OUTDOOR UNIT FOR A HEAT PUMP

Abstract

An outdoor unit for a heat pump includes a refrigerant circuit, the outdoor unit including a compressor, a discharge pipe of the refrigerant circuit connected to a discharge side of the compressor, a bottom plate, the bottom plate having a base and an outer flange protruding upward from an outer edge of the base, a heat source heat exchanger supported on the bottom plate, a liquid refrigerant pipe of the refrigerant circuit connected to the heat source heat exchanger, and a defrosting bypass pipe connected at one end to the discharge pipe and at the opposite end to the liquid refrigerant pipe, the defrosting bypass pipe being arranged between an inner side of the flange and an outer side of the heat source heat exchanger.

Claims

1. An outdoor unit for a heat pump comprising a refrigerant circuit, the outdoor unit comprising: a compressor; a discharge pipe of the refrigerant circuit connected to a discharge side of the compressor; a bottom plate, the bottom plate having a base and an outer flange protruding upward from an outer edge of the base; a heat source heat exchanger supported on the bottom plate; and a defrosting bypass pipe connected at one end to the discharge pipe, the defrosting bypass pipe being arranged between an inner side of the flange and an outer side of the heat source heat exchanger.

2. The outdoor unit according to claim 1, wherein the defrosting bypass pipe is a loop comprising an upper pipe and a lower pipe, wherein the upper pipe is further away from the base of the bottom plate than the lower pipe.

3. The outdoor unit according to claim 1, further comprising an additional defrosting bypass pipe connected at one end to the discharge pipe, the additional defrosting bypass pipe being arranged between the base of the bottom plate and a lower side of the heat source heat exchanger.

4. The outdoor rye unit according to claim 3, wherein the additional defrosting bypass pipe comprises an auxiliary loop which is in a view perpendicular to the bottom plate not located below the heat source heat exchanger.

5. The outdoor unit according to claim 4, wherein the additional defrosting bypass pipe is made of at least two tubes connected to each other at a connecting portion, the connecting portion being positioned in the auxiliary loop so that the connecting portion is in a view perpendicular to the bottom plate not located below the heat source heat exchanger.

6. The outdoor unit according to claim 4, wherein the auxiliary loop extends towards a support structure supporting a fan on the bottom plate in a view perpendicular to the bottom plate.

7. The outdoor unit according to claim 3, wherein the defrosting bypass pipe and the additional defrosting bypass pipe are connected in parallel.

8. The outdoor unit according to claim 7, wherein a valve is arranged in each of the defrosting bypass pipe and the additional defrosting bypass pipe.

9. The outdoor unit according to claim 7, wherein a valve is arranged to control the flow of refrigerant from the discharge pipe through both the defrosting bypass pipe and the additional defrosting bypass pipe.

10. The outdoor unit according to claim 8, further comprising a controller, wherein the controller is configured to close the valve/-s during normal operation and to open the valve/-s during a defrost operation.

11. The outdoor unit according to claim 3, wherein the additional defrosting bypass pipe passes around a drainage hole in the bottom plate.

12. The outdoor unit according to claim 5, wherein the auxiliary loop extends towards a support structure supporting a fan on the bottom plate in a view perpendicular to the bottom plate.

13. The outdoor unit according to claim 4, wherein the defrosting bypass pipe and the additional defrosting bypass pipe are connected in parallel.

14. The outdoor unit according to claim 5, wherein the defrosting bypass pipe and the additional defrosting bypass pipe are connected in parallel.

15. The outdoor unit according to claim 6, wherein the defrosting bypass pipe and the additional defrosting bypass pipe are connected in parallel.

16. The outdoor unit according to claim 9, further comprising a controller, wherein the controller is configured to close the valve/-s during normal operation and to open the valve/-s during a defrost operation.

17. The outdoor unit according to claim 4, wherein the additional defrosting bypass pipe passes around a drainage hole in the bottom plate.

18. The outdoor unit according to claim 5, wherein the additional defrosting bypass pipe passes around a drainage hole in the bottom plate.

19. The outdoor unit according to claim 6, wherein the additional defrosting bypass pipe passes around a drainage hole in the bottom plate.

20. The outdoor unit according to claim 7, wherein the additional defrosting bypass pipe passes around a drainage hole in the bottom plate.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0039] FIG. 1 shows a perspective view of an outdoor unit in accordance with the present disclosure, wherein a front panel including a grille and a valve mouth are removed and the heat source heat exchanger is schematically shown transparently;

[0040] FIG. 2 shows a partially enlarged cross-sectional view of the outdoor unit in FIG. 1 along a horizontal plane, wherein the heat source heat exchanger is schematically shown transparently;

[0041] FIG. 3 shows a partially enlarged perspective view of the outdoor unit in FIG. 1, wherein the heat exchanger has been removed;

[0042] FIG. 4 shows a partially enlarged cross-sectional view of the outer unit in FIG. 1 along a vertical plane, wherein the heat source heat exchanger is schematically shown transparently;

[0043] FIG. 5 shows a piping diagram of a heat pump implementing an outdoor unit as shown in FIG. 1.

DESCRIPTION OF EMBODIMENTS

[0044] An embodiment will now be explained with reference to the drawings. It will be apparent to those skilled in the field of heat pumps from this disclosure that the following description of the embodiment is provided for illustration only and not for the purpose of limiting the invention as defined by the appended claims.

[0045] FIG. 1 shows a perspective view of an outdoor unit 10 of a split type heat pump 1 (FIG. 5).

[0046] The heat pump 1 comprises the outdoor unit 10 and an indoor unit 100. The indoor unit 100 comprises a heat consumer heat exchanger (indoor heat exchanger 101) and an indoor fan 102.

[0047] In the present example, the outdoor unit 10 comprises a heat source heat exchanger 11 and an outdoor fan 12. Additional components that may be accommodated in the outdoor unit 10 are a compressor 13, an accumulator 14, an expansion valve 15 and/or a 4-way switching valve 16.

[0048] Referring to FIG. 5, the components of the refrigerant circuit are connected by refrigerant pipes. In this context, a refrigerant pipe 17 (discharge pipe) is connected to the discharge side of the compressor 13 and the 4-way switching valve 16. Moreover, the 4-way switching valve 16 is connected by a refrigerant pipe 18 to the heat source heat exchanger 11. A liquid refrigerant pipe 19 connects the heat source heat exchanger 11 and the expansion valve 15.

[0049] The outdoor unit 10 and the indoor unit 100 are connected by a liquid refrigerant connection pipe 20 and a gaseous refrigerant connection pipe 21. The liquid refrigerant connection pipe connects to the expansion valve 15 and the heat consumer heat exchanger 101. The gaseous refrigerant connection pipe 21 connects to the heat consumer heat exchanger 101 and the 4-way switching valve 16.

[0050] Moreover, the 4-way switching valve 16 is connected by a further refrigerant pipe 22 to the accumulator 14, which in turn is connected to an inlet side of the compressor by a refrigerant piping 23.

[0051] During heating operation of the heat pump 1, which is indicated by the solid lines and arrows in FIG. 5, refrigerant discharged from the compressor 13 flows via the discharge pipes 17, the 4-way switching valve 16 and the gaseous refrigerant connection pipe 21 through the heat consumer heat exchanger 101 functioning as a condenser.

[0052] Subsequently, liquid refrigerant flows from the heat consumer heat exchanger 101 via the liquid refrigerant connection pipe 20, the expansion valve 15 and the liquid refrigerant pipe 19 to the heat source heat exchanger 11 functioning as an evaporator.

[0053] Gaseous refrigerant leaves the heat source heat exchanger 11 and flows via the refrigerant pipe 18, the 4-way switching valve 16, the refrigerant piping 22, the accumulator 14 and the refrigerant piping 23 to the inlet side of the compressor 13.

[0054] During heating operation, when the heat source heat exchanger 11 functions as evaporator, frost is formed on the heat source heat exchanger 11. The formation of frost reduces the heat exchange efficiency of the heat source heat exchanger 11. Thus, a defrosting operation has to be performed on a regular basis.

[0055] During defrosting operation, the above cycle is reversed, which is indicated in FIG. 5 by the dotted lines and the dotted arrows.

[0056] During defrosting operation, refrigerant discharged from the compressor 13 flows via the discharge pipe 17, the 4-way switching valve 16 and the refrigerant pipe 18 through the heat source heat exchanger 11 functioning as a condenser. Thereby, the heat source heat exchanger 11 is heated and any frost formed thereon is thawed.

[0057] Subsequently, liquid refrigerant flows from the heat source heat exchanger 11 via the liquid refrigerant pipe 19, the expansion valve 15 and the liquid refrigerant connection pipe 20 to the heat consumer heat exchanger 101 functioning as an evaporator.

[0058] Gaseous refrigerant leaves the heat consumer heat exchanger 101 and flows via the gaseous refrigerant connection pipe 21, the 4-way switching valve 16, the refrigerant piping 22, the accumulator 14 and the refrigerant piping 23 to the inlet side of the compressor 13.

[0059] In the following, the structure of the outdoor unit 10 is explained in more detail with reference to FIGS. 1 to 4.

[0060] The shown outdoor unit 10 comprises a casing 30. The casing 30 has a top plate 33 and a side plate 34. In the shown embodiment, the side plate 34 extends around a rearward corner of casing 30 of the outdoor unit 10 being connected to (integrally formed with/forming a one piece structure with) a back plate 35 of the casing 30.

[0061] Further, the casing 30 has a bottom plate 31. Feet 32 (see FIGS. 1 and 3) for mounting the outdoor unit on a horizontal surface or via brackets to a vertical wall are fixed to the bottom plate 31.

[0062] The bottom plate 31 has a base 36. The feet 32 are attached to a lower side of the base 36. A circumferential flange 37 protrudes outward from the base 36. Thus, the flange 37 is basically oriented vertically, whereas the base 36 is oriented horizontally. The flange 37 may extend about the entire circumference of the base 36. Thus, the bottom plate 31 resembles a drain pan.

[0063] A drainage structure 38 is provided in the base 36 of the bottom plate 31. This drainage structure 38 comprises a plurality of channels 39a-39e. Moreover, the drainage structure 38 comprises a drainage hole 40. In the example, the drainage hole 40 is positioned within the drainage channel 39a. The drainage channels 39a-39e guide any water accumulated on the base 36 of the bottom plate 31 towards the drainage hole 40. The drainage hole 40 is connected to a drainage port 41 at a lower side of the bottom plate 31 in order to lead any water away from the outdoor unit 10.

[0064] The outdoor fan 12 is as well accommodated in the casing 30 of the outdoor unit 10. The outdoor fan 12 is fixed to the base 36 of the bottom plate 31 via a support structure 42. A fan motor 43 is attached to the support structure 42 and rotationally supports a fan rotor 44 including fan blades 45. In the depicted embodiment, the support structure 42 is directly screwed onto the base 36 of the bottom plate 31. The drainage channels 39c and 39e pass by the support structure 42 and particularly the portion of the base 36 to which the support structure is fixed.

[0065] As will be best visible from FIG. 2, the heat source heat exchanger 11 occupies a part of the rear side of the casing 30 and the side of the casing 30 opposite to the side plate 34. The heat source heat exchanger 11 is “L”-shaped in a top view.

[0066] The heat source heat exchanger 11 is supported on an upper surface of the base 36 as shown in FIG. 4. The drainage channels 39a basically follow an outer edge portion of the base 36 at which the heat source heat exchanger 11 is supported on the base 36. Thus, a lower side 11c of the heat source heat exchanger 11 is directed towards the base 36 and the drainage channel 39a. The heat source heat exchanger 11 may even close an upper opening of the drainage channels 39a.

[0067] Further, the heat source heat exchanger 11 is positioned on the bottom plate 31 so that an outer side 11a of the heat source heat exchanger 11 is positioned inside the flange 37 or more particularly an inner surface 37a of the flange 37.

[0068] As previously mentioned, the heat source heat exchanger 11 is heated during the defrosting operation, whereby any frost formed thereon melts. Accordingly, water flows along surfaces of the heat source heat exchanger 11 including the outer side 11a and an inner side 11b of the heat source heat exchanger 11 downwards to the bottom plate 31. Some of the water will flow in the gap between the inner side 37a of the flange 37 and the outer side 11a of the heat source heat exchanger 11.

[0069] Some of the water will also flow towards the drainage structure 38 in the base 36 of the bottom plate 31. This water is guided via the drainage channels 39a-e towards the drainage hole 40 and from there via the drainage port 41 away from the outdoor unit 10.

[0070] In order to prevent the formation of ice during the defrosting operation in a portion between the inner side 37a and the outer side 11a, a defrosting bypass pipe 50 is provided in the space between the inner side 37a of the flange 37 and the outer side 11a of the heat source heat exchanger 11. The defrosting bypass pipe 50 comprises a lower pipe 50a and an upper pipe 50b. The lower pipe 50a and the upper pipe 50b extend vertically parallel to each other. Thus, the upper pipe 50b is further away from the base 36 than the lower pipe 50a.

[0071] The lower pipe 50a and the upper pipe 50b are connected by a bend 50c at one end forming a loop. The opposite ends of the lower pipe 50a and the upper pipe 50b are respectively connected indirectly or directly to the discharge pipe 17 and the liquid refrigerant pipe 19 (FIG. 5).

[0072] Moreover, an additional defrosting bypass pipe 60 is provided underneath the heat source heat exchanger 11, particularly underneath the lower side 11c of the heat source heat exchanger 11. In the shown example, the additional defrosting bypass pipe 60 is disposed within the drainage channels 39a. The additional defrosting bypass pipe 60 comprises an outer pipe 60a and an inner pipe 60b. The outer pipe 60a and the inner pipe 60b extend horizontally parallel to each other. Thus, the inner pipe 60b is further away from the inner side 37a of the flange 37 than outer pipe 60a.

[0073] The outer pipe 60a and the inner pipe 60b are connected at one end by a bend 60c forming a loop. The opposite ends of the outer pipe 60a and the inner pipe 60b are respectively connected indirectly or directly to the discharge pipe 17 and the liquid refrigerant pipe 19 (FIG. 5).

[0074] Moreover, the additional defrosting bypass pipe 60 has an auxiliary loop 61. The auxiliary loop 61 is formed by bending the defrosting bypass pipe 60 so as to extend towards the support structure 42 of the outdoor fan 12. In the example, the auxiliary loop 61 extends from the drainage channel 39a into the drainage channel 39c passing by the support structure 42. In this context, the inner and outer pipes 60a and 60b are bent outward away from the flange 37 and respectively connected (brazed) by a 180 degree bend 61a. As will be best apparent from FIG. 2, the connecting portions, i.e. the portions where the bends 61a are respectively connected (brazed) to the inner and outer pipes looks out from the heat source heat exchanger 11 in a top view. Thus, the brazed portions may be readily inspected without having to remove the heat source heat exchanger 11 for maintenance. The bend 60c as well looks out from the heat source heat exchanger 11 (see FIG. 1) so that also this connection portion may readily be inspected without having to remove the heat source heat exchanger 11. The bend 50c is visible anyway when inspecting the gap between the inner side 37a of the flange 37 and the outer side 11a of the heat source heat exchanger 11.

[0075] In addition, the additional defrosting bypass pipe 60 comprises a curved portion 62 passing around the drainage hole 40 (FIG. 2) in order to block at most a minor portion of the cross-section of the drainage hole 40 and thereby enable a reliable drainage of water via the drainage hole 40.

[0076] As will be apparent from FIG. 5, the defrosting bypass pipe 50 and the additional defrosting bypass pipe 60 are connected in parallel. A valve 63 may be provided in order to control the flow of gaseous refrigerant into the defrosting bypass pipe 50 in the additional defrosting bypass pipe 60 during defrosting operation. Alternatively to the valve 63, two valves 63a and 63b may be provided respectively in the defrosting bypass pipe 50 and the additional defrosting bypass pipe 60, which would allow independent control of the flow in the respective pipes 50 and 60. A controller 70 is provided to control the valve 63 or alternatively the valves 63a and 63b. In particular, the controller 70 opens the valve 63 or alternatively the valves 63a and 63b in the defrosting operation and closes the valve 63 or alternatively the valves 63a and 63b in a normal operation, such as heating operation.

[0077] As a consequence, during defrosting operation hot gaseous refrigerant flows through the defrosting bypass pipe 50 and the additional defrosting bypass pipe 60.

[0078] Accordingly, the space between the inner side 37a of the flange 37 and the outer side 11a of the heat source heat exchanger 11 is heated by the defrosting bypass pipe 50 preventing the formation of ice in said space.

[0079] Similarly, the drainage channel 39a is heated by the additional defrosting bypass pipe 60 so that the formation of ice in the drainage channel 39a is avoided. Due to the auxiliary loop 61 which extends towards the support structure 42 into the drainage channel 39c, a portion in the vicinity of the support structure 42 is heated and the formation of ice at the support structure 42 may be prevented. Accordingly, displacement of the support structure 42 due to the formation of ice can be avoided.

[0080] It is to be understood that the present description of an embodiment is not considered to be limiting. Rather several modifications may be realized by the skilled person. For example, more than one auxiliary loop can be provided in the additional defrosting bypass pipe 60. Further, the defrosting bypass pipe 50 and/or the additional defrosting bypass pipe 60 may also be connected to the liquid refrigerant connecting pipe 20. Even further it is also conceivable to connect one end of the defrosting bypass pipe 50 and/or the additional defrosting bypass pipe 60 to the discharge pipe 17 and the other opposite end to the refrigerant pipe 18 rather than the liquid refrigerant pipe 19 or a liquid refrigerant connecting pipe 20.

REFERENCE SIGNS LIST

[0081] 1 heat pump [0082] 10 outdoor unit [0083] 11 heat source heat exchanger [0084] 11a outer side [0085] 11b inner side [0086] 11c lower side [0087] 12 outdoor fan [0088] 13 compressor [0089] 14 accumulator [0090] 15 expansion valve [0091] 16 4 way switching valve [0092] 17 discharge pipe [0093] 18 refrigerant pipe [0094] 19 liquid refrigerant pipe [0095] 20 liquid connection pipe [0096] 21 gaseous connection pipe [0097] 22 refrigerant pipe [0098] 23 refrigerant pipe [0099] 30 casing [0100] 31 bottom plate [0101] 32 foot [0102] 33 top plate [0103] 34 side plate [0104] 35 back plate [0105] 36 base of the bottom plate [0106] 37 flange [0107] 37a inner side of the flange [0108] 38 drainage structure [0109] 39a-e drainage channels [0110] 40 drainage hole [0111] 41 drainage port [0112] 42 support structure [0113] 43 fan motor [0114] 44 fan rotor [0115] 45 fan blade [0116] 50 defrosting bypass pipe [0117] 50a lower pipe [0118] 50b upper pipe [0119] 50c bend [0120] 60 additional defrosting bypass pipe [0121] 60a outer pipe [0122] 60b inner pipe [0123] 60c bend [0124] 61 auxiliary loop [0125] 61a bend [0126] 62 curved portion [0127] 100 indoor unit [0128] 101 heat consumer heat exchanger [0129] 102 indoor fan