Patent Publication Number: US-2023148075-A1

Title: Gas furnace and air conditioner having the same

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application claims priority to Korean Patent Application No. 10-2021-0151809, filed Nov. 5, 2021, whose entire disclosures are hereby incorporated by reference. 
     BACKGROUND OF THE DISCLOSURE 
     Field of the Disclosure 
     The present disclosure relates to a gas furnace and an air conditioner having the same. 
     Related Art 
     In general, an air conditioner refers to an apparatus for cools and heating an indoor space through compression, condensation, expansion, and evaporation of refrigerant. The air conditioner can improve indoor air quality by exchanging indoor unit with outdoor air through a ventilator. In addition, the ventilator may increase the temperature of air supplied to the indoor space by using high-temperature combustion gas of a gas furnace. 
     Korean Patent Application Publication No. 2021-0014518 (published on Feb. 9, 2021) discloses a gas furnace having primary and secondary heat exchangers through which combustion gas flows. In this case, the temperature of the air supplied to the indoor space may be increased while the air passes through the primary heat exchanger and the secondary heat exchanger. However, it may be difficult to apply a gas furnace having a secondary heat exchanger to an air conditioner due to a restriction on an installation environment of the air conditioner (for example, in cold regions, a gas furnace having a secondary heat exchange may have problems with condensation or condensation of moisture contained in exhaust gas) or a restriction on an installation space within the air conditioner. In other words, there is a need to improve performance of heat transfer of a gas furnace having only a primary heat exchanger for air. 
     Korean Patent No. 20-2000-0204760 (registered on Sep. 18, 2000) discloses a water pipe through which water flows, and a burner in which combustion gas passing around the water pipe is generated. In this case, a plurality of baffles is formed in an outer circumferential surface of the water pipe. However, since the baffles are simply arranged in an up-down direction, it is difficult to control the combustion gas passing around the water pipe to flow in a specific direction. That is, the baffles cannot control the flow direction of the combustion gas from the burner to the water pipe. In addition, the baffles are formed with the water pipe integrally (as one body), so there is a problem in that it is difficult to change the shape of the baffle or the water pipe, for example, replacing the existing water pipe and manufacturing a new water pipe having baffles. 
     SUMMARY OF THE DISCLOSURE 
     An aspect of the present disclosure is to solve the above and other problems. 
     Another aspect of the present disclosure provides a gas furnace that guides the flow of air so that the heat transfer performance of the heat exchanger for the air passing around the heat exchanger is improved. 
     Yet another aspect of the present disclosure provides a gas furnace in which the part of the heat exchanger that is in contact with the air is enlarged. 
     Yet another aspect of the present disclosure provides a gas furnace in which a time for air to contact the heat exchanger is increased. 
     Yet another aspect of the present disclosure provides various examples of structures for guiding the flow of air passing through the perimeter of the heat exchanger. 
     Yet another aspect of the present disclosure provides a structure of a guide detachably coupled to the heat exchanger. 
     Yet another aspect of the present disclosure provides a structure of a guide capable of integrally fixing a plurality of heat exchangers. 
     Yet another aspect of the present disclosure provides a plurality of guides compatible with each other. 
     According to an aspect of the present disclosure, there is provided a gas furnace including: a burner for burning fuel; a heat exchanger extending long and providing a passage for combustion gas generated by the burner; a blower for causing a flow of air passing around the heat exchanger; and a plurality of guides penetrated by the heat exchanger and spaced apart from each other in a longitudinal direction of the heat exchanger. 
     According to another aspect of the present disclosure, the heat exchanger may include: a first tube forming an entry of the heat exchanger; a second tube forming an exit of the heat exchanger and spaced apart from the first tube in a direction crossing the longitudinal direction of the heat exchanger; and a bend connecting the first tube and the second tube. 
     According to another aspect of the present disclosure, the plurality of guides may be alternately disposed in a direction in which the first tube and the second tube are spaced apart from each other. 
     According to another aspect of the present disclosure, the first tube and the second tube may extend in the longitudinal direction of the heat exchanger. 
     According to another aspect of the present disclosure, the plurality of guides may include: a plurality of lower guides penetrated by the first tube and sequentially arranged along the first tube; and a plurality of upper guides penetrated by the second tube and sequentially arranged along the second tube. 
     According to another aspect of the present disclosure, the plurality of lower guides may be disposed vertically to the first tube and spaced apart from the second tube. 
     According to another aspect of the present disclosure, the plurality of upper guides may be disposed vertically to the second tube and spaced apart from the first tube. 
     According to another aspect of the present disclosure, the gas furnace may further include a top plate positioned between the heat exchanger and the blower, and having a top hole through which air passes; and a bottom plate facing the top plate with respect to the heat exchanger. 
     According to another aspect of the present disclosure, the gas furnace may further include: a mount plate positioned between the burner and the heat exchanger; and a side plate facing the mount plate with respect to the heat exchanger. 
     According to another aspect of the present disclosure, the bottom plate may further include a bottom hole formed to penetrate the bottom plate. 
     According to another aspect of the present disclosure, the top hole and the bottom hole may be formed to extend in a longitudinal direction of the heat exchanger and face each other in a direction in which the first tube and the second tube are spaced apart from each other. 
     According to another aspect of the present disclosure, the side plate may further include: a side hole formed to penetrate the side plate. 
     According to another aspect of the present disclosure, the top hole may be positioned to be biased toward the mount plate with respect to the center of the blower. 
     According to another aspect of the present disclosure, the plurality of upper guides may be positioned above a first reference line extending in the longitudinal direction of the heat exchanger between the first tube and the second tube and intersecting a center of the bend. The plurality of lower guides may be positioned below the first reference line. 
     According to another aspect of the present disclosure, each of the plurality of upper guides may further include: upper bending portions bent toward the side plate by an acute angle at lower ends of the plurality of upper guides, respectively. 
     According to another aspect of the present disclosure, each of the plurality of lower guides may further include: lower bending portions bent toward the mount plate by an acute angle at upper ends of the plurality of lower guides, respectively. 
     According to another aspect of the present disclosure, the upper bending portion may be adjacent to the lower bending portions in bending directions of the upper bending portions with respect to the plurality of upper guides, respectively. 
     According to another aspect of the present disclosure, the second reference line may extend along a longitudinal direction of the heat exchanger between the second tube and the top plate, and may be located below the top plate. 
     According to another aspect of the present disclosure, a distance between the second reference line and the first reference line may be equal to a distance between the first reference line and the bottom plate. 
     According to another aspect of the present disclosure, the plurality of upper guides may respectively further include: openings formed to pass through the plurality of upper guides and aligned with the second reference line. 
     According to another aspect of the present disclosure, the mount plate may be located to the left of the heat exchanger. 
     According to another aspect of the present disclosure, the plurality of upper guides may further include: left protrusions obliquely protruding obliquely leftward of the openings from lower ends of the openings; and right protrusions protruding obliquely rightward of the openings from upper ends of the openings. 
     According to another aspect of the present disclosure, the longitudinal direction of the heat exchanger may be defined as a first direction, the direction in which the first tube and the second tube are spaced apart from each other may be defined as a second direction, and a direction orthogonal to the first direction and the second direction may be defined as a third direction. The heat exchanger may further include: a plurality of heat exchangers spaced apart from each other in the third direction. 
     According to another aspect of the present disclosure, each of the plurality of lower guides may extend in the third direction, and may be penetrated by a plurality of first tubes of the plurality of heat exchangers. 
     According to another aspect of the present disclosure, each of the plurality of upper guides may extend in the third direction, and a plurality of second tubes of the plurality of heat exchangers may pass therethrough. 
     According to another aspect of the present disclosure, each of the plurality of lower guides may further include: a first part; and a second part detachably coupled to the first part in the second direction. 
     According to another aspect of the present disclosure, the plurality of first tubes may passes through a plurality of through-holes formed between the first part and the second part. 
     According to another aspect of the present disclosure, the plurality of through holes may be formed between a plurality of lower grooves of the first part and a plurality of upper grooves of the second part. 
     According to another aspect of the present disclosure, the first part may further include: a plurality of lower ribs respectively protruding in the first direction from the plurality of lower grooves and respectively extending along the plurality of lower grooves. 
     According to another aspect of the present disclosure, the second part comprises: a plurality of upper ribs respectively protruding in the first direction from the plurality of upper grooves and respectively extending along the plurality of upper grooves. 
     According to another aspect of the present disclosure, the second part may further include a stepped portion protruding from one end of the second part facing the first part and being stepped with respect to the second part. 
     According to another aspect of the present disclosure, the one end of the second part may be seated on one end of the first part facing the second part. 
     According to another aspect of the present disclosure, the stepped portion may be detachably coupled to the first part. 
     According to another aspect of the present disclosure, the first part may further include: a pair of legs extending from the first part in the second direction and spaced apart from each other in the third direction. 
     According to another aspect of the present disclosure, at least one of a plurality of upper guides may be compatible with at least one of the plurality of lower guides. 
     According to another aspect of the present disclosure, there may be provided an air conditioner having an outdoor unit and a ventilator that are connected to each other through a refrigerant pipe. The ventilator may include: an air supply fan for causing a flow of air along an air supply passage; an exhaust fan for causing a flow of air along an exhaust passage separated from the air supply passage; a plurality of coils located in the air supply passage and having refrigerant flowing therethrough; and a gas furnace positioned downstream of the plurality of coils in the air supply passage. 
     The gas furnace and the air conditioner having the same according to the present disclosure may have effects as below. 
     According to at least one of the embodiments of the present disclosure, a plurality of guides may be penetrated by a heat exchanger and may guide air passing through the heat exchanger. That is, a gas furnace capable of improving the heat exchanger’s performance of heat transfer with the air passing around the heat exchanger may be provided. 
     According to at least one of the embodiments of the present disclosure, an area of the heat exchanger in contact with air may be increased due to the plurality of guides that are alternately arranged. That is, a gas furnace capable of improving the heat exchanger’s performance of heat transfer with the air passing around the heat exchanger may be provided. 
     According to at least one of the embodiments of the present disclosure, a time for air to contact the heat exchanger may be increased due to the plurality of guides that are alternately disposed with each other. That is, a gas furnace capable of improving the heat exchanger’s performance of heat transfer with the air passing around the heat exchanger may be provided. 
     According to at least one of the embodiments of the present disclosure, various examples of a structure for guiding a flow of air passing around the heat exchanger may be provided. 
     According to at least one of the embodiments of the present disclosure, air may smoothly flow between alternately arranged guides through bending portions of the guides. 
     According to at least one of the embodiments of the present disclosure, it is possible to minimize a vortex of air or a flow loss of air formed adjacent to the guides through openings of the guides. 
     According to at least one of the embodiments of the present disclosure, a guide may include a first part and a second part, which are detachably coupled to each other. That is, it is possible to provide a structure of a guide detachably coupled to a heat exchanger. 
     According to at least one of the embodiments of the present disclosure, a plurality of heat exchangers may penetrate between a first part and a second part of a guide. That is, it is possible to provide a structure of a guide capable of integrally fixing a plurality of heat exchangers. 
     According to at least one of the embodiments of the present disclosure, at least one of lower guides detachably coupled to a first tube of a heat exchanger may be compatible with at least one of upper guides detachably coupled to a second tube of the heat exchanger. That is, a plurality of guides compatible with each other may be provided. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS.  1  and  2    are views showing a durable configuration of an air conditioner according to an embodiment of the present disclosure. 
         FIG.  3    is a view showing a gas furnace according to an embodiment of the present disclosure. 
         FIG.  4    is an example in which air discharged from a blower flows from top to bottom of a heat exchanger. 
         FIG.  5    shows an example in which air discharged from the blower flowing sideways from the top of the heat exchanger. 
         FIG.  6    is a view showing a gas furnace according to an embodiment of the present disclosure. 
         FIG.  7    shows guides for dispersing air flowing from top to bottom of a heat exchanger to the left and right side of the heat exchanger. 
         FIG.  8    is a view showing a gas furnace according to an embodiment of the present disclosure. 
         FIG.  9    shows guides for causing air, flowing from the top to the side of the heat exchanger, to flow upward in a zigzag fashion. 
         FIGS.  10  and  11    show guides having lower bending portions and upper bending portions. 
         FIGS.  12  and  13    show guides with openings. 
         FIGS.  14  and  15    show guides detachably coupled to a heat exchanger and interchangeable with each other. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, the embodiments disclosed in the present specification will be described in detail with reference to the accompanying drawings, but the same or similar components are assigned the same reference numerals regardless of reference numerals, and redundant description thereof will be omitted. 
     The suffixes “module” and “part” for components used in the following description are given or mixed in consideration of only the ease of writing the specification, and do not have distinct meanings or roles by themselves. 
     In addition, in describing the embodiments disclosed in the present specification, if it is determined that detailed descriptions of related known technologies may obscure the gist of the embodiments disclosed in this specification, the detailed description thereof will be omitted. In addition, the accompanying drawings are only for easy understanding of the embodiments disclosed in the present specification, and the technical spirit disclosed in the present specification is not limited by the accompanying drawings, and all changes included in the spirit and scope of the present disclosure, should be understood to include equivalents or substitutes. 
     Terms including ordinal numbers such as first, second, etc. may be used to describe various elements, but the elements are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. 
     When a component is referred to as being “connected” or “connected” to another component, it may be directly connected or connected to the other component, but it is understood that other components may exist in between. On the other hand, when it is said that a certain component is “directly connected” or “directly connected” to another component, it should be understood that the other component does not exist in the middle. 
     A singular expression includes a plural expression unless the context clearly dictates otherwise. 
     In the following description, even if an embodiment is described with reference to specific figure, a reference numeral not indicated in the specific figure may be referred to if necessary, and the reference numeral not indicated in the specific figure may be used when indicated in the other figure. 
     The directions of upward (U, y), downward (D), leftward (Le, x), rightward (Ri), forward (F, z), and rear direction (R) indicated in  FIG.  2    are used for convenience of explanation, and the technical spirit of the present disclosure is not limited thereby. 
     Referring to  FIGS.  1  and  2   , an air conditioner  1  may include an outdoor unit  20  and a ventilator  10 . The outdoor unit  20  may include a compressor (not shown) for compressing refrigerant and an outdoor heat exchanger (not shown) for performing heat exchange between refrigerant and outdoor air. The outdoor unit  20  may be connected to the ventilator  10  through a refrigerant pipe  11   a . The refrigerant may circulate the outdoor unit  20  and the ventilator  10  through the refrigerant pipe. A housing  10 H of the ventilator  10  may form the exterior of the ventilator  10 . 
     The housing  10 H may include a first long side LS 1  and a second long side LS 2  opposite to the first long side LS 1 . The first long side LS 1  and the second long side LS 2  may be collectively referred to as a long side LS 1  and LS 2 . The housing  10 H may include a first short side SS 1  adjacent to the long side LS 1  and LS 2  and a second short side SS 2  opposite the first short side SS 1 . The first short side SS 1  and the second short side SS 2  may be collectively referred to as a short side SS 1  and SS 2 . 
     A direction vertically to the long side LS 1  and LS 2  and the short side SS 1  and SS 2  may be referred to as a first direction DR 1  or a left-right direction. A direction parallel to the short side SS 1  and SS 2  may be referred to as a second direction DR 2  or an up-down direction. A direction parallel to the long side LS 1  and LS 2  may be referred to as a third direction DR 3  or a front-rear direction. 
     A side of the first long side LS 1  may be referred to as an upper side (U, y), and a side of the second long side LS 2  may be referred to as a lower side (D). A side of the first short side SS 1  may be referred to as a front side (F, z), and a side of the second short side SS 2  may be referred to as a rear side (R). In the first direction DR 1 , a direction toward one end of the short side SS 1  and SS 2  may be referred to as a left side (Le, x), and a direction toward the other end of the short side SS 1  and SS 2  may be referred to as a right side (Ri). 
     The ventilator  10  may include a refrigerant distributor  11 , a plurality of heat exchangers  12 ,  13 ,  14 ,  15 , and  19 , a blower  16 , a partition  17 , and an exhaust fan  18 . The refrigerant distributor  11 , the plurality of heat exchangers  12 ,  13 ,  14 ,  15 , and  19 , the blower  16 , the partition  17 , and the exhaust fan  18  may be installed inside the housing  10 H. 
     An air supply passage OA-SA may be formed between a first inlet  10   i  and a first outlet (not shown). The first inlet  10   i  may be formed to penetrate the second short side SS 2  and may be adjacent to the first long side LS 1 . The first outlet may be formed to penetrate the second long side LS 2  and may be adjacent to the first short side SS 1 . Outdoor air OA may be introduced into the first inlet  10   i , and the first inlet  10   i  may be referred to as an outdoor air inlet. Supply air SA may be supplied into a room through the first outlet, and the first outlet may be referred to as a supply air outlet. 
     The blower  16  may be adjacent to the first outlet and located in the air supply passage OA-SA. The blower  16  may cause a flow of air along the air supply passage OA-SA. The blower  16  may be referred to as an air supply fan or a plug fan. Meanwhile, an air supply duct (not shown) may be connected to the second long side LS 2  and may communicate with the first outlet and the indoor space. For example, the air volume per minute of the blower  16  may be 3,000 to 5,000 cubic feet per minute (CFM). 
     The exhaust passage RA-EA may be formed between the second inlet  10   p  and the second outlet  10   g . The second inlet  10   p  may be formed to penetrate the second long side LS 2  and may be spaced apart from the first outlet. The second outlet  10   g  may be formed through the second short side SS 2  and may be adjacent to the second long side LS 2 . The bet (RA, room air, or return air) may be introduced into the second inlet  10   p , and the second inlet  10   p  may be referred to as a bet inlet. Exhaust air (EA) may be discharged to the outside through the second outlet  10   g , and the second outlet  10   g  may be referred to as an exhaust outlet. 
     The exhaust fan  18  may be located in the exhaust passage RA-EA adjacent to the second discharge port  10   g . The exhaust fan  18  may cause a flow of air along the exhaust passage RA-EA. The exhaust fan  18  may be referred to as a blower or a plug fan. On the other hand, the inner duct (not shown) may be connected to the second long side (LS 2 ), it may be in communication with the second inlet ( 10   p ) and the indoor space. 
     The partition wall  17  may divide the inner space of the housing  10 H into a space in which the air supply passage OA-SA is formed and a space in which the exhaust passage RA-SA is formed. The partition wall  17  may be installed near the second inlet  10   p  of the housing  10 H, and may include an inclined portion (unsigned) and a horizontal portion (unsigned). Accordingly, the air supply passage OA-SA may be located above the partition wall  17 , and the exhaust passage RA-SA may be located below the partition wall  17 . 
     The refrigerant distributor  11  may be adjacent to the first long side LS 1  and the first short side SS 1 . One side of the refrigerant distributor  11  may be connected to the refrigerant pipe (11a). The other side of the refrigerant distributor  11  may be connected to a plurality of pipes  11   b ,  11   c ,  11   d , and  11   e . For example, the refrigerant distributor  11  may open and close the passage of each pipe through a solenoid valve. Here, each pipe  11   b ,  11   c ,  11   d , or  11   e  may include a refrigerant pipe providing a passage of refrigerant supplied to each heat exchanger  12 ,  14 ,  15 , or  19 , and a refrigerant pipe providing a passage of refrigerant passing through each heat exchanger  12 ,  14 ,  15 , or  19 . In addition, each expansion valve (not shown) may expand the refrigerant flowing through each of the pipes  11   b ,  11   c ,  11   d , and  11   e . For example, the expansion valve may be an Electronic Expansion Valve (EEV) capable of adjusting the opening degree. In this case, when the expansion valve is fully opened, the expansion valve may not expand the refrigerant. 
     The preheater  12  may be located in the air supply passage OA-SA adjacent to the first inlet  10   i . A preheater  12  may be disposed vertically within the housing  10 H. A first pipe  11   b  may provide a refrigerant passage connecting the refrigerant distributor  11  and the preheater  12 . Accordingly, the preheater  12  may heat air introduced into the first inlet  10   i . The preheater  12  may be referred to as a preheat coil. 
     The heat exchanger  14  may be located downstream of the preheater  12  in the air supply passage OA-SA. The heat exchanger  14  may be vertically disposed within the housing  10 H. A size of the heat exchanger  14  may be larger than a size of the preheater  12 . The second pipe  11   c  may provide a refrigerant passage connecting the refrigerant distributor  11  and the heat exchanger  14 . The heat exchanger  14  may be referred to as a main heat exchanger or a cooling/heating coil. 
     A reheater  15  may be located downstream of the heat exchanger  14  in the air supply passage OA-SA. The reheater  15  may be vertically disposed within the housing  10 H. A size of the reheater  15  may be smaller than a size of the heat exchanger  14 . The third pipe  11   d  may provide a refrigerant passage connecting the refrigerant distributor  11  and the reheater  15 . The reheater  15  may be referred to as a reheat coil. Meanwhile, the reheater  15  may be operated based on a set indoor temperature and a set humidity. The reheater  15  may face the blower  16  with respect to a base  10 W on which the reheater  15  is installed. 
     A recovery coil  19  may be located in an exhaust passage RA-EA adjacent to the exhaust fan  18 . The recovery coil  19  may be vertically disposed within the housing  10 H. A fourth pipe  11   e  may provide a refrigerant passage connecting the refrigerant distributor  11  and the recovery coil  19 . Meanwhile, a heat transfer direction of the recovery coil  19  to air may be opposite to a heat transfer direction of the heat exchanger  14  to air. 
     A part of the recovery wheel  13  may be located in the air supply passage OA-SA between the preheater  12  and the heat exchanger  14 , and the other part of the recovery wheel  13  may be located in the exhaust passage RA-EA between the recovery coil  19  and the inclined portion of the partition wall  17 . The recovery wheel  13  may be referred to as an energy recovery wheel (ERW). 
     In this case, the recovery wheel  13  may have a flat cylinder shape as a whole. A honeycomb structure may be formed inside the recovery wheel  13 , and air may pass through the honeycomb structure. The recovery wheel  13  may be rotated at a low speed. Accordingly, the recovery wheel  13  may recover sensible heat and latent heat by using temperature difference and humidity difference between the outdoor air OA and the indoor air RA. 
     Referring to  FIGS.  2  and  3   , the blower  16  may include a motor  16   a , a hub  16   b , a shroud  16   c , and a plurality of blades  16   d . The hub  16   b , the shroud  16   c , and the plurality of blades  16   d  may be collectively referred to as an impeller  16   a ,  16   b , and  16   c . 
     The motor  16   a  may provide a rotational force. The motor  16   a  may be a centrifugal fan motor. The motor  16   a  may form a front end of the blower  16 , and a rotational shaft of the motor  16   a  may extend rearward from the motor  16   a . A longitudinal direction of the rotational shaft of the motor  16   a  may be referred to as an axial direction of the blower  16 . 
     The hub  16   b  may be located at the rear of the motor  16   a  and may be fixed to the rotational shaft of the motor  16   a . The hub  16   b  may have a disk shape. 
     The shroud  16   c  may be located at the rear of the hub  16   b  and may have a ring plate shape. The shroud  16   c  may be rotatably coupled to the base  10 W. For example, an inlet (unsigned) may be fixed to a front surface of the base  10 W between the shroud  16   c  and the base  10 W, and may have a hyperbolic cylinder or funnel shape. In this case, the shroud  16   c  may be rotatably coupled to the inlet. A hole formed inside the shroud  16   c , an inner space of the inlet, and a hole (not shown) formed in the base  10 W may communicate with one another and be located in the air supply passage OA-SA (see  FIG.  1   ). 
     The plurality of blades  16   d  may be located between an inner periphery and an outer periphery of the ring-shaped shroud  16   c . The plurality of blades  16   d  may be coupled to the hub  16   b  and the shroud  16   c  between the hub  16   b  and the shroud  16   c . The plurality of blades  16   d  may be formed integrally with the shroud  16   c  and the hub  16   b . 
     In addition, the plurality of blades  16   d  may be spaced apart from each other in a rotating direction of the rotational shaft of the motor  16   a . Each of the plurality of blades  16   d  may be convexly curved in the rotating direction of the rotational shaft (see  FIGS.  4  and  5   ). Among the plurality of blades  16   d , a blade positioned close to a mount plate  110  to be described later may be convex toward the mount plate  110 . 
     Accordingly, when the impeller  16   a ,  16   b , and  16   c  is rotated in a clockwise direction in response to driving of the motor  16   a , air may be introduced in an axial direction of the blower  16   through a hole of the base  10 W and may be pressed by the plurality of blades  16   d  to be discharged in a radial direction of the blower  16 . In this case, a flow of air discharged by the blower  16  may be concentrated on the left side of the blower  16  rather than the right side of the blower  16 . 
     A horizontal plate  10   a  may be vertically disposed on a front surface of the base  10 W, and may be coupled to the front surface of the base  10 W. The horizontal plate  10   a  may be located above the blower  16 . The horizontal plate  10   a  may be referred to as a first horizontal wall or a first panel. Meanwhile, a frame  16   e  may form a skeleton of the blower  16 , and a motor mount 1600 on which the motor  16   a  is mounted may be coupled to the frame  16   a . The frame  16   e  may be coupled to the bottom of the horizontal plate  10   a . 
     A top plate  10   b  may be disposed vertically to the front surface of the base  10 W, and may be coupled to the front surface of the base  10 W. The top plate  10   b  may be located below of the blower  16 . The top plate  10   b  may be referred to as a second horizontal wall or a second panel. A top hole  100   a  may be formed to penetrate the top plate  10   b  in the up-down direction. The top hole  100   a  may be formed to be long in the left-right direction. In the up-down direction, at least a portion of the top hole  100   a  may overlap the blower  16 . 
     A bottom plate  10   c  may be disposed vertically to the front surface of the base W, and may be coupled to the front surface of the base  10 W. The bottom plate  10   c  may face the horizontal plate  10   a  with respect to the top plate  10   b . The bottom plate  10   c  may form a part of the second long side LS 2  of the housing  10 H. The bottom hole  100   b  may be formed to penetrate the bottom plate  10   c  in the up-down direction. The bottom hole  100   b  may be formed to be long in the left-right direction. In the up-down direction, the bottom hole  100   b  may face the top hole  100   a . 
     The side plate  10   d  may be disposed vertically to the front surface of the base W, and may be coupled to the front surface of the base W. The side plate  10   d  may be coupled to a right side of the horizontal plate  10   a , a right side of the top plate  10   b , and a right side of the bottom plate  10   c . A side hole  100   c  may be formed to penetrate the side plate  10   d  in the left-right direction. The side hole  100   c  may be formed to be long in the front-rear direction. The side hole  100   c  may be located between a right side of the top plate  10   b  and a right side of the bottom plate  10   c . 
     The mount plate  110  may include a first plate  111  and a second plate  112 . The first plate  111  may be vertically disposed on the front surface of the base W and an upper surface of the bottom plate  10   c , and may be coupled to the front surface of the base W and the upper surface of the bottom plate  10   c . The first plate  111  may be coupled to a left side of the top plate  10   b . The second plate  112  may extend obliquely in a direction away from the blower  16  from an upper end of the first plate  111 . In this case, a left side of the base  10 W, a left side of the horizontal plate  10   a , a left side of the second plate  112 , and a left side of the bottom plate  10   c  may be connected to a left side of the housing  10 H. 
     A first space  101 S may be formed between the horizontal plate  10   a  and the top plate  10   b . A vertical plate (not shown) may be connected to a front end of the horizontal plate  10   a  and a front end of the top plate  10   b , and may close a front side of the first space  101 S. The first space  101 S may communicate with the top hole  100   a . 
     A second space  102 S may be formed between the top plate  10   b  and the bottom plate  10   c . The vertical plate may be connected to a front end of the top plate  10   b  and a front end of the bottom plate  10   c , and may close the front side of the second space  102 S. The second space  102 S may communicate with the bottom hole  100   b  and the side hole  100   c . 
     Referring to  FIGS.  3  to  5   , the gas furnace  100  includes a fuel valve  120 , a manifold  130 , a burner box  140 , a burner  141 , a heat exchanger  150 , a collect box  160 , and an inducer  170 . 
     The fuel valve  120  may supply fuel from a fuel pipe FP connected to a fuel source (not shown) to the manifold  130 , or may block the supply of the fuel to the manifold  130 . For example, the fuel may be Liquefied Natural Gas (LNG) or Liquefied Petroleum Gas (LPG). Meanwhile, by adjusting an opening degree of the fuel valve  120 , it is possible to adjust an amount of the fuel supplied to the manifold  130 . 
     The burner  141  may receive the fuel from the manifold  130 . The fuel may be mixed with air, and the burner  141  may burn a mixture of the fuel and the air. When the mixture of fuel and air is combusted, a flame Fm (see  FIGS.  4  and  5   ) and a high-temperature combustion gas Fg (see  FIGS.  4  and  5   ) may be generated. For example, the burner  141  may be provided in plural. A plurality of burners  141  may be installed inside the burner box  140 . The burner box  140  may be installed to the left of the first plate  111  of the mount plate  110 . 
     For example, an igniter may be adjacent to an exit of a burner located at one end of the plurality of burners  141  and may burn fuel that has passed through the corresponding burner. In this case, the flame formed at the outlet of the burner may be propagated to exits of the remaining burners through a flame propagation port between the plurality of burners  141 . The propagated flame may burn fuel that has passed through the remaining burners. In addition, a flame detector may be adjacent to an exit of a burner located at the other end of the plurality of burners  141 . When the flame detector detects a flame, it may be considered that a flame is formed as a result of combustion by the remaining burners due to characteristics of the flame propagation described above. 
     The heat exchanger  150  may be located in the second space  102 S between the top plate  10   b  and the bottom plate  10   c . The heat exchanger  150  may provide a passage for the combustion gas Fg. One end of the heat exchanger  150  may be coupled to the right of the first plate  111  of the mount plate  110 , and may communicate with the burner  141 . The other end of the heat exchanger  150  may be spaced apart from the one end of the heat exchanger  150 , and may be coupled to the right of the first plate  111 . In this case, a first hole (not shown) may be formed to penetrate the first plate  111  in the left-right direction, and may be located between the one end of the heat exchanger  150  and the burner  141 . 
     In addition, the heat exchanger  150  may be provided in plural. The number of heat exchangers  150  may be equal to the number of burners  141 . Each of a plurality of heat exchangers  150  may be connected to each of the plurality of burners  141 . The plurality of heat exchangers  150  may be spaced apart from each other in the front-rear direction. 
     In addition, the heat exchanger  150  may be a tubular type heat exchanger. The heat exchanger  150  may include a first tube  150   a , a bend  150   b , and a second tube  150   c . The passage of the combustion gas Fg may be formed in the inside of the first tube  150   a , the inside of the bend  150   b , bend, and the inside of the second tube  150   c . For example, a diameter of the first tube  150   a  may be substantially equal to a diameter of the bend  150   b  and a diameter of the second tube  150   c . 
     The first tube  150   a  may extend long in the left-right direction. A left end of the first tube  150   a  may form the one end of the heat exchanger  150 , and may be coupled to the right of the first plate  111 . An entry (unsigned) of the heat exchanger  150  may be formed at the left end of the first tube  150   a . 
     The second tube  150   c  may extend long in the left-right direction. The second tube  150   c  may be spaced upwardly from the first tube  150   a . A left end of the second tube  150   c  may form the other end of the heat exchanger  150  and may be coupled to the right of the first plate  111 . An exit (unsigned) of the heat exchanger may be formed at the left end of the second tube  150   c . 
     The band  150   b  may be connected to the right end of the first tube  150   a  and the right end of the second tube  150   c . The band  150   b  may be convex to the right. The band  150   b  may transfer the combustion gas Fg that has passed through the first tube  150   a  to the second tube  150   c . Accordingly, the combustion gas Fg may flow to the right in the first tube  150   a , and may flow to the left in the second tube  150   b . The band  150   b  may be referred to as a U-shaped bend. 
     Meanwhile, according to an embodiment, a bend connected to the left end of the second tube  150   c  and convex to the left, and a tube connected to the bend and disposed in parallel with the second tube  150   c  may be added. 
     A pillar P 1  and P 2  may be coupled to the bottom plate  10   c  and may be coupled to the bottom of the top plate  10   b . A vertical portion (unsigned) of the pillar P 1  and P 2  may extend long in the up-down direction between the bottom plate  10   c  and the top plate  10   b . A horizontal portion (unsigned) of the pillar P 1  and P 2  may extend long from the lower side of the top plate  10   b  in the front-rear direction. The pillar P 1  and P 2  may surround a portion of the outside of the heat exchanger  150 . The pillar P 1  and P 2  may include a first pillar P 1  and a second pillar P 2 , which are spaced apart from each other in the left-right direction. 
     The collect box  160  may be located above the burner box  140 , and may be installed to the left of the first plate  111  of the mount plate  110 . The collect box  160  may communicate with the other end of the heat exchanger  150 . In this case, the second hole (not shown) may be formed to penetrate the first plate  111  in the left-right direction, and may be located between the other end of the heat exchanger  150  and the collect box  160 . That is, the combustion gas Fg passing through the heat exchanger  150  may be introduced into the collector box  160 . 
     The inducer  170  may be installed to the left of the collect box  160 . An entry of the inducer  170  may communicate with the inside of the collect box  160 . An exit  171  of the inducer  170  may be connected to the exhaust pipe  180  (see  FIG.  2   ). The inducer  170  may cause the combustion gas Fg to flow through the heat exchanger  150 , the collect box  160 , the inducer  170 , and the exhaust pipe  180 . In addition, the inducer  170  may cause the mixture of fuel and air to flow through the burner  141 . The inducer  170  may be referred to as a fan, a blower, or an induced draft motor (IDM). 
     The exhaust pipe  180  (see  FIG.  2   ) may extend upward from the exit  171  of the inducer  170 . The exhaust pipe  180  may pass through the second plate  112  of the mount plate  110 , the horizontal plate  10   a , and the first long side LS 1 , and may discharge the combustion gas Fg to the outside. The combustion gas Fg flowing through the exhaust pipe  180  may be referred to as exhaust gas. 
     Referring to  FIGS.  3  and  4   , for example, the bottom hole  100   b  may be opened and the side hole  100   c  may be closed. The side hole  100   c  may be closed by a detachable cover (not shown) or may not be initially formed in the side plate  10   d . 
     The plurality of blades  16   d  may be rotated in a clockwise direction with respect to a center C of the blower  16  in response to driving of the motor  16   a . Air discharged from the blower  16  may pass around the heat exchanger  150  through the top hole  100   a . The air passing around the heat exchanger  150  may receive thermal energy from the combustion gas Fg flowing along the heat exchanger  150 . That is, temperature of the air may be increased while the air passes around the heat exchanger  150 . 
     In this case, the air supply duct may be coupled to a portion in which the bottom hole  100   b  of the bottom plate  10   c  is formed. That is, the air that has passed around the heat exchanger  150  may be supplied into an indoor space through the bottom hole  100   b  and the air supply duct (see SA in  FIG.  4   ). 
     In another example with reference to  FIGS.  3  and  5   , the bottom hole  100   b  may be closed and the side hole  100   c  may be opened. The bottom hole  100   b  may be closed by a detachable cover (not shown) or may not be initially formed in the bottom plate  10   c . 
     The plurality of blades  16   d  may be rotated in a clockwise direction with respect to a center C of the blower  16  in response to driving of the motor  16   a . Air discharged from the blower  16  may pass around the heat exchanger  150  through the top hole  100   a . The air passing around the heat exchanger  150  may receive thermal energy from the combustion gas Fg flowing along the heat exchanger  150 . That is, temperature of the air may be increased while the air passes around the heat exchanger  150 . 
     In this case, the air supply duct may be coupled to a portion in which the side hole  100   c  of the side plate  10   d  is formed. That is, the air that has passed around the heat exchanger  150  may be supplied to an indoor space through the side hole  100   c  and the air supply duct (see SA in  FIG.  5   ). 
     Referring to  FIGS.  6  and  7   , the heat exchanger  150  may include six heat exchangers  151 ,  152 ,  153 ,  154 ,  155 , and  156  which are spaced apart from each other in the front-rear direction. However, the number of heat exchangers  150  is not limited thereto. A first heat exchanger  151 , a second heat exchanger  152 , a third heat exchanger  153 , a fourth heat exchanger  154 , a fifth heat exchanger  155 , and a sixth heat exchanger  156  may be sequentially arranged in the left-right direction. In this case, the burner  141  may include six burners connected to the six heat exchangers  151 ,  152 ,  153 ,  154 ,  155 , and  156 . 
     The plurality of guides  190  may be coupled to an outer circumferential surface of the heat exchanger  150 . The plurality of guides  190  may be disposed vertically to the heat exchanger  150 . The plurality of guides  190  may be spaced apart from each other in a longitudinal direction of the first tube  150   a  or the second tube  150   c  of the heat exchanger  150 , that is, in the left-right direction. Each of the plurality of guides  190  may connect the plurality of heat exchangers  150 . In other words, the plurality of heat exchangers  150  may pass through each of the plurality of guides  190 . For example, the number of guides  190  may be eight. The plurality of guides  190  may include a plurality of lower guides  191 ,  192 ,  193 , and  194  coupled to the outer circumferential surface of the first tube  150   a , and a plurality of upper guides  195 ,  196 ,  197 , and  198  coupled to the outer circumferential surface of the second tube  150   c . Meanwhile, the guides  190  may be referred to as baffles. 
     The plurality of lower guides  191 ,  192 ,  193 , and  194  may be disposed vertically to the first tube  150   a . A lower end of each of the plurality of lower guides  191 ,  192 ,  193 , and  194  may be coupled to an upper surface of the bottom plate  10   c . An upper end of each of the plurality of lower guides  191 ,  192 ,  193 , and  194  may be spaced downward from the second tube  150   c . The first lower guide  191 , the second lower guide  192 , the third lower guide  193 , and the fourth lower guide  194  may be sequentially arranged along the longitudinal direction of the first tube  150   a . Specifically, the first lower guide  191  may be adjacent to a left end of the first tube  150   a , and the fourth lower guide  194  may be adj acent to a right end of the first tube  150   a . In addition, the second lower guide  192  and the third lower guide  193  may be positioned between the first lower guide  191  and the fourth lower guide  194 . 
     The plurality of upper guides  195 ,  196 ,  197 , and  198  may be disposed vertically to the second tube  150   c . An upper end of each of the plurality of upper guides  195 ,  196 ,  197 , and  198  may be coupled to a lower surface of the top plate  10   b . A lower end of each of the plurality of upper guides  195 ,  196 ,  197 , and  198  may be spaced upward from the first tube  150   a . The first upper guide  195 , the second upper guide  196 , the third upper guide  197 , and the fourth upper guide  198  may be sequentially arranged along the longitudinal direction of the second tube  150   c . Specifically, the first upper guide  195  may be adjacent to a right end of the second tube  150   c , and the fourth upper guide  198  may be adjacent to a left end of the second tube  150   c . In addition, the second upper guide  196  and the third upper guide  197  may be positioned between the first upper guide  195  and the fourth upper guide  198 . 
     In addition, in the left-right direction which is the longitudinal direction of the first tube150a or the third tube  150   c , the plurality of upper guides  195 ,  196 ,  197 , and  198  and the plurality of lower guides  191 ,  192 ,  193 , and  194  may be alternately arranged. In other words, in the up-down direction in which the first tube  150   a  and the third tube  150   c  are spaced apart from each other, the plurality of upper guides  195 ,  196 ,  197 , and  198  and the plurality of lower guides  191 ,  192 ,  193 , and  194  may be alternately arranged. 
     In addition, the second space  102 S between the top plate  10   b  and the bottom plate  10   c  may be opened through the top hole  100   a  and the bottom hole  100   b . The top hole  100   a  and the bottom hole  100   b  may be formed to be elongated in the left-right direction. The bottom hole  100   b  may face the top hole  100   a  with respect to the heat exchanger  150 . The plurality of guides  190  may be disposed in an area between the top hole  100   a  and the bottom hole  100   b . 
     Accordingly, the plurality of guides  190  may disperse air, flowing from the top hole  100   a  to the bottom hole  100   b  by the blower  16 , in the longitudinal direction of the heat exchanger  150 , that is, in the left-right direction. In this case, air may pass around the heat exchanger  150  in a relatively wide area (see SA of  FIG.  7   ), compared to a case in which the plurality of guides  190  are not provided (see  FIG.  4   ). In other words, an amount of heat transfer between air and the heat exchanger  150  occupying a relatively small space may be sufficiently secured by the plurality of guides  190 . 
     Referring to  FIGS.  8  and  9   , the second space  102 S between the top plate  10   b  and the bottom plate  10   c  may be opened through the top hole  100   a  and the side hole  100   c . 
     Referring to  FIG.  8   , for example, the top hole  100   a  may be positioned to be biased leftward with respect to the center C of the blower  16 . The top hole  100   a  may be adjacent to the first plate  111  of the mount plate  110 . For another example with reference to  FIG.  3   , the top hole  100   a  may be positioned to be symmetric in the left-right direction with respect to the center C of the blower  16 . The side hole  100   c  may be located to the right of the heat exchanger  150 . 
     Therefore, the plurality of guides  190  may increase a length of a passage for the air flowing from the top hole  100   a  to the side hole  100   c  by the blower  16 . In other words, in the up-down direction, air may flow in a zigzag fashion by the plurality of guides  190  (see SA of  FIG.  9   ). In this case, a residence time of air around the heat exchanger  150  may be increased, compared to a case in which the plurality of guides  190  are not provided (see  FIG.  5   ). In other words, an amount of heat transfer between air and the heat exchanger  150  occupying a relatively small space may be sufficiently secured by the plurality of guides  190 . 
     Referring to  FIGS.  10  and  11   , a plurality of lower bending portions  191   a ,  192   a ,  193   a , and  194   a  may be bent to the left by an acute angle at upper ends of the plurality of lower guides  191 ,  192 ,  193 , and  194 , respectively. The plurality of upper bending portions  195   a ,  196   a , and  197   a  may be bent to the right by an acute angle at lower ends of the plurality of upper guides  195 ,  196 , and  197 , respectively. 
     A first lower bending portion  191   a  may be bent to the left by a first angle theta  1  from an upper end of the first lower guide  191 . A second lower bending portion  192   a  may be bent to the left by a second angle theta  2  from an upper end of the second lower guide  192 . A third lower bending portion  193   a  may be bent to the left by a third angle theta  3  from an upper end of the third lower guide  193 . A fourth lower bending portion  194   a  may be bent to the left by a fourth angle theta  4  from an upper end of the fourth lower guide  194 . For example, the first angle theta  1  may be substantially equal to the second angle theta  2 , the third angle theta  3 , and the fourth angle theta  4 . 
     A first upper bending portion  195   a  may be bent to the right by a fifth angle theta  5  from a lower end of the first upper guide  195 . A second upper bending portion  196   a  may be bent to the right by a sixth angle theta  6  from a lower end of the second upper guide  196 . A seventh upper bending portion  197   a  may be bent to the right by a seventh angle theta  7  from a lower end of the seventh upper guide  197 . For example, the fifth angle theta  5  may be substantially equal to the sixth angle theta  6  and the seventh angle theta  7 . 
     For example, the fifth angle theta  5 , the sixth angle theta  6 , and the seventh angle theta  7  may be substantially equal to the first angle theta  1 , the second angle theta  2 , the third angle theta  3 , and the fourth angle theta  4 . That is, bending directions of the plurality of lower bending portions  191   a ,  192   a ,  193   a , and  194   a  relative to the plurality of lower guides  191 ,  192 ,  193 , and  194  may be parallel to bending directions of the plurality of upper guides  195 ,  196 , and  197  relative to the plurality of upper bending portions  195   a ,  196   a , and  197   a . 
     In addition, in the aforementioned upper bending directions, the plurality of lower bending portions  191   a ,  192   a ,  193   a , and  194   a  may be respectively spaced apart from and face the plurality of upper guides  195 ,  196 , and  197  adjacent thereto. Specifically, in the bending direction of the first upper bending portion  195   a  relative to the first upper guide  195 , the first upper bending portion  195   a  may be adjacent to and face the fourth lower bending portion  194   a . In the bending direction of the second upper bending portion  196   a  relative to the second upper guide  196 , the second upper bending portion  196   a  may be adjacent to and face the third lower bending portion  193   a . In the bending direction of the third upper bending portion  197   a  relative to the third upper guide  197 , the third upper bending portion  197   a  may be adjacent to and face the second lower bending portion  192   a . 
     In addition, the plurality of lower bending portions  191   a ,  192   a ,  193   a , and  194   a  may be positioned below a first reference line CL 1 , and the plurality of upper bending portions  195   a ,  196   a , and  197   a  may be positioned above the first reference line CL 1 . In this case, the first reference line CL 1  may be a virtual line extending in the left-right direction between the first tube  150   a  and the second tube  150   b , and may cross the center of the bend  150   b . 
     Accordingly, the plurality of upper bending portions  195   a ,  196   a , and  197   a  may guide air, which is flowing mainly to the left of the heat exchanger  150  due to the characteristics of the blower  16 , to the lower right side. In addition, the plurality of lower bending portions  191   a ,  192   a ,  193   a , and  194   a  may guide air, which is guided by the plurality of upper bending portions  195   a ,  196   a , and  197   a , to an area around the first tube  150   a . Air may pass around the heat exchanger  150   in a wider area by the plurality of upper bending portions  195   a ,  196   a , and  197   a  and the plurality of lower bending portions  191   a ,  192   a ,  193   a , and  194   a . That is, efficiency of heat transfer between the heat exchanger  150  and the air may be further increased. 
     Meanwhile, according to an embodiment, any one in the plurality of upper bending portions  195   a ,  196   a , and  197   a  and the plurality of lower bending portions  191   a ,  192   a ,  193   a , and  194   a  may be omitted. 
     Referring to  FIGS.  12  and  13   , a second reference line CL 2  may be a virtual line extending in the left-right direction between the second tube  150   b  and the top plate  10   b . A distance d2 between the second reference line CL 2  and the first reference line CL 1  may be equal to a distance d1 between the first reference line CL 1  and the bottom plate  10   c . For example, the second reference line CL 2  may be positioned below the top plate  10   b . In addition, as described above, the plurality of upper guides  195 ,  196 , and  197  may be coupled to the lower surface of the top plate  10   b , and the plurality of lower guides  191 ,  192 ,  193  and  194  may be coupled to an upper surface of the bottom plate  10   c . That is, in the up-down direction, a height of the upper guides  195 ,  196 , and  197  may be higher than a height of the lower guides  191 ,  192 ,  193 , and  194  by a distance d3 between the second reference line CL 2  and the top plate  10   b . 
     A plurality of openings  195   h ,  196   h , and  197   h  may be respectively formed to penetrate the plurality of upper guides  195 ,  196 , and  197  in the left-right direction, and may be elongated in the front and rear directions. The plurality of openings  195   h ,  196   h , and  197   h  may be aligned along the second reference line CL 2 . 
     Accordingly, some of the air flowing by the blower  16  (see  FIGS.  7  and  9   ) may pass through the plurality of openings  195   h ,  196   h , and  197   h . That is, the plurality of openings  195   h ,  196   h , and  197   h  may minimize generation of air vortex or a flow loss of air between the second tube  150   c  and the top plate  10   b . 
     A plurality of left protrusions  195   b ,  196   b , and  197   b  may respectively protrude obliquely leftward of the plurality of openings  195   h ,  196   h , and  197   h  from lower ends of the plurality of openings  195   h ,  196   h , and  197   h . A plurality of right protrusions  195   c ,  196   c , and  197   c  may respectively protrude obliquely rightward of the plurality of openings  195   h ,  196   h , and  197   h  from upper ends of the plurality of openings  195   h ,  196   h , and  197   h . 
     For example, the left protrusions  195   b ,  196   b , and  197   b  and the right protrusions  195 ,  196   c  and  197   c  may be formed by cutting and bending respective portions of the upper guides  195 ,  196  and  197 . In this case, the openings  195   h ,  196   h , and  197   h  may be formed in cut portions of the upper guides  195 ,  196 , and  197 . In another example, the left protrusions  195   b ,  196   b , and  197   b  and the right protrusions  195 ,  196   c , and  197   c  may be respectively coupled to the lower and upper ends of the openings  195   h ,  196   h , and  197   h  by welding or the like. 
     A first left protrusion  195   b  may protrude from a lower end of the first opening  195   h  to the left of the first opening  195   h , and may form an eighth angle theta 5b relative to the first opening  195   h . A second left protrusion  196   b  may protrude from a lower end of the second opening  196   h  to the left of the second opening  196   h , and may form a ninth angle theta 6b relative to the second opening  196   h . A third left protrusion  197   b  may protrude from a lower end of the third opening  197   h  to the left of the third opening  197   h , and may form a tenth angle theta 7b relative to the third opening  197   h . For example, the eighth angle theta 5b may be substantially equal to the ninth angle theta 6b and the tenth angle theta 7b. 
     A first right protrusion  195   c  may protrude from an upper end of the first opening  195   h  to the right of the first opening  195   h , and may form an eleventh angle theta 5c relative to the first opening  195   h . A second right protrusion  196   c  may protrude from an upper end of the second opening  196   h  to the right of the second opening  196   h , and may form a twelfth angle theta 6c relative to the second opening  196   h . A third right protrusion  197   c  may protrude from an upper end of the third opening  197   h  to the right of the third opening  197   h , and may form a thirteenth angle theta 7c relative to the third opening  197   h . For example, the eleventh angle theta 5c may be substantially equal to the twelfth angle theta 6c and the thirteenth angle theta 7c. 
     Accordingly, in the vicinity of the plurality of openings  195   h ,  196   h , and  197   h , the plurality of left protrusions  195   b ,  196   b , and  197   b  and the plurality of right protrusions  195   c ,  196   c , and  197   c  may guide air to easily pass through the plurality of openings  195   h ,  196   h , and  197   h . In particular, the plurality of right protrusions  195   c ,  196   c , and  197   c  may guide the air passing through the plurality of openings  195   h ,  196   h , and  197   h  to flow downward to the right. That is, efficiency of heat transfer between the heat exchanger  150  and the air may be further increased by the left protrusions  195   b ,  196   b , and  197   b  and the right protrusions  195   c ,  196   c , and  197   c . 
     Referring to  FIGS.  14  and  15   , the guide  190  may include a first part  190   a  and a second part  190   b . The first part  190   a  and the second part  190   b  may extend long in the front-rear direction and may have the same width W. Meanwhile, the first part  190   a  may be referred to as a first plate or a first panel, and the second part  190   b  may be referred to as a second plate or a second panel. 
     The first part  190   a  may extend long in the front-rear direction. The width W of the first part  190   a  may be defined in the front-rear direction, a height of the first part  190   a  may be defined in the up-down direction, and a thickness of the first part  190   a  may be defined in the left-right direction. A left surface and a right surface of the first part  190   a  may be flat. 
     A plurality of lower grooves (unsigned) may be formed to be recessed downward from an upper side of the first part  190   a , and may be spaced apart from each other in the front-rear direction. The number of the lower grooves may be equal to the number of heat exchangers  150 . A shape of each of the lower grooves may be identical to a shape of a lower portion of the first tube  150   a  of the heat exchanger  150 . That is, each of the lower grooves may have a semicircular shape. A plurality of lower ribs  190   c   1 ,  190   d   1 ,  190   e   1 ,  190   f   1 ,  190   g   1 , and  190   h   1  may protrude leftward from the plurality of lower grooves, respectively, and may extend along the plurality of lower grooves, respectively. 
     A plurality of couplers  190   t  may be positioned between the plurality of lower ribs  190   c   1 ,  190   d   1 ,  190   e   1 ,  190   f   1 ,  190   g   1 , and  190   h   1 , and may protrude leftward from a left surface of the first part  190   a . 
     The second part  190   b  may extend long in the front-rear direction. The width W of the second part  190   b  may be defined in the front-rear direction, a height of the second part  190   b  may be defined in the up-down direction, and a thickness of the second part  190   b  may be defined in the left-right direction. A left surface and a right surface of the second part  190   b  may be flat. 
     A plurality of upper grooves (unsigned) may be formed to be recessed upward from a lower side of the second part  190   b , and may be spaced apart from each other in the front-rear direction. The number of the upper grooves may be equal to the number of heat exchangers  150 . A shape of each of the upper grooves may be identical to a shape of an upper portion of the first tube  150   a  of the heat exchanger  150 . That is, each of the upper grooves may have a semicircular shape. A plurality of upper ribs  190   c   2 ,  190   d   2 ,  190   e   2 ,  190   f   2 ,  190   g   2 , and  190   h   2  may protrude leftward from the plurality of upper grooves, respectively, and may extend along the plurality of upper grooves, respectively. 
     A plurality of through holes  190   c ,  190   d ,  190   e ,  190   f ,  190   g , and  190   h  may be formed between the plurality of upper ribs  190   c   2 ,  190   d   2 ,  190   e   2 ,  190   f   2 ,  190   g   2 ,  190   h   2  and the plurality of lower ribs  190   c   1 ,  190   d   1 ,  190   e   1 ,  190   f   1 ,  190   g   1 , and  190   h   1 . In addition, a diameter of each of the plurality of through holes  190   c ,  190   d ,  190   e ,  190   f ,  190   g , and  190   h  may be substantially equal to an outer diameter of each of the plurality of heat exchangers  151 ,  152 ,  153 ,  154 ,  155 , and  156 . 
     Specifically, a first through hole  190   c  may be formed between a first upper rib  190   c   2  and a first lower rib  190   c   1 , and may have a diameter equal to an outer diameter of the first heat exchanger  151 . A second through hole  190   d  may be formed between a second upper rib  190   d   2  and a second lower rib  190   d   1  and may have a diameter equal to an outer diameter of the second heat exchanger  152 . A third through hole  190   e  may be formed between a third upper rib  190   e   2  and a third lower rib  190   e   1  and may have a diameter equal to an outer diameter of the third heat exchanger  153 . A fourth through hole  190   f  may be formed between a fourth upper rib  190   f   2  and a fourth lower rib  190   f   1  and may have a diameter equal to an outer diameter of the fourth heat exchanger  154 . A fifth through hole  190   g  may be formed between a fifth upper rib  190   g   2  and a fifth lower rib  190   g   1 , and may have a diameter equal to an outer diameter of the fifth heat exchanger  155 . A sixth through hole  190   h  may be formed between a sixth upper rib  190   h   2  and a sixth lower rib  190   h   1 , and may have a diameter equal to an outer diameter of the sixth heat exchanger  156 . 
     A stepped portion  190 P may protrude downward from a lower end of the second part  190   b , and may be formed to be rightward down from the second part  190   b . That is, the stepped portion  190 P may be stepped with respect to the second part  190   b . For example, the stepped portion  190 P may be formed while a portion of the left surface of the second part  190   b  is pressed to the right, and may be referred to as a pressed portion. In the up-down direction, portions of the stepped portion  190 P corresponding to the plurality of upper grooves may be cut-out. 
     A plurality of coupling holes  190   u  may be positioned between the plurality of upper ribs  190   c   2 ,  190   d   2 ,  190   e   2 ,  190   f   2 ,  190   g   2 , and  190   h   2 , and may be formed to penetrate the stepped portion  190 P in the left-right direction. 
     Accordingly, a left surface of the stepped portion  190 P may contact a right surface of an upper portion of the first part  190   a , and a lower side of the second part  190   b  may be seated on an upper side of the first part  190   a . In the left and right direction, the plurality of coupling holes  190   u  may be aligned with the plurality of coupling holes  190   t . As fastening members (not shown), such as screws, are fastened to the coupling holes  190   t  and the coupling holes  190   u , the second part  190   b  may be detachably coupled to the first part  190   a . 
     A pair of legs  190 M a  and  190 M b  may extend rightward from the lower end of the first part  190   a , and may be spaced apart from each other in the front-rear direction. The pair of legs  190 M a  and  190 M b  may be orthogonal to the first part  190   a . A first leg  190 M a  may be adjacent to a front end of the first part  190   a  and may be positioned on a third plate  10   c  (see  FIGS.  6  and  8   ). As a fastening member, such as a screw, passes through a hole  190   aa  formed in the first leg  190 M a  and is then fastened to the bottom plate  10   c , the first leg  190 M a  may be coupled to the bottom plate  10   c . A second leg  190 M b  may be adjacent to a rear end of the first part  190   b  and may be positioned on the third plate  10   c  (see  FIGS.  6  and  8   ). As a fastening member, such as a screw, passes through the hole  190   bb  formed in the second leg  190 M b  and is then fastened to the bottom plate  10   c , the second leg  190 M b  may be coupled to the bottom plate  10   c . 
     Accordingly, a plurality of first tubes  150   a  of the plurality of heat exchangers  151 ,  152 ,  153 ,  154 ,  155 , and  156  may be seated on the plurality of lower ribs  190   c   1 ,  190   d   1 ,  190   e   1 ,  190   f   1 ,  190   g   1 , and  190   h   1  of the first part  190   a  coupled to the bottom plate  10   c . In addition, the second part  190   b  may be seated on the plurality of first tubes  150   a  of the plurality of heat exchangers  151 ,  152 ,  153 ,  154 ,  155 , and  156 , and may be coupled to the first part  190   a . That is, the plurality of first tubes  150   a  of the plurality of heat exchangers  151 ,  152 ,  153 ,  154 ,  155 , and  156  may pass through the plurality of through-holes  190   c ,  190   d ,  190   e ,  190   f ,  190   g , and  190   h  of the guide  190 , and may be integrally coupled to the bottom plate  10   c  by the guide  190 . That is, convenience of installation of the heat exchanger and the guide may be improved. In addition, the guide  190  may reduce or present the shaking of the plurality of heat exchangers  151 ,  152 ,  153 ,  154 ,  155 , and  156 . 
     Meanwhile, the left surface of the second part  190   b  may be disposed parallel to the left surface of the first part  190   a . That is, the left surface of the guide  190  may be formed to be flat. In this case, a flow resistance of air in contact with the left surface of the guide  190  may be minimized. 
     Referring to  FIGS.  6 ,  8 , and  15   , the plurality of lower guides  191 ,  192 ,  193 , and  194  may have the same shape. The plurality of upper guides  195 ,  196 ,  197 , and  198  may have the same shape. 
     In addition, the plurality of lower guides  191 ,  192 ,  193 , and  194  and the plurality of upper guides  195 ,  196 ,  197  and  198  may have the same overall shape. That is, the description of the guide  190  provided above with reference to  FIGS.  14  and  15    may apply not just to the plurality of lower guides  191 ,  192 ,  193 , and  194 , but also to the plurality of upper guides  195 ,  196 ,  197 , and  198 . 
     For example, a height h1 of each of the plurality of lower guides  191 ,  192 ,  193 , and  194  may be smaller than a height h2 of each of the plurality of upper guides  195 ,  196 ,  197  and  198 . In this case, a shape of a second part  190   b  of each of the lower guides  191 ,  192 ,  193 , and  194  may be identical to a shape of a second part  190   b  of each of the upper guides  195 ,  196 ,  197 , and  198 . In addition, putting aside a height difference, a shape of a first part  190   a  of each of the lower guides  191 ,  192 ,  193 , and  194  may be identical to a shape of a first part  190   a  of each of the upper guides  195 ,  196 ,  197 , and  198 . 
     In another example, a height of each of the plurality of lower guides  191 ,  192 ,  193 , and  194  may be equal to a height of each of the plurality of upper guides  195 ,  196 ,  197  and  198 . In this case, the shape of each of the lower guides  191 ,  192 ,  193 , and  194  may be identical to the shape of each of the upper guides  195 ,  196 ,  197  and  198 . 
     Accordingly, at least one of the lower guides  191 ,  192 ,  193 , and  194  may be compatible with at least one of the upper guides  195 ,  196 ,  197 , and  198 . The lower guides  191 ,  192 ,  193 , and  194  may be penetrated by the plurality of first tubes  150   a  of the plurality of heat exchangers  151 ,  152 ,  153 ,  154 ,  155 , and  156 , and may be coupled to the upper surface of the bottom plate  10 C through the pair of legs  190 M a  and  190 M b . The upper guides  195 ,  196 ,  197 , and  198  may be penetrated by the plurality of second tubes  150   c  of a plurality of heat exchangers  151 ,  152 ,  153 ,  154 ,  155 , and  156 , and may be coupled to the lower surface of the top plate  10   b  through the pair of legs  190 M b  and  190 M a . 
     Meanwhile, the same description about the shape compatibility regarding the lower guides  191 ,  192 ,  193 , and  194  and the upper guides  195 ,  196 ,  197 , and  198  may apply to the lower guides  191 ,  192 ,  193 , and  194  and the upper guides  195 ,  196 , and  197  with the bending portions and protrusions described above with reference to  FIGS.  10  or  12   . 
     Certain embodiments or other embodiments of the disclosure described above are not mutually exclusive or distinct from each other. Any or all components of the embodiments of the disclosure described above may be combined with another or combined with each other in configuration or function. 
     For example, a configuration “A” described in one embodiment of the disclosure and the drawings and a configuration “B” described in another embodiment of the disclosure and the drawings may be combined with each other. Namely, although the combination between the configurations is not directly described, the combination is possible except in the case where it is described that the combination is impossible. 
     Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the scope of the principles of this disclosure.