Patent Publication Number: US-11639800-B2

Title: Dehumidification drainage system with mist eliminator

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 15/999,546 filed Aug. 20, 2018, by Grant M. Lorang, and entitled “Dehumidification Drainage System with Mist Eliminator,” which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This disclosure relates generally to dehumidification, and more particularly to a dehumidification drainage system with a mist eliminator. 
     BACKGROUND 
     In certain situations, it is desirable to increase water removal capacity from a dehumidification system. For example, in fire and flood restoration application, it may be desirable to quickly remove water from areas of a damaged structure. To accomplish this, air flow may be increased through the dehumidification system. However, current dehumidification systems have proven inefficient in increasing water removal capacity by increasing air flow in the same space. The increased air flow leads to increased velocity, especially during defrost conditions. With high enough air velocity, the water droplets will eventually entrain in the air, reducing water removal performance. 
     SUMMARY 
     According to embodiments of the present disclosure, disadvantages and problems associated with previous dehumidification systems may be reduced or eliminated. 
     In some embodiments, a dehumidification system includes an evaporator, a condenser, and a drain pan. The condenser is positioned proximate to the evaporator. The drain pan is disposed at least partially below the evaporator and the condenser. The drain pan includes a basin, a central ridge, a shelf, and a mist eliminator. The basin of the drain pan is configured to collect water condensed from the evaporator and includes a sloped bottom, a first rib, a second rib, a third rib, an angled rib, and a drain opening. The sloped bottom of the basin is configured to allow water to flow from a first side of the basin towards a second side of the basin, wherein the first and the second side are parallel to a longitudinal direction. The first rib is disposed on the sloped bottom and positioned between a third side of the basin and a fourth side of the basin, wherein the third and the fourth side are perpendicular to the longitudinal direction. The first rib extends upwardly from the sloped bottom and partially across the sloped bottom along a lateral direction, wherein the lateral direction is perpendicular to the longitudinal direction. The second rib is disposed on the sloped bottom and positioned between the first rib and the third side of the basin. The second rib extends upwardly from the sloped bottom and partially across the sloped bottom. The second rib is parallel to the first rib and includes a central gap configured to restrict air flowing through the drain pan. The third rib is disposed on the sloped bottom and positioned between the first rib and the second rib. The third rib extends upwardly from the sloped bottom and partially across the sloped bottom. The third rib is parallel to and shorter than the first rib. The third rib is configured to at least partially block the central gap of the second rib along the longitudinal direction. The angled rib is disposed on the sloped bottom and positioned between the first rib and the second rib. The angled rib is further positioned between the third rib and the second side of the basin. The angled rib extends upwardly from the bottom and is attached to the second rib. The angled rib has an angle with respect to the second rib and is inclined towards the third rib. The drain opening is disposed at the fourth side of the basin. The central ridge of the drain pan is disposed proximate to the third side of the basin of the drain pan. The central ridge includes a wall along the lateral direction and is configured to accommodate a mist eliminator. The mist eliminator includes a member extending along the lateral direction. The member further includes a plurality of apertures. The shelf of the drain pan is disposed proximate to the central ridge so that the central ridge is sandwiched between the basin and the shelf. The shelf is configured to support the condenser. 
     In some embodiments, a dehumidification system includes an evaporator, a condenser, and a drain pan. The condenser is positioned proximate to the evaporator. The drain pan is disposed at least partially below the evaporator and the condenser. The drain pan at least includes a basin configured to collect water condensed from the evaporator. The basin includes a sloped bottom, a first rib, a second rib, a third rib, an angled rib, and a drain opening. The sloped bottom of the basin is configured to allow water to flow from a first side of the basin towards a second side of the basin, wherein the first and the second side are parallel to a longitudinal direction. The first rib is disposed on the sloped bottom and positioned between a third side of the basin and a fourth side of the basin. The first rib extends upwardly from the sloped bottom and partially across the sloped bottom along a lateral direction, wherein the lateral direction is perpendicular to the longitudinal direction. The second rib is disposed on the sloped bottom and positioned between the first rib and the third side of the basin. The second rib extends upwardly from the sloped bottom and partially across the sloped bottom. The second rib is parallel to the first rib and includes a central gap configured to restrict air flowing through the drain pan. The third rib is disposed on the sloped bottom and positioned between the first rib and the second rib. The third rib extends upwardly from the sloped bottom and partially across the sloped bottom. The angled rib is disposed on the sloped bottom and positioned between the first rib and the second rib. The angled rib extends upwardly from the bottom and has an angle with respect to the second rib. The drain opening is disposed at the fourth side of the basin. 
     In some embodiments, a dehumidifier drainage system includes a drain pan. The drain pan is disposed at least partially below an evaporator and a condenser. The drain pan at least includes a basin configured to collect water condensed from the evaporator. The basin includes a sloped bottom, a first rib, a second rib, a third rib, an angled rib, and a drain opening. The sloped bottom of the basin is configured to allow water to flow from a first side of the basin towards a second side of the basin, wherein the first and the second side are parallel to a longitudinal direction. The first rib is disposed on the sloped bottom and positioned between a third side of the basin and a fourth side of the basin. The first rib extends upwardly from the sloped bottom and partially across the sloped bottom along a lateral direction, wherein the lateral direction is perpendicular to the longitudinal direction. The second rib is disposed on the sloped bottom and positioned between the first rib and the third side of the basin. The second rib extends upwardly from the sloped bottom and partially across the sloped bottom. The second rib is parallel to the first rib and includes a central gap configured to restrict air flowing through the drain pan. The third rib is disposed on the sloped bottom and positioned between the first rib and the second rib. The third rib extends upwardly from the sloped bottom and partially across the sloped bottom. The angled rib is disposed on the sloped bottom and positioned between the first rib and the second rib. The angled rib extends upwardly from the bottom and has an angle with respect to the second rib. The drain opening is disposed at the fourth side of the basin. 
     Certain embodiments of the present disclosure may provide one or more technical advantages. For example, the ribs of certain embodiments of the drain pan, including the first rib and the second rib, are directly underneath below the lowest coils of the evaporator and are configured to restrict an area between the evaporator and the drain pan through which air may pass. This configuration minimizes the gap between the evaporator and the drain pan, restricting the air flowing between the evaporator and the drain pan, thereby reducing velocity of the air flowing through the drain pan, and preventing water from being entrained in the air. This may improve the efficiency of the dehumidification system. The central gap in the second rib allows water to drain from the backside of the second rib, in relation to the direction of airflow, but controls the air flow through the drain pan. The third rib that partially blocks the central gap of the second rib facilities reducing the velocity of the air flowing towards the central gap and reduces water entrainment in the air. The angled rib attached to the second rib is configured to reduce air velocity and change the velocity vector of the air exiting the central gap of the second rib so that the air does not drift sideways and carry the water droplets out of the drain pan. The mist eliminator has multiple advantages including separating entrained water droplets that fall from the bottom of the evaporator and changing the velocity vector of the air coming off of the bottom of the evaporator. This increases the performance of the dehumidifier by maximizing the amount of water drained after it has condensed on the evaporator. In some embodiments, the apertures of the mist eliminator are specifically designed to minimize air restriction during normal operation but also directly control water drainage during defrost conditions. 
     Other technical advantages of the present disclosure will be readily apparent to one skilled in the art from the following figures, descriptions, and claims. Moreover, while specific advantages have been enumerated above, various embodiments may include all, some, or none of the enumerated advantages. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present disclosure and for further features and advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings, in which: 
         FIGS.  1 A- 1 B  illustrate perspective views of a dehumidification system, according to certain embodiments; 
         FIG.  2    illustrates internal components of the dehumidification system of  FIG.  1   , according to certain embodiments; 
         FIG.  3 A  illustrates a perspective view of a drain pan in the dehumidification system of  FIG.  2   , according to certain embodiments; 
         FIG.  3 B- 3 D  illustrate cross-sectional perspective views of the drain pan of  FIG.  3 A , according to certain embodiments; 
         FIG.  3 E  illustrates a top view of the drain pan of  FIG.  3 A , according to certain embodiments; 
         FIG.  3 F  illustrates a side view of the drain pan of  FIG.  3 A , according to certain embodiments; 
         FIG.  3 G  illustrates a perspective view of a mist eliminator, according to certain embodiments; and 
         FIG.  3 H  illustrates a side view of the drain pan of  FIG.  3 A , according to certain embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     In certain situations, it is desirable to increase water removal capacity from a dehumidification system. For example, in fire and flood restoration applications, it may be desirable to quickly remove water from areas of a damaged structure. As another example, in resident applications, large amounts of dehumidification may become necessary when the latent load becomes uncomfortable. To accomplish this, air flow may be increased through the dehumidification system. However, current dehumidification systems have proven inefficient in increasing water removal capacity. For example, in current dehumidification systems, when the evaporator is operating at a temperature below dew point, ice may start to build in the coils of the evaporator. This drives a portion of the air drawn into the dehumidification system to flow underneath the evaporator and pick up water condensed in the drain pan below the evaporator. This negatively impacts the dehumidification system performance and durability by allowing water to be reabsorbed into the air and saturating internal components with water. 
     The disclosed embodiments provide a dehumidification system that includes various features to address the inefficiencies and other issues with current dehumidification systems. In some embodiments, the dehumidification system includes a dehumidifier drainage system that is configured to efficiently increase the water removal capacity of the dehumidification system. Specifically, the dehumidifier drainage system includes a drain pan including a basin, a central ridge, and a mist eliminator. The basin of the drain pan includes a sloped bottom, a first rib, a second rib, a third rib, an angled rib, and a drain opening. In some embodiments, the first rib and the second rib are directly underneath the lowest coils of the evaporator and are configured to restrict an area between the evaporator and the drain pan through which air may pass. This configuration minimizes the gap between the evaporator and the drain pan, thereby restricting the air flowing between the evaporator and the drain pan, reducing velocity of the air flowing through the drain pan, and preventing water from being entrained in the air. This may improve the efficiency of the dehumidification system. The second rib includes a central gap which allows water to drain from the backside of the second rib to the drain opening. This configuration allows the drain pan to be more compact and still directly control air flow and water. The third rib partially blocks the central gap of the second rib. This reduces the velocity of the air flowing towards the central gap and reduces water entrainment in the air. The angled rib is attached to the second rib and is configured to reduce air velocity and change the velocity vector of the air exiting the central gap of the second rib. The change of the velocity vector will direct the highest velocity airflow towards the most aggressive portion of the mist eliminator. The mist eliminator has multiple advantages including separating entrained water droplets that fall from the bottom of the evaporator and changing the velocity vector of the air coming off of the bottom of the evaporator coil. This increases the performance of the dehumidifier by maximizing the amount of water drained after it has condensed on the evaporator. In some embodiments, the apertures of the mist eliminator are specifically designed to minimize air restriction during normal operation but also directly control water drainage during defrost conditions. 
     These and other advantages and features of certain embodiments are discussed in more detail below in reference to  FIGS.  1 A- 3 H .  FIGS.  1 A- 1 B  illustrate perspective views of certain embodiments of a dehumidification system;  FIG.  2    illustrates certain embodiments of internal components of a dehumidification system;  FIG.  3 A  illustrates a perspective view of certain embodiments of a drain pan in a dehumidification system;  FIG.  3 B  illustrates a cross-sectional perspective view of certain embodiments of a drain pan in a dehumidification system;  FIG.  3 C  illustrates a cross-sectional perspective view of certain embodiments of a drain pan in a dehumidification system;  FIG.  3 D  illustrates a cross-sectional perspective view of certain embodiments of a drain pan in a dehumidification system;  FIG.  3 E  illustrates a top view of certain embodiments of a drain pan in a dehumidification system;  FIG.  3 F  illustrates a side view of certain embodiments of a drain pan in a dehumidification system;  FIG.  3 G  illustrates a perspective view of certain embodiments of a mist eliminator in a dehumidification system; and  FIG.  3 H  illustrates a side view of certain embodiments of a drain pan in a dehumidification system. 
       FIGS.  1 A- 1 B  illustrate perspective views of a dehumidification system  100 , according to certain embodiments. In some embodiments, dehumidification system  100  includes a cabinet  102 , an airflow inlet  104 , and an airflow outlet  106 . While a specific arrangement of these and other components of dehumidifier  100  are illustrated in these figures, other embodiments may have other arrangements and may have more or fewer components than those illustrated. 
     In general, dehumidification system  100  provides dehumidification to an area (e.g., a room, a floor, etc.) by moving air through dehumidification system  100 . To dehumidify air, dehumidification system  100  draws in a moist airflow  101  that enters cabinet  102  via airflow inlet  104 , travels through the internal components of dehumidification system  100 , and then exits cabinet  102  via airflow outlet  106 . Water removed from airflow  101  may be captured within a water reservoir (e.g., a drain pan) of dehumidification system  100 . 
     Cabinet  102  may be of any appropriate shape and size. In some embodiments, cabinet  102  includes multiple panels (or sides). In some embodiments as illustrated, airflow inlet  104  is on a front side panel of cabinet  102 , and airflow outlet  106  is on a back side panel. 
     Airflow inlet  104  is generally any opening in which airflow  101  enters dehumidification system  100 . In some embodiments, airflow inlet  104  is located on a front side panel as illustrated, but may be in any other appropriate location on other embodiments of dehumidification system  100 . In some embodiments, airflow inlet  104  is square or rectangular in shape. In some embodiments, airflow inlet  102  is oval or circular in shape. In other embodiments, airflow inlet  102  may have any other appropriate shape or dimension. In some embodiments, airflow inlet  102  includes a grate or grill that is formed out of geometric shapes. For example, some embodiments of airflow inlet  102  includes a grill formed from hexagons, octagons, and the like. In some embodiments, a removable air filter may be installed proximate to airflow inlet  104  to filter airflow  101  as it enters dehumidification system  100 . 
     Airflow outlet  106  is generally any opening in which airflow  101  exits dehumidification system  100 . In some embodiments, airflow outlet  106  is located on a back side panel as illustrated, but may be in any other appropriate location on other embodiments of dehumidification system  100 . Similar to airflow inlet  104 , airflow outlet  106  includes a grate or grill that is formed out of geometric shapes such as hexagons, octagons, and the like. In some embodiments, airflow outlet  106  may be circular or oval in shape, but may have any other appropriate shape or dimension. 
     Dehumidification system  100  includes various internal components to provide dehumidification to airflow  101 . As illustrated in  FIG.  2   , some embodiments of dehumidification system  100  include an air filter  202 , an evaporator  204 , a condenser  206 , a drain pan  208 , an impeller  210 , and a compressor  212 . These and other internal components of dehumidification system  100  are uniquely arranged to minimize the size of dehumidification system  100 . In some embodiments as illustrated, condenser  206  is sandwiched between evaporator  204  and impeller  210 . In some embodiments, evaporator  204  is located proximate to airflow inlet  104 . In some embodiments, a removable air filter  202  is provided between evaporator  204  and airflow inlet  104  to filter airflow  101  before it enters evaporator  204 . In some embodiments, drain pan  208  is located partially below evaporator  204  and condenser  206 . In some embodiments, compressor  212  is located between impeller  210  and airflow outlet  106  as illustrated. 
     Air filter  202  is configured to remove solid particles such as dust, pollen, mold, and bacterial from airflow  101  entering dehumidification system  100 . In some embodiments, air filter  202  is located proximate to the airflow inlet  104 . Air filter  202  is generally any appropriate type of filter that can capture mold, pollen, dust mites, and other particulates out of air. 
     Evaporator  204  is configured to absorb heat from airflow  101  and condense the moisture in airflow  101 . In some embodiments, evaporator  204  includes a finned-tube evaporator comprising tube coils covered with fins. The fins added to the tubes extend into the spaces between the tubes to permit more of airflow  101  to come into contact with cold evaporator  204 . This design allows evaporator  204  to be made dimensionally smaller while still providing a reasonable heat transfer capability. During operation, evaporator  204  gets cold enough (below the dewpoint) to pull water out of airflow  101 . Water will drip down the coils of evaporator  204  to drain pan  208 . In some embodiments, the tubes and the fins of evaporator  204  are made of copper or aluminum. In yet other embodiments, evaporator  204  may be any type of evaporators such as microchannel, bare tube evaporator, plate evaporators, etc., and may be made of any appropriate material such as steel or aluminum. 
     Condenser  206  is configured to reject heat to airflow  101 . In some embodiments, condenser  206  includes a microchannel condenser comprising condenser coils that are made of aluminum in some embodiments. In general, a microchannel condenser provides numerous features including a high heat transfer coefficient, a low air-side pressure restriction, and a compact design (compared to other solutions such as finned tub exchangers). These and other features make microchannel condensers good options for condensers in air conditioning systems where inlet air temperatures are high and airflow is high with low fan power. In some embodiments, condenser  206  includes one condenser coil. In some embodiments, condenser  206  includes two or more condenser coils to achieve a reasonable temperature. In yet other embodiments, condenser  206  may be any type of condensers, and may be made of any appropriate material. 
     Evaporator  204  and condenser  206  make it possible to complete the heat exchange process. Cold evaporator  204  condenses the water in airflow  101 , which is removed, and then airflow  101  is reheated by the condenser coils of condenser  206 . The now dehumidified, re-warmed airflow  101  is released into the environment. 
     Drain pan  208  is configured to collect water condensed from evaporator  204 . Drain pan  208  is located partially below evaporator  204  and condenser  206 . In some embodiments, drain pan  208  is any appropriate tank, basin, container, or area within cabinet  102  to collect and hold water removed from airflow  101 . A particular embodiment of drain pan  208  is described in more detail below in reference to  FIGS.  3 A- 3 F . 
     Dehumidification system  100  further includes an impeller  210  that, when activated, draws airflow  101  into dehumidification system  100  via airflow inlet  104 , causes airflow  101  to flow through dehumidification system  100 , and exhausts airflow  101  out of airflow outlet  106 . In some embodiments, impeller  210  is located within cabinet  102  adjacent to condenser  206  as illustrated in  FIG.  2   . In some embodiments, impeller  210  is a backward inclined impeller configured to generate airflow  101  that flows through dehumidification system  100  for dehumidification and exits dehumidification system  100  through airflow outlet  106 . In some embodiments, impeller  210  may be any other type of air mover (e.g., axial fan, forward inclined impeller, etc.) in other embodiments of dehumidification system  100 . 
     Compressor  212  is configured to circulate the refrigerant in dehumidification system  100  under pressure. In some embodiments, compressor  212  is located adjacent to airflow outlet  106  as illustrated in  FIG.  2   . In some embodiments, compressor  212  creates the necessary flow of refrigerant that travels through the coils in dehumidification system  100 . For example, compressor  212  may pump the refrigerant to the condenser  206 , through the expansion valve, and into the evaporator  204  to complete the refrigeration cycle. In some embodiments, compressor  212  is a rotary compressor that includes a shaft with an eccentric lobe. The eccentric lobe of the rotary compressor rotates inside the cylinder of the compressor  212 , and pushes the refrigerant through the cylinder of the compressor generating the necessary flow. Rotary compressors are small in size and quiet, which makes them a good candidate for compressors used in a residential or commercial dehumidifier. In some embodiments, compressor  212  may be any other type of compressor (e.g., reciprocating compressor, scroll compressor, screw compressor, centrifugal compressor, etc.) in other embodiments of dehumidification system  100 . 
     In operation, moist airflow  101  is drawn into dehumidification system  100  via airflow inlet  104  by impeller  210 . Airflow  101  travels through an air filter  202  before it reaches evaporator  204 . The air filter  202  may be used to remove solid particles such as dust, pollen, mold, and bacterial from airflow  101 . The filtered airflow  101  then enters evaporator  204  where airflow  101  is cooled and water is condensed and removed from airflow  101 . The water removed from airflow  101  drips down the coils of evaporator  204  and falls into drain pan  208 . Next, the dry airflow  101  passes through condenser  206  and is reheated by the refrigerant in the condenser  206 . The now dehumidified, re-warmed airflow  101  exits dehumidification system  100  via airflow outlet  106 . In some embodiments, a hose (not shown) connected to drain pan  210  will guide the water out of dehumidification system  100 . 
       FIG.  3 A  illustrates a perspective view of drain pan  208  of dehumidification system  100 , according to certain embodiments. Drain pan  208  is generally used to collect water condensed from evaporator  204 . In some embodiments, drain pan  208  is any appropriate tank, basin, container, or area within cabinet  102  to collect and hold water removed from airflow  101 . In some embodiments, drain pan  208  is located partially below evaporator  204  and condenser  206 . In some embodiments, drain pan  208  includes a basin  302 , a central ridge  304 , a shelf  306 , and a mist eliminator  308  as illustrated. Basin  302  of the drain pan  208  is located partially below the evaporator  204  and configured to collect water condensed from the evaporator  204 . Basin  302  may be further configured to provide support for the evaporator  204 . Central ridge  304  is located proximate to the basin  302  and configured to accommodate a mist eliminator  308  and prevent water from leaving basin  302  towards the downstream side, relative to airflow direction  101 . Shelf  306  is located proximate to central ridge  304  so that central ridge  304  is sandwiched between the basin  302  and shelf  306  along a longitudinal direction  310 . Shelf  306  is configured to provide support for condenser  206 . Mist eliminator  308  is coupled to or otherwise located on central ridge  304  along a lateral direction  312  that is perpendicular to the longitudinal direction  310 . Mist eliminator  308  is configured to remove water entrained in the air flowing through the drain pan  208 . 
     Basin  302  of the drain pan  208  includes a first rib  314 , a second rib  316 , a third rib  318 , an angled rib  320 , a drain opening  322 , and a sloped bottom  324 .  FIGS.  3 B- 3 D  further illustrates various cross-sectional perspective views of the basin  302 , according to some embodiments. Sloped bottom  324  includes multiple panels that are sloped to allow water to flow from a first side  326 - 1  of basin  302  to a second side  326 - 2  of basin  302 . First side  326 - 1  and second side  326 - 2  are generally parallel to the longitudinal direction  310 , in some embodiments. First rib  314 , second rib  316 , third rib  318 , and angled rib  320  are disposed on sloped bottom  324 . Specifically, first rib  314  is positioned between a third side  326 - 3  and a fourth side  326 - 4  of basin  302 . Third side  326 - 3  and fourth side  326 - 4  are generally perpendicular to the longitudinal direction  310 , in some embodiments. First rib  314  extends upwardly from sloped bottom  324  and partially across sloped bottom  324  along lateral direction  312 . Second rib  316  is positioned between first rib  314  and third side  326 - 3  of basin  302 . Like first rib  314 , second rib  316  extends upwardly from sloped bottom  324  and partially across sloped bottom  324  along lateral direction  312 . Second rib  316  is generally parallel to first rib  314 , in some embodiments. 
     In some embodiments, first rib  314  and second rib  316  are configured to be positioned underneath the lowest coils of evaporator  204  and are configured to restrict an area between evaporator  204  and drain pan  208  through which air may pass. This configuration minimizes the gap between evaporator  204  and drain pan  208 , restricts the air flowing between the evaporator  204  and the drain pan  208 , reduces the volume of the air flowing through the drain pan  208 , and prevents airflow  101  from flowing underneath evaporator  204  and picking up the condensed water in the drain pan  208 , thereby preventing water from being entrained in the air and improving the efficiency of the dehumidification system  100 . 
     In some embodiments, second rib  316  includes a central gap  328  as illustrated. Central gap  328  is configured to allow water to drain from backside of the second rib, in relation to air flow direction  101 , towards drain opening  322 . Specifically, central gap  328  is configured to allow water to pass through second rib  316 . This avoids completely restricting the air flowing through drain pan  208  which would reduce the amount of air passing through the dehumidification system  100 , thereby reducing the efficiency of the dehumidification system  100 . Additional air flow through the drain pan would directly contribute to the total airflow across the condenser, reducing the head pressure and increasing efficiency of the unit. 
     In some embodiments, third rib  318  is positioned between first rib  314  and second rib  316 . Third rib  318  extends upwardly from sloped bottom  324  and partially across sloped bottom  324  along lateral direction  312 . In some embodiments, third rib  318  is parallel to first rib  314  and is shorter in length than first rib  314  as illustrated. Third rib  318  is configured to at least partially block airflow through central gap  328  of second rib  316  along longitudinal direction  310 . The requirement of the third rib  318  is determined by the distance between the first rib  314  and second rib  316 . If the distance between first rib  314  and second rib  316  is small, then the first rib  314  will be able to sufficiently reduce airflow through the central gap in the longitudinal direction  310 . 
     Like third rib  318 , angled rib  320  is positioned between first rib  314  and second rib  316 . In some embodiments, angled rib  320  is further positioned between third rib  318  and second side  326 - 2  of basin  302 . Angled rib  320  extends upwardly from sloped bottom  324  and is attached to second rib  316  as illustrated. Referring to  FIG.  3 E , angled rib  320  may be inclined towards third rib  318  and have an angle  330  with respect to second rib  316 . In some embodiments, angle  330  is in a range of 30° to 50°. Yet in other embodiments, angle  330  may be any appropriate angle. 
     First rib  314 , second rib  316 , third rib  318 , and angled rib  320  work together to change the velocity vector of the air flowing through drain pan  208 .  FIG.  3 E  illustrates an example of the velocity vectors for a streamline in airflow  101  passing through drain pan  208 . As noted before, first rib  314  is configured to restrict airflow by minimizing the gap between evaporator  204  and drain pan  208 . First rib  314  further reduce the velocity of airflow  101  by the time it reaches second rib  316 . Specifically, first rib  314  reduces the velocity of the airflow  101  by allowing a portion of airflow  101  to flow around first rib  314 . Third rib  318  and angled rib  320  are configured to change the velocity vector of airflow  101 . Without third rib  318  and angled rib  320 , airflow  101  may flow around first rib  314 , exit central gap  328  of second rib  316 , and be directed sideways towards first side  326 - 1  of basin  302 . A portion of the airflow  101  exiting central gap  328  may carry entrained water out of the drain pan  208  or from the bottom corner of evaporator  204 , thereby decreasing the efficiency of dehumidification system  100 . Third rib  318  and angled rib  320  change the velocity vector of the portion of airflow  101  exiting central gap  328  to be more parallel to longitudinal direction  310 . The change in velocity vector works to direct the highest velocity airflow through the mist eliminator  308  to remove any water droplets that have been entrained in the airflow  101 . Referring back to  FIG.  3 A , basin  302  further includes a drain opening  322 . In some embodiments, drain opening  322  is located at fourth side  326 - 4  of basin  302 . Drain opening  322  may be proximate to second side  326 - 2  of basin  302  so that water flowing from first side  326 - 1  to second side  326 - 2  may be drained out of dehumidification system  100  via drain opening  322 . 
     In some embodiments, drain pan  208  further includes a central ridge  304  located proximate to basin  302 . Specifically, the central ridge  304  is located proximate to third side  326 - 3  of basin  302 . In some embodiments, central ridge  304  includes a wall along lateral direction  312  as illustrated. Central ridge  304  is configured to accommodate a mist eliminator  308  and prevent water from leaving basin  302  to the downstream side. As illustrated, mist eliminator  308  is disposed on central ridge  304  and is extending along lateral direction  312 . Referring to  FIG.  3 G , in some embodiments, mist eliminator  308  includes a member  333  extending along lateral direction  312 , a plurality of apertures  332  on member  333 , and one or more hooks  338  that allow mist eliminator  308  to be coupled to central ridge  304 . Mist eliminator  308  is generally configured to remove the water entrained in the air flowing through drain pan  208 . Referring to  FIG.  3 F , mist eliminator  308  may have an angle  334  with respect to a vertical direction  336 . Angle  334  may be in a range of 0-90°. For example, when angle  334  is zero degree with respect to vertical direction  336 , mist eliminator  308  is parallel to the vertical direction. When angle  334  is 90° with respect to vertical  336  direction, mist eliminator  308  is perpendicular to vertical direction  336 . In some embodiments, mist eliminator  308  includes a plurality of apertures  332  configured to minimize air restriction during normal operation but remove water droplets during defrost conditions. Most often, defrost conditions are the worst for water entrainment because the coil is still completely frozen in some locations, which restricts air flow in that location leading to higher velocities through the remaining evaporator coil or drain pan, and there is a large amount of water being melted from the coil. The melting water is then subject to the higher velocities, leading to increased water entrainment, decreasing the performance of the dehumidifier. In some embodiments, the apertures  332  are arranged in multiple rows in mist eliminator  308 . For example, referring to  FIG.  3 G , mist eliminator  308  includes two rows of apertures  332 . In some embodiments as illustrated, mist eliminator  308  includes an area that is not occupied by apertures  332 . The area that is not occupied by apertures  332  is located in the area of highest air velocity caused by central gap  328 . The area not occupied by apertures  332  creates a larger air side restriction and subsequently changing the air velocity vectors coming off the bottom side of evaporator  204 . For example, when airflow  101  carrying water droplets flows through mist eliminator  308 , the water will make contact with the area of mist eliminator  308  that is not occupied by apertures  332 . The water droplets will then flow back down into the drain pan  208  and can be removed from the dehumidifier via drain opening  322 , increasing the efficiency of the dehumidifier. The water droplets are prevented from going away from drain pan opening  322  by the central ridge  304 . 
       FIG.  3 H  illustrates how mist eliminator  308  changes vectors of airflow  101 . Without mist eliminator  308 , airflow  101  flowing through drain pan  208  will have a velocity vector  340  as illustrated. This allows the water droplets on the bottom right side of evaporator  204  to be pulled over central ridge  304  and out of basin  302 . On the other hand, with mist eliminator  308 , airflow  101  flowing through drain pan  208  will have velocity vectors  342  as illustrated. Here, mist eliminator  308  changes the velocity of airflow  101  from vector  340  to vectors  342 , thereby preventing the water droplets from leaving an area where it would drain back to drain opening  322 . 
     Referring back to  FIG.  3 A , drain pan  208  further includes a shelf  306 . Shelf  306  is located proximate to central ridge  304  partially below condenser  206 . Shelf  306  may include a horizontal member configured to provide support for condenser  206 . 
     The scope of this disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the example embodiments described or illustrated herein that a person having ordinary skill in the art would comprehend. The scope of this disclosure is not limited to the example embodiments described or illustrated herein. Moreover, although this disclosure describes and illustrates respective embodiments herein as including particular components, elements, feature, functions, operations, or steps, any of these embodiments may include any combination or permutation of any of the components, elements, features, functions, operations, or steps described or illustrated anywhere herein that a person having ordinary skill in the art would comprehend. Furthermore, reference in the appended claims to an apparatus or system or a component of an apparatus or system being adapted to, arranged to, capable of, configured to, enabled to, operable to, or operative to perform a particular function encompasses that apparatus, system, component, whether or not it or that particular function is activated, turned on, or unlocked, as long as that apparatus, system, or component is so adapted, arranged, capable, configured, enabled, operable, or operative. Additionally, although this disclosure describes or illustrates particular embodiments as providing particular advantages, particular embodiments may provide none, some, or all of these advantages.