may provide heated and cooled air to a residential structure, as well as provide outside air for ventilation and provide improved indoor air quality (IAQ) through devices such as ultraviolet lights and air filters. In the illustrated embodiment, the residential heating and cooling system  50  is a split HVAC system. In general, a residence  52  conditioned by a split HVAC system may include refrigerant conduits  54  that operatively couple the indoor unit  56  to the outdoor unit  58 . The indoor unit  56  may be positioned in a utility room, an attic, a basement, and so forth. The outdoor unit  58  is typically situated adjacent to a side of residence  52  and is covered by a shroud to protect the system components and to prevent leaves and other debris or contaminants from entering the unit. The refrigerant conduits  54  transfer refrigerant between the indoor unit  56  and the outdoor unit  58 , typically transferring primarily liquid refrigerant in one direction and primarily vaporized refrigerant in an opposite direction. 
     When the system shown in  FIG. 3  is operating as an air conditioner, a heat exchanger  60  in the outdoor unit  58  serves as a condenser for re-condensing vaporized refrigerant flowing from the indoor unit  56  to the outdoor unit  58  via one of the refrigerant conduits  54 . In these applications, a heat exchanger  62  of the indoor unit functions as an evaporator. Specifically, the heat exchanger  62  receives liquid refrigerant, which may be expanded by an expansion device, and evaporates the refrigerant before returning it to the outdoor unit  58 . 
     The outdoor unit  58  draws environmental air through the heat exchanger  60  using a fan  64  and expels the air above the outdoor unit  58 . When operating as an air conditioner, the air is heated by the heat exchanger  60  within the outdoor unit  58  and exits the unit at a temperature higher than it entered. The indoor unit  56  includes a blower or fan  66  that directs air through or across the indoor heat exchanger  62 , where the air is cooled when the system is operating in air conditioning mode. Thereafter, the air is passed through ductwork  68  that directs the air to the residence  52 . The overall system operates to maintain a desired temperature as set by a system controller. When the temperature sensed inside the residence  52  is higher than the set point on the thermostat, or the set point plus a small amount, the residential heating and cooling system  50  may become operative to refrigerate additional air for circulation through the residence  52 . When the temperature reaches the set point, or the set point minus a small amount, the residential heating and cooling system  50  may stop the refrigeration cycle temporarily. The outdoor unit  58  includes a reheat system in accordance with present embodiments. 
     The residential heating and cooling system  50  may also operate as a heat pump. When operating as a heat pump, the roles of heat exchangers  60  and  62  are reversed. That is, the heat exchanger  60  of the outdoor unit  58  will serve as an evaporator to evaporate refrigerant and thereby cool air entering the outdoor unit  58  as the air passes over the outdoor heat exchanger  60 . The indoor heat exchanger  62  will receive a stream of air blown over it and will heat the air by condensing the refrigerant. 
     In some embodiments, the indoor unit  56  may include a furnace system  70 . For example, the indoor unit  56  may include the furnace system  70  when the residential heating and cooling system  50  is not configured to operate as a heat pump. The furnace system  70  may include a burner assembly and heat exchanger, among other components, inside the indoor unit  56 . Fuel is provided to the burner assembly of the furnace  70  where it is mixed with air and combusted to form combustion products. The combustion products may pass through tubes or piping in a heat exchanger, separate from heat exchanger  62 , such that air directed by the blower  66  passes over the tubes or pipes and extracts heat from the combustion products. The heated air may then be routed from the furnace system  70  to the ductwork  68  for heating the residence  52 . 
       FIG. 4  is an embodiment of a vapor compression system  72  that can be used in any of the systems described above. The vapor compression system  72  may circulate a refrigerant through a circuit starting with a compressor  74 . The circuit may also include a condenser  76 , an expansion valve(s) or device(s)  78 , and an evaporator  80 . The vapor compression system  72  may further include a control panel  82  that has an analog to digital (A/D) converter  84 , a microprocessor  86 , a non-volatile memory  88 , and/or an interface board  90 . The control panel  82  and its components may function to regulate operation of the vapor compression system  72  based on feedback from an operator, from sensors of the vapor compression system  72  that detect operating conditions, and so forth. 
     In some embodiments, the vapor compression system  72  may use one or more of a variable speed drive (VSDs)  92 , a motor  94 , the compressor  74 , the condenser  76 , the expansion valve or device  78 , and/or the evaporator  80 . The motor  94  may drive the compressor  74  and may be powered by the variable speed drive (VSD)  92 . The VSD  92  receives alternating current (AC) power having a particular fixed line voltage and fixed line frequency from an AC power source, and provides power having a variable voltage and frequency to the motor  94 . In other embodiments, the motor  94  may be powered directly from an AC or direct current (DC) power source. The motor  94  may include any type of electric motor that can be powered by a VSD or directly from an AC or DC power source, such as a switched reluctance motor, an induction motor, an electronically commutated permanent magnet motor, or another suitable motor. 
     The compressor  74  compresses a refrigerant vapor and delivers the vapor to the condenser  76  through a discharge passage. In some embodiments, the compressor  74  may be a centrifugal compressor. The refrigerant vapor delivered by the compressor  74  to the condenser  76  may transfer heat to a fluid passing across the condenser  76 , such as ambient or environmental air  96 . The refrigerant vapor may condense to a refrigerant liquid in the condenser  76  as a result of thermal heat transfer with the environmental air  96 . The liquid refrigerant from the condenser  76  may flow through the expansion device  78  to the evaporator  80 . 
     The liquid refrigerant delivered to the evaporator  80  may absorb heat from another air stream, such as a supply air stream  98  provided to the building  10  or the residence  52 . For example, the supply air stream  98  may include ambient or environmental air, return air from a building, or a combination of the two. The liquid refrigerant in the evaporator  80  may undergo a phase change from the liquid refrigerant to a refrigerant vapor. In this manner, the evaporator  80  may reduce the temperature of the supply air stream  98  via thermal heat transfer with the refrigerant. Thereafter, the vapor refrigerant exits the evaporator  80  and returns to the compressor  74  by a suction line to complete the cycle. 
     In some embodiments, the vapor compression system  72  may further include a reheat coil. In the illustrated embodiment, the reheat coil is represented as part of the evaporator  80 . The reheat coil is positioned downstream of the evaporator heat exchanger relative to the supply air stream  98  and may reheat the supply air stream  98  when the supply air stream  98  is overcooled to remove humidity from the supply air stream  98  before the supply air stream  98  is directed to the building  10  or the residence  52 . 
     It should be appreciated that any of the features described herein may be incorporated with the HVAC unit  12 , the residential heating and cooling system  50 , or other HVAC systems. Additionally, while the features disclosed herein are described in the context of embodiments that directly heat and cool a supply air stream provided to a building or other load, embodiments of the present disclosure may be applicable to other HVAC systems as well. For example, the features described herein may be applied to mechanical cooling systems, free cooling systems, chiller systems, or other heat pump or refrigeration applications. 
     As briefly discussed above, embodiments of the present disclosure are directed to a reheat control system that facilitates supply of dehumidified air to a room or zone within a building via an HVAC system. Additionally, the reheat control system facilitates mitigating or substantially eliminating charge migration in a vapor compression system of the HVAC system during dehumidification operations performed by the HVAC system. To provide context for the following discussion,  FIG. 5  is a schematic of an embodiment of an HVAC system  100  having a reheat control system  102 . The HVAC system  100  may be configured to direct a flow of conditioned air (e.g., heated air, cooled air, dehumidified air) to a thermal load  110 , such as a space within a building, residential home, or other suitable structure. It should be appreciated that the HVAC system  100  may include embodiments or components of the HVAC unit  12  shown in  FIGS. 1 and 2 , embodiments or components of the split residential heating and cooling system  50  shown in  FIG. 3 , a rooftop unit (RTU), or any other suitable air handling unit or HVAC system. 
     In the illustrated embodiment, the HVAC system  100  includes an enclosure  112  that forms an air flow path  114  through the HVAC system  100 . The air flow path  114  extends from an upstream end portion  116  of the HVAC system  100  to a downstream end portion  118  of the HVAC system  100 . The enclosure  112  may be in fluid communication with the thermal load  110  via an air distribution system, such as a system of ductwork  120 , which includes a supply duct  122  and a return duct  124 . The return duct  124  may be coupled to a plenum  126  of the enclosure  112  that is configured to receive a flow of return air  128  from the thermal load  110 . Particularly, a fan or blower  130  of the HVAC system  100  may be operable to draw the return air  128  into the enclosure  112  via the return duct  124 . The enclosure  112  may include an exhaust air outlet  134  that enables the HVAC system  100  to exhaust a portion of the return air  128  into an ambient environment, such as the atmosphere. The exhaust air outlet  134  generally includes an exhaust air damper  136  that is configured to regulate a flow rate of the exhaust air discharging through the exhaust air outlet  134 . In some embodiments, the enclosure  112  includes an outdoor air inlet  142  that enables the HVAC system  100  to intake (e.g., via the blower  130 ) fresh outdoor air from the ambient environment. The outdoor air inlet  142  may include an outdoor air damper  144  that is configured to regulate a flow rate of the outdoor air entering the plenum  126 . In some embodiments, at least a portion of the return air  128  may mix with outdoor air entering the plenum  126  to form a flow of supply air  148 , which may include both the outdoor air and the return air  128 . In other embodiments, the supply air  148  may include only the return air  128  received via the return duct  124  or only the outdoor air dawn into the plenum  126  via the outdoor air inlet  142 . 
     In the illustrated embodiment, the HVAC system includes a vapor compression system  150 , such as the vapor compression system  72 , which includes an evaporator  152 . The evaporator  152  is positioned within the air flow path  114  and is configured to receive a flow of cooled refrigerant from an expansion device  154  of the vapor compression system  150 . The blower  130  may force the supply air  148  across the evaporator  152  to enable cooled refrigerant circulating through one or more evaporator coils  153  of the evaporator  152  to absorb thermal energy from the supply air  148 . The evaporator coils  153  may, in some embodiments, absorb an amount of thermal energy from the supply air  148  that is sufficient to cause moisture suspended within the supply air  148  to condense on the evaporator coils  153 . Accordingly, the supply air  148  may discharge from the evaporator  152  as cooled, dehumidified air  156  having a temperature value and a humidity level that are less than a temperature value and a humidity level of the supply air  148  received at the evaporator  152 . Condensate accumulating on the evaporator coils  153  may gradually drip into a drain pan positioned beneath the evaporator  152 , with respect to a direction of gravity, such that the condensate may be collected within the drain pan and subsequently drained from the enclosure  112  (e.g., via a drain port formed in the drain pan). 
     The evaporator  152  may discharge, via a conduit  162 , a flow of heated refrigerant that has absorbed thermal energy from the supply air  148 . The heated refrigerant may flow through the conduit  162  and toward a compressor  160  of the vapor compression system  150 . The compressor  160  may compress the refrigerant, which adds heat, and direct the heated refrigerant through a reheat valve  164  that, as discussed in detail below, is configured to regulate diversion (e.g., division) of the heated refrigerant between a condenser  166  and a reheat coil  168  of the vapor compression system  150 . 
     The condenser  166  may include one or more condenser coils that are configured to facilitate heat exchange between heated refrigerant received from the reheat valve  164  and the ambient environment. For example, the condenser  166  may include one or more condenser fans  170  that are operable to draw a flow of ambient air across the condenser coils of the condenser  166 . Accordingly, the ambient air may absorb thermal energy from the refrigerant circulating through the condenser coils, thereby cooling the refrigerant before the refrigerant is discharged from the condenser  166  via a conduit  172 . The compressor  160  may direct the cooled refrigerant discharging from the condenser  166  back to the evaporator  152  for reuse via the conduit  172 . As such, the evaporator  152 , the expansion device  154 , the compressor  160 , the condenser  166 , and the corresponding refrigerant conduits extending therebetween may collectively form a refrigerant loop or circuit of the vapor compression system  150 . 
     In the illustrated embodiment, the reheat coil  168  is disposed within the air flow path  114  and is positioned downstream, with respect to a direction of air flow through the enclosure  112 , of the evaporator  152 . One or more coils  190  of the reheat coil  168  are fluidly coupled to the reheat valve  164  via a conduit  192 . Accordingly, the coils  190  may receive heated refrigerant from the reheat valve  164  and place the heated refrigerant in thermal communication with cooled, dehumidified air  156  flowing along the air flow path  114 . 
     In certain embodiments, respective check valves  194  may be positioned along conduits of the vapor compression system  150  and configured to block refrigerant flow through the conduits in undesired directions (e.g., in an upstream direction, with respect to a flow of the refrigerant through the compressor  160 ). In some embodiments, a bleed down conduit  196  may extend between the conduit  162  and a conduit  197  extending from the reheat coil  168 . The bleed down conduit  196  may include a bleed down valve  198  configured to regulate refrigerant flow between the conduit  192  and the conduit  197  during bleed down operations of the vapor compression system  150 . 
     In some embodiments, the reheat valve  164  may be a three-way modulating valve that, as noted above, is operable to regulate diversion of refrigerant from the compressor  160  to the reheat coil  168  and/or from the compressor  160  to the condenser  166 . In particular, the reheat valve  164  may control flow parameters, such as a flow rate and/or a flow pressure, of the refrigerant flowing from the compressor  160  into the coils  190  of the reheat coil  168  and/or of the refrigerant flowing from the compressor  160  into the condenser coils of the condenser  166 . As such, the reheat valve  164  enables operation of the HVAC system  100  in a reheat or dehumidification mode, in which at least a portion of the heated refrigerant discharging from the compressor  160  is directed through the reheat coil  168  to reheat the cooled, dehumidified air  156 , and in a cooling mode, in which substantially no heated refrigerant discharging from the compressor  160  is directed through the reheat coil  168 . 
     For example, the reheat valve  164  may be configured to transition between a fully open position, a fully closed position, and a plurality of intermediate or partially open positions that are between the fully open and fully closed positions. In the fully open position, the reheat valve  164  may divert all of or substantially all of (e.g., 80 percent or more) of the heated refrigerant discharging from the compressor  160  into the conduit  192  and to the reheat coil  168 , while diverting none of or a minimal portion of (e.g., 20 percent or less) of the heated refrigerant discharging from the compressor  160  into a conduit  199  and to the condenser  166 . In the fully closed position, the reheat valve  164  may block flow of the heated refrigerant from the compressor  160  to the reheat coil  168 , such that all of the heated refrigerant output by compressor  160  is directed toward the condenser  166 . Accordingly, when the reheat valve  164  has a relatively low degree of opening (e.g., less than 50 percent of a total permitted valve opening), the reheat valve  164  may bias refrigerant distribution from the compressor  160  to the condenser  166 . Conversely, while the reheat valve  164  has a relatively high degree of opening (e.g., equal to or greater than 50 percent of the total permitted valve opening), the reheat valve  164  may bias refrigerant distribution from the compressor  160  to the reheat coil  168 . 
     For clarity, as used herein, a “modulating valve” may refer to any suitable valve or flow control device, such as a step-less valve, which is operable to incrementally adjust a flow rate and/or a flow pressure of a fluid flow across the modulating valve. For example, in some embodiments, the reheat valve  164  may be adjustable to 1, 5, 10, 20, 30, 50, or more than 50 discrete positions that enable precise adjustment of fluid flow parameters across the reheat valve  164 . Although the reheat valve  164  is illustrated as a three-way valve in the illustrated embodiment of  FIG. 5 , it should be appreciated that, in other embodiments, the reheat valve  164  may include a plurality of two-way valves (e.g., on/off valves) configured to regulate diversion of refrigerant from the compressor  160  to the reheat coil  168  and/or to the condenser  166  in accordance with the techniques discussed herein. 
     The blower  130  may force the cooled, dehumidified air  156  discharging from the evaporator  152  across the coils  190  of the reheat coil  168 . Accordingly, while the HVAC system  100  operates in the dehumidification mode, the cooled, dehumidified air  156  may absorb thermal energy from the heated refrigerant circulating through the coils  190 . Accordingly, the reheat coil  168  may discharge reheated, dehumidified air  200  at a temperature value that is greater than a temperature value of the cooled, dehumidified air  156  received at the reheat coil  168 . 
     In the illustrated embodiment, the reheat control system  102  includes a controller  204  this is configured to adjust the degree of opening of the reheat valve  164  (e.g., configured to modulate a position of the reheat valve  164 ) based on one or more operational parameters of the HVAC system  100  to provide a desired quantity (e.g., flow rate) of heated refrigerant to the reheat coil  168 . As such, the controller may operate the reheat valve  164  to adjust an amount of reheat provided by the reheat coil  168 . For example, the controller  204  may be communicatively coupled to one or more temperature sensors  206  configured to provide the controller  204  with feedback indicative of a temperature within an interior  208  of the thermal load  110 , a temperature of the return air  128 , a temperature of the reheated, dehumidified air  200 , a temperature of ambient outdoor air  210  surrounding the HVAC system  100 , and/or other suitable temperature feedback. Additionally, the controller  204  may be communicatively coupled to one or more humidity sensors  212  configured to provide the controller  204  with feedback indicative of a humidity level within the interior  208  of the thermal load  110 , a humidity level of the return air  128 , a humidity level of the reheated, dehumidified air  200 , and/or other suitable humidity feedback. 
     As discussed in detail below, the controller  204  may adjust the degree of opening of the reheat valve  164  based on feedback from the sensors  206  and/or  212  such that the reheat coil  168  provides thermal energy transfer to the cooled, dehumidified air  156  that is sufficient to discharge the reheated, dehumidified air  200  at a temperature that is substantially equal to a temperature of the return air  128  drawn from the thermal load  110 , for example. In this manner, the controller  204  may facilitate operating the HVAC system  100  to supply neutral air to the thermal load  110 . As used herein, a flow of “neutral air” may refer to a flow of reheated, dehumidified air  200  having a temperature value that is substantially equal to, such as within ten percent of, or within two degrees of, a temperature value of the return air  128 , and that includes a humidity level that is less than a humidity level of the return air  128 . That is, “neutral air” may refer to a flow of the reheated, dehumidified air  200  that, at a particular instance in time, has a temperature that is substantially equal to an actual temperature within the interior  174  of the thermal load  110  and/or to a target set point temperature for the interior  174  at that same instance in time, and has a humidity level that is less than the humidity level within the thermal load  110 . Accordingly, it should be understood that, when supplying the thermal load  110  with the reheated, dehumidified air  200  having properties of the “neutral air,” the HVAC system  100  may circulate air throughout the thermal load  110  to dehumidify the thermal load  110  substantially without heating or cooling the interior  174  of the thermal load  110 . 
     In some embodiments, the controller  204  may include a portion or all of the control panel  82  (see  FIG. 4 ) or may be another suitable controller included in the HVAC system  100 . In any case, the controller  204  may be used to control components of the HVAC system  100  in accordance with the techniques discussed herein to enable operation of the HVAC system  100  in the dehumidification mode. For example, one or more control transfer devices, such as wires, cables, wireless communication devices, and the like, may communicatively couple the blower  130 , the expansion device  154 , the compressor  160 , the one or more condenser fans  170 , the reheat valve  164 , the sensors  206  and  212 , and/or any other suitable components of the HVAC system  100  to the controller  204 . That is, the blower  130 , the expansion device  154 , the compressor  160 , the condenser fans  170 , the reheat valve  164 , and/or the sensors  206  and  212  may each have a communication component that facilitates wired or wireless communication between the controller  204 , the blower  130 , the expansion device  154 , the compressor  160 , the condenser fans  170 , the reheat valve  164 , and/or the sensors  206  and  212  via a network. In some embodiments, the communication component may include a network interface that enables the components of the HVAC system  100  to communicate via various protocols such as EtherNet/IP, ControlNet, DeviceNet, or any other communication network protocol. Alternatively, the communication component may enable the components of the HVAC system  100  to communicate via mobile telecommunications technology, Bluetooth®, near-field communications technology, and the like. As such, the controller  204 , the blower  130 , the expansion device  154 , the compressor  160 , the condenser fans  170 , the reheat valve  164 , and/or the sensors  206  and  212  may wirelessly communicate data between each other. 
     The controller  204  includes a processor  220 , such as a microprocessor, which may execute software for controlling the components of the HVAC system  100  and/or the components of the reheat control system  102 . The processor  220  may include multiple microprocessors, one or more “general-purpose” microprocessors, one or more special- purpose microprocessors, and/or one or more application specific integrated circuits (ASICS), or some combination thereof. For example, the processor  220  may include one or more reduced instruction set (RISC) processors. The controller  204  may also include a memory device  222  that may store information such as instructions, control software, look up tables, configuration data, etc. The memory device  222  may include a volatile memory, such as random access memory (RAM), and/or a nonvolatile memory, such as read-only memory (ROM). The memory device  222  may store a variety of information and may be used for various purposes. For example, the memory device  222  may store processor-executable instructions including firmware or software for the processor  220  execute, such as instructions for controlling components of the HVAC system  100 . In some embodiments, the memory device  222  is a tangible, non-transitory, machine-readable-medium that may store machine-readable instructions for the processor  220  to execute. The memory device  222  may include ROM, flash memory, a hard drive, or any other suitable optical, magnetic, or solid-state storage medium, or a combination thereof. The memory device  222  may store data, instructions, and any other suitable data. 
       FIG. 6  is flow diagram of an embodiment of a process  230  that may be used to control the HVAC system  100  to facilitate supply of dehumidified air, such as neutral air, to the thermal load  110 . Moreover, as discussed in detail below, execution of the process  230  may reduce or substantially eliminating charge migration in the vapor compression system  150  that may otherwise impede generation and supply of the neutral air via the HVAC system  100 .  FIG. 6  will be referred to concurrently with  FIG. 5  throughout the following discussion. It should be noted that the steps of the process  230  discussed below may be performed in any suitable order and are not limited to the order shown in the illustrated embodiment of  FIG. 6 . Moreover, it should be noted that additional steps of the process  230  may be performed, and certain steps of the process  230  may be omitted. In some embodiments, the process  230  may be executed on the processor  220 , the microprocessor  86 , and/or any other suitable processor of the HVAC system  100 . The process  230  may be stored on, for example, the memory  88  or the memory device  222 . 
     The process  230  may begin with the controller  204  receiving an indication to initiate operation of the HVAC system  100  in the dehumidification mode, as indicated by block  232 . For example, in some embodiments, the controller  204  may receive user input instructing the controller  204  to initiate operation of the HVAC system  100  in the dehumidification mode via a user interface  234  (see  FIG. 5 ) coupled to the controller  204 . Additionally or alternatively, the controller  204  may initiate operation of the HVAC system  100  in the dehumidification mode upon receiving feedback from the one or more humidity sensors  212  indicating that a humidity level within the interior  208  of the thermal load  110  reaches or exceeds a threshold humidity level. 
     In any case, upon receiving the indication to operate the HVAC system  100  in the dehumidification mode, the controller  204  may determine whether a temperature of the outdoor air  210  surrounding the HVAC system  100  meets or exceeds an upper threshold temperature value, as indicated by block  236 . For example, the controller  204  may receive feedback from the one or more temperature sensors  206 , from a remote weather station, or from another suitable source indicating the temperature of the outdoor air  210 . The controller  204  may compare the temperature of the outdoor air  210  to the upper threshold temperature value to determine whether the temperature of the outdoor air  210  meets or exceeds the upper threshold temperature value. As a non-limiting example, the upper threshold temperature value may be between 70 degrees Fahrenheit and 95 degrees Fahrenheit. In some embodiments, the upper threshold temperature value may be a predetermined value stored in, for example, the memory device  222  of the controller  204 . In other embodiments, the upper threshold temperature value may be variable and adjusted based on feedback received at the controller  204 . For example, the upper threshold temperature value may be adjusted based on feedback (e.g., user input) received via the user interface  234 . Additionally or alternatively, the upper threshold temperature value may be adjusted based on feedback received from the one or more sensors  206  and/or  212  or other suitable sensors of the HVAC system  100 . 
     In any case, in response to determining, at block  236 , that the temperature of the outdoor air  210  is less than the upper threshold temperature value, the controller  204  may block operation of the condenser fan  170  or fans, as indicated by block  238 . Particularly, if the condenser fan  170  is operational (e.g., activated) prior to execution of block  236 , the controller  204  may deactivate the condenser fan  170  at block  238 . Conversely, if the condenser fan  170  is already non-operational (e.g., in-active) prior to execution of the block  236 , the controller  204  may continue to maintain the condenser fan  170  in the non-operational state. 
     In some embodiments, upon execution of the block  238 , the controller  204  may modulate the reheat valve  164  in accordance with a dehumidification control algorithm, as indicated by block  240 , to provide dehumidified air to the thermal load  110  in accordance with the techniques discussed above. Particularly, the controller  204  may operate the reheat valve  164  to provide neutral air to the thermal load  110 . For example, the controller  204  may receive feedback indicative of a reference temperature for the neutral air. The reference temperature may be indicative of a temperature within the interior  208  or a temperature of the return air  128 , as measured by the one or more temperature sensors  206 . In certain embodiments, the reference temperature may include a target temperature set point for the interior  208  that is input via the user interface  234 . In any case, the controller  204  may compare a temperature of the reheated, dehumidified air  200  (e.g., as measured by the one or more temperature sensors  206 ) to the reference temperature to determine whether the temperature of the reheated, dehumidified air  200  is within a threshold range of the reference temperature. 
     As a non-limiting example, in response to determining that that temperature of the reheated, dehumidified air  200  is below the reference temperature (e.g., by a threshold amount, such as 2 degrees Fahrenheit), the controller  204  may increase a degree of opening of the reheat valve  164  (e.g., by a threshold increment) to increase a mass flow rate of heated refrigerant from the compressor  160  to the reheat coil  168  and decrease a mass flow rate of heated refrigerant from the compressor  160  to the condenser  166 . As such, the controller  204  may increase a heat transfer rate between the heated refrigerant circulating through the reheat coil  168  and the air flowing across the reheat coil  168 , such that the controller  204  may effectuate an increase in the temperature of the reheated, dehumidified air  200  discharging from the reheat coil  168 . Conversely, in response to determining that that the temperature of the reheated, dehumidified air  200  exceeds the reference temperature (e.g., by a threshold amount, such as 2 degree Fahrenheit), the controller  204  may decrease a degree of opening of the reheat valve  164  (e.g., by a threshold increment) to decrease a mass flow rate of heated refrigerant from the compressor  160  to the reheat coil  168  and increase a mass flow rate of heated refrigerant from the compressor  160  to the condenser  166 . As such, the controller  204  may decrease a heat transfer rate between the heated refrigerant circulating through the reheat coil  168  and the air flowing across the reheat coil  168 , such that the controller  204  may effectuate a decrease in the temperature of the reheated, dehumidified air  200 . The controller  204  may iteratively execute blocks  236 ,  238 , and  240  such that an actual temperature of the reheated, dehumidified air  200  output by the HVAC system  100  may approach and/or reach the reference temperature. As such, the HVAC system  100  may provide the reheated, dehumidified air  200  to the thermal load as neutral air. 
     In response to determining (e.g., based on feedback from the one or more temperature sensors  206 ), at block  236 , that the temperature of the outdoor air  210  meets or exceeds the upper threshold temperature value, the controller  204  may determine whether a position (e.g., a current degree of opening) of the reheat valve  164  is less than a threshold degree of opening, as indicated by the block  242 . The controller  204  may determine the position of the reheat valve  164  based on feedback from a sensor (e.g., a position sensor) that is integrated with or separate from the reheat valve  164 , based on feedback from an actuator used to operate the reheat valve  164 , or based on feedback from another suitable source. In response to determining that the position of the reheat valve  164  is less than the threshold degree of opening, the controller  204  may activate or continue to operate the condenser fan  170  to draw air across the condenser  166 , as indicated by block  244 . That is, if the condenser fan  170  is non-operational (e.g., de-activated) prior to execution of block  242 , the controller  204  may activate the condenser fan  170  at block  244 . If the condenser fan  170  is already operational (e.g., active) prior to execution of block  242 , the controller  204  may continue to maintain the condenser fan  170  in the operational state. As shown in the illustrated embodiment of  FIG. 6 , upon execution of block  244 , the controller  204  may execute block  240  to control operation of the reheat valve  164  in accordance with the techniques discussed above and may subsequently initiate another iteration of the process  230 . 
     In response to determining, at the block  242 , that the position of the reheat valve  164  reaches or exceeds the threshold degree of opening, the controller  204  may deactivate or continue to block operation of the condenser fan  170 , as indicated by block  238 . By blocking operation of the condenser fan  170  when the reheat valve  164  opens beyond the threshold degree of opening, such as when a heated refrigerant demand of the reheat coil  168  is elevated, the controller  204  may ensure that a sufficient quantity of refrigerant is available in the reheat section of the vapor compression system  150  to satisfy the demand of the reheat coil  168 . That is, in accordance with the techniques discussed above, the controller  204  may ensure that refrigerant does not accumulate within the condenser  166  and result in a deficiency of available refrigerant in the reheat section of the vapor compression system  150 . For clarity, the reheat section of the vapor compression system  150  may include, for example, the expansion device  154 , the evaporator  152 , the compressor  160 , the reheat valve  164 , the reheat coil  168 , and the conduits extending therebetween. As a non-limiting example, the threshold degree of opening of the reheat valve  164  may correspond to a position of the reheat valve  164  that is between 60 percent and 100 percent of a total permitted valve opening of the reheat valve  164 . Moreover, in some embodiments, when the reheat valve  164  is positioned at the threshold degree of opening, the reheat valve  164  may divert between 60 percent and 100 percent of the refrigerant discharging from the compressor  160  to the reheat coil  168 . 
     Upon execution of the block  238  during a particular iteration of the process  230 , the controller  204  may cycle through another iteration of the process  230 . As such, it should be understood that the controller  204  may repeatedly iterate through any of the aforementioned steps of the process  230  to adjust operation of the condenser fan  170  and/or adjust the position of the reheat valve  164  in accordance with the techniques discussed herein. 
     As set forth above, embodiments of the present disclosure may provide one or more technical effects useful for eliminating or substantially mitigating undesired charge migration within a vapor compression system during dehumidification operations performed by an HVAC system. Specifically, the reheat control system disclosed herein may adjust operation of a condenser fan based on a position of a reheat valve to ensure that sufficient refrigerant is available in a reheat section of the vapor compression system to satisfy a refrigerant demand of the reheat coil. In this manner, the reheat control system may facilitate supply and delivery of dehumidified air to a building or other structure serviced by the HVAC system. It should be understood that the technical effects and technical problems in the specification are examples and are not limiting. Indeed, it should be noted that the embodiments described in the specification may have other technical effects and can solve other technical problems. 
     While only certain features and embodiments have been illustrated and described, many modifications and changes may occur to those skilled in the art, such as variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, such as temperatures and pressures, mounting arrangements, use of materials, colors, orientations, and so forth, without materially departing from the novel teachings and advantages of the subject matter recited in the claims. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the disclosure. Furthermore, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not have been described, such as those unrelated to the presently contemplated best mode, or those unrelated to enablement. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation specific decisions may be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure, without undue experimentation.