Patent Publication Number: US-11022328-B2

Title: Heat source unit

Description:
TECHNICAL FIELD 
     The present invention relates to a heat source unit, and particularly a heat source unit where refrigerant circuit constituent parts are provided inside a casing. 
     BACKGROUND ART 
     Conventionally, there is an air conditioning system configured as a result of a heat source unit and a utilization unit being connected by pipes. In the heat source unit configuring this kind of air conditioning system, refrigerant circuit constituent parts are provided inside a casing, such as described in patent document 1 (JP-A No. 2011-158137). Here, a bottom frame forming a bottom surface of the casing has a structure divided in the front and rear direction. 
     SUMMARY 
     In the conventional heat source unit, when refrigerant circuit constituent parts are to be changed or added in accordance with capacity or function, questions such as on which of the divided bottom frames are the refrigerant circuit constituent parts that are to be changed or added to be provided, and which bottom frame is to be increased in size in order to provide the refrigerant circuit constituent parts that are to be changed or added, are not considered. That is, the placement of all the refrigerant circuit constituent parts including the refrigerant circuit constituent parts that are to be changed or added is reviewed and, on the basis of the results of the review, a change in the placement of the refrigerant circuit constituent parts and/or the size of the casing is executed. 
     However, with this approach, each time the refrigerant circuit constituent parts are changed or added in accordance with capacity or function, it is necessary to review the placement of all the refrigerant circuit constituent parts including the refrigerant circuit constituent parts that are to be changed or added, and deciding on the placement of the refrigerant circuit constituent parts to be changed or added and/or changing the size of the casing cannot be easily executed. 
     One or more embodiments of the present invention ensure that, in a heat source unit where refrigerant circuit constituent parts are provided inside a casing, when the refrigerant circuit constituent parts are changed or added in accordance with capacity or function, changing the size of the casing and placing the refrigerant circuit constituent parts can be easily executed. 
     A heat source unit according to one or more embodiments is a heat source unit where refrigerant circuit constituent parts are provided inside a casing and where the refrigerant circuit constituent parts are changed or added in accordance with capacity or function. Additionally, here, a bottom frame forming a bottom surface of the casing has a first bottom frame, on which are provided first refrigerant circuit constituent parts that are common regardless of capacity or function among the refrigerant circuit constituent parts, and a second bottom frame, on which are provided second refrigerant circuit constituent parts that are changed or added depending on capacity or function among the refrigerant circuit constituent parts. 
     Here, the bottom frame is divided in two, and the refrigerant circuit constituent parts that are common regardless of capacity or function (the first refrigerant circuit constituent parts) are provided on one bottom frame (the first bottom frame), so the placement of the refrigerant circuit constituent parts and the size of the casing on the first bottom frame side can be spared from being changed, regardless of whether or not the refrigerant circuit constituent parts are changed or added in accordance with capacity or function. Moreover, the refrigerant circuit constituent parts that are changed or added depending on capacity or function (the second refrigerant constituent circuit parts) are provided on the other bottom frame (the second bottom frame), so it suffices to change just the placement of the refrigerant circuit constituent parts and/or the size of the casing on the second bottom frame side. 
     Because of this, here, when the size of the casing is changed as a result of the refrigerant circuit constituent parts being changed or added in accordance with capacity or function, changing the size of the casing and placing the refrigerant circuit constituent parts can be easily executed. 
     A heat source unit according to one or more embodiments is the heat source unit of aforementioned embodiments, wherein the first refrigerant circuit constituent parts include a compressor that compresses refrigerant, an accumulator that temporarily accumulates the refrigerant before the refrigerant is sucked into the compressor, and an oil separator that separates refrigerating machine oil from the refrigerant after the refrigerant has been discharged from the compressor. 
     In the heat source unit, there is the concern that refrigerant pipes connected to the compressor and area devices (the compressor, the accumulator, and the oil separator) will sustain damage from vibrations during operation and during transport, so to ensure that such damage does not occur, the placement of these devices and the placement and shapes of the refrigerant pipes connected to these devices are appropriately set. For this reason, even in a case where the refrigerant circuit constituent parts are changed or added in accordance with capacity or function, the placement of these devices and the placement and shapes of the refrigerant pipes connected to these devices should be spared from being changed. 
     Therefore, here, the compressor and area devices (the compressor, the accumulator, and the oil separator) are collectively placed as the first refrigerant circuit constituent parts on the first bottom frame. 
     Because of this, here, even in a case where the refrigerant circuit constituent parts are changed or added in accordance with capacity or function, the compressor, the accumulator, and the oil separator and the placement and shapes of the refrigerant pipes connected to these devices can be spared from being changed. 
     A heat source unit according to one or more embodiments is the heat source unit of the aforementioned embodiments, wherein the first bottom frame has a larger plate thickness than the second bottom frame. 
     There are cases where the refrigerant circuit constituent parts that are common regardless of capacity or function (the first refrigerant circuit constituent parts) include heavy parts (e.g., the compressor and the accumulator) and where the refrigerant circuit constituent parts that are changed or added in accordance with capacity or function (the second refrigerant circuit constituent parts) include only light parts. 
     Therefore, here, the first bottom frame is configured to have a larger plate thickness than the second bottom frame. 
     Because of this, here, the strength of the first bottom frame can be increased and the weight of the second bottom frame can be reduced. 
     A heat source unit according to one or more embodiments is the heat source unit of the aforementioned embodiments, wherein the second refrigerant circuit constituent parts include a heat source-side heat exchanger that functions as a radiator or an evaporator of refrigerant, and the heat source-side heat exchanger is provided extending across both the first bottom frame and the second bottom frame. 
     In the heat source unit, the heat source-side heat exchanger is provided along an edge portion of the bottom frame, so by changing the length of the edge portion of the bottom frame, the size of the heat source-side heat exchanger can also be changed. 
     Therefore, here, the heat source-side heat exchanger is configured to serve as a second refrigerant circuit constituent part, and the heat source-side heat exchanger is provided extending across both the first bottom frame and the second bottom frame. 
     Because of this, here, by changing the size of the second bottom frame, the size of the heat source-side heat exchanger can be easily changed without changing the size of the first bottom frame. 
     A heat source unit of aforementioned embodiments is the heat source unit of the aforementioned embodiments, wherein the first bottom frame and the second bottom frame are corrugated plate-like members in which ridge portions and furrow portions extending across the front and rear direction of the casing are formed. 
     Here, the first bottom frame and the second bottom frame are configured to be corrugated plate-like members, so a high-strength bottom frame can be obtained. Moreover, here, the ridge portions and the furrow portions of the corrugated plate-like first bottom frame and second bottom frame are formed extending across the front and rear direction of the casing, so the first bottom frame and the second bottom frame can be placed side by side to the left and right of each other, when the casing is viewed from the front surface side, to change the size of the casing. It will be noted that although there are many cases where, when installing the heat source unit, there are restrictions on the size of the casing in the front and rear direction, here, the first bottom frame and the second bottom frame can be placed side by side to the left and right of each other to change the size of the casing, so the heat source unit can be spared from being subjected to restrictions on the size of the casing in the front and rear direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a general configuration diagram of an air conditioning system in which a heat source unit according to one or more embodiments of the invention is employed. 
         FIG. 2  is an external perspective view of the heat source unit according to one or more embodiments. 
         FIG. 3  is an exploded perspective view of the heat source unit (showing only the general shapes of an accumulator, a compressor, an oil separator, and a heat source-side heat exchanger) according to one or more embodiments. 
         FIG. 4  is a plan view showing a bottom frame and mounting feet (showing only the general shapes of the accumulator, the compressor, the oil separator, and the heat source-side heat exchanger) according to one or more embodiments. 
         FIG. 5  is a general configuration diagram of the air conditioning system (in a case where an injection function has been added) according to one or more embodiments. 
         FIG. 6  is a plan view showing the bottom frame and the mounting feet in a case where the injection function has been added (showing only the general shapes of the accumulator, the compressor, the oil separator, the heat source-side heat exchanger, and a receiver) according to one or more embodiments. 
         FIG. 7  is a plan view showing the bottom frame and the mounting feet in a case where capacity has been increased (showing only the general shapes of the accumulator, the compressor, the oil separator, the heat source-side heat exchanger, a second compressor, a second oil separator, and the receiver) according to one or more embodiments. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Embodiments of a heat source unit and example modifications thereof will be described below on the basis of the drawings. It will be noted that the specific configurations of the heat source unit are not limited to those in the following embodiments and the example modifications thereof and can be changed in a range that does not depart from the spirit of the invention. 
     (1) Configuration of Air Conditioning System 
       FIG. 1  is a general configuration diagram of an air conditioning system  1  in which a heat source unit  2  according to one or more embodiments of the invention is employed. 
     The air conditioning system  1  is a system that can execute cooling and heating of rooms in a building, for example, by executing a vapor compression refrigeration cycle. The air conditioning system  1  is configured as a result of mainly the heat source unit  2  and utilization units  3   a  and  3   b  being connected. Here, the heat source unit  2  and the utilization units  3   a  and  3   b  are connected via a liquid refrigerant communication pipe  4  and a gas refrigerant communication pipe  5 . That is, a vapor compression refrigerant circuit  6  of the air conditioning system  1  is configured as a result of the heat source unit  2  and the utilization units  3   a  and  3   b  being connected via the refrigerant communication pipes  4  and  5 . 
     The heat source unit  2  is installed outdoors (e.g., on the roof of the building or adjacent to a wall surface of the building) and configures part of the refrigerant circuit  6 . The heat source unit  2  mainly has an accumulator  7 , a compressor  8 , an oil separator  9 , a four-port switching valve  10 , a heat source-side heat exchanger  11 , a heat source-side expansion valve  12 , a liquid-side stop valve  13 , a gas-side stop valve  14 , and a heat source-side fan  15 . The devices and valves are connected to each other by refrigerant pipes  16  to  24 . 
     The utilization units  3   a  and  3   b  are installed in rooms (e.g., living rooms or spaces on the reverse sides of ceilings) and configure part of the refrigerant circuit  6 . The utilization unit  3   a  mainly has a utilization-side expansion valve  31   a , a utilization-side heat exchanger  32   a , and a utilization-side fan  33   a . The utilization unit  3   b  mainly has a utilization-side expansion valve  31   b , a utilization-side heat exchanger  32   b , and a utilization-side fan  33   b.    
     The refrigerant communication pipes  4  and  5  are refrigerant pipes constructed on site when installing the air conditioning system  1  in an installation location such as a building. One end of the liquid refrigerant communication pipe  4  is connected to the liquid-side stop valve  13  of the heat source unit  2 , and the other end of the liquid refrigerant communication pipe  4  is connected to liquid-side ends of the utilization-side expansion valves  31   a  and  31   b  of the utilization units  3   a  and  3   b . One end of the gas refrigerant communication pipe  5  is connected to the gas-side stop valve  14  of the heat source unit  2 , and the other end of the gas refrigerant communication pipe  5  is connected to gas-side ends of the utilization-side heat exchangers  32   a  and  32   b  of the utilization units  3   a  and  3   b.    
     (2) Configuration of Heat Source Unit 
       FIG. 2  is an external perspective view of the heat source unit  2 .  FIG. 3  is an exploded perspective view of the heat source unit  2  (showing only the general shapes of the accumulator  7 , the compressor  8 , the oil separator  9 , and the heat source-side heat exchanger  11 ).  FIG. 4  is a plan view showing a bottom frame  51  and mounting feet  41  (showing only the general shapes of the accumulator  7 , the compressor  8 , the oil separator  9 , and the heat source-side heat exchanger  11 ).  FIG. 5  is a general configuration diagram of the air conditioning system  1  (in a case where an injection function has been added).  FIG. 6  is a plan view showing the bottom frame  51  and the mounting feet  41  in a case where the injection function has been added (showing only the general shapes of the accumulator  7 , the compressor  8 , the oil separator  9 , the heat source-side heat exchanger  11 , and a receiver  26 ).  FIG. 7  is a plan view showing the bottom frame  51  and the mounting feet  41  in a case where capacity has been increased (showing only the general shapes of the accumulator  7 , the compressor  8 , the oil separator  9 , the heat source-side heat exchanger  11 , a second compressor  28 , a second oil separator  29 , and the receiver  26 ). 
     &lt;Overall Structure&gt; 
     The heat source unit  2  has what is called an upward-blowing structure that takes air into a casing  40  from below and blows the air out to the outside of the casing  40  from above. The heat source unit  2  mainly has the casing  40 , which is shaped substantially like a rectangular parallelepiped box, the heat source-side fan  15 , and refrigerant circuit constituent parts that configure part of the refrigerant circuit  6  and include the devices  7 ,  8 ,  9 , and  11  such as the compressor and the heat source-side heat exchanger, the valves  10  and  12  to  14  such as the four-port switching valve and the heat source-side expansion valve, and the refrigerant pipes  16  to  24 . It will be noted that in the following description, unless otherwise specified, “upper,” “lower,” “left,” “right,” “front,” “rear,” “front surface,” and “back surface” will mean directions in a case where the heat source unit  2  shown in  FIG. 2  is seen from the front (diagonally forward and to the left in the drawing). 
     The casing  40  mainly has a bottom frame  51  that bridges a pair of mounting feet  41  extending in the right and left direction, struts  61  that extend in the vertical direction from corner portions of the bottom frame  51 , a fan module  71  that is attached to the upper ends of the struts  61 , and a front surface panel  81 . 
     The bottom frame  51  forms a bottom surface of the casing  40 , and the heat source-side heat exchanger  11  is provided on the bottom frame  51 . Here, the heat source-side heat exchanger  11  is a heat exchanger that is substantially U-shaped as seen in a plan view and faces the back surface and both right and left side surfaces of the casing  40 , and substantially forms the back surface and both right and left side surfaces of the casing  40 . 
     The fan module  71  is provided on the upper side of the heat source-side heat exchanger  11  and forms a top surface of the casing  40  and sections of the front surface, the back surface, and both right and left side surfaces of the casing  40  on the upper side of the struts  61 . Here, the fan module  71  is a composite body where the heat source-side fan  15  and a bell mouth  72  are housed in a substantially rectangular parallelepiped box whose upper surface and lower surface are open, and an air outlet grille  73  is provided in the opening in the upper surface. 
     The front surface panel  81  bridges the struts  61  on the front surface side and forms a front surface of the casing  40 . 
     Also housed inside the casing  40  are refrigerant circuit constituent parts other than the heat source-side fan  15  and the heat source-side heat exchanger  11  ( FIG. 3  and  FIG. 4  show the accumulator  7 , the compressor  8 , and the oil separator  9 ). Here, the compressor  8  is a device that compresses refrigerant and is provided on the bottom frame  51 . Furthermore, the accumulator  7  is a refrigerant vessel that temporarily accumulates the refrigerant before the refrigerant is sucked into the compressor  8 , and the accumulator  7  is provided on the bottom frame  51 . The oil separator  9  is a device that separates refrigerating machine oil from the refrigerant after the refrigerant has been discharged from the compressor  8 , and the oil separator  9  is provided on the bottom frame  51 . 
     &lt;Detailed Structure (Including Divided Structure of Bottom Frame  51  Considering Placement of Refrigerant Circuit Constituent Parts)&gt; 
     The bottom frame  51  is a corrugated plate-like member in which ridge portions and furrow portions extending across the front and rear direction of the casing  40  are formed, and the bottom frame  51  has a first bottom frame  51   a  and a second bottom frame  51   b  that result from the bottom frame  51  being divided in two in the right and left direction. Here, the first bottom frame  51   a  configures the left portion of the bottom frame  51  when the casing  40  is viewed from the front surface side, and the first bottom frame  51   a  is a corrugated plate-like member in which ridge portions  52   a  and furrow portions  53   a  extending across the front and rear direction of the casing  40  are formed. The second bottom frame  51   b  configures the right portion of the bottom frame  51  when the casing  40  is viewed from the front surface side, and the second bottom frame  51   b  is a corrugated plate-like member in which ridge portions  52   b  and furrow portions  53   b  extending across the front and rear direction of the casing  40  are formed. The first bottom frame  51   a  and the second bottom frame  51   b  are placed side by side in the right and left direction when the casing  40  is viewed from the front surface side. The first bottom frame  51   a  and the second bottom frame  51   b  bridge the mounting feet  41 . End portions of the first and second bottom frames  51   a  and  51   b  on sides (here, in the front and rear direction) where the ridge portions  52   a  and  52   b  and the furrow portions  53   a  and  53   b  can be seen are supported by the mounting feet  41 . An outer wall portion  55   a  that extends upward beyond the ridge portions  52   a  and the furrow portions  53   a  is formed on the end portion of the first bottom frame  51   a  orthogonal (here, in the right and left direction) to the front and rear direction end portions of the first bottom frame  51   a  and on the side (here, the left side) distant from the second bottom frame  51   b . A connecting wall portion  59   a  that borders the second bottom frame  51   b  is formed on the end portion of the first bottom frame  51   a  orthogonal (here, in the right and left direction) to the front and rear direction end portions of the first bottom frame  51   a  and on the side (here, the right side) close to the second bottom frame  51   b . Furthermore, an outer wall portion  55   b  that extends upward beyond the ridge portions  52   b  and the furrow portions  53   b  is formed on the end portion of the second bottom frame  51   b  orthogonal (here, in the right and left direction) to the front and rear direction end portions of the second bottom frame  51   b  and on the side (here, the right side) distant from the first bottom frame  51   a . A connecting wall portion  59   b  that borders the first bottom frame  51   a  is formed on the end portion of the second bottom frame  51   b  orthogonal (here, in the right and left direction) to the front and rear direction end portions of the second bottom frame  51   b  and on the side (here, the left side) close to the first bottom frame  51   a . Additionally, in contrast to the right and left direction end portions of the first and second bottom frames  51   a  and  51   b , outer wall portions are not formed on the front and rear direction end portions of the first and second bottom frames  51   a  and  51   b , and so the shapes of the first and second bottom frames  51   a  and  51   b  are simplified. 
     Furthermore, here, the first bottom frame  51   a  and the second bottom frame  51   b  are configured to be corrugated plate-like members, so high-strength bottom frames  51   a  and  51   b  can be obtained. Moreover, here, the ridge portions  52   a  and  52   b  and the furrow portions  53   a  and  53   b  of the corrugated plate-like first bottom frame  51   a  and second bottom frame  51   b  are formed extending across the front and rear direction of the casing  40 , so this is suited for placing the first bottom frame  51   a  and the second bottom frame  51   b  side by side to the left and right of each other when the casing  40  is viewed from the front surface side. 
     The mounting feet  41  are members that are substantially C-shaped as seen in a side view and extend in the right and left direction of the casing  40 . The mounting feet  41  each mainly have an anchored portion  42  that becomes anchored to an installation surface, a vertical portion  43  that extends upward from an end portion of the anchored portion  42  on one side in the front and rear direction, and a support portion  44  that extends horizontally from the upper end portion of the vertical portion  43  toward the other side in the front and rear direction. The support portions  44  support the front and rear direction end portions of the first and second bottom frames  51   a  and  51   b  from below. Furthermore, the mounting feet  41  each have a wall portion  45  that extends upward from the end portion of the support portion  44  on the other side in the front and rear direction. The wall portions  45  are positioned on outer sides of the front and rear direction end portions of the first and second bottom frames  51   a  and  51   b . That is, in the case of the mounting foot  41  placed on the front surface side of the casing  40 , the wall portion  45  is positioned on the front side of the front and rear direction end portions of the first and second bottom frames  51   a  and  51   b , and in the case of the mounting foot  41  placed on the back surface side of the casing  40 , the wall portion  45  is positioned on the back surface side of the front and rear direction end portions of the first and second bottom frames  51   a  and  51   b . Additionally, the wall portions  45  of the mounting feet  41  function as outer wall portions of the front and rear direction end portions of the first and second bottom frames  51   a  and  51   b . That is, here, the wall portions  45  of the mounting feet  41  have the same function as the outer wall portions  55   a  and  55   b  of the right and left direction end portions of the first and second bottom frames  51   a  and  51   b , while simplifying the shape of the first and second bottom frames  51   a  and  51   b.    
     In the heat source unit  2  employing the bottom frame  51  with this divided structure, refrigerant circuit constituent parts such as the compressor  8  are provided, but at this time there are cases where the refrigerant circuit constituent parts are changed or added in accordance with capacity or function. In such cases, it is desired that questions such as on which of the divided bottom frames  51   a  and  51   b  are the refrigerant circuit constituent parts that are to be changed or added to be provided, and which bottom frame  51   a  or  51   b  is to be increased in size in order to provide the refrigerant circuit constituent parts that are to be changed or added, be considered, so that changing the size of the casing  40  and placing the refrigerant circuit constituent parts can be easily executed. 
     Therefore, here, as described above, the bottom frame  51  is divided in two (the first and second bottom frames  51   a  and  51   b ), and refrigerant circuit constituent parts that are common regardless of capacity or function (first refrigerant circuit constituent parts) are provided on one bottom frame (the first bottom frame  51   a ). Here, the first refrigerant circuit constituent parts are the refrigerant circuit constituent parts  7  to  10 ,  12  to  14 , and  16  to  24  excluding the heat source-side heat exchanger  11  among the refrigerant circuit constituent parts  7  to  14  and  16  to  24  provided inside the casing  40 . The first refrigerant circuit constituent parts are refrigerant circuit constituent parts that are the minimum needed to be provided inside the heat source unit  2  to configure to the air conditioning system  1  and are not changed even in a case where a change or addition is made to capacity or function. That is, the first refrigerant circuit constituent parts include the compressor  8  that compresses the refrigerant, the accumulator  7  that temporarily accumulates the refrigerant before the refrigerant is sucked into the compressor  8 , and the oil separator  9  that separates the refrigerating machine oil from the refrigerant after the refrigerant has been discharged from the compressor  8 . Furthermore, refrigerant circuit constituent parts that are changed or added depending on capacity or function (second refrigerant circuit constituent parts) are provided on the other bottom frame (the second bottom frame  51   b ). Here, a second refrigerant circuit constituent part among the above-described refrigerant circuit constituent parts is the heat source-side heat exchanger  11  that functions as a radiator or an evaporator of the refrigerant and is provided extending across both the first bottom frame  51   a  and the second bottom frame  51   b . The heat source-side heat exchanger  11  is included in the second refrigerant circuit constituent parts because sometimes its size is changed in order to change the heat exchange capacity when executing a capacity change as described later. It will be noted that, in  FIG. 4 , the heat source-side heat exchanger  11  is set to a size suited to the first refrigerant circuit constituent parts, and in accompaniment with this, the size of the second bottom frame  51   b  is also set to a size with which the heat source-side heat exchanger  11  can be placed in the entire bottom frame  51 . 
     Additionally, by employing this structure, the placement of the refrigerant circuit constituent parts (i.e., the first refrigerant circuit constituent parts) and the size of the casing  40  on the first bottom frame  51   a  side can be spared from being changed regardless of whether or not the refrigerant circuit constituent parts (i.e., the second refrigerant circuit constituent parts) are changed or added in accordance with capacity or function. Moreover, it suffices to change just the placement of the refrigerant circuit constituent parts (i.e., the second refrigerant circuit constituent parts) and/or the size of the casing  40  on the second bottom frame  51   b  side. Because of this, here, when the size of the casing  40  is changed as a result of the refrigerant circuit constituent parts being changed or added in accordance with capacity or function, changing the size of the casing  40  and placing the refrigerant circuit constituent parts can be easily executed. 
     For example, in the configuration having the basic refrigerant circuit  6  shown in  FIG. 1 , there are cases where one wants to make a change in or addition to the refrigerant circuit constituent parts configuring the refrigerant circuit  6  to add a function for enhancing performance or the like. As a specific example, as shown in  FIG. 5 , there are cases where one connects a receiver  26  to the refrigerant pipe  23  inside the heat source unit  2  and connects a degassing pipe  27 , which removes gas refrigerant from the upper portion of the receiver  26 , to add the function of executing gas injection to the compressor  8 . That is, the receiver  26  and the degassing pipe  27  are added as second refrigerant circuit constituent parts. 
     With respect to such changing or adding of the second refrigerant circuit constituent parts (here, mainly adding the receiver  26  and the degassing pipe  27 ), here, as shown in  FIG. 6 , the receiver  26  is provided on the second bottom frame  51   b , the refrigerant pipe  23  (not shown in  FIG. 6 ) is connected to the receiver  26 , and the degassing pipe  27  (not shown in  FIG. 6 ) is connected to the receiver  26  and the compressor  8 . 
     In this way, here, the receiver  26  and the degassing pipe  27  are provided on the second bottom frame  51   b , so the gas injection function can be easily added without changing the placement of the first refrigerant circuit constituent parts such as the compressor  8  provided on the first bottom frame  51   a . Furthermore, here, the receiver  26  serving as a refrigerant circuit constituent part (a second refrigerant circuit constituent part) that is changed or added in accordance with capacity or function is provided on the second bottom frame  51   b , but the receiver  26  is lighter in weight compared to the first refrigerant circuit constituent parts including the compressor  8  and the accumulator  7  provided on the first bottom frame  51   a . For this reason, here, the first bottom frame  51   a  is configured to have a larger plate thickness than the second bottom frame  51   b . Because of this, here, the strength of the first bottom frame  51   a  can be increased and the weight of the second bottom frame  51   b  can be reduced. 
     Furthermore, for example, in the configuration having the basic refrigerant circuit  6  shown in  FIG. 1 , there are cases where one wants to make a change in or addition to the refrigerant circuit constituent parts configuring the refrigerant circuit  6 . As a specific example, there are cases where one executes a capacity change that provides, together with a second oil separator, a second compressor connected in parallel to the first compressor  8  to increase the operating capacity of the compressor and, in accordance therewith, increases the size of the heat source-side heat exchanger  11 . That is, the second compressor and the second oil separator are added as second refrigerant circuit constituent parts and the size of the heat source-side heat exchanger  11  serving as a second refrigerant circuit constituent part is changed. 
     With respect to such changing or adding of the second refrigerant circuit constituent parts (here, mainly adding a second compressor  28  and a second oil separator  29  and changing the size of the heat source-side heat exchanger  11 ), here, as shown in  FIG. 7 , the second compressor  28  and the second oil separator  29  are provided on the second bottom frame  51   b  and connected in parallel to the first compressor  8 , the size of the heat source-side heat exchanger  11  is increased, and the size of the second bottom frame  51   b  is increased. 
     In this way, here, the size of the second bottom frame  51   b  is changed in response to providing the second compressor  28  and the second oil separator  29  on the second bottom frame  51   b  and changing the size of the heat source-side heat exchanger  11 , so a capacity change can be easily executed without changing the placement of the first refrigerant circuit constituent parts such as the compressor  8  provided on the first bottom frame  51   a . Furthermore, here, the heat source-side heat exchanger  11  is provided along an edge portion of the bottom frame  51 , so by changing the length of the edge portion of the second bottom frame  51   b , the size of the heat source-side heat exchanger  11  serving as a second refrigerant circuit constituent part can be easily changed. 
     Furthermore, in the heat source unit  2 , there is the concern that refrigerant pipes connected to the compressor  8  and area devices (the compressor  8 , the accumulator  7 , and the oil separator  9 ) will sustain damage from vibrations during operation and during transport, so to ensure that such damage does not occur, the placement of these devices and the placement and shapes of the refrigerant pipes connected to these devices are appropriately set. For this reason, even in a case where the refrigerant circuit constituent parts are changed or added in accordance with capacity or function, the placement of these devices and the placement and shapes of the refrigerant pipes connected to these devices should be spared from being changed. With respect to this, here, the compressor  8  and area devices (the compressor  8 , the accumulator  7 , and the oil separator  9 ) are collectively placed as the first refrigerant circuit constituent parts on the first bottom frame  51   a . Because of this, here, even in a case where the refrigerant circuit constituent parts are changed or added in accordance with capacity or function, the compressor  8 , the accumulator  7 , and the oil separator  9  and the placement and shapes of the refrigerant pipes connected to these devices can be spared from being changed. Furthermore, the size of the first bottom frame  51   a  and the refrigerant circuit constituent parts provided on the first bottom frame  51   a  (i.e., the first refrigerant circuit constituent parts) are not changed, so simulation predictions for evaluating vibration and noise performance can be easily executed. 
     Furthermore, here, the ridge portions  52   a  and  52   b  and the furrow portions  53   a  and  53   b  of the corrugated plate-like first bottom frame  51   a  and second bottom frame  51   b  are formed extending across the front and rear direction of the casing  40 , so the first bottom frame  51   a  and the second bottom frame  51   b  can be placed side by side to the left and right of each other, when the casing  40  is viewed from the front surface side, to change the size of the casing  40 . It will be noted that although there are many cases where, when installing the heat source unit  2 , there are restrictions on the size of the casing  40  in the front and rear direction, here, the first bottom frame  51   a  and the second bottom frame  51   b  can be placed side by side to the left and right of each other to change the size of the casing  40 , so the heat source unit  2  can be spared from being subjected to restrictions on the size of the casing  40  in the front and rear direction. 
     (3) Example Modifications 
     &lt;A&gt; 
     In the aforementioned embodiments, the first bottom frame  51   a  configures the left portion of the bottom surface of the casing  40  and the second bottom frame  51   b  configures the right portion of the bottom surface of the casing  40 , but the first bottom frame  51   a  and the second bottom frame  51   b  are not limited to this and may also be switched in the right and left direction. 
     &lt;B&gt; 
     In the aforementioned embodiments, cases where a gas injection function is added and the capacity is changed to increase were given as cases where the refrigerant circuit constituent parts are changed or added in accordance with capacity or function, but the invention is not limited to this and can also be applied to other cases where functions are added and the capacity is changed. 
     Although the disclosure has been described with respect to only a limited number of embodiments, those skill in the art, having benefit of this disclosure, will appreciate that various other embodiments may be devised without departing from the scope of the present invention. Accordingly, the scope of the invention should be limited only by the attached claims. 
     INDUSTRIAL APPLICABILITY 
     The present invention is widely applicable to a heat source unit where refrigerant circuit constituent parts are provided inside a casing. 
     REFERENCE SIGNS LIST 
     
         
           2  Heat Source Unit 
           7  Accumulator 
           8  Compressor 
           9  Oil Separator 
           40  Casing 
           51  Bottom Frame 
           51   a  First Bottom Frame 
           51   b  Second Bottom Frame 
           52   a ,  52   b  Ridge Portions 
           53   a ,  53   b  Furrow Portions 
       
    
     CITATION LIST 
     Patent Literature 
     
         
         Patent Document 1: JP-A No. 2011-158137