Patent Publication Number: US-11639810-B2

Title: Air handling system and method with angled air diffuser

Description:
TECHNICAL FIELD 
     The disclosed devices and methods relate generally to an air handling system such as an air-conditioner that heats or cools air in a larger air-conditioning system. More particularly, the disclosed devices and methods relate to an air handler that includes an air diffuser to control the expansion and conversion of kinetic energy of air passing through the air handler to even out the flow of air throughout the air handler, thereby reducing flow resistance, increasing the static pressure of air processed by the air handler, and reducing the power requirements of the air handler. 
     BACKGROUND 
     An air handler is a device that draws in air from a room or an outside environment, conditions the air (e.g., heats or cools the air), and passes the conditioned air to a target location at a set point temperature. The air handler will typically contain a fan that operates to push or pull the air through the air handler. 
     In order to achieve sufficient heating and cooling for a target location, the fan in the air handler must circulate a certain amount of air over a given period of time and must also raise the static pressure of that air after it is conditioned to a sufficient level to allow the air to circulate through the ductwork associated with the larger air-conditioning system at the target location. Typically, the fan in an air handler requires significant power input to raise the discharge static pressure of its output air. Furthermore, a centrifugal fan, which is commonly used in air handlers, causes an increase the air speed of the air passing through the air handler. Within the fan, some of the speed is converted into static pressure but not all. 
     When the air is discharged from the fan, there is typically still significant kinetic energy that has not been converted into static pressure. As a result of this, when air is discharged from a fan into an open duct, much of the remaining speed (kinetic energy) is wasted as eddies and vortices form in the ducts and dissipate this energy. This wasted energy translates into wasted power and can require increased power expenditures to operate the fan at a higher speed (and thus power) to achieve the required air pressure in the air handler. 
     It is therefore desirable to minimize the air kinetic energy lost in the air handler by eddies and vortices, thereby improving the power efficiency of the fan in the air handler. 
     SUMMARY OF THE INVENTION 
     According to one or more embodiments, an air handler is provided, comprising: an air inlet configured to pass input air into the air handler; a heating and cooling coil configured to exchange heat with the input air as the input air passes over the heating and cooling coil to generate conditioned air; an air diffuser configured to diffuse the conditioned air to generate diffused air; an air outlet configured to expel the diffused air as outlet air; an air blower configured to draw the input air into the air handler, pass the input air over the heating and cooling coil, pass the conditioned air through the diffuser, and expel the diffused air through the air outlet as output air; and an air-handler controller configured to control operation of the heating and cooling coil and the air blower, wherein the air diffuser contains one or more baffles configured to create two or more air passages, the air passages being configured to control the expansion and reduction of kinetic energy of the conditioned air to generate the diffused air, a first direction represents a direction of a shortest line between the air blower and the outlet, the air diffuser is further configured such that air passing through the air diffuser passes in a second direction displaced at from the first direction by a deflection angle, and the deflection angle may be greater than 5°. 
     The air handler may further comprise: a heater coil located between the air diffuser and the outlet and configured to heat the diffused air before providing it as outlet air. 
     The output of the air blower may be tilted at a blower tilt angle from a direction perpendicular to the first direction such that the conditioned air blown from the air blower flows in a third direction that is the blower tilt angle from the first direction, and the blower tilt angle may be greater than 0°. 
     The blower tilt angle may be the same as the deflection angle. 
     The deflection angle may be between 10° and 30°. 
     The third direction may be the same as the second direction. 
     A diffuser angle between a first wall of the air diffuser and a second wall of the air diffuser may be between 20° and 50°, the one or more baffles may be arranged between the first wall and the second wall such that the two or more air passages each define a corresponding passage angle, and a sum of all the passage angles may equal the diffuser angle. 
     The corresponding passage angles may all be equivalent or at least two of the corresponding passage angles may be different. 
     The air diffuser and the blower may be formed as separate devices or the air diffuser and the blower are formed may be a unified device. 
     An air handler is provided, comprising: an air inlet configured to pass input air into the air handler; a heating and cooling coil configured to exchange heat with the input air as the input air passes over the heating and cooling coil to generate conditioned air; an air diffuser configured to diffuse the conditioned air to generate diffused air; an air outlet configured to expel the diffused air as outlet air; an air blower configured to draw the input air into the air handler, pass the input air over the heating and cooling coil, pass the conditioned air through the diffuser, and expel the diffused air through the air outlet as output air; and an air-handler controller configured to control operation of the heating and cooling coil and the air blower, wherein a first direction represents a direction of a shortest line between the air blower and the outlet, the air diffuser is further configured such that air passing through the air diffuser passes in a second direction displaced from the first direction by a deflection angle, an output of the air blower is tilted at a blower tilt angle from a direction perpendicular to the first direction such that the conditioned air blown from the air blower flows in a third direction that is the blower tilt angle from the first direction, the air diffuser configured to divide flow of the conditioned air to generate the diffused air, the blower tilt angle may be greater than 0°, and the deflection angle may be greater than 5°. 
     The third direction may be the same as the second direction. 
     The air handler may further comprise: a heater coil located between the air diffuser and the outlet and configured to heat the diffused air before providing it as outlet air. 
     The blower tilt angle may be greater than 10°. 
     The blower tilt angle may be the same as the deflection angle. 
     The deflection angle may be between 10° and 30°. 
     A diffuser angle between a first wall of the air diffuser and a second wall of the air diffuser may be between 20° and 50°. 
     A method for operating an air handler is provided, the method comprising: drawing input air into the air handler through an air inlet; conditioning the input air to generate conditioned air; diffusing the conditioned air to create diffused air while passing the conditioned air from an air blower to an air outlet; expelling the diffused air as output air through the air outlet, wherein a first direction represents a direction of a shortest line between the air blower and the outlet, during the operation of diffusing the conditioned air, the conditioned air flows in a second direction displaced at from the first direction by a deflection angle, during the operation of diffusing the conditioned air, the conditioned air is separated into two or more air paths, and the deflection angle may be greater than 5°. 
     The diffused air may be heated before being passed as the outlet air through the air outlet. 
     The deflection angle may be between 10° and 30°. 
     The two or more air paths may run along parallel air passages, each of the parallel air passages defining a corresponding passage angle from a corresponding air passage start to a corresponding air passage end, and a sum of all the passage angles may be between 20° and 50°. 
     The corresponding passage angles may all be equivalent or at least two of the corresponding passage angles may be different. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying figures, where like reference numerals refer to identical or functionally similar elements and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate an exemplary embodiment and to explain various principles and advantages in accordance with the present disclosure. 
         FIG.  1    is a diagram of an air handler according to first disclosed embodiments; 
         FIG.  2    is a diagram of an air handler according to second disclosed embodiments; 
         FIG.  3    is a diagram of a thirty-degree diffuser with no baffles according to disclosed embodiments; 
         FIG.  4    is a diagram of a thirty-degree diffuser with evenly arranged baffles according to disclosed embodiments; 
         FIG.  5    is a diagram of a thirty-degree diffuser with unevenly arranged baffles according to disclosed embodiments; 
         FIG.  6    is a diagram of a diffuser with two baffles according to disclosed embodiments; 
         FIG.  7    is a diagram of a diffuser with three baffles according to disclosed embodiments; 
         FIG.  8    is a diagram of a diffuser with two baffles according to disclosed embodiments; 
         FIG.  9    is a diagram of an air handler according to third disclosed embodiments; 
         FIG.  10    is a flow chart showing the operation of an air handler according to disclosed embodiments; and 
         FIG.  11    is a flow chart showing the operation of passing conditioned air from a blower to an air outlet from  FIG.  10    according to disclosed embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Air Handler—First Embodiments 
       FIG.  1    is a diagram of an air handler  100  according to first disclosed embodiments. As shown in  FIG.  1   , the air handler  100  includes an air handler housing  105 , an air inlet duct  110 , a heating and cooling coil  115 , a fan  120 , a separation plate  125 , an air diffuser  130 , a heater coil  140 , an outlet duct  145 , and an air handler control box  150 . The fan  120  further includes a blower  160  and a fan housing  165 . The air diffuser  130  may include one or more baffles  180 . 
     The air handler housing  105  is a frame that contains the other components of the air handler  100 . The air handler housing  105  serves to protect these components and provide an enclosed avenue for air to pass from the air inlet duct  110  to the air outlet duct  145 . 
     The air inlet duct  110  is an opening in the air handler housing  105  that allows inlet air  113  to enter the air handler housing  105 . 
     The heating and cooling coil  115  is a heat exchange coil that operates to exchange heat between a refrigerant passing through the heating and cooling coil  115  and the inlet air  113  passing over the heating and cooling coil  115  to generate conditioned air  170 . In a heating mode the exchange of heat between the heating and cooling coil  115  and the inlet air  113  will heat the inlet air  113 , and in a cooling mode the exchange of heat between the heating and cooling coil  115  and the inlet air  113  will cool the inlet air  113 . 
     The fan  120  operates to draw the inlet air  113  into air handler housing  105  via the air inlet duct  110 , pass the inlet air  113  through the heating and cooling coil  115  to generate the conditioned air  170 , pass the conditioned air  170  through the diffuser  130  to generate diffused air  190 , and pass the diffused air  190  through the heater coil  140  and out the outlet duct  145  as outlet air  195 . 
     The fan  120  operates to circulate the air through the air handler housing  105  such that it passes over the heating and cooling coil  115  so that it can be properly conditioned and such that it achieves a sufficient static pressure that the air can properly circulate through the ductwork in the remainder of an air-conditioning system. In the embodiment of  FIG.  1   , the fan  120  is located between the heating and cooling coil  115  and the separation plate  125 . The fan  120  draws in the conditioned air  170  that is conditioned by passing through the heating and cooling coil  115  and blows it through an opening in the separation plate  125  to the air diffuser  130 . 
     In the embodiment of  FIG.  1   , the fan  120  is a centrifugal fan that includes the blower  160  and a fan housing  165 . However, this is by way of example only. Alternate embodiments can employ any suitable fan that moves air from the air inlet duct  110 , through the air handler  100 , and out the air outlet. 
     The blower  160  rotates around an axis, draws in the conditioned air  170  (which can be considered first blown air) from the heating and cooling coil  115 , and blows the conditioned air  170  through an opening in the separation plate  125  and into the diffuser  130 . The discharge air from a centrifugal fan is generally concentrated toward the outer end of the fan output rather than being evenly distributed across the fan output. 
     The fan housing  165  contains the conditioned air  170  (first blown air) that is being blown by the blower  160  such that the conditioned air  170  (first blown air) is expelled from an opening in the fan housing  165  coincident with a similar opening in the separation plate  125 . 
     The separation plate  125  is a structure located in the air handler housing  105  between the fan  120  and the diffuser  130  that operates to prevent any air from passing from one side of the separation plate  125  to the other in the air handler housing  105  except through an opening in the separation plate  125  coincident with the output of the fan  120 . In this way, only the conditioned  170  air expelled from the fan  120  will pass from one side of the separation plate  125  to the other inside the air handler housing  105 . 
     In the embodiment of  FIG.  1   , the separation plate  125  is tilted by a blower tilt angle β from a line perpendicular to a first direction that represents the shortest line between the inlet duct  110  and the outlet duct  145 . The blower tilt angle β can vary in different embodiments but is preferably in the range of 5° to 45°. More preferably, the blower tilt angle β is in a range of 10° to 30°. 
     Because the separation plate  125  is tilted by the blower tilt angle β, the conditioned air  170  expelled by the fan  120  into the air diffuser  130  will be at an angle from the first direction. The air diffuser  130  may further deflect the conditioned air  170  away from the first direction. In this way, the conditioned air  170  is deflected by a deflection angle α from the first direction. Depending upon how the air diffuser  130  is arranged, the deflection angle α may be the same as the blower tilt angle β or may differ from the blower tilt angle β. By having the conditioned air  170  expelled by the fan  120  into the air diffuser  130  be at a deflection angle α, the conditioned air  170  will be spread in a second direction diagonally across the first direction rather than in a direction parallel to the first direction. This will serve to move the bulk of the flow of the conditioned air  170  toward the center of the air handler  130  rather than allowing it to concentrate on one side of the air handler  130 . In doing so, this will allow the air diffuser  130  to better mix the conditioned air  170  as it is transformed into diffused air  190 , further reducing the creation of eddies and vortices in the air and making it more efficient for the air handler  100  to increase the static air pressure of the diffused air  190 . 
     The air diffuser  130  receives the conditioned air  170  from the fan  120  and operates to perform a controlled expansion of the conditioned air  170  to generate diffused air  190 . This controlled expansion increases the amount of air speed that is converted to static air pressure as compared to a system without the air diffuser  130  attached to the output of the fan  120 . In doing so, the air diffuser  130  reduces the air speed needed at the output of the fan  120  to achieve a desired static air pressure. This means that the fan  120  will use less power to achieve the desired static air pressure than a system without the air diffuser  130  attached to the output of the fan  120 . 
     A cross-section of the air diffuser  130  has a trapezoidal shape with the shorter parallel side facing the fan  120  and the longer parallel side facing the outlet duct  145 . In other words, an air input for the air diffuser  130  is smaller than an air output of the air diffuser  130  and the air diffuser  130  gradually widens along its length. As a result, an air diffuser  130  can be defined by the angle of this expansion, measured by a hypothetical apex where the two non-parallel sides of the air diffuser  130  would meet if extended toward the fan  120 . 
     In various embodiments, the angle of expansion of the air diffuser  130  can vary between 20° and 45°. However, smaller angles of expansion for air paths in the air diffuser can provide for more advantageous air diffusion. Therefore, the air diffuser  130  can include one or more baffles  180  that break up the air flow through the air diffuser  130  into separate air passages that each have an expansion angle smaller than the expansion angle of the air diffuser  130  as a whole. Generally, the total of the expansion angles of the separate air passages will equal the expansion angle of the air diffuser  130  as a whole. However, this may not be true for some embodiments. 
     For example, a single 30° air diffuser  130  could have two baffles  180  that create three separate air passages that are 10° each. Many other arrangements are possible by modifying the number and position of the baffles  180 . The angles of the air passages created by the baffles  180  in the air diffuser  130  can be the same for each passage or may differ among the passages. 
     When using a centrifugal fan as the fan  120 , the conditioned air  170  discharged from the fan  120  is concentrated toward the outer end of the fan  120 . An air diffuser  130  that was relatively short (e.g., six inches) and had no baffles  180  might need an expansion angle as high as 30°, which would not allow for the recovery of significant pressure. However, an air diffuser  130  of the same length but with two baffles  180  could significantly increase pressure recovery by reducing the width and expansion angle of the air passages in the air diffuser  130 . 
     The baffles  180  are plates that operate to divide the space inside the air diffuser  130  into multiple separate air passages. The baffles  180  are formed so that no air can pass through one of the baffles  180  from one air passage to another over the course of the air passage. In various embodiments the baffles  180  can extend over the entire course of the air diffuser  130  from an input opening to an output opening. In other embodiments, the baffles  180  can run less than the entire course of the air baffle  130  from the input opening to the output opening. 
     Since the separation plate  125  is tilted with respect to a first direction causing the conditioned air  170  output from the fan  120  to be in a second direction that is a deflection angle α from the first direction, the air diffuser  130  is not symmetrical around the first direction. This angling of the conditioned air output from the fan  120  can help reduce the formation of eddies and vortices and increase the pressure of the resulting diffused air as compared to an air diffuser  130  of the same length but which received air in the first direction. 
     The heater coil  140  is provided to exchange heat with the diffused air  190  prior to it being ejected from the air diffuser  130  through the outlet vent  190  as outlet air  195  (which can be considered second blown air). The heater coil  140  is a heat exchanger that can be used, for example, in a cooling operation in which the conditioned air  170  is brought to a temperature lower than a desired set point to dehumidify the inlet air  113 . The heater coil  140  need not be operated in every operation mode and could be eliminated in some alternate embodiments. 
     The outlet duct  145  is an opening in the air handler housing  105  that allows outlet air  195  to exit the air handler housing  105  after it has been conditioned and diffused. Based on the operation of the fan  120  and the diffuser  130 , the outlet air  195  (second blown air) will have a pressure sufficient to pass through the ductwork of the remainder of the air-conditioning system the air handler  100  is a part of and heat or cool the target space. 
     The air handler control box  150  controls the operation of the air handler  100 . It can include a processor that generates signals to control the fan  120  or any other element that requires control signals. The air handler control box  150  can store information in a memory and run instructions stored in the memory. The processor can be a microprocessor (e.g., a central processing unit), an application-specific integrated circuit (ASIC), or any suitable device for controlling the operation of all or part of the air handler  100 . The memory can include a read-only memory (ROM), a random-access memory (RAM), an electronically programmable read-only memory (EPROM), an electrically erasable programmable read only memory (EEPROM), flash memory, or any suitable memory device. 
     Some alternate embodiments can have the air handler control box  150  control more than just the air handler  100 . Other alternate embodiments can have the air handler  100  controlled by a controller external to the air handler  100 . 
     Although the embodiment of  FIG.  1    shows the fan  120  being located between the heating and cooling coil  115  and the separation plate  125 , this is by way of example only. Alternate embodiments could alter the position of the fan  120  so long as it moves air through the air handler  100  in an efficient manner. In embodiments in which the location of the fan  120  is altered, the location of the diffuser  130  would likewise be altered to diffuse the air expelled from the fan  120  such that the formation of eddies and vortices can be reduced. 
     An exemplary embodiment will show the benefits of this arrangement. For a PVA-5 ton (1900 standard cubic feet per minute flow), the amount of recoverable pressure is 0.73 inWC. A system without the air deflection in the diffuser  130  described above will typically recover 15% of this, resulting in a total loss of 0.62 inWC for the system. In contrast, a system with an angled separation plate  125  and an air diffuser  130  that further deflects the diffused air  190  allows 55% recovery of pressure, resulting in a total loss of pressure of 0.33 inWC. The use of an angled separation plate  125  and an air diffuser  130  that further deflects the diffused air  190  could therefore add a 0.30 inWC improvement in output air handler pressure for this design. This could result in ˜20% reduction in required fan power to generate a desired static pressure for the outlet air  195  as compared to an air handler without these features. Such power reduction is significant to both system efficiency and motor selection. 
     Air Handler—Second Embodiment 
       FIG.  2    is a diagram of an air handler  200  according to alternate disclosed embodiments. As shown in  FIG.  2   , the air handler  200  includes an air handler housing  205 , an air inlet duct  110 , a heating and cooling coil  115 , a fan  220 , a separation plate  225 , an air diffuser  230 , a heater coil  240 , an outlet duct  245 , an air handler control box  250 . The fan  220  further includes a blower  260  and a fan housing  265 . The air diffuser  230  may include one or more baffles  280 . 
     The air handler housing  205  is similar in structure and operation to the air handler housing  105  in  FIG.  1    save that it is sized to hold the elements that form the air handler  200 . 
     The air inlet duct  110  and the heating and cooling coil  115  operate as described above with respect to the embodiment of  FIG.  1   . 
     The fan  220  operates in a manner similar to the fan  120  in the embodiment of  FIG.  1   , i.e., to draw the inlet air into air handler housing  205  via the air inlet duct  110 , pass the inlet air  113  through the heating and cooling coil  115  to generate the conditioned air  270 , pass the conditioned air  270  through the diffuser  230  to generate diffused air  290 , and pass the diffused air through the heater coil  240  and out the outlet duct  245  as outlet air  295 . The fan  220  in the embodiment of  FIG.  2    differs from the fan  120  in the embodiment of  FIG.  1    in that the separation plate  225  extends perpendicular to the first direction. As a result, the conditioned air  270  blown out of the fan  220  through the opening in the separation plate  225  will initially be blown in the first direction. The fan  220  draws in the conditioned air  270  that is conditioned by passing through the heating and cooling coil  115  and blows it through the opening in the separation plate  225  to the air diffuser  230 . 
     In the embodiment of  FIG.  2   , the fan is a centrifugal fan that includes the blower  260  and a fan housing  265 . However, this is by way of example only. Alternate embodiments can employ any suitable fan that moves air from the air inlet duct  210 , through the air handler  200 , and out the air outlet. The blower  260  and the fan housing  265  operate in a manner like that of comparably numbered elements in the embodiment of  FIG.  1   . 
     The separation plate  225  is a structure located between the fan  220  and the diffuser  230  that operates to prevent any air from passing through it except through an opening coincident with the output of the fan  220 . In this way, only the conditioned air  270  expelled from the fan  220  will pass from one side of the separation plate  225  to the other. However, unlike the embodiment of  FIG.  1   , the separation plate  225  in the embodiment of  FIG.  2    extends perpendicular to the first direction, i.e., a blower tilt angle is zero. 
     Because the separation plate  225  is perpendicular to the first direction, the conditioned air  270  expelled by the fan  220  into the air diffuser  230  will initially be parallel to the first direction. However, the air diffuser  230  is tilted at an angle such that the conditioned air  270  expelled by the fan  220  into the air diffuser  230  will be deflected at a deflection angle θ from the first direction. By having the conditioned air  270  deflected by the air diffuser  230  to a deflection angle θ, the conditioned air  270  will be spread diagonally across the first direction rather than parallel to the first direction. This will serve to move the bulk of the flow of the conditioned air  270  toward the center of the air handler  230  rather than allowing it to concentrate on one side of the air handler  230 . This will allow the air diffuser  230  to better mix the conditioned air  270  as it is transformed into diffused air  290 , further reducing the creation of eddies and vortices in the air and making it more efficient for the air handler  200  to increase the static air pressure of the diffused air  290 . Thus, in the second embodiment the air diffuser  230  alone is responsible for the deflection angle θ of the diffused air  290  rather than a deflection angle α being a result of both the blower tilt angle β and the structure of the air diffuser  130  in the first embodiment. 
     The air diffuser  230  receives the conditioned air  270  from the fan  220  and operates to perform a controlled expansion of the conditioned air to generate diffused air  290 . This controlled expansion increases the amount of air speed that is converted to static air pressure as compared to a system without the air diffuser  230  attached to the output of the fan  220 . In doing so, the air diffuser  230  reduces the air speed needed at the output of the fan  220  to achieve a desired static air pressure. This means that the fan  220  will use less power to achieve the desired static air pressure than a system without the air diffuser  230  attached to the output of the fan  220 . 
     A cross-section of the air diffuser  230  has a trapezoidal shape with the shorter parallel side facing the fan  220  and the longer parallel side facing the outlet duct  245 . In other words, an air input for the air diffuser  230  is smaller than an air output of the air diffuser  230  and the air diffuser  230  gradually widens along its length. As a result, an air diffuser  230  can be defined by the angle of this expansion, measured by a hypothetical apex where the two non-parallel sides of the air diffuser  230  would meet if extended toward the fan  220 . 
     In various embodiments, the angle of expansion of the air diffuser  230  can vary between 20° and 45°. However, smaller angles of expansion for air paths in the air diffuser can provide for more advantageous air diffusion. Therefore, the air diffuser  230  can include one or more baffles  280  that break up the air flow through the air diffuser  230  into separate air passages that each have an expansion angle smaller than the expansion angle of the air diffuser  230  as a whole. For example, a single 30° air diffuser  230  could have two baffles  280  that create three separate air passages that are 10° each. Many other arrangements are possible by modifying the number and position of the baffles  280 . The angles of the air passages created by the baffles  280  in the air diffuser  230  can be the same for each passage or may differ among the passages. 
     For example, when using a centrifugal fan as the fan  220 , the conditioned air  270  discharged from the fan  220  is concentrated toward the outer end of the fan  220 . An air diffuser  230  that was relatively short (e.g., six inches) and had no baffles  280  might have to have an expansion angle as high as 30°, which would not allow for the recovery of significant pressure. However, an air diffuser  230  of the same length but with two baffles  280  could significantly increase pressure recovery by reducing the width of the air passages in the air diffuser  230 . 
     The baffles  280  are configured and operate similarly to the baffles  180  in the first embodiment save that they may be oriented or arranged differently resulting in differently shaped air passages. 
     Although the separation plate  225  is perpendicular to the first direction, the air diffuser  230  is still not symmetrical around the first direction since it is configured to deflect the diffused air  290  by the deflection angle θ. This angling of the conditioned air output from the fan  220  can help reduce the formation of eddies and vortices and increase the pressure of the resulting diffused air as compared to an air diffuser  230  of the same length but which received air in the first direction. 
     The heater coil  240 , the outlet duct  245 , and the air handler control box  250  operate in manners comparable to the heater coil  140 , the outlet duct  145 , and the air handler control box  150  in the first embodiment. As with the first embodiment, the heater coil  240  need not be operated in every operation mode and could be eliminated in some alternate embodiments. 
     Although the embodiment of  FIG.  2    shows the fan  220  being located between the heating and cooling coil  115  and the separation plate  225 , this is by way of example only. Alternate embodiments could alter the position of the fan  220  so long as it moves air through the air handler  200  in an efficient manner. In embodiments in which the location of the fan  220  is altered, the location of the diffuser  230  would likewise be altered to diffuse the air expelled from the fan  220  such that the formation of eddies and vortices can be reduced. 
     Diffusers 
       FIG.  3    is a diagram of a thirty-degree diffuser  300  with no baffles according to disclosed embodiments. As shown in  FIG.  3   , the diffuser  300  is defined by a diffuser housing  310  and has a diffuser air inlet  320  and a diffuser air outlet  330 . 
     The diffuser housing  310  has a trapezoidal cross-section with an expansion angle of 30° between the two nonparallel walls of its cross-section. The expansion of the diffuser  300  will cause air flowing through it to recover some pressure from the air as it passes through the diffuser. 
     The diffuser air inlet  320  is formed at the smaller of the parallel sides of the cross-section. The diffuser air inlet  320  is positioned where air that needs to be diffused will enter the diffuser  300 . 
     The diffuser air outlet  330  is formed at the larger of the parallel sides of the cross-section. The diffuser air outlet  330  is positioned where air that has been diffused by the diffuser  300  will exit the diffuser  300 . 
       FIG.  4    is a diagram of a thirty-degree diffuser  400  with evenly arranged baffles  440 ,  445  according to disclosed embodiments. As shown in  FIG.  4   , the diffuser  400  is defined by a diffuser housing  310  and has a diffuser air inlet  320 , and a diffuser air outlet  330 . Two baffles  440 ,  445  are formed inside the diffuser  400 . 
     The diffuser housing  310 , the diffuser air inlet  320 , the diffuser air outlet  330  are configured as described above with respect to the diffuser  300  of  FIG.  3   . 
     The diffuser  400  has an expansion angle of 30° between the two nonparallel walls of its cross-section. The diffuser  400  also has two evenly arranged baffles  440 ,  445  that create first, second, and third air passages  460 ,  465 ,  470  inside the diffuser  400 . Since the baffles  440 ,  445  are evenly arranged, the expansion angles of the air passages  460 ,  465 ,  470  are likewise equal. Specifically, the expansion angle of each air passage  460 ,  465 ,  470  is 10°. 
     Because each air passage  460 ,  465 ,  470  has a smaller expansion angle than the diffuser  400  in general, the diffused air passing through each individual air passage  460 ,  465 ,  470  will recover a greater amount of pressure as compared to a diffuser  300  with no baffles of a similar length. This will result in a greater static air pressure of the air exiting the diffuser  400  when the air from the three air passages  460 ,  465 ,  470  are combined. 
     Because the conditioned air output from a fan in an air handler may not be uniform over the output vent of the fan, the precise configuration and number of the baffles in a diffuser to configure air passages that will maximize the amount of pressure recovery from the operation of the diffuser may vary among different air handlers. However, it will be possible to test an individual air handler design to determine what number, placement, and arrangement of baffles would create a set of air passages that will maximize the amount of pressure recovery. Once the precise arrangement is determined by testing, an appropriate air handler can be created for the particular air handler. Such an air handler may not have air passages whose expansion angles are the same. 
       FIG.  5    is a diagram of a thirty-degree diffuser  500  with unevenly arranged baffles  540 ,  545  according to disclosed embodiments. As shown in  FIG.  5   , the diffuser  500  is defined by a diffuser housing  310  and has a diffuser air inlet  320 , and a diffuser air outlet  330 . Two baffles  540 ,  545  are formed inside the diffuser  500 . 
     The diffuser housing  310 , the diffuser air inlet  320 , the diffuser air outlet  330  are configured as described above with respect to the diffuser  300  of  FIG.  3   . 
     The diffuser  500  has an expansion angle of 30° between the two nonparallel walls of its cross-section. The diffuser  500  also has two unevenly arranged baffles  540 ,  545  that create first, second, and third air passages  560 ,  565 ,  570  inside the diffuser  500 . Since the baffles  540 ,  545  are unevenly arranged, the expansion angles of the air passages  560 ,  565 ,  570  are not equal. Specifically, a first expansion angle of a first air passage  560  is 50, a second expansion angle of a second air passage  565  is 15°, and a third expansion angle of a third air passage  570  is 10°. 
     Because each air passage  560 ,  565 ,  570  has a smaller expansion angle than the diffuser  500  in general, the diffused air passing through each individual air passage  560 ,  565 ,  570  will recover a greater amount of pressure as compared to a diffuser  300  with no baffles of a similar length. This will result in a greater static air pressure of the air exiting the diffuser  500  when the air from the three air passages  560 ,  565 ,  570  are combined. 
     However, this is by way of example only to show how a diffuser  500  with uneven baffles  540 ,  545  might be arranged. The specific placement of the baffles  540 ,  545  and the expansion angles of the resulting air passages  560 ,  565 ,  570  can vary with each separate air handler design. 
       FIG.  6    is a diagram of a diffuser  600  with two baffles  640 ,  645  according to disclosed embodiments. As shown in  FIG.  6   , the diffuser  600  is defined by a diffuser housing  610  and has a diffuser air inlet  620 , and a diffuser air outlet  630 . Two baffles  640 ,  645  are formed inside the diffuser  600 . 
       FIG.  6    is like  FIGS.  4  and  5    in construction and operation and elements in  FIG.  6    operate similarly to comparable elements in  FIGS.  4  and  5   . 
       FIG.  6    discloses that for any given diffuser  600  of a given expansion angle, a number of baffles  640 ,  645  can be provided that divide the space inside the diffuser  600  into multiple, separate air passages  660 ,  665 ,  670  of varying expansion angles. A first air passage  660  is A°, a second air passage  665  is B°, and a third air passage  670  is C°. The values for A, B, and C can vary between different air handler designs. 
     Because each air passage  660 ,  665 ,  670  has a smaller expansion angle than the diffuser  600  in general, the diffused air passing through each individual air passage  660 ,  665 ,  670  will recover a greater amount of pressure as compared to a diffuser  300  with no baffles of a similar length. This will result in a greater static air pressure of the air exiting the diffuser  600  when the air from the three air passages  660 ,  665 ,  670  are combined. 
     Although  FIG.  6    discloses an air diffuser  600  with two baffles  640 ,  645 , this is by way of example only. More or fewer baffles can be used in alternate embodiments. 
       FIG.  7    is a diagram of a diffuser  700  with three baffles  740 ,  745 ,  750  according to disclosed embodiments. As shown in  FIG.  7   , the diffuser  700  is defined by a diffuser housing  610  and has a diffuser air inlet  620 , and a diffuser air outlet  630 . Three baffles  740 ,  745 ,  750  are formed inside the diffuser  700 . 
       FIG.  7    is like  FIG.  6    in construction and operation and elements in  FIG.  7    operate similarly to comparable elements in  FIG.  6   . 
       FIG.  7    discloses that for any given diffuser  700  of a given expansion angle, a number of baffles  740 ,  745 ,  750  can be provided that divide the space inside the diffuser  700  into multiple, separate air passages  760 ,  765 ,  770 ,  775  of varying expansion angles. A first air passage  760  is K°, a second air passage  765  is L°, a third air passage  770  is M°, and a fourth air passage  775  is N°. The values for K, L, M, and N can vary between different air handler designs. 
     Because each air passage  760 ,  765 ,  770 ,  775  has a smaller expansion angle than the diffuser  700  in general, the diffused air passing through each individual air passage  760 ,  765 ,  770 ,  775  will recover a greater amount of pressure as compared to a diffuser  300  with no baffles of a similar length. This will result in a greater static air pressure of the air exiting the diffuser  500  when the air from the four air passages  760 ,  765 ,  770 ,  775  are combined. 
       FIG.  7    specifically shows an example using three baffles  740 ,  745 ,  750  that create four separate air passages  760 ,  765 ,  770 ,  775 . Again, this is by way of example only. More or fewer baffles can be used in alternate embodiments. 
       FIG.  8    is a diagram of a diffuser  800  with two baffles  840 ,  845  according to disclosed embodiments. As shown in  FIG.  8   , the diffuser  800  is defined by a diffuser housing  810  and has a diffuser air inlet  820 , and a diffuser air outlet  830 . Two baffles  840 ,  845  are formed inside the diffuser  800 . 
       FIG.  8    is like  FIG.  6    in construction and operation and elements in  FIG.  8    operate similarly to comparable elements in  FIG.  6   . 
       FIG.  8    discloses a diffuser  800  that is wider than the diffuser  600  of  FIG.  6   . It is intended to show, by way of example, that the precise expansion angle of a diffuser may vary among different embodiments. The diffuser  800  has multiple baffles  840 ,  845  that divide the space inside the diffuser  800  into multiple, separate air passages  860 ,  865 ,  870  of varying expansion angles. A first air passage  860  is X°, a second air passage  865  is Y°, and a third air passage  870  is Z°. The values for X, Y, and Z can vary between different air handler designs. 
     Because each air passage  860 ,  865 ,  870  has a smaller expansion angle than the diffuser  800  in general, the diffused air passing through each individual air passage  860 ,  865 ,  870  will recover a greater amount of pressure as compared to a diffuser  300  with no baffles of a similar length. This will result in a greater static air pressure of the air exiting the diffuser  800  when the air from the three air passages  860 ,  865 ,  870  are combined. 
     The air diffusers  300 ,  400 ,  500 ,  600 ,  700 ,  800  are intended to illustrate design features that may form a part of any of the air diffusers discussed in this disclosure. Although the air diffusers  300 ,  400 ,  500 ,  600 ,  700 ,  800  in  FIGS.  3 - 8    may appear symmetrical along a line perpendicular to both parallel sides, these drawings are not intended to show the precise angles of the nonparallel walls or baffles of the air diffusers  300 ,  400 ,  500 ,  600 ,  700 ,  800 . As noted above, the air diffusers  300 ,  400 ,  500 ,  600 ,  700 ,  800  may not be symmetrical around a line perpendicular to both parallel sides. Instead, they may be tilted such that the diffused air  290  is deflected at a desired deflection angle α. 
     Air Handler—Third Embodiment 
       FIG.  9    is a diagram of an air handler  900  according to another alternate disclosed embodiments. As shown in  FIG.  9   , the air handler  900  includes an air handler housing  905 , an air inlet duct  110 , a heating and cooling coil  115 , a fan  920 , a separation plate  925 , an air diffuser  930 , a heater coil  940 , an outlet duct  945 , an air handler control box  950 . The fan  920  further includes a blower  960  and a fan housing  965 . The air diffuser  930  may include one or more baffles  980 . 
     The air handler housing  905  is similar in structure and operation to the air handler housing  105  in  FIG.  1    save that it is sized to hold the elements that form the air handler  900 . 
     The air inlet duct  110  and the heating and cooling coil  115  operate as described above with respect to the embodiment of  FIG.  1   . 
     The fan  920  operates in a manner similar to the fan  120  in the embodiment of  FIG.  1   , i.e., to draw the inlet air  113  into air handler housing  105  via the air inlet duct  110 , pass the inlet air  113  through the heating and cooling coil  115  to generate the conditioned air  970 , pass the conditioned air  970  through the diffuser  930  to generate diffused air  990 , and pass the diffused air through the heater coil  940  and out the outlet duct  945  as outlet air  995 . 
     The fan  920  in the embodiment of  FIG.  2    differs from the fan  120  in the embodiment of  FIG.  1    in that the separation plate  925  extends perpendicular to the first direction and the air diffuser  930  does not deflect the diffused air  990  away from the first direction. As a result, the conditioned air  970  blown out of the fan  920  through the opening in the separation plate  925  will be blown in the first direction. The fan  920  draws in the conditioned air  970  that is conditioned by passing through the heating and cooling coil  115  and blows it through the opening in the separation plate  925  to the air diffuser  930 . 
     In the embodiment of  FIG.  9   , the fan is a centrifugal fan that includes the blower  960  and a fan housing  965 . However, this is by way of example only. Alternate embodiments can employ any suitable fan that moves air from the air inlet duct  110 , through the air handler  900 , and out the air outlet. The blower  960  and the fan housing  965  operate in a manner like that of comparably numbered elements in the embodiment of  FIG.  1   . 
     The separation plate  925  is a structure located between the fan  920  and the diffuser  930  that operates to prevent any air from passing through it from one side of the air handler housing  905  to the other except through an opening in the separation plate  925  coincident with the output of the fan  920 . In this way, only the conditioned air  970  expelled from the fan  920  will pass from one side of the separation plate  925  to the other. However, unlike the embodiment of  FIG.  1   , the separation plate  925  in the embodiment of  FIG.  9    extends perpendicular to the first direction. Because the separation plate  925  is perpendicular to the first direction, the conditioned air  970  expelled by the fan  920  into the air diffuser  930  will be parallel to the first direction. 
     The air diffuser  930  receives the conditioned air  970  from the fan  920  and operates to perform a controlled expansion of the conditioned air to generate diffused air  990 . This controlled expansion increases the amount of air speed that is converted to static air pressure as compared to a system without the air diffuser  930  attached to the output of the fan  920 . In doing so, the air diffuser  930  reduces the air speed needed at the output of the fan  920  to achieve a desired static air pressure. This means that the fan  920  will use less power to achieve the desired static air pressure than a system without the air diffuser  930  attached to the output of the fan  920 , the air diffuser  930  is configured such that it does not deflect the diffused air  990  from the first direction. In other words, the diffused air  990  will continue through the air diffuser  930  in the first direction. 
     A cross-section of the air diffuser  930  has a trapezoidal shape with the shorter parallel side facing the fan  920  and the longer parallel side facing the outlet duct  945 . In other words, an air input for the air diffuser  930  is smaller than an air output of the air diffuser  930 . The air diffuser  930  gradually widens along its length. As a result, an air diffuser  930  can be defined by the angle of this expansion, measured by a hypothetical apex where the two non-parallel sides of the air diffuser  930  would meet if extended toward the fan  920 . 
     In various embodiments, the angle of expansion of the air diffuser  930  can vary between 20° and 45°. However, smaller angles of expansion for air paths in the air diffuser can provide for more advantageous air diffusion. Therefore, the air diffuser  930  can include one or more baffles  980  that break up the air flow through the air diffuser  930  into separate air passages that each have an expansion angle smaller than the expansion angle of the air diffuser  930  as a whole. For example, a single 30° air diffuser  930  could have two baffles  980  that create three separate air passages that are 10° each. Many other arrangements are possible by modifying the number and position of the baffles  980 . The angles of the air passages created by the baffles  980  in the air diffuser  930  can be the same for each passage or may differ among the passages as set forth with respect to the air diffusers  130 ,  230  in  FIGS.  1  and  2   . 
     The baffles  980  are configured and operate similarly to the baffles  180  in the first embodiment save that they may be oriented or arranged differently. 
     Since the separation plate  925  is perpendicular to the first direction and the air diffuser  930  is not arranged to deflect the diffused air  990  from the first direction, the air diffuser  930  may be symmetrical around the first direction. 
     Because the fan  920  is not tilted at a tilt angle and the air diffuser  930  does not deflect the diffused air  990  from the first direction, the air diffuser  930  must be longer than the air diffusers  130 ,  230  in  FIGS.  1  and  2    to achieve the same amount of pressure recovery in the diffused air. This is because the conditioned air  970  discharge from the fan is concentrated on one end of the output of the fan  920 , requiring a longer distance to equalize through the non-deflected air diffuser  930 . As a result, all other things being equal, the air handler  900  will be longer in a direction between the air inlet duct  110  and the air outlet duct  945  than either the air handler  100  or the air handler  200 , which do deflect the diffused air  190 ,  290 . 
     The heater coil  940 , the outlet duct  945 , and the air handler control box  250  operate in manners comparable to the heater coil  940 , the outlet duct  945 , and the air handler control box  950  in the first embodiment. As with the first embodiment, the heater coil  940  need not be operated in every operation mode and could be eliminated in some alternate embodiments. 
     Although the embodiment of  FIG.  9    shows the fan  920  being located between the heating and cooling coil  115  and the separation plate  925 , this is by way of example only. Alternate embodiments could alter the position of the fan  920  so long as it moves air through the air handler  900  in an efficient manner. In embodiments in which the location of the fan  920  is altered, the location of the diffuser  930  would likewise be altered to diffuse the air expelled from the fan  920  such that the formation of eddies and vortices can be reduced. 
     Method of Operating an Air Handler 
       FIG.  10    is a flow chart  1000  showing the operation of an air handler according to disclosed embodiments. 
     Operation begins when input air (inlet air) is drawn into an air handler ( 1010 ). This can be accomplished by operating an air blower (fan) inside the air handler. 
     The input air is then conditioned in the air handler to generate conditioned air ( 1020 ). This air conditioning can involve either heating the input air in a heating mode or cooling the input air in a cooling mode. 
     The conditioned air is drawn into an air blower and passed from the air blower to an air outlet in a second direction different than a first direction of a shortest line between the air blower and the air outlet ( 1030 ). In other words, the conditioned air passes from the air blower to the air outlet via a path other than the shortest straight line between the air inlet and the air outlet. 
     The conditioned air is diffused as it passes from the air blower to the air outlet to create diffused air ( 1040 ). In other words, the conditioned air is mixed to recover pressure that might otherwise be lost to eddies and vortices in the conditioned air. This can be achieved by passing the conditioned air through an air diffuser, as disclosed above, which passes conditioned air along an air path that gradually widens between an input of the air diffuser and an output of the air diffuser. In this way, the resulting static pressure of the diffused air can be increased without a corresponding increase in the operating speed of the air blower. 
     Because the conditioned air has been passed from the air blower to the air outlet in the second direction, which is different from the first direction, air blown from the air blower that might have been concentrated along one side of a direct air path between the air blower and the air outlet will instead be directed diagonally across the direct air path between the air blower and the air outlet, allowing the diffuser to more efficiently recover pressure from the conditioned air as it transforms the conditioned air to the diffused air. 
     The diffused air may then be heated ( 1050 ) if necessary. This can be done, for example, if the conditioning of the air involved cooling it to a temperature lower than a desired temperature set point to dehumidify the air. By heating the diffused air, it can be brought back to a desired temperature set point before being provided to the remainder of an air-conditioning system. This operation is not necessary in every system or even in every operation and may be omitted in some embodiments. 
     Finally, the diffused air is output from the air handler through an air outlet as output air (outlet air) to the remainder of the air conditioning system ( 1060 ). 
     By diffusing the air as it passes through the air handler, this operation increases the static pressure of the output air without a required an increase in the airspeed (and thus power consumption) of the air blower (fan) in the air handler. When a specific static pressure is required at the outlet port, this allows the disclosed operation to provide the desired static pressure at the outlet port using a lower air speed for the air blower than a comparable system without air diffusion or deflection of the conditioned air between the air blower and the air outlet. This lower airspeed translates into less power consumption by the air blower and thus the air handler in general. 
       FIG.  11    is a flow chart showing the operation  1030  of passing conditioned air from a blower to an air outlet from  FIG.  10    according to disclosed embodiments. 
     The operation  1030  begins by splitting the conditioned air into a plurality of separate air paths ( 1110 ). 
     Each of these air paths will pass through one of a plurality of separate air passages ( 1120 ). 
     The conditioned air passing through each of these separate air passages will be individually diffused in the corresponding air passage ( 1130 ). This can be achieved by having each air passage gradually widen as it passes from an air input to an air output. 
     Once the air in each air path has been properly diffused, the air outputs from the respective air paths are then combined to form the diffused air ( 1140 ). By splitting the conditioned air into multiple air paths, each air path can be more efficiently diffused along the same distance as compared to the diffusion of the entire conditioned air along a single air path. 
     The various embodiments which demonstrate a method for controlling an air handler have been discussed in detail above. It should be further noted that the above-described processes can be stored as instructions in computer-readable storage medium. When the instructions are executed by a computer (e.g., a processor in an air handler control box  150 ,  250 ,  950 ), for example after being loaded from a computer-readable storage medium (e.g., a memory in an air handler control box  150 ,  250 ,  950 ), the process(es) are performed. In one or more embodiments, a non-transitory computer readable medium may be provided which comprises instructions for execution by a computer, the instructions including a computer-implemented method for controlling an air-conditioning system to defrost a condenser coil, as described above. The non-transitory computer readable medium may comprise, for example, a read-only memory (ROM), a random-access memory (RAM), a programmable ROM (PROM), and/or an electrically erasable read-only memory (EEPROM). 
     CONCLUSION 
     This disclosure is intended to explain how to fashion and use various embodiments in accordance with the invention rather than to limit the true, intended, and fair scope and spirit thereof. The foregoing description is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications or variations are possible in light of the above teachings. The embodiment(s) was chosen and described to provide the best illustration of the principles of the invention and its practical application, and to enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims, as may be amended during the pendency of this application for patent, and all equivalents thereof, when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled. The various circuits described above can be implemented in discrete circuits or integrated circuits, as desired by implementation.