Patent Publication Number: US-2022221199-A1

Title: Heat pump system

Description:
FOREIGN PRIORITY 
     This application claims priority to Chinese Patent Application No. 202110047744.9, filed Jan. 14, 2021, and all the benefits accruing therefrom under 35 U.S.C. § 119, the contents of which in its entirety are herein incorporated by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a heat exchange device, in particular to a heat pump system with a heat recovery function. 
     BACKGROUND 
     Nowadays, heat pump systems with a water heating function, which comprise a thermal unit that recovers part of the heat to produce hot water, are often used for residential and villa application. The system can recover heat to produce hot water while heating or cooling. 
     SUMMARY 
     The purpose of the present disclosure is to solve or at least alleviate the problems in the prior art. 
     According one aspect, a heat pump system is provided, comprising: 
     a first unit which comprises a compressor, a switching device connected to the compressor, a first flow path and a second flow path connected to the switching device, and at least one first heat exchangers on the first flow path, wherein the switching device is switchable between a first position and a second position so as to deliver refrigerant compressed by the compressor to the first flow path or the second flow path, respectively; 
     a second unit connected to the first flow path of the first unit and comprising a second heat exchanger; and 
     a third unit connected to the second flow path of the first unit and connected to the second unit, and comprising at least one third heat exchangers; 
     wherein the heat pump system is capable of operating in a cooling and water heating mode and a heating and water heating mode, wherein, in the cooling and water heating mode, the heat pump system is configured to switch the switching assembly to the first position and connect the at least one first heat exchangers and the second heat exchanger in series, and the refrigerant compressed by the compressor passes through the at least one first heat exchangers and the second heat exchanger connected in series via the first flow path, and returns to the compressor after passing through a first expansion device and the at least one third heat exchangers; and 
     wherein, in the heating and water heating mode, the heat pump system is configured to switch the switching assembly to the second position and connect the second heat exchanger and the at least one third heat exchangers in parallel, and the refrigerant compressed by the compressor passes through the second heat exchanger and the at least one third heat exchangers connected in parallel via the second flow path, and returns to the compressor after passing through a second expansion device and the at least one first heat exchangers. 
     Optionally, in an embodiment of the heat pump system, the heat pump system further comprises a cooling mode. In the cooling mode, the heat pump system is configured to switch the switching assembly to the first position, and bypass the second heat exchanger. 
     Optionally, in an embodiment of the heat pump system, the heat pump system further comprises a heating mode. In the heating mode, the heat pump system is configured to switch the switching assembly to the second position, and shut off the bypass branch where the second heat exchanger is located. 
     Optionally, in an embodiment of the heat pump system, the first unit comprises a first regulating valve connected in parallel with the at least one first heat exchanger. In the cooling and water heating mode, opening of the first regulating valve is adjustable so as to regulate the amount of refrigerant bypassing the at least one first heat exchangers. In the heating and water heating mode, the first regulating valve is closed. 
     Optionally, in an embodiment of the heat pump system, the at least one first heat exchangers comprise a plurality of first heat exchangers connected in parallel. In the cooling and water heating mode, the amount of refrigerant condensed in the at least one first heat exchangers is regulated by regulating the number of the first heat exchangers activated. 
     Optionally, in an embodiment of the heat pump system, the at least one third heat exchangers comprise a plurality of third heat exchangers connected in parallel. A first expansion device is arranged on each bypass branch where each of the third heat exchanger is located, wherein the first expansion device performs a throttling function in the cooling and water heating mode, and acts as a flow regulating valve to control the flow of refrigerant passing through the third heat exchangers in the heating and water heating mode. 
     Optionally, in an embodiment of the heat pump system, the at least one third heat exchangers comprise heat exchangers for an air conditioning system and heat exchangers for a floor heating system. 
     Optionally, in an embodiment of the heat pump system, in the cooling and water heating mode, the second expansion device is located downstream of the at least one first heat exchangers on the first flow path. The heat pump system further comprises a first check valve connected in parallel with the second expansion device. In the cooling and water heating mode, the second expansion device is fully opened or closed, and the refrigerant passing through the at least one first heat exchangers flows to the second heat exchanger. In the heating and water heating mode, the first check valve inhibits the passage of fluid, and the second expansion device performs a throttling function. 
     Optionally, in an embodiment of the heat pump system, the first flow path is branched into a main flow path passing through the second unit and a bypass branch. A second check valve, a second heat exchanger and a flow regulating valve are arranged in sequence on the main flow path. The second check valve only allows the fluid flowing to the second heat exchanger to pass through. The bypass branch is connected to the third unit and is provided with a solenoid valve thereon. The flow regulating valve is fully opened in the cooling and water heating mode, and regulates the flow of refrigerant passing through the second heat exchanger in the heating and water heating mode. 
     Optionally, in an embodiment of the heat pump system, the second flow path is branched into a first branch path connected to at least one third heat exchangers of the third unit and a second branch path connected to the second heat exchanger of the second unit. The first branch path merges with the second branch path before passing through the solenoid valve. 
     Optionally, in an embodiment of the heat pump system, the second branch path is provided with a third check valve that only allows the fluid flowing to the second heat exchanger to pass through. 
     The heat pump system according to the embodiments of the present invention has a simple structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       With reference to the drawings, the disclosure of the present invention will become easier to understand. It is easy for those skilled in the art to understand that these drawings are only for illustrative purposes, and are not intended to limit the scope of protection of the invention. In addition, similar numerals in the figures are used to denote similar components, among which: 
         FIG. 1  shows a schematic structural diagram of a heat pump system according to an embodiment of the present invention; and 
         FIG. 2  shows a schematic structural diagram of a heat pump system according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , a schematic diagram of a heat pump system according to an embodiment of the present invention is illustrated. The heat pump system comprises: a first unit  1 , a second unit  2 , and a third unit  3 . The first unit  1  may be, for example, an outdoor unit or an external unit, which is usually arranged outdoors, and may comprise a compressor  10 . The compressor  10  may comprise a compressor inlet  12  and a compressor outlet  11 . The compressor outlet  11  can be connected with a check valve  41 , and then a switching device  13  is provided downstream of the check valve  41 . The switching device  13  may be, for example, a four-way valve, which comprises four ports a, b, c, and d. The port a of the switching device  13  is connected to the compressor outlet  11 , and the port d of the switching device  13  is connected to the compressor inlet  12  via a gas-liquid separator  5 , which is used for separating gaseous and liquid refrigerants, for example. In addition, the port b of the switching device  13  is connected to a first flow path  14 , and the port c of the switching device  13  is connected to a second flow path  15 . The switching device  13  is switchable between a first position and a second position, so that the refrigerant compressed by the compressor  10  is delivered to the first flow path  14  or the second flow path  15 , respectively. More specifically, in the embodiment of the four-way valve, in the first position, port a is connected to port b, and port c is connected to port d. In the second position, port a is connected to port c, and port b is connected to port d. A first heat exchanger  16  is arranged on the first flow path  14 . The first flow path  14  of the first unit  1  is connected to the second unit  2  via, for example, a first pipeline  61 . The second unit  2  can be a thermal unit for producing hot water. The second unit  2  may comprise a second heat exchanger  21 , which may be used to exchange heat between the refrigerant and water in order to heat the water. The second flow path  15  of the first unit  1  is connected to the third unit  3  via, for example, a second pipeline  62 . The third unit  3  may be, for example, an indoor unit or an internal unit, which may comprise at least one third heat exchangers  32 ,  33 , wherein the at least one third heat exchangers  32 ,  33  may be used, for example, to regulate indoor temperature. In some embodiments, the at least one third heat exchangers  32 ,  33  may comprise a plurality of third heat exchangers connected in parallel. For example, as shown in  FIG. 1 , the third unit  3  comprises two third heat exchangers  32 ,  33  connected in parallel, which are respectively located on two branch paths  312 ,  311 . And, the branch paths may each comprise corresponding first expansion devices  34 ,  35 , such as an electronic expansion valve. The first expansion devices  34 ,  35  may, for example, perform a throttling function, or control the flow of refrigerant passing through each third heat exchanger based on the load by regulating the opening. For example, each of the third heat exchangers  32 ,  33  may correspond to an area in a house, so as to regulate the temperature of the area and so on. 
     In addition to the conventional cooling mode and heating mode, the heat pump system according to the embodiments of the present invention can also operate in a cooling and water heating mode and a heating and water heating mode, in which part of the heat is recovered for producing hot water. Specifically, in the cooling and water heating mode, the switching assembly  14  is switched to the first position. The heat pump system is configured to connect the first heat exchanger  16  and the second heat exchanger  21  in series, for example, through switch of the valve (in the illustrated embodiment, the second expansion device  18  is fully opened or closed and the solenoid valve  25  is closed). The refrigerant compressed by the compressor passes through the first heat exchanger  16  and the second heat exchanger  21  connected in series via the first flow path  14 , passes through the corresponding third heat exchangers  32 ,  33  after being throttled by the first expansion devices  34 ,  35 , and then returns to the compressor inlet  12  via the second flow path  15 . Under such circumstances, the first heat exchanger  16  and the second heat exchanger  21  operate as condensers, while the at least one third heat exchangers  32 ,  33  operate as evaporators, and the first expansion devices  34 ,  35  perform a throttling function or act as expansion valves. In another aspect, in the heating and water heating mode, the switching assembly  14  is switched to the second position. The heat pump system is configured to connect the second heat exchanger  21  and the at least one third heat exchangers  32 ,  33  in parallel, for example, through switch of the valve (in the illustrated embodiment, by opening the solenoid valve, and regulating the opening of the first expansion devices  34 ,  35  and the flow regulating valve  22 ). The refrigerant compressed by the compressor passes through the second heat exchanger  21  and the at least one third heat exchangers  32 ,  33  connected in parallel via the second flow path  15 , passes through the first heat exchanger  16  after being throttled by the second expansion device  18 , and then returns to the compressor inlet  12  via the first flow path  14 . In the heating and water heating mode, the second heat exchanger  21  and the at least one third heat exchangers  32 ,  33  operate as condensers, while the first heat exchanger  16  operates as an evaporator, and the second expansion device  18  performs a throttling function or acts as an expansion valve. 
     In some embodiments, the heat pump system may also operate in a cooling mode. In the cooling mode, the heat pump system is configured such that the switching assembly  14  is switched to the first position, and the second heat exchanger  21  is bypassed. For example, the first flow path  14  may be branched into a main flow path  23  passing through the second unit  2  and a bypass branch  24  after passing through the first pipeline  61 . A second check valve  43 , the second heat exchanger  21  and the flow regulating valve  22  are arranged in sequence on the main flow path. The second check valve  43  only allows the fluid flowing to the second heat exchanger  21  to pass through. The flow regulating valve  22  is fully opened in the cooling and water heating mode, and is used to regulate the flow of refrigerant passing through the second heat exchanger  21  in the heating and water heating mode. The bypass branch  24  is connected to the third unit  3  and is provided with a solenoid valve  25  thereon. In the cooling and water heating mode, the solenoid valve  25  is closed and the flow regulating valve  22  is fully opened, so that the refrigerant passes through the main flow path  23 , and passes through the check valve  43 , the second heat exchanger  21  and the flow regulating valve  22  in sequence. However, when only cooling is required while water heating is not, the solenoid valve  25  can be opened and the flow regulating valve  22  can be closed, so that the refrigerant directly enters the third unit  3  without passing through the second heat exchanger  21 , that is, the second heat exchanger  21  is bypassed. 
     In some embodiments, the first unit  1  further comprises a first regulating valve  17  connected in parallel with the first heat exchanger  16 . In the cooling and water heating mode, the opening of the first regulating valve  17  can be regulated, so as to regulate the amount of refrigerant bypassing the first heat exchanger  16 , in other words, to regulate the amount of refrigerant condensed in the first heat exchanger  16 , or the proportion of the refrigerant condensed in the first heat exchanger  16  and the second heat exchanger  21 . Specifically, for example, when there is a relatively high demand for water heating, the opening of the first regulating valve  17  can be increased, so that more refrigerant will bypass the first heat exchanger  16  to come to the second heat exchanger  21  to be condensed. Whereas, when there is a relatively low demand for water heating, the opening of the first regulating valve  17  can be reduced, so that more refrigerant will be condensed in the first heat exchanger  16 . In another aspect, in the heating and water heating mode or the heating mode, the first regulating valve  17  is closed, so that all refrigerant passes through the first heat exchanger  16 . 
     In some embodiments, after passing through the second pipeline  62 , the second flow path  15  is branched into the first branch paths  311 ,  312  connected to the at least one third heat exchangers  32 ,  33  of the third unit  3 , and a second branch path  313  connected to the second heat exchanger  21  of the second unit  2 . The first branch paths  311 ,  312  and the second branch path  313  merge at a position P, and the refrigerant before passes through the solenoid valve  25 . Subsequently, the refrigerant passes through the first pipeline  61  and the second expansion device  18  that performs a throttling function, and then returns to the compressor inlet  12  of the compressor  10  after passing through the first heat exchanger  16 . In some embodiments, the second branch path  313  is provided with a third check valve  44  that only allows the fluid flowing to the second heat exchanger  21  to pass through. As shown in the figure, the second expansion device  18  that performs a throttling function in the heating mode or the heating and water heating mode is located downstream of the first heat exchanger  16  on the first flow path  14 . The heat pump system further comprises a first check valve  42  connected in parallel with the second expansion device  18 , wherein, in the heating mode or the heating and water heating mode, the first check valve  42  inhibits the passage of fluid so that all the fluid passes through the second expansion device  18 , and the second expansion device  18  at this time performs a throttling function or acts as an expansion valve. In the cooling mode or the cooling and water heating mode, the second expansion device  18  is closed or fully open, and the refrigerant passing through the first heat exchanger  16  flows to the second heat exchanger  21  or directly flows to the at least one third heat exchangers  32 ,  33  via the first check valve  42  and/or the second expansion device  18 . 
     In some embodiments, in the heating mode, the heat pump system is configured to switch the switching assembly to the second position, and the branch path where the second heat exchanger  21  is located is shut off. For example, by closing the flow regulating valve  22 , all the refrigerant passes through the at least one third heat exchangers  32 ,  33  at this time. 
     No matter in the cooling and water heating mode or the heating and water heating mode, the flow regulating valve  22  is located downstream of the second heat exchanger  21 . As mentioned above, in the cooling and water heating mode, the flow regulating valve  22  is fully opened. In the heating and water heating mode, the flow regulating valve  22  controls the flow of refrigerant passing through the second heat exchanger  21 . Therefore, in the heating and water heating mode, the opening of the flow regulating valve  22  and the first expansion devices  34  and  35  can be regulated based on the load to allocate the proportion of the refrigerant in each flow path. 
     With continued reference to  FIG. 2 , another embodiment of the heat pump system according to the embodiments of the present invention is introduced. In this embodiment, the at least one first heat exchangers comprise a plurality of heat exchangers connected in parallel, for example, a first heat exchanger  161 , a second heat exchanger  162 , and a third heat exchanger  163  connected in parallel shown in the figure. In the cooling and water heating mode, the number of activated heat exchangers can be controlled to regulate the amount of refrigerant condensed in the at least one first heat exchangers. For example, part of the first heat exchangers can be set to be direct pass-through without heat exchange. In addition, although not shown, a first regulating valve  17  connected in parallel with these first heat exchangers may also be provided as shown in  FIG. 1 . Furthermore, in the embodiment of  FIG. 2 , it is shown that in addition to the third heat exchangers  32 ,  33  for an air conditioning system, the third unit  3  may further comprise one or more third heat exchangers  36  for a floor heating system, which are arranged on the branch path  314  and can be connected in parallel with the other third heat exchangers  32 ,  33 . The corresponding first expansion device  37  is also arranged on the branch path  314 . The third heat exchangers  36  are used to exchange heat with the hot water flow W of the floor heating system. 
     The heat pump system according to the present invention can recover heat for hot water production, thereby improving the efficiency of the entire system. The internal components of the heat pump system, such as a relatively small number of control valves, makes the heat pump system simple in structure and easy to operate. In addition, the heat pump system according to the embodiments of the present invention comprises only two pipelines between the first unit  1  located outdoors and the second unit  2  and the third unit  3  located indoors, namely, a first pipeline  61  and a second pipeline  62 , which simplifies the construction and reduces the construction cost compared with a system with more pipelines. 
     The specific embodiments described above are only used to describe the principle of the present invention more clearly, wherein each component is clearly shown or described to make the principle of the present invention easier to understand. Without departing from the scope of the present invention, those skilled in the art can easily make various modifications or changes to the present invention. Therefore, it should be understood that these modifications or changes should be included in the scope of patent protection of the invention.