Chiller

Abstract

The present disclosure relates to a chiller. The chiller according to an embodiment of the present disclosure comprises: a first compressor for compressing a first refrigerant; a first heat exchanger connected to the first compressor so that the first refrigerant passes therethrough; a second compressor for compressing a second refrigerant; a second heat exchanger connected to the second compressor so that the second refrigerant passes therethrough; a heat medium heat exchanger by which heat is exchanged between the first refrigerant or the second refrigerant and a predetermined heat medium; and a third heat exchanger by which heat is selectively exchanged between the first refrigerant flowing between the first heat exchanger and the heat medium heat exchanger and the second refrigerant flowing between the second heat exchanger and the heat medium heat exchanger.

Description

chiller

[0001] The present disclosure relates to a chiller, and more specifically, to a chiller comprising two cycles.

[0002] Chillers are devices widely used primarily in industrial and commercial HVAC systems, serving to cool or heat desired spaces or equipment through a heat exchange process utilizing refrigerants. By providing efficient and stable temperature control, these chiller systems have established themselves as essential equipment in various application fields.

[0003] Conventional chiller systems commonly utilized configurations including two refrigerant cycles, often designed with a structure that shared a fan and a water-refrigerant heat exchanger. However, due to these structural characteristics, there was a disadvantage in that it was difficult for each cycle to perform defrosting operations independently. In particular, the inability to perform heating operations during defrosting operations resulted in a significant decrease in the overall efficiency of the system.

[0004] Furthermore, conventional chiller systems were designed to use the same refrigerant in both cycles. This resulted in limitations where the outlet water temperature during heating operation was restricted to a specific range, making it difficult to meet the diverse needs of users.

[0005] In addition, under conditions of low ambient temperature, there were technical limitations in sufficiently increasing the compression ratio, which also resulted in a problem of significantly reduced heating capacity.

[0006] The technical problem of the present disclosure is to provide a chiller capable of solving the various problems of the aforementioned prior art.

[0007] Another object of the present disclosure is to provide a chiller comprising two cycles using different refrigerants.

[0008] Another objective of the present disclosure is to provide a chiller capable of heat-exchanging refrigerants circulating in each cycle.

[0009] Another objective of the present disclosure is to provide a chiller capable of high-temperature heating compared to conventional chillers.

[0010] Another objective of the present disclosure is to provide a chiller capable of continuous heating by alternately defrosting the evaporator.

[0011] Another objective of the present disclosure is to provide a chiller that does not lose heating capacity even at low ambient temperatures.

[0012] The problems of the present disclosure are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0013] To solve the above problem, a chiller according to the present disclosure comprises: a first compressor for compressing a first refrigerant; a first heat exchanger connected to the first compressor through which the first refrigerant passes; a second compressor for compressing a second refrigerant; a second heat exchanger connected to the second compressor through which the second refrigerant passes; a heat medium heat exchanger for heat-exchanging a predetermined heat medium with the first refrigerant or the second refrigerant; and a third heat exchanger for selectively heat-exchanging the first refrigerant flowing between the first heat exchanger and the heat medium heat exchanger, and the second refrigerant flowing between the second heat exchanger and the heat medium heat exchanger.

[0014] The chiller may include a first bypass connected so that the first refrigerant bypasses the heat transfer medium heat exchanger, and a first bypass valve disposed in the first bypass.

[0015] The second refrigerant may have a higher saturation temperature than the first refrigerant at the same pressure.

[0016] The chiller may include a second bypass connected so that the second refrigerant bypasses the third heat exchanger, and a second bypass valve disposed in the second bypass.

[0017] The chiller may include a second bypass connected so that the first refrigerant bypasses the third heat exchanger, and a second bypass valve disposed in the second bypass.

[0018] Specific details of other embodiments are included in the detailed description and drawings.

[0019] According to the chiller of the present disclosure, there is one or more of the following effects.

[0020] Through the third heat exchanger, heat exchange between the refrigerants circulating in each cycle can be selectively performed.

[0021] Due to a third heat exchanger that allows the refrigerants circulating in each cycle to exchange heat with each other, a cascade cycle using different refrigerants can be configured.

[0022] By enabling different refrigerants constituting a binary cycle to exchange heat, it is possible to achieve higher temperatures than when using a single refrigerant.

[0023] Continuous high-temperature heating can be performed even at low ambient temperatures through heat exchange between the refrigerants constituting the dual cycle.

[0024] While one cycle performs defrosting of the evaporator, another cycle performs heating, thereby enabling continuous heating.

[0025] The effects of the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description in the claims.

[0026] FIG. 1 is a drawing showing a chiller by symbol according to one embodiment of the present disclosure.

[0027] FIG. 2 is a drawing showing a chiller by symbol according to another embodiment of the present disclosure.

[0028] FIG. 3 illustrates a chiller according to one embodiment of the present disclosure operating in a cooling mode.

[0029] FIG. 4 illustrates a chiller according to one embodiment of the present disclosure operating in a first heating mode.

[0030] FIG. 5 illustrates that a chiller according to one embodiment of the present disclosure operates in a second heating mode.

[0031] FIG. 6 illustrates that a chiller according to one embodiment of the present disclosure operates in a third heating mode.

[0032] FIG. 7 illustrates a chiller according to one embodiment of the present disclosure operating in a fourth heating mode.

[0033] FIG. 8 illustrates that a control unit of a chiller according to one embodiment of the present disclosure controls each cycle.

[0034] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Identical or similar components regardless of drawing symbols are given the same reference number, and redundant descriptions thereof will be omitted.

[0035] The suffixes "module" and "part" used for components in the following description are assigned or used interchangeably solely for the ease of drafting the specification, and do not inherently possess distinct meanings or roles.

[0036] In addition, when describing the embodiments disclosed in this specification, if it is determined that a detailed description of related prior art may obscure the essence of the embodiments disclosed in this specification, such detailed description is omitted. Furthermore, the attached drawings are intended only to facilitate understanding of the embodiments disclosed in this specification, and the technical concept disclosed in this specification is not limited by the attached drawings; it should be understood that they include all modifications, equivalents, and substitutions that fall within the concept and technical scope of this disclosure.

[0037] Terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but said components are not limited by said terms. These terms are used solely for the purpose of distinguishing one component from another.

[0038] When it is stated that one component is "connected" or "connected" to another component, it should be understood that while it may be directly connected or connected to that other component, there may also be other components in between. On the other hand, when it is stated that one component is "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between.

[0039] A singular expression includes a plural expression unless the context clearly indicates otherwise.

[0040] In this application, terms such as “comprising” or “having” are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0041] Referring to FIG. 1, the configuration of a chiller (1) according to one embodiment of the present disclosure can be seen.

[0042] The chiller (1) may include a first cycle (10) and a second cycle (40). The first cycle (10) and the second cycle (40) may be configured and operated independently. A first refrigerant may circulate in the first cycle (10), and a second refrigerant may circulate in the second cycle (40).

[0043] The first cycle (10) may be composed of a first compressor (11), a first oil separator (12), a first switching valve (13), a first heat exchanger (14), a third heat exchanger (3), a first subcooler (15), a heat medium heat exchanger (2), and a first accumulator (17), etc.

[0044] The first compressor (11) compresses the first refrigerant. The first compressor (11) can discharge the first refrigerant in gaseous form after compressing it. A flow of the first refrigerant can be formed by the pressure difference created by the first compressor (11). The compressed first refrigerant may be in a high-temperature, high-pressure superheated vapor state.

[0045] The first oil separator (12) may be connected to the discharge port of the first compressor (11). The first oil separator (12) may be placed in the first discharge channel (21) to be described later. The first compressor (11) may use oil to reduce friction occurring during the compression process of the first refrigerant. The oil may be discharged together with the compressed first refrigerant. The first oil separator (12) may separate and recover the oil discharged from the first compressor (11) from the first refrigerant.

[0046] The first switching valve (13) can switch the flow path of the first cycle (10). The first switching valve (13) can be connected to the first compressor (11) and the first discharge flow path (21). The first switching valve (13) can send the refrigerant discharged from the first compressor (11) to the first heat exchanger (14) or heat medium heat exchanger (2) to be described later. The first switching valve (13) may be a four-way valve.

[0047] The heat medium heat exchanger (2) can be connected to the first switching valve (13) and the first-1 flow path (23). The heat medium heat exchanger (2) exchanges heat with a predetermined heat medium with a first refrigerant or a second refrigerant. The heat medium heat exchanger (2) may be a water refrigerant heat exchanger (2). The predetermined heat medium may be water.

[0048] The first refrigerant may pass through the heat transfer medium heat exchanger (2). The second refrigerant may pass through the heat transfer medium heat exchanger (2). In the heat transfer medium heat exchanger (2), the first refrigerant and the second refrigerant may not exchange heat with each other.

[0049] The first bypass (71) can be connected so that the first refrigerant bypasses the heat transfer medium heat exchanger (2). One end of the first bypass (71) is connected to the first-1 flow path (23), and the other end can be connected to the first-2 flow path (24).

[0050] The first bypass valve (72) may be placed in the first bypass (71). The first bypass valve (72) may be a solenoid valve. By opening or closing the first bypass valve (72), the first refrigerant may or may not pass through the heat transfer medium heat exchanger (2).

[0051] The first subcooler (15) can cool the first refrigerant. The first subcooler (15) can cool the first refrigerant to below the saturation temperature, thereby improving the efficiency of the chiller (1). The first subcooler (15) can be placed in the first-2 flow path (24) and the first subcooling flow path (27). The first subcooling flow path (27) can connect the first compressor (11) to a point between the first subcooler (15) and the heat transfer medium heat exchanger (2) in the first-2 flow path (24).

[0052] The first-3 expansion valve (33) can expand a portion of the first refrigerant introduced from the first-2 flow path (24). The first subcooler (15) can cool the first refrigerant to below the saturation temperature by exchanging heat between the expanded low-temperature refrigerant and the remaining first refrigerant.

[0053] The third heat exchanger (3) can be connected to the heat transfer medium heat exchanger (2) and the first-second flow path (24). The first refrigerant can pass through the third heat exchanger (3).

[0054] The first heat exchanger (14) can exchange heat between the first refrigerant and air. The first heat exchanger (14) is connected to the first compressor (11) so that the first refrigerant passes through it.

[0055] The first heat exchanger (14) can be connected to the third heat exchanger (3) and the first-third flow path (25). The first heat exchanger (14) can be connected to the first switching valve (13) and the first-fourth flow path (26).

[0056] The first accumulator (17) can supply the first refrigerant in gaseous form to the first compressor (11). The first accumulator (17) can separate the gaseous refrigerant from the liquid refrigerant. The first accumulator (17) can prevent the first refrigerant in liquid form from flowing into the first compressor (11).

[0057] The first switching valve (13) and the first compressor (11) can be connected to the first inlet passage (22). The first accumulator (17) can be placed in the first inlet passage (22).

[0058] The first-1 pressure sensor (18) can be placed in the first inlet passage (22). The first-1 pressure sensor (18) can measure the pressure of the first refrigerant flowing through the first inlet passage (22).

[0059] The first-second pressure sensor (19) may be placed in the first discharge channel (21). The first-second pressure sensor (19) can measure the pressure of the first refrigerant flowing through the first discharge channel (21).

[0060] The first-1 expansion valve (31) may be positioned between the heat transfer medium heat exchanger (2) and the first subcooler (15) in the first-2 flow path (24). The first-2 expansion valve (32) may be positioned between the third heat exchanger (3) and the first subcooler (15) in the first-2 flow path (24). The first-3 expansion valve (33) may be positioned between the point where the first-2 flow path (24) is connected and the first subcooler (15) in the first subcooling flow path (27).

[0061] The first-1 expansion valve (31), the first-2 expansion valve (32), and the first-3 expansion valve (33) can expand the first liquid refrigerant by controlling the opening degree. Alternatively, they may be fully open or closed. The first-1 expansion valve (31), the first-2 expansion valve (32), and the first-3 expansion valve (33) may be electric expansion valves.

[0062] A sub-expansion valve (75) may be placed in the first-third flow path (25). The sub-expansion valve (75) may be placed between the third heat exchanger (3) and the first heat exchanger (14). The sub-expansion valve (75) may be controlled to expand the first liquid refrigerant. Alternatively, it may be fully open or closed. The sub-expansion valve (75) may be an electric expansion valve.

[0063] The second cycle (40) may be composed of a second compressor (41), a second oil separator (42), a second switching valve (43), a second heat exchanger (44), a third heat exchanger (3), a second subcooler (45), a heat medium heat exchanger (2), and a second accumulator (47), etc.

[0064] The second compressor (41) compresses the second refrigerant. The second compressor (41) can discharge the second refrigerant in gaseous form after compressing it. A flow of the second refrigerant can be formed by the pressure difference created by the second compressor (41). The compressed second refrigerant may be in a high-temperature, high-pressure superheated vapor state.

[0065] The second oil separator (42) may be connected to the discharge port of the second compressor (41). The second oil separator (42) may be placed in the second discharge channel (51) to be described later. The second compressor (41) may use oil to reduce friction occurring during the compression process of the second refrigerant. The oil may be discharged together with the compressed second refrigerant. The second oil separator (42) may separate and recover the oil discharged from the second compressor (41) from the second refrigerant.

[0066] The second switching valve (43) can switch the flow path of the second cycle (40). The second switching valve (43) can be connected to the second compressor (41) and the second discharge flow path (51). The second switching valve (43) can send the refrigerant discharged from the second compressor (41) to the second heat exchanger (44) or heat medium heat exchanger (2) to be described later. The second switching valve (43) may be a four-way valve.

[0067] The heat transfer medium heat exchanger (2) can be connected to the second switching valve (43) and the second-1 flow path (53).

[0068] The second subcooler (45) can cool the second refrigerant. The second subcooler (45) can cool the second refrigerant to below the saturation temperature, thereby improving the efficiency of the chiller (1). The second subcooler (45) can be placed in the second-2 flow path (54) and the second subcooling flow path (57). The second subcooling flow path (57) can connect the point between the second subcooler (45) and the heat transfer medium heat exchanger (2) in the second-2 flow path (54) with the second compressor (41).

[0069] The second-3 expansion valve (63) can expand a portion of the second refrigerant introduced from the second-2 flow path (54). The second subcooler (45) can cool the second refrigerant to below the saturation temperature by exchanging heat between the expanded low-temperature refrigerant and the remaining second refrigerant.

[0070] The third heat exchanger (3) can be connected to the heat transfer medium heat exchanger (2) and the second-2 flow path (54). The second refrigerant can pass through the third heat exchanger (3).

[0071] The second bypass can be connected so that the second refrigerant bypasses the third heat exchanger (3). One end of the second bypass (73) is connected to the second-2 flow path (54), and the other end can be connected to the second-3 flow path (55).

[0072] The second bypass valve (74) may be placed in the second bypass (73). The second bypass valve (74) may be a solenoid valve. Depending on the opening and closing of the second bypass valve (74), the second refrigerant may or may not pass through the third heat exchanger (3).

[0073] The second heat exchanger (44) can exchange heat between the second refrigerant and air. The second heat exchanger (44) is connected to the second compressor (41) so that the second refrigerant passes through it.

[0074] The second heat exchanger (44) can be connected to the third heat exchanger (3) via the second-third flow path (55). The second heat exchanger (44) can be connected to the second switching valve (43) via the second-fourth flow path (56).

[0075] The second accumulator (47) can supply gaseous second refrigerant to the second compressor (41). The second accumulator (47) can separate gaseous refrigerant from liquid refrigerant. The second accumulator (47) can prevent liquid second refrigerant from flowing into the second compressor (41).

[0076] The second switching valve (43) and the second compressor (41) can be connected to the second inlet passage (52). The second accumulator (47) can be placed in the second inlet passage (52).

[0077] The second-1 pressure sensor (48) may be placed in the second inlet passage (52). The second-1 pressure sensor (48) can measure the pressure of the second refrigerant flowing through the second inlet passage (52).

[0078] The second-2 pressure sensor (49) may be placed in the second discharge channel (51). The second-2 pressure sensor (49) may measure the pressure of the second refrigerant flowing through the second discharge channel (51).

[0079] The second-1 expansion valve (61) may be placed between the heat medium heat exchanger (2) and the second subcooler (45) in the second-2 flow path (54). The second-2 expansion valve (62) may be placed between the third heat exchanger (3) and the second subcooler (45) in the second-2 flow path (54). The second-3 expansion valve (63) may be placed between the point where the second-2 flow path (54) is connected and the second subcooler (45) in the second subcooling flow path (57).

[0080] The second-1 expansion valve (61), second-2 expansion valve (62), and second-3 expansion valve (63) can expand the second liquid refrigerant by controlling the opening degree. Alternatively, they may be fully open or closed. The second-1 expansion valve (61), second-2 expansion valve (62), and second-3 expansion valve (63) may be electric expansion valves.

[0081] The third heat exchanger (3) selectively heat exchanges the first refrigerant flowing between the first heat exchanger (14) and the heat medium heat exchanger (2), and the second refrigerant flowing between the second heat exchanger (44) and the heat medium heat exchanger (2).

[0082] For example, when the second bypass valve (74) is opened, the second refrigerant may bypass to the second bypass (73) without passing through the third heat exchanger (3). Accordingly, the first refrigerant and the second refrigerant may not exchange heat with each other. Alternatively, when the second bypass valve (74) is closed, the second refrigerant passes through the third heat exchanger (3) and may exchange heat with the first refrigerant passing through the third heat exchanger (3).

[0083] The second refrigerant may have a higher saturation temperature than the first refrigerant at the same pressure. For example, the first refrigerant may be R32 and the second refrigerant may be R290.

[0084] The fan (4) can form an air flow to the first heat exchanger (14) and the second heat exchanger (44). Heat exchange between the first refrigerant and air in the first heat exchanger (14) can be promoted by the fan (4). Heat exchange between the second refrigerant and air in the second heat exchanger (44) can be promoted by the fan (4). The fan (4) can be placed above the first heat exchanger (14) and the second heat exchanger (44).

[0085] The chiller (1) may include a mode input unit (8, see FIG. 8) and a control unit (9, see FIG. 8). A user can input a desired operating mode of the chiller (1) through the mode input unit (8). Depending on the input operating mode, the operating mode of the chiller (1) is changed, and the frequency of the compressor (11, 41), the opening and closing of the valve, the power supply of the fan (4), etc., can be controlled.

[0086] Referring to FIG. 2, the configuration of a chiller (1) according to another embodiment of the present disclosure can be seen. Since FIG. 2 is an embodiment that differs from the embodiment of FIG. 1 only in the position of the second bypass (73a) and the second bypass valve (74a), a detailed description of other configurations is omitted.

[0087] The second bypass (73a) can be connected so that the first refrigerant bypasses the third heat exchanger (3). One end of the second bypass (73a) is connected to the first-2 flow path (24), and the other end is connected to the first-3 flow path (25).

[0088] The second bypass valve (74a) may be placed in the second bypass (73a). The second bypass valve (74a) may be a solenoid valve. Depending on the opening and closing of the second bypass valve (74a), the first refrigerant may or may not pass through the third heat exchanger (3).

[0089] Referring to FIG. 3, the chiller (1) can operate in a cooling mode. In the cooling mode, the chiller (1) can cool the heat transfer medium passing through the heat transfer medium heat exchanger (2).

[0090] In cooling mode, the first switching valve (13) can be switched to connect the first discharge path (21) with the first-4 path (26) and to connect the first-1 path (23) with the first inflow path (22). The second switching valve (43) can be switched to connect the second discharge path (51) with the second-4 path (56) and to connect the second-1 path (53) with the second inflow path (52).

[0091] In cooling mode, the sub-expansion valve (75), the first-second expansion valve (32), and the second-second expansion valve (62) can be fully opened. The first bypass valve (72) can be closed. The second bypass valve (74) can be opened. The fan (4) can form an airflow to the first heat exchanger (14) and the second heat exchanger (44).

[0092] The first refrigerant discharged from the first compressor (11) can flow through the first switching valve (13) to the first heat exchanger (14). The first refrigerant can condense by exchanging heat with the air passing through the first heat exchanger (14).

[0093] The condensed first refrigerant can pass through the third heat exchanger (3). Since the second bypass valve (74) is open so that the second refrigerant does not pass through the third heat exchanger (3), the first refrigerant may pass through the third heat exchanger (3) without undergoing a phase change.

[0094] The first refrigerant passes through the first subcooler (15) and can be cooled to a temperature below the saturation temperature.

[0095] The first refrigerant can be expanded by passing through the first-1 expansion valve (31). Accordingly, the first refrigerant can become a saturated liquid-vapor mixture.

[0096] The expanded first refrigerant can be introduced into the heat medium heat exchanger (2). The temperature of the heat medium passing through the heat medium heat exchanger (2) may be higher than the temperature of the first refrigerant. Accordingly, the first refrigerant may evaporate as it passes through the heat medium heat exchanger (2).

[0097] The heat medium can lose heat to the first refrigerant. Therefore, the temperature of the heat medium passing through the heat medium heat exchanger (2) can be lowered, and the chiller (1) can perform cooling through the heat medium with the lowered temperature.

[0098] The first refrigerant that has evaporated while passing through the heat transfer medium heat exchanger (2) can pass through the first switching valve (13) and flow into the first accumulator (17). The gaseous first refrigerant separated in the first accumulator (17) flows into the first compressor (11) and can be circulated.

[0099] The second refrigerant discharged from the second compressor (41) can flow through the second switching valve (43) to the second heat exchanger (44). The second refrigerant can condense by exchanging heat with the air passing through the second heat exchanger (44).

[0100] The second bypass valve (74) is opened so that the second refrigerant can bypass the third heat exchanger (3) without passing through it.

[0101] The second refrigerant passes through the second subcooler (45) and can be cooled below the saturation temperature.

[0102] The second refrigerant can be expanded by passing through the second-1 expansion valve (61). Accordingly, the second refrigerant can become a saturated liquid-vapor mixture.

[0103] The expanded second refrigerant can be introduced into the heat medium heat exchanger (2). The temperature of the heat medium passing through the heat medium heat exchanger (2) may be higher than the temperature of the second refrigerant. Accordingly, the second refrigerant may evaporate as it passes through the heat medium heat exchanger (2).

[0104] The heat medium can lose heat to the second refrigerant. Therefore, the temperature of the heat medium passing through the heat medium heat exchanger (2) can be lowered, and the chiller (1) can perform cooling through the heat medium with the lowered temperature.

[0105] The second refrigerant that has evaporated while passing through the heat transfer medium heat exchanger (2) can pass through the second switching valve (43) and flow into the second accumulator (47). The gaseous second refrigerant separated in the second accumulator (47) flows into the second compressor (41) and can be circulated.

[0106] In cooling mode, the temperatures of the first refrigerant and the second refrigerant passing through the heat exchanger (2) are controlled to be the same, so that the heat medium passing through the heat exchanger (2) can be uniformly cooled.

[0107] Since the second refrigerant can have a higher saturation temperature than the first refrigerant at the same pressure, the pressure of the second refrigerant may be lower than the pressure of the first refrigerant in order to set the temperatures of the first and second refrigerants to be the same. At this time, the pressure and temperature of the first refrigerant can be controlled by adjusting the frequency of the first compressor (11), and the pressure and temperature of the second refrigerant can be controlled by adjusting the frequency of the second compressor (41).

[0108] Meanwhile, the first-1 pressure sensor (18) is positioned in the first inlet passage (22) to measure the pressure of the first refrigerant passing through the heat medium heat exchanger (2), and the second-1 pressure sensor (48) is positioned in the second inlet passage (52) to measure the pressure of the second refrigerant passing through the heat medium heat exchanger (2), so that the pressure control of the first refrigerant and the second refrigerant can be easily controlled and the chiller (1) can be controlled to match the temperature of the desired heat medium.

[0109] When the refrigerant is in a saturated liquid-vapor mixture state, the saturation temperature and saturation pressure have a one-to-one correspondence, so the temperature can be controlled through the pressure of the refrigerant. For example, if one wants to lower the temperature of the heat medium passing through the heat medium heat exchanger (2), the frequency of the first compressor (11) and the second compressor (41) can be adjusted so that the evaporation pressure is lower than the pressure measured by the first-1 pressure sensor (18) and the second-1 pressure sensor (48).

[0110] Referring to FIG. 4, the chiller (1) can operate in a first heating mode. In the first heating mode, the chiller (1) can heat a heat medium passing through a heat medium heat exchanger (2).

[0111] In the first heating mode, the first switching valve (13) can be switched to connect the first discharge path (21) with the first-1 path (23) and to connect the first-4 path (26) with the first inflow path (22). The second switching valve (43) can be switched to connect the second discharge path (51) with the second-1 path (53) and to connect the second-4 path (56) with the second inflow path (52).

[0112] In the first heating mode, the first-1 expansion valve (31), the second-1 expansion valve (61), and the sub-expansion valve (75) can be fully opened. The first bypass valve (72) can be closed. The second bypass valve (74) can be opened. The fan (4) can form an air flow to the first heat exchanger (14) and the second heat exchanger (44).

[0113] The first refrigerant discharged from the first compressor (11) can flow through the first switching valve (13) to the heat transfer medium heat exchanger (2).

[0114] The temperature of the heat medium passing through the heat medium heat exchanger (2) may be lower than the temperature of the first refrigerant. Accordingly, the first refrigerant condenses as it passes through the heat medium heat exchanger (2), and the heat medium can be heated by receiving heat from the first refrigerant. The chiller (1) can perform heating through the heated heat medium.

[0115] The first refrigerant passes through the first subcooler (15) and can be cooled to a temperature below the saturation temperature.

[0116] The first refrigerant can be expanded by passing through the first-2 expansion valve (32). Accordingly, the first refrigerant can become a saturated liquid-vapor mixture.

[0117] The expanded first refrigerant can pass through the third heat exchanger (3) and flow into the first heat exchanger (14). The temperature of the expanded first refrigerant may be lower than the temperature of the air, and the first refrigerant may evaporate while exchanging heat with the air passing through the first heat exchanger (14).

[0118] The evaporated first refrigerant can pass through the first switching valve (13) and flow into the first accumulator (17). The gaseous first refrigerant separated in the first accumulator (17) flows into the first compressor (11) and can be circulated.

[0119] The second refrigerant discharged from the second compressor (41) can flow through the second switching valve (43) to the heat transfer medium heat exchanger (2).

[0120] The temperature of the heat medium passing through the heat medium heat exchanger (2) may be lower than the temperature of the second refrigerant. Accordingly, the second refrigerant condenses as it passes through the heat medium heat exchanger (2), and the heat medium can be heated by receiving heat from the second refrigerant. The chiller (1) can perform heating through the heated heat medium.

[0121] The second refrigerant passes through the second subcooler (45) and can be cooled to a temperature below the saturation temperature.

[0122] The second refrigerant can be expanded by passing through the second-2 expansion valve (62). Accordingly, the second refrigerant can become a saturated liquid-vapor mixture.

[0123] The expanded second refrigerant can flow through the second bypass (73) to the second heat exchanger (44). The temperature of the expanded second refrigerant may be lower than the temperature of the air, and the second refrigerant may evaporate while exchanging heat with the air passing through the second heat exchanger (44).

[0124] The evaporated second refrigerant can pass through the second switching valve (43) and flow into the second accumulator (47). The gaseous second refrigerant separated in the second accumulator (47) flows into the second compressor (41) and can be circulated.

[0125] In the first heating mode, the temperatures of the first refrigerant and the second refrigerant passing through the heat medium heat exchanger (2) are controlled to be the same, so that the heat medium passing through the heat medium heat exchanger (2) can be heated uniformly.

[0126] The first-2 pressure sensor (19) is positioned in the first discharge path (21) to measure the pressure of the first refrigerant before it passes through the heat medium heat exchanger (2), and the second-2 pressure sensor (49) is positioned in the second discharge path (51) to measure the pressure of the second refrigerant before it passes through the heat medium heat exchanger (2), so that the pressure control of the first refrigerant and the second refrigerant can be easily controlled and the chiller (1) can be controlled to match the temperature of the desired heat medium.

[0127] For example, if you want to increase the temperature of the heat medium passing through the heat medium heat exchanger (2), you can adjust the frequency of the first compressor (11) and the second compressor (41) to have a higher condensation pressure than the pressure measured by the first-2 pressure sensor (19) and the second-2 pressure sensor (49).

[0128] Referring to FIG. 5, the chiller (1) can operate in a second heating mode. In the second heating mode, the chiller (1) can heat a heat medium passing through a heat medium heat exchanger (2).

[0129] In the second heating mode, the first switching valve (13) can be switched to connect the first discharge path (21) with the first-1 path (23) and to connect the first-4 path with the first inflow path (22). The second switching valve (43) can be switched to connect the second discharge path (51) with the second-1 path (53) and to connect the second-4 path (56) with the second inflow path (52).

[0130] In the second heating mode, the first-1 expansion valve (31), the first-2 expansion valve (32), and the second-1 expansion valve (61) can be fully opened. The first-3 expansion valve (33) can be closed. The first bypass valve (72) can be opened. The second bypass valve (74) can be closed. The fan (4) can form an air flow to the first heat exchanger (14) and the second heat exchanger (44).

[0131] The first refrigerant discharged from the first compressor (11) can flow through the first switching valve (13) to the first bypass (71). The first refrigerant flows to the first bypass (71) and can avoid passing through the heat transfer medium heat exchanger (2).

[0132] The first-third expansion valve (33) is closed, so the first refrigerant may not be cooled even if it passes through the first subcooler (15).

[0133] The first refrigerant passes through the third heat exchanger (3) and can exchange heat with the second refrigerant. The first refrigerant can condense while exchanging heat with the second refrigerant.

[0134] The condensed first refrigerant can be expanded by passing through the sub-expansion valve (75) and evaporated by passing through the first heat exchanger (14).

[0135] The evaporated first refrigerant can pass through the first switching valve (13) and flow into the first accumulator (17). The gaseous first refrigerant separated in the first accumulator (17) can flow into the first compressor (11) and be circulated.

[0136] The second refrigerant discharged from the second compressor (41) can flow through the second switching valve (43) to the heat medium heat exchanger (2). Accordingly, the second refrigerant passes through the heat medium heat exchanger (2) and condenses, and the heat medium can be heated by receiving heat from the second refrigerant. The chiller (1) can perform heating through the heated heat medium.

[0137] At this time, the temperature of the second refrigerant flowing into the heat medium heat exchanger (2) may be higher than the temperature of the second refrigerant flowing into the heat medium heat exchanger (2) in the first heating mode (see FIG. 4).

[0138] As a result, the temperature of the heat medium passing through the heat medium heat exchanger (2) in the second heating mode may be higher than the temperature of the heat medium passing through the heat medium heat exchanger (2) in the first heating mode. The temperature of the heat medium passing through the heat medium heat exchanger (2) in the second heating mode may be higher than the saturation temperature at which the first refrigerant condenses. The second heating mode may be a suitable mode for supplying a heat medium at a higher temperature compared to the first heating mode.

[0139] The second refrigerant that has passed through the heat exchanger (2) passes through the second subcooler (45) and can be cooled to below the saturation temperature.

[0140] The second refrigerant can be expanded by passing through the second-2 expansion valve (62).

[0141] The expanded second refrigerant passes through the third heat exchanger (3) and can exchange heat with the first refrigerant. The second refrigerant can evaporate while exchanging heat with the first refrigerant.

[0142] At this time, the temperature of the first refrigerant may be higher than the temperature of the second refrigerant. Since the first refrigerant is discharged from the first compressor (11) and bypasses the heat transfer medium heat exchanger (2), it may be higher than the temperature of the second refrigerant that has condensed while passing through the heat transfer medium heat exchanger (2) and the second subcooler (45).

[0143] In the second heating mode for supplying a high-temperature heat medium, the pressure and temperature of the second refrigerant circulating in the second cycle (40) may be higher than the pressure and temperature of the second refrigerant in the first heating mode. As a result, the temperature at which the second refrigerant evaporates may be higher than the ambient temperature, and even if the second refrigerant passes through the second heat exchanger (44), it may not evaporate because it does not obtain sufficient heat from the air. However, since the second refrigerant can exchange heat with the high-temperature first refrigerant through the third heat exchanger (3), it can obtain sufficient heat necessary for evaporation.

[0144] The evaporated second refrigerant can pass through the second heat exchanger (44) and the second switching valve (43) in sequence and flow into the second accumulator (47). The gaseous second refrigerant separated in the second accumulator (47) can flow into the second compressor (41) and be circulated.

[0145] As described above, in the second heating mode, the first cycle (10) and the second cycle (40) can form a cascade cycle. As a result, the heat required for the second refrigerant to evaporate can be provided from the first refrigerant, and the heating capacity of the chiller (1) may not decrease even if the outside temperature is low.

[0146] Referring to FIG. 6, the chiller (1) can operate in a third heating mode. In the third heating mode, the chiller (1) can heat the heat medium passing through the heat medium heat exchanger (2) and can perform defrosting of the first heat exchanger (14).

[0147] In the third heating mode, the first switching valve (13) can be switched to connect the first discharge path (21) with the first-4 path (26) and to connect the first-1 path (23) with the first inflow path (22). The second switching valve (43) can be switched to connect the second discharge path (51) with the second-1 path (53) and to connect the second-4 path (56) with the second inflow path (52).

[0148] In the third heating mode, the first-2 expansion valve (32), the second-1 expansion valve (61), and the sub-expansion valve (75) can be fully opened. The first bypass valve (72) can be closed. The second bypass valve (74) can be closed. The fan (4) can be stopped.

[0149] The first refrigerant discharged from the first compressor (11) can flow through the first switching valve (13) to the first heat exchanger (14). The first refrigerant passing through the first heat exchanger (14) can exchange heat with the frost formed on the surface of the first heat exchanger (14) and remove it.

[0150] At this time, since the fan (4) does not operate, the melted water on the surface of the first heat exchanger (14) is prevented from freezing again, so that defrosting can be performed efficiently. In addition, energy required to operate the fan (4) can be saved, and the first refrigerant passing through the first heat exchanger (14) is prevented from exchanging heat with the air, thereby increasing the amount of heat exchange with the second refrigerant in the third heat exchanger (3). As a result, the efficiency of the chiller (1) can be improved.

[0151] The first refrigerant that has passed through the first heat exchanger (14) can be condensed by exchanging heat with the second refrigerant in the third heat exchanger (3).

[0152] The first refrigerant that has passed through the third heat exchanger (3) can be cooled to below the saturation temperature by passing through the first subcooler (15).

[0153] The first refrigerant can be expanded by passing through the first-1 expansion valve (31), and the expanded first refrigerant can flow into the heat transfer medium heat exchanger (2).

[0154] The first refrigerant flowing through the heat exchanger (2) can evaporate while exchanging heat with the heat exchanger, and the evaporated first refrigerant can pass through the first switching valve (13) and flow into the first accumulator (17). The gaseous first refrigerant separated in the first accumulator (17) can flow into the first compressor (11) and be circulated.

[0155] The second refrigerant discharged from the second compressor (41) can flow through the second switching valve (43) to the heat medium heat exchanger (2). Accordingly, the second refrigerant passes through the heat medium heat exchanger (2) and condenses, and the heat medium can be heated by receiving heat from the second refrigerant. The chiller (1) can perform heating through the heated heat medium.

[0156] Even if the first refrigerant evaporates in the heat exchanger (2) and absorbs heat from the heat medium, the chiller (1) can perform heating because there is more heat provided to the heat medium by the second refrigerant.

[0157] The second refrigerant that has passed through the heat exchanger (2) can be cooled to below the saturation temperature by passing through the second subcooler (45).

[0158] The second refrigerant can be expanded by passing through the second-2 expansion valve (62).

[0159] The expanded second refrigerant passes through the third heat exchanger (3) and can exchange heat with the first refrigerant. The second refrigerant can receive heat from the first refrigerant and evaporate.

[0160] The evaporated second refrigerant may flow sequentially through the second heat exchanger (44) and the second switching valve (43) and then enter the second accumulator (47). The gaseous second refrigerant separated from the second accumulator (47) may be introduced into the second compressor (41) and circulated.

[0161] Referring to FIG. 7, the chiller (1) can operate in a fourth heating mode. In the fourth heating mode, the chiller (1) can heat the heat medium passing through the heat medium heat exchanger (2) and can perform defrosting of the second heat exchanger (44).

[0162] In the fourth heating mode, the first switching valve (13) can be switched to connect the first discharge path (21) with the first-1 path (23) and to connect the first-4 path (26) with the first inflow path (22). The second switching valve (43) can be switched to connect the second discharge path (51) with the second-4 path (56) and to connect the second-1 path (53) with the second inflow path (52).

[0163] In the fourth heating mode, the first-1 expansion valve (31), the second-2 expansion valve (62), and the sub-expansion valve (75) can be fully opened. The first bypass valve (72) can be closed. The second bypass valve (74) can be closed. The fan (4) can be stopped.

[0164] At this time, since the fan (4) does not operate, the melted water on the surface of the second heat exchanger (44) is prevented from freezing again, so that defrosting can be performed efficiently. In addition, energy required to operate the fan (4) can be saved, and the second refrigerant passing through the second heat exchanger (44) is prevented from exchanging heat with the air, thereby increasing the amount of heat exchange with the first refrigerant in the third heat exchanger (3). As a result, the efficiency of the chiller (1) can be improved.

[0165] The first refrigerant discharged from the first compressor (11) can flow through the first switching valve (13) to the heat medium heat exchanger (2). Accordingly, the first refrigerant passes through the heat medium heat exchanger (2) and condenses, and the heat medium can be heated by receiving heat from the first refrigerant. The chiller (1) can perform heating through the heated heat medium.

[0166] The first refrigerant that has passed through the heat transfer medium heat exchanger (2) can be cooled to below the saturation temperature by passing through the first subcooler (15).

[0167] The first refrigerant can be expanded by passing through the first-2 expansion valve (32).

[0168] The expanded first refrigerant passes through the third heat exchanger (3) and can exchange heat with the second refrigerant. The first refrigerant can receive heat from the second refrigerant and evaporate.

[0169] The evaporated first refrigerant may flow sequentially through the first heat exchanger (14) and the first switching valve (13) and then enter the first accumulator (17). The gaseous first refrigerant separated from the first accumulator (17) may be introduced into the first compressor (11) and circulated.

[0170] The second refrigerant discharged from the second compressor (41) can flow through the second switching valve (43) to the second heat exchanger (44). The second refrigerant passing through the second heat exchanger (44) can exchange heat with the frost formed on the surface of the second heat exchanger (44) and remove it.

[0171] At this time, since the fan (4) does not operate, it is possible to prevent the melted water on the surface of the heat exchanger from freezing again. In addition, energy required to operate the fan (4) can be saved, and the second refrigerant passing through the second heat exchanger (44) can be prevented from exchanging heat with the air, thereby increasing the amount of heat exchange with the first refrigerant in the third heat exchanger (3) thereafter.

[0172] The second refrigerant that has passed through the second heat exchanger (44) can be condensed by exchanging heat with the first refrigerant in the third heat exchanger (3).

[0173] The second refrigerant that has passed through the third heat exchanger (3) can pass through the second subcooler (45) and be cooled to below the saturation temperature.

[0174] The second refrigerant can be expanded by passing through the second-1 expansion valve (61), and the expanded second refrigerant can flow into the heat transfer medium heat exchanger (2).

[0175] The second refrigerant flowing through the heat exchanger (2) can evaporate while exchanging heat with the heat exchanger. Even if the second refrigerant evaporates in the heat exchanger (2) and absorbs heat from the heat exchanger, the chiller (1) can perform heating because there is more heat provided to the heat exchanger by the first refrigerant.

[0176] The evaporated second refrigerant can pass through the second switching valve (43) and flow into the second accumulator (47). The gaseous second refrigerant separated in the second accumulator (47) can flow into the second compressor (41) and be circulated.

[0177] In the third heating mode (see FIG. 5) and the fourth heating mode, the first refrigerant and the second refrigerant are refrigerants having different evaporation temperatures at the same pressure, and since the first refrigerant and the second refrigerant can exchange heat through the third heat exchanger (3), the first cycle (10) and the second cycle (40) can perform defrosting operations independently. While one cycle is defrosting the evaporator, the other cycle is performing heating, thereby enabling continuous heating of the chiller (1). As a result, the efficiency of the chiller can be improved.

[0178] Referring to FIG. 8, the first cycle (10) and the second cycle (40) can be controlled through the mode input unit (8) and the control unit (9).

[0179] When a user inputs an operating mode of the chiller (1) through the mode input unit (8), the mode input unit (8) can transmit a control signal to the control unit (9).

[0180] By means of a signal transmitted to the control unit (9), the control unit (9) can control the first cycle (10) and the second cycle (40).

[0181] The first switching valve (13), first-1 expansion valve (31), first-2 expansion valve (32), first bypass valve (72), and sub-expansion valve (75) constituting the first cycle (10) can switch the flow path or open / close according to the control signal of the control unit (9).

[0182] The second switching valve (43), second-1 expansion valve (61), second-2 expansion valve (62), and second bypass valve (74) constituting the second cycle (40) can switch the flow path or open / close according to the control signal of the control unit (9).

[0183] Although preferred embodiments of the present disclosure have been illustrated and described above, the present disclosure is not limited to the specific embodiments described above. Various modifications are possible by those skilled in the art without departing from the essence of the present disclosure as claimed in the claims, and such modifications should not be understood individually from the technical spirit or perspective of the present disclosure.

Claims

1. A first compressor that compresses the first refrigerant; A first heat exchanger connected to the first compressor through which the first refrigerant passes; A second compressor that compresses the second refrigerant; A second heat exchanger connected to the second compressor through which the second refrigerant passes; A heat transfer medium heat exchanger that exchanges heat with the first refrigerant or the second refrigerant and a predetermined heat transfer medium; and A chiller comprising a third heat exchanger that selectively heat exchanges the first refrigerant flowing between the first heat exchanger and the heat medium heat exchanger, and the second refrigerant flowing between the second heat exchanger and the heat medium heat exchanger.

2. In Paragraph 1, A first bypass connected so that the first refrigerant bypasses the heat transfer medium heat exchanger, and A chiller comprising a first bypass valve disposed in the first bypass.

3. In Paragraph 2, A chiller comprising a sub-expansion valve disposed between the third heat exchanger and the first heat exchanger.

4. In Paragraph 3, The above second refrigerant is a chiller having a higher saturation temperature than the above first refrigerant at the same pressure.

5. In Paragraph 1, A second bypass connected so that the second refrigerant bypasses the third heat exchanger, and A chiller comprising a second bypass valve disposed in the second bypass.

6. In Paragraph 1, A second bypass connected so that the first refrigerant bypasses the third heat exchanger, and A chiller comprising a second bypass valve disposed in the second bypass.

7. In Paragraph 5 or 6, The above chiller operates in a cooling mode in which the heat transfer medium heat exchanger cools the heat transfer medium, and In the above cooling mode, The second bypass valve is a chiller that is opened so that the first refrigerant or the second refrigerant bypasses the third heat exchanger.

8. In Paragraph 5 or 6, The above chiller operates in a first heating mode in which the heat transfer medium heat exchanger heats the heat transfer medium, and In the above first heating mode, The second bypass valve is a chiller that is opened so that the first refrigerant or the second refrigerant bypasses the third heat exchanger.

9. In Paragraph 1, The chiller above includes a first bypass connected so that the first refrigerant bypasses the heat transfer medium heat exchanger, and It includes a first bypass valve disposed in the first bypass, and The above chiller operates in a second heating mode in which the second refrigerant is condensed in the heat transfer medium heat exchanger, and In the above second heating mode, The first bypass valve is opened so that the first refrigerant bypasses the heat transfer medium heat exchanger, and The above third heat exchanger is a chiller that exchanges heat between the above first refrigerant and the above second refrigerant.

10. In Paragraph 9, The above chiller further includes a sub-expansion valve disposed between the third heat exchanger and the first heat exchanger, and In the above second heating mode, The first refrigerant discharged from the first compressor is condensed in the third heat exchanger and expanded in the sub-expansion valve of the chiller.

11. In Paragraph 10, The second refrigerant has a higher saturation temperature than the first refrigerant at the same pressure, and The heat transfer medium that has passed through the heat transfer medium heat exchanger is a chiller at a temperature higher than the saturation temperature at which the first refrigerant condenses.

12. In Paragraph 1, The above chiller operates in a third heating mode in which the second refrigerant is condensed in the heat transfer medium heat exchanger, and In the above third heating mode, The first refrigerant discharged from the first compressor flows sequentially through the first heat exchanger and the third heat exchanger, and The second refrigerant discharged from the second compressor flows sequentially through the heat transfer medium heat exchanger and the third heat exchanger in a chiller.

13. In Paragraph 12, The above chiller operates in a fourth heating mode in which the first refrigerant is condensed in the heat transfer medium heat exchanger, and In the above fourth heating mode, The first refrigerant discharged from the first compressor flows sequentially through the heat transfer medium heat exchanger and the third heat exchanger, and The second refrigerant discharged from the second compressor flows sequentially through the second heat exchanger and the third heat exchanger in a chiller.

14. In Paragraph 13, In the above third heating mode or the above fourth heating mode, The above third heat exchanger is a chiller that exchanges heat between the above first refrigerant and the above second refrigerant.

15. In Paragraph 13, A chiller that alternately performs the above third heating mode and the above fourth heating mode.

16. In Paragraph 13, The above chiller further includes a fan positioned above the first heat exchanger and the second heat exchanger, and In the above third heating mode or the above fourth heating mode, the fan is stopped in the chiller.

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