heat pump

Abstract

The present disclosure includes a first heat exchanger including a first pipe through which a first refrigerant flows and a second pipe disposed on the other side of the first pipe through which a second refrigerant flows, a boiler connected to the first pipe, a second heat exchanger and compressor connected to the second pipe through which the second refrigerant circulates, a bypass pipe disposed to allow heat exchange between the second heat exchanger and the first refrigerant, and a three-way valve that switches the first refrigerant to pass through the bypass pipe. According to the present disclosure, it is possible to prevent frost formation when the evaporator of the outdoor heat exchanger is operating.

Description

[Technical field]

[0001] The present invention relates to a heat pump, and more particularly to a heat pump that increases heating efficiency and reduces energy in a heating mode. [Background technology]

[0002] In the conventional heat pump, in the cooling operation mode, the refrigerant is discharged from the compressor, transferred to the outdoor heat exchanger via the four-way valve, transferred from the outdoor heat exchanger to the indoor heat exchanger via the expansion device, and then sucked into the compressor via the accumulator. When the operation mode is changed to the heating operation mode, the flow direction of the refrigerant is changed to the opposite direction from that in the cooling operation mode.

[0003] In the heating operation mode, the refrigerant flowing into the outdoor heat exchanger is in a liquid state.

[0004] The heat required to evaporate the liquid refrigerant into a gaseous state is obtained from the outside air.

[0005] Therefore, when the outdoor temperature is low, the evaporation process does not proceed smoothly, and as a result, the liquid component of the refrigerant flowing into the indoor heat exchanger increases, resulting in a significant decrease in heating capacity.

[0006] When the outdoor temperature drops below 0℃, which is the freezing point of water, frost forms on the outdoor heat exchanger, significantly reducing the efficiency of heating operation.

[0007] In order to solve the above problems, recently, air conditioners are designed to have a defrosting mode that switches the air conditioner from the heating mode back to the cooling mode for a certain period of time. When the air conditioner is switched to the defrosting mode, the frost on the outdoor heat exchanger can be removed.

[0008] However, in conventional heat pumps, the indoor heat exchanger simply performs heating by circulating the refrigerant in the heat pump cycle when operating in heating mode, and therefore is unable to meet recent consumer expectations for increased heating efficiency and reduced energy consumption.

[0009] In addition, when heating, the evaporating temperature can drop too much, causing the heater to freeze and burst.

[0010] Therefore, there is a demand for a structure that can prevent or delay the formation of frost on the outdoor heat exchanger of an air conditioner that is exposed to a low-temperature environment. Summary of the Invention [Problem to be solved by the invention]

[0011] An object of the present invention is to efficiently prevent frost formation that may occur on an outdoor heat exchanger during heating operation, or to efficiently reduce the amount of frost that does occur.

[0012] The objects of the present invention are not limited to the objects mentioned above, and other objects not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0013] In order to achieve the above object, a heat pump according to an embodiment of the present invention includes (has; constitutes; constructs; sets; contains; includes; contains) a first pipe through which a first refrigerant flows, a second pipe disposed on one side of the first pipe through which a second refrigerant flows, a first heat exchanger connected to the first pipe and the second pipe and exchanging heat between the first refrigerant and the second refrigerant, a boiler connected to the first pipe through which the first refrigerant flows, a compressor connected to the second pipe and compressing the second refrigerant, a second heat exchanger connected to the second pipe and exchanging heat between the second refrigerant and outside air, a bypass pipe branching off from the first pipe and exchanging heat with the second heat exchanger, and a three-way valve for guiding the first refrigerant to pass through the bypass pipe.

[0014] Other specific details of the embodiments are included in the detailed description and drawings. Effect of the Invention

[0015] According to this embodiment, a water pipe is installed near the second heat exchanger 120, 220 used as an evaporator during heating, or a refrigerant pipe is installed immediately after the condenser is discharged, and high-temperature fluid is circulated to the side, so that freezing on the surface of the second heat exchanger 120, 220 when used as an evaporator can be delayed.

[0016] In addition, by applying this to boiler B which is in communication with the heat pump, the temperature of the heat entering the plate type heat exchanger which serves as the condenser can be lowered, thereby increasing efficiency.

[0017] It also allows the inlet temperature to be lowered to extend the operating range of the heat pump, reducing operating costs. [Brief description of the drawings]

[0018] [Figure 1] 1 shows a schematic diagram of a heat pump according to an embodiment of the present invention. [Diagram 2] 2 shows a schematic representation of a heat pump according to another embodiment of the invention; [Diagram 3] 3 is a temperature-performance graph during the boiler-heat pump linked operation according to FIGS. 1 and 2. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The advantages and features of the present invention, and the method of achieving them, will become clear from the detailed description of the embodiments with accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and can be embodied in various different forms, but the present embodiments are provided to make the disclosure of the present invention complete and to fully inform those skilled in the art of the present invention of the scope of the invention, and the present invention is only defined by the scope of the claims. Parts designated with the same reference numerals throughout the specification refer to the same components.

[0020] FIG. 1 shows a schematic diagram of a heat pump according to an embodiment of the present invention.

[0021] As shown in FIG. 1, the heat pump includes a first heat exchanger 110 including a first pipe 111 through which a first refrigerant flows and a second pipe 112 arranged on the other side of the first pipe 111 and through which a second refrigerant flows, a boiler B connected to the first pipe 111 and a second heat exchanger 120 connected to the second pipe 112 through which the second refrigerant circulates, and a compressor 130, and may include a three-way valve 140 that switches the first refrigerant to exchange heat with the second heat exchanger 120 when the second heat exchanger 120 functions as an evaporator.

[0022] The first heat exchanger 110 variably operates according to the flow direction of the first or second refrigerant, which varies depending on the cooling or heating mode of the heat pump.

[0023] Specifically, the first heat exchanger 110 serves as a condenser that condenses the refrigerant in a high-temperature, high-pressure gas state into a room-temperature, high-pressure liquid state during heating operation of the heat pump, and serves as an evaporator that evaporates the refrigerant in a low-temperature, low-pressure liquid state into a gas state during cooling operation of the air conditioner.

[0024] In this manner, the first heat exchanger 110 and the second heat exchanger 120 are driven in the opposite direction according to the circulation of the first or second refrigerant, thereby allowing air conditioning to be performed as desired by the user.

[0025] Additionally, the first heat exchanger 110 may be a plate-type heat exchanger having refrigerants that flow independently of each other.

[0026] The first heat exchanger 110 has a first pipe 111 and a second pipe 112 disposed at both ends thereof, so that the first refrigerant and the second refrigerant have their own flows without meeting each other.

[0027] To explain the internal flow of the first heat exchanger 110 in more detail, the first refrigerant has a single path in which it flows in through an inlet (not shown) of the first pipe 111 formed at one end on the left side, moves to one side, travels in the length direction of the plate 113, and is discharged through the other side of the first pipe 111.

[0028] In addition, the second refrigerant flows in through an inlet (not shown) of the second pipe 112 formed at one end on the right side, moves to one side, travels in the length direction of the plate 113 (opposite the flow direction of the first heat exchange medium), and has a single path to be discharged through an outlet (not shown) of the second pipe 112.

[0029] In addition, the plate 113 may define the above-mentioned first fluid portion (not shown) and second fluid portion (not shown) by joining two types of first plate (not shown) and second plate (not shown) at a joining portion (not shown). Here, adjacent plates 113 may be bonded to each other by brazing.

[0030] A blower fan 121 may be provided on one side of the second heat exchanger 120. The blower fan 121 guides outdoor air to the second heat exchanger 120.

[0031] The air forced to flow by the blower fan 121 exchanges heat with the second refrigerant flowing inside the second heat exchanger 120 .

[0032] The boiler B is connected to the first pipe 111 and contains the water refrigerant flowing inside the first pipe 111 to perform a hot water supply function.

[0033] The second refrigerant circulates through the second heat exchanger 120 and the compressor 130 and may include R32 or R290 refrigerant.

[0034] In other words, the second refrigerant may include any one or more mixed refrigerants selected from the group consisting of difluoromethane (R32) and propane (R290), which are alternative refrigerants with an OZONE DEPLETION POTENTIAL (ODP) of 0.0.

[0035] The compressor 130 compresses a low-temperature, low-pressure gas refrigerant to a high-temperature, high-pressure refrigerant and supplies it to the condenser.

[0036] In addition, a plurality of compressors 130 may be provided. For example, when the compressor 130 is an inverter compressor capable of changing the operating frequency, the compressor 130 may include a constant speed compressor using a fixed operating frequency.

[0037] The three-way valve 140 may include a first flow path 141, a second flow path 142, and a third flow path 143, where the first flow path 141 is connected to the boiler B to circulate the first refrigerant, the second flow path 142 is connected to the first pipe 111, and the third flow path 143 is arranged to discharge in a direction other than the first flow path 141 and the second flow path 142, but to merge with the second flow path 142 via a bypass pipe 144 that exchanges heat with the second heat exchanger 120.

[0038] In the cooling mode of the air conditioner, the three-way valve 140 is controlled to close so that the first refrigerant passing through the boiler B is not supplied to the second heat exchanger 120, and in the heating mode, the three-way valve 140 is controlled to open so that the first refrigerant passing through the boiler B is supplied to the second heat exchanger 120. The operation related to this will be described later.

[0039] An accumulator 150 may further be included between the compressor 130 and the second heat exchanger 120 .

[0040] In the accumulator 150, the liquid refrigerant that has not yet evaporated is filtered, and only the gaseous refrigerant is selected and supplied to the compressor 130.

[0041] The accumulator 150 may be provided between the suction side pipes of the compressor 130. The accumulator 150 receives the refrigerant from the first heat exchanger 110 or the second heat exchanger 120, separates the refrigerant into gas and liquid states, and supplies only the gaseous refrigerant to the compressor 130.

[0042] An expansion valve 160 may further be included between the second pipe 112 and the second heat exchanger 120 .

[0043] The expansion valve 160 expands the normal temperature, high pressure liquid refrigerant that has passed through the condenser, and supplies the liquid refrigerant to the evaporator as a low temperature, low pressure liquid refrigerant.

[0044] The expansion valve 160 may be an electric expansion valve whose opening degree can be controlled.

[0045] When the heat pump operates in heating mode, the four-way valve 170 guides the refrigerant passing through the compressor 130 to flow to the first heat exchanger 110, and guides the refrigerant passing through the second heat exchanger 120 to flow to the accumulator 150.

[0046] On the other hand, when the heat pump operates in cooling mode, the refrigerant passing through the compressor 130 is guided to flow to the second heat exchanger 120, and the refrigerant passing through the first heat exchanger 110 is controlled to flow to the accumulator 150.

[0047] A muffler 180 may be further included between the four-way valve 170 and the compressor 130. The expansion valve 160 generally uses a capillary tube, which does not affect the refrigeration performance, but generates noise due to a sudden change in the flow of the refrigerant.

[0048] The noise generated at this time is a fairly large flow noise due to the complex changes in the refrigerant's phase, pressure, speed, and internal energy, and a muffler 180 may be included to reduce such noise.

[0049] In other words, the muffler 180 functions to suppress vibration or noise of the refrigerant discharged from the compressor 130 .

[0050] The operation of the heat pump according to the embodiment of the present invention will now be described.

[0051] When the heat pump according to the embodiment of the present invention operates in a heating mode, the refrigerant discharged from the compressor 130 flows to the first heat exchanger 110 in a high-temperature and high-pressure state under the control of the four-way valve 170 .

[0052] Thereafter, the second refrigerant in a high-temperature and high-pressure state undergoes a phase change to be condensed and liquefied while passing through the first heat exchanger 110 and exchanging heat with the first refrigerant.

[0053] Thereafter, the second refrigerant passes through the expansion valve 160 and then passes through the second heat exchanger 120 in a high-temperature, low-pressure two-phase refrigerant state.

[0054] As a result, the second heat exchanger 120 acts as an evaporator, and the surface temperature of the second heat exchanger 120 becomes low.

[0055] Here, since the surface temperature of the second heat exchanger 120 becomes lower than the outside temperature, condensed water forms on the surface.

[0056] In addition, when the outside temperature is below the freezing point, the condensed water freezes on the surface of the second heat exchanger 120. If this state continues for a long time, the heat exchange performance of the second heat exchanger 120 with the outside air decreases due to the freezing phenomenon, and eventually a defrosting operation must be performed to remove the ice that has frozen on the surface.

[0057] For this purpose, the first refrigerant is discharged from the boiler B and is in a relatively high temperature state, and the first refrigerant is bypassed to the bypass pipe 144 by controlling the three-way valve 140 .

[0058] Therefore, the ice formed on the outer surface of the second heat exchanger 120 is melted and removed by the process in which the second refrigerant exchanges heat with the second heat exchanger 120.

[0059] The bypass pipe 144 is disposed as close as possible to the second heat exchanger 120 so as to be able to exchange heat with the second heat exchanger 120, and the position of the bypass pipe 144 may be variously applied depending on the design position.

[0060] Meanwhile, when the heat pump according to the embodiment of the present invention operates in a cooling mode, the refrigerant discharged from the compressor 130 flows to the second heat exchanger 120 in a high-temperature and high-pressure state under the control of the four-way valve 170 .

[0061] Thereafter, the second refrigerant in a high-temperature and high-pressure state undergoes a phase change to be condensed and liquefied while passing through the second heat exchanger 120 and exchanging heat with the outside air by the blower fan 121.

[0062] Thereafter, the second refrigerant passes through the expansion valve 160 and then passes through the first heat exchanger 110 in a high-temperature, low-pressure two-phase refrigerant state.

[0063] This causes the first heat exchanger 110 to function as an evaporator.

[0064] The second refrigerant, whose phase has been changed to a low-temperature, low-pressure refrigerant in the first heat exchanger 110, flows into the compressor 130 after passing through the muffler 180 where noise and pulsation are reduced.

[0065] FIG. 2 shows a schematic representation of a heat pump according to another embodiment of the invention.

[0066] Referring to FIG. 2, a heat pump according to another embodiment of the present invention is different from the air conditioner of FIG. 1 in that the position of the three-way valve is different, but the other components are the same, so a description of the overlapping components will be omitted.

[0067] The three-way valve 240 shown in FIG. 2 includes a first flow path 241, a second flow path 242, and a third flow path 243, but the first flow path 241 is connected to a first heat exchanger 241, the second flow path 242 is connected to a second heat exchanger 242, and the third flow path 243 can be arranged to discharge in a direction other than the first flow path 241 and the second flow path 242, and then merge with the first flow path 241 via a bypass pipe 244 that exchanges heat with the second heat exchanger 242.

[0068] 2 operates in the heating mode, the refrigerant discharged from the compressor 230 flows into the first heat exchanger 210 under the control of the four-way valve 270 at high temperature and pressure, similar to the case of FIG.

[0069] Thereafter, the second refrigerant in a high-temperature and high-pressure state undergoes a phase change to be condensed and liquefied while passing through the first heat exchanger 210 and exchanging heat with the first refrigerant.

[0070] Thereafter, the second refrigerant passes through the expansion valve 260 and then passes through the second heat exchanger 220 in a high-temperature, low-pressure two-phase refrigerant state.

[0071] As a result, the second heat exchanger 220 acts as an evaporator, and the surface temperature of the second heat exchanger 220 becomes low.

[0072] Here, since the surface temperature of the second heat exchanger 220 becomes lower than the outside temperature, condensed water forms on the surface.

[0073] In addition, when the outside temperature is below the freezing point, the condensed water freezes on the surface of the second heat exchanger 220. If this state continues for a long time, the heat exchange performance of the second heat exchanger 220 with the outside air decreases due to the freezing phenomenon, and as a result, a defrosting operation must be performed to remove the ice that has frozen on the surface.

[0074] To this end, the second refrigerant is allowed to flow directly to the second heat exchanger 220 via a bypass pipe 244 so that the second refrigerant before flowing into the expansion valve 260 installed in the middle of the flow from the first heat exchanger 210 to the second heat exchanger 220 is bypassed without passing through the expansion valve 260 under the control of the three-way valve 240.

[0075] In other words, the second refrigerant that has passed through the first heat exchanger 210 is in a high-pressure state at room temperature or a low temperature, and in this state, the second refrigerant has a relatively higher temperature than the second refrigerant in the second heat exchanger 220 acting as an evaporator, so that the ice formed on the outer surface of the second heat exchanger 220 can be melted and removed.

[0076] The bypass pipe 244 shown in FIG. 2 is disposed as close as possible to the second heat exchanger 220 so as to be able to exchange heat therewith, and the position of the bypass pipe 244 may be varied depending on the design position.

[0077] Meanwhile, when the heat pump according to another embodiment of the present invention operates in a cooling mode, the refrigerant discharged from the compressor 230 flows to the second heat exchanger 220 in a high-temperature and high-pressure state under the control of the four-way valve 270 .

[0078] Thereafter, the second refrigerant in a high-temperature and high-pressure state undergoes a phase change to be condensed and liquefied while passing through the second heat exchanger 220 and exchanging heat with the outside air by the blower fan 221.

[0079] Thereafter, the second refrigerant passes through the expansion valve 260 and then passes through the first heat exchanger 210 in a high-temperature, low-pressure two-phase refrigerant state.

[0080] This causes the first heat exchanger 210 to function as an evaporator.

[0081] As in the case of FIG. 1, the second refrigerant, which has been phase-changed to a low-temperature, low-pressure refrigerant in the first heat exchanger 210, flows to the compressor 230 after passing through the muffler 280 where noise and pulsation are reduced.

[0082] FIG. 3 is a temperature-performance graph during the boiler-heat pump linked operation according to FIGS.

[0083] Referring to Figure 3, in the region below a certain temperature (region below a+b), only the boiler is operated, but when the outdoor temperature is in the range of a+b, the boiler and heat pump can be operated simultaneously to increase efficiency. In this case, if the temperature entering the heat pump is low, the condensation temperature of the condenser can be lowered, thereby ensuring the degree of subcooling and improving efficiency.

[0084] Although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the above-mentioned specific embodiments, and various modifications may be made by a person having ordinary skill in the art to which the invention pertains without departing from the gist of the present invention as claimed in the claims. However, such modifications should not be understood individually from the technical ideas and perspectives of the present invention.

Claims

1. A heat pump comprising: a first pipe through which a first refrigerant flows; a second pipe disposed on one side of the first pipe and through which a second refrigerant flows; a first heat exchanger connected to the first pipe and the second pipe and configured to exchange heat between the first refrigerant and the second refrigerant; a boiler connected to the first pipe and through which the first refrigerant flows; a compressor connected to the second pipe to compress the second refrigerant; a second heat exchanger connected to the second pipe and configured to exchange heat between the second refrigerant and outside air; a bypass pipe branching off from the second pipe and exchanging heat with the second heat exchanger; a three-way valve for directing the second refrigerant through the bypass pipe; The three-way valve includes a first flow path, a second flow path, and a third flow path, The first flow path is connected to the second pipe, The second flow path is connected to the second heat exchanger, The third flow path merges with the second flow path via the bypass pipe, When the heat pump operates in a heating mode, a refrigerant discharged from the compressor flows into the first heat exchanger, and When the heat pump operates in a cooling mode, the refrigerant discharged from the compressor flows into the second heat exchanger, When operating in the heating mode, the first refrigerant discharged from the first heat exchanger is sent to the bypass pipe.

2. The heat pump of claim 1 , further comprising an accumulator disposed between the compressor and the second heat exchanger.

3. The heat pump of claim 2 , further comprising an expansion valve disposed between the second pipe and the second heat exchanger.

4. 4. The heat pump according to claim 3, further comprising a four-way valve disposed between the compressor, the first heat exchanger, the accumulator, and the second heat exchanger, and configured to switch a flow direction of the second refrigerant between the compressor, the first heat exchanger, the accumulator, or the second heat exchanger.

5. The heat pump of claim 4 , wherein the first heat exchanger comprises a plate heat exchanger.

6. The heat pump of claim 5 , wherein the first refrigerant comprises water.

7. 6. The heat pump of claim 5, wherein the second refrigerant comprises R32, R290, or a mixture of R32 and R290.

8. The heat pump of claim 5 , further comprising a muffler disposed between the four-way valve and the compressor.

Images