Hot water supply unit

Abstract

A hot water supply unit includes: a refrigerant unit (U) including a refrigerant circuit (R1) that performs a refrigeration cycle using a first refrigerant that is a flammable refrigerant; a tank (41) configured to store water directly or indirectly heated by the first refrigerant; and a casing (60) disposed in the indoor space (I) and configured to house the refrigerant unit (U) and the tank (41). The refrigerant unit (U) is disposed below the tank (41).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a hot water supply unit.BACKGROUND ART

[0002] Patent Document 1 discloses a hot water supply unit. The hot water supply unit includes a refrigerant circuit including a first heat exchanger and a second heat exchanger, and a tank for hot water supply. The tank stores water heated by a refrigerant in the refrigerant circuit.CITATION LISTPATENT DOCUMENT

[0003] Patent Document 1: Japanese Unexamined Patent Publication No. 2004-132647SUMMARY OF THE INVENTIONTECHNICAL PROBLEM

[0004] The inventors of this application have designed a hot water supply unit including a casing that houses a tank and a refrigerant unit including a refrigerant circuit. The hot water supply unit (casing) is disposed in an indoor space. The hot water supply unit is used for, for example, hot water supply or air conditioning. Unfortunately, the casing housing therein the refrigerant unit makes a transportation task and an installation task difficult.

[0005] Specifically, when the hot water supply unit is transported to the indoor space or installed in the indoor space, the tank can be made empty. In contrast, the refrigerant unit includes heavy objects, such as a compressor, a first heat exchanger, and a second heat exchanger. Thus, the refrigerant unit is relatively heavier than the tank, and the center of gravity of the entire hot water supply unit may be unbalanced. No consideration has been given to the center of gravity of the hot water supply unit during the transportation or installation of the casing.

[0006] It is an object of the present disclosure to reduce difficulty in transportation and installation of the hot water supply unit, caused by an imbalance in center of gravity of the hot water supply unit.SOLUTION TO THE PROBLEM

[0007] A first aspect is directed to a hot water supply unit. The hot water supply unit includes: a refrigerant unit (U) including a refrigerant circuit (R1) that performs a refrigeration cycle using a first refrigerant that is a flammable refrigerant; a tank (41) configured to store water directly or indirectly heated by the first refrigerant; and a casing (60) disposed in an indoor space (I) and configured to house the refrigerant unit (U) and the tank (41), The refrigerant circuit (R1) includes: a compressor (21); a first heat exchanger (23) configured to exchange heat between the first refrigerant in the refrigerant circuit (R1) and water in a water circuit (W); a decompression mechanism (24); and a second heat exchanger (22) configured to exchange heat between the first refrigerant in the refrigerant circuit (R1) and a heating medium in a heating medium circuit (R2, 100). The refrigerant unit (U) is disposed below the tank (41).

[0008] According to the first aspect, by disposing the refrigerant unit (U) below the tank (41), the center of gravity of the hot water supply unit (20) can be lowered. As a result, an operator can easily perform a transportation task and an installation task for the casing (60).

[0009] A second aspect is an embodiment of the first aspect. In the second aspect, the casing (60) has a first side surface (63) and a second side surface (64). The first side surface (63) has an access port (A) for a first space (S1) in which the refrigerant unit (U) is housed. The second side surface (64) is located on a side of the casing (60) opposite to the first side surface (63). The hot water supply unit further includes a support (70) configured to support the refrigerant unit (U) and to be able to be taken in and out through the access port (A).

[0010] According to the second aspect, by moving the support (70) to the outside of the casing (60) through the access port (A), the refrigerant unit (U) can be taken out of the casing (60). Thus, an operator can perform a predetermined task with the refrigerant unit (U) in an outdoor space. This can reduce the risk of leakage of the first refrigerant that is the flammable refrigerant.

[0011] A third aspect is an embodiment of the second aspect. In the third aspect, the refrigerant unit (U) includes a water-side connection portion (C1, C2) configured to detachably connect the first heat exchanger (23) and the water circuit (W) together, and a heating medium-side connection portion (C3, C4) configured to detachably connect the second heat exchanger (22) and the heating medium circuit (R2, 100) together.

[0012] According to the third aspect, by disconnecting the water-side connection portion (C1, C2), the first heat exchanger (23) can be separated from the water circuit (W). By disconnecting the heating medium-side connection portion (C3, C4), the second heat exchanger (22) can be separated from the heating medium circuit (R2, 100). As a result, the refrigerant unit (U) separated from the water circuit (W) and the heating medium circuit (R2, 100) can be taken out of the casing (60) through the access port (A).

[0013] A fourth aspect is an embodiment of the third aspect. In the fourth aspect, the water-side connection portion (C1, C2) is closer to the first side surface (63) than to the second side surface (64).

[0014] According to the fourth aspect, the water-side connection portion (C1, C2) is close to the access port (A). Thus, an operator can easily perform a task for attachment / detachment of the water-side connection portion (C1, C2).

[0015] A fifth aspect is an embodiment of the third or fourth aspect. In the fifth aspect, the heating medium-side connection portion (C3, C4) is closer to the first side surface (63) than to the second side surface (64).

[0016] According to the fifth aspect, the heating medium-side connection portion (C3, C4) is close to the access port (A). Thus, an operator can easily perform a task for attachment / detachment of the heating medium-side connection portion (C3, C4).

[0017] A sixth aspect is an embodiment of any one of the second to fifth aspects. In the sixth aspect, the hot water supply unit (20) further includes: a first outer connection portion (83, 84, 85, 86) provided outside the casing (60) and to which a water pipe (93, 94, 95, 96) of the water circuit (W) is connected; and a second outer connection portion (81, 82) provided outside the casing (60) and to which a refrigerant pipe (91, 92) of the heating medium circuit (R2, 100) is connected. The second outer connection portion (81, 82) is closer to the first side surface (63) than the first outer connection portion (83, 84, 85, 86).

[0018] In general, a task for connecting the refrigerant pipe (91, 92) is more difficult than a task for connecting the water pipe (93, 94, 95, 96). According to the sixth aspect, the second outer connection portion (81, 82) is closer to the first side surface (63) than the first outer connection portion (83, 84, 85, 86) is. Thus, the second outer connection portion (81, 82) can be reached easily by an operator. Thus, the operator can easily perform the task for connecting the refrigerant pipe (91, 92).

[0019] A seventh aspect is an embodiment of the sixth aspect. In the seventh aspect, the second outer connection portion (81, 82) is closer to the first side surface (63) than to the second side surface (64). The first outer connection portion (83, 84, 85, 86) is closer to the second side surface (64) than to the first side surface (63).

[0020] According to the seventh aspect, the second outer connection portion (81, 82) and the first outer connection portion (83, 84, 85, 86) are apart from each other in a direction in which the first side surface (63) and the second side surface (64) face each other. Thus, an operator can easily perform the tasks for connecting the water pipe (93, 94, 95, 96) and for connecting the refrigerant pipe (91, 92).

[0021] An eighth aspect is an embodiment of any one of the third to fifth aspects. In the eighth aspect, the hot water supply unit (20) further includes: a shielding member (98) configured to shield the heating medium-side connection portion (C3, C4) and the refrigerant circuit (R1) from each other.

[0022] According to the eighth aspect, the refrigerant circuit (R1) filled with the first refrigerant that is the flammable refrigerant is shielded from the heating medium-side connection portion (C3, C4) by the shielding member (98). This can reduce the risk of ignition of the first refrigerant resulting from connection of the heating medium-side connection portion (C3, C4).

[0023] A ninth aspect is an embodiment of any one of the first to eighth aspects. In the ninth aspect, the hot water supply unit further includes: an electric component unit (71) housed in the casing (60). The electric component unit (71) is disposed below the tank (41).

[0024] According to the ninth aspect, the electric component unit (71) disposed below the tank (41) further lowers the center of gravity of the hot water supply unit (20).

[0025] A tenth aspect is an embodiment of any one of the first to ninth aspects. In the tenth aspect, the heating medium circuit (R2, 100) is a second refrigerant circuit (R2) that performs a refrigeration cycle using a second refrigerant.

[0026] According to the tenth aspect, the hot water supply unit performs a so-called binary refrigeration cycle.BRIEF DESCRIPTION OF THE DRAWINGS

[0027] [FIG. 1] FIG. 1 is a piping system diagram of a hot water supply system according to an embodiment. [FIG. 2] FIG. 2 is a perspective view of an appearance of the hot water supply unit. [FIG. 3] FIG. 3 is a schematic plan view of a layout of devices in a first space. [FIG. 4] FIG. 4 is a top view of a top panel. [FIG. 5] FIG. 5 is a schematic plan view of a layout of devices in a first space in a hot water supply unit according to a first variation. [FIG. 6] FIG. 6 is a piping system diagram of a hot water supply system according to a second variation. DESCRIPTION OF EMBODIMENTS

[0028] Embodiments of the present disclosure will be described in detail below with reference to the drawings. The present disclosure is not limited to the embodiments shown below, and various changes can be made within the scope without departing from the technical concept of the present disclosure. Since each of the drawings is intended to illustrate the present disclosure conceptually, dimensions, ratios, or numbers may be exaggerated or simplified as necessary for ease of understanding.(1) Configuration of Hot Water Supply System(1-1) General Configuration

[0029] A hot water supply system (1) supplies hot water to a target. The target of this embodiment includes not only hot water supply targets such as faucets, showers, and bathtubs, but also a heater (5) that uses hot water. The hot water supply system (1) is connected to the hot water supply target and the heater (5) through water pipes. The hot water supply system (1) has an outdoor unit (10) disposed in an outdoor space and a hot water supply unit (20) disposed in an indoor space.

[0030] The hot water supply system (1) includes, as constituent circuits, a first refrigerant circuit (R1), a second refrigerant circuit (R2), and a water circuit (W). The first refrigerant circuit (R1) is filled with a flammable refrigerant as a first refrigerant. The second refrigerant circuit (R2) is filled with carbon dioxide as a second refrigerant. The second refrigerant circuit (R2) is an example of a heating medium circuit, and carbon dioxide is an example of a heating medium.

[0031] The first refrigerant is propane (R290), which is a highly flammable natural refrigerant. The natural refrigerant is a refrigerant having an ozone depletion potential of zero, having a low global warming potential, and having a small impact on the environment. Propane ignites at 500°C or less. The flammable refrigerant may also be methane (R50), ethane (R170), butane (R600), or isobutane (R600a). The flammable refrigerant may be a slightly flammable refrigerant instead of a highly flammable refrigerant. The slightly flammable refrigerant may be difluoromethane (R32) or tetrafluoropropene (HFO-1234yf). The first refrigerant may be a single component refrigerant consisting of the above-described one type of refrigerant, or may be a refrigerant mixture including the above-described one type of refrigerant and another or other refrigerant(s).

[0032] The hot water supply system (1) includes a refrigerant heat exchanger (22), a first water heat exchanger (23), and a second water heat exchanger (26). The refrigerant heat exchanger (22) is shared by the first refrigerant circuit (R1) and the second refrigerant circuit (R2). The first water heat exchanger (23) is shared by the first refrigerant circuit (R1) and the water circuit (W). The second water heat exchanger (26) is shared by the second refrigerant circuit (R2) and the water circuit (W). The refrigerant heat exchanger (22) is an example of a first heat exchanger, and the first water heat exchanger (23) is an example of a second heat exchanger. The hot water supply system (1) performs a so-called binary refrigeration cycle using the first refrigerant circuit (R1) and the second refrigerant circuit (R2).(1-2) Outdoor Unit

[0033] The outdoor unit (10) includes a portion of the second refrigerant circuit (R2). The outdoor unit (10) includes, as constituent devices of the second refrigerant circuit (R2), a second compressor (11), an outdoor heat exchanger (12), a second expansion valve (13), a four-way switching valve (14), and a second accumulator (15). The outdoor unit (10) includes an outdoor fan (16). The second compressor (11) compresses a refrigerant sucked thereinto and discharges the compressed refrigerant. The outdoor heat exchanger (12) exchanges heat between outdoor air transported by the outdoor fan (16) and the second refrigerant. The second expansion valve (13) decompresses the refrigerant. The four-way switching valve (14) switches between a first state indicated by solid curves in FIG. 1 and a second state indicated by broken curves in FIG. 1. The second accumulator (15) stores the liquid refrigerant that has not yet been sucked into the second compressor (11).(1-3) Circuit Configuration of Hot Water Supply Unit

[0034] The hot water supply unit (30) includes the entire first refrigerant circuit (R1). The hot water supply unit (20) includes, as constituent devices of the first refrigerant circuit (R1), a first compressor (21), the refrigerant heat exchanger (22), the first water heat exchanger (23), a first expansion valve (24), and a first accumulator (25). The first compressor (21) compresses a refrigerant sucked thereinto and discharges the compressed refrigerant. The refrigerant heat exchanger (22) includes a first flow path (P1) connected to the first refrigerant circuit (R1) and a second flow path (P2) connected to the second refrigerant circuit (R2). The refrigerant heat exchanger (22) exchanges heat between the first refrigerant in the first flow path (P1) of the first refrigerant circuit (R1) and the second refrigerant in the second flow path (P2) of the second refrigerant circuit (R2). The first water heat exchanger (23) includes a third flow path (P3) connected to the first refrigerant circuit (R1) and a fourth flow path (P4) connected to the water circuit (W). The first water heat exchanger (23) exchanges heat between the first refrigerant in the third flow path (P3) of the first refrigerant circuit (R1) and water in the fourth flow path (P4) of the water circuit (W). The first expansion valve (24) is an example of a decompression mechanism that decompresses the refrigerant. The first accumulator (25) stores the liquid refrigerant that has not yet been sucked into the first compressor (21). The refrigerant heat exchanger (22) and the first water heat exchanger (23) are each configured as, for example, a plate heat exchanger.

[0035] The hot water supply unit (20) includes a portion of the second refrigerant circuit (R2). The hot water supply unit (20) includes, as constituent devices of the second refrigerant circuit (R2), the second water heat exchanger (26) in addition to the first water heat exchanger (23) described above. The second water heat exchanger (26) includes a fifth flow path (P5) connected to the second refrigerant circuit (R2) and a sixth flow path (P6) connected to the water circuit (W). The second water heat exchanger (26) exchanges heat between the second refrigerant in the fifth flow path (P5) of the second refrigerant circuit (R2) and water in the sixth flow path (P6) of the water circuit (W). The second water heat exchanger (26) is configured as, for example, a plate heat exchanger.

[0036] The hot water supply unit (20) includes a first pipe (31), a second pipe (32), a third pipe (33), and a bypass pipe (34) as refrigerant pipes that form the second refrigerant circuit (R2). One end of the first pipe (31) is connected to a gas line of the second refrigerant circuit (R2). The other end of the first pipe (31) is connected to one end of the fifth flow path (P5) of the second water heat exchanger (26). One end of the second pipe (32) is connected to the other end of the fifth flow path (P5) of the second water heat exchanger (26). The other end of the second pipe (32) is connected to one end of the second flow path (P2) of the refrigerant heat exchanger (22). One end of the third pipe (33) is connected to the other end of the second flow path (P2) of the refrigerant heat exchanger (22). The other end of the third pipe (33) is connected to a liquid line of the second refrigerant circuit (R2). One end of the bypass pipe (34) is connected to an intermediate portion of the first pipe (31). The other end of the bypass pipe (34) is connected to an intermediate portion of the second pipe (32). The first pipe (31) is provided with a first on-off valve (35) between the junction thereof with the bypass pipe (34) and the fifth flow path (P5). The bypass pipe (34) is provided with a second on-off valve (36).

[0037] The hot water supply unit (20) includes a portion of the water circuit (W). The hot water supply unit (20) includes, as constituent devices of the water circuit (W), a pump (40), a tank (41), and an internal heat exchanger (42) in addition to the first water heat exchanger (23) and the second water heat exchanger (26) described above.

[0038] The pump (40) circulates water in the water circuit (W). FIG. 1 indicates the direction of circulation of the water in the water circuit (W) by the arrows.

[0039] The tank (41) stores water (strictly, hot water) to be supplied to the target. The tank (41) is a hollow container, and has therein a hot water storage space (41a). A water supply pipe (43) and a hot water delivery pipe (44) are connected to the tank (41). One end of the water supply pipe (43) is connected to the bottom of the tank (41), and the other end of the water supply pipe (43) is connected to a water service pipe. When the amount of water in the tank (41) decreases, the water supply pipe (43) supplies low-temperature water in the water service pipe into the tank (41). One end of the hot water delivery pipe (44) is connected to an upper portion of the tank (41), and the other end of the hot water delivery pipe (44) is connected to a predetermined hot water supply target. The hot water delivery pipe (44) supplies high-temperature water in the tank (41) to the hot water supply target such as a tap, a shower, or a bath.

[0040] The internal heat exchanger (42) is disposed in the hot water storage space (41a). The internal heat exchanger (42) of this embodiment is a helical heat transfer tube. Hot water heated in the first water heat exchanger (23) and the second water heat exchanger (26) flows through the interior of the internal heat exchanger (42). The internal heat exchanger (42) exchanges heat between the hot water flowing therethrough and water therearound. As a result, the water in the hot water storage space (41a) is heated by the internal heat exchanger (42). As can be seen, the tank (41) of this embodiment stores water indirectly heated by the first refrigerant in the first water heat exchanger (23).

[0041] The water circuit (W) includes a main flow path (50), a hot water supply flow path (51), and a heater flow path (52). An inlet end of the hot water supply flow path (51) and an inlet end of the heater flow path (52) are connected to an outlet end of the main flow path (50). A three-way valve (53) is connected to the water circuit (W). The three-way valve (53) switches between a first state where the main flow path (50) and the hot water supply flow path (51) are brought into communication with each other and a second state where the main flow path (50) and the heater flow path (52) are brought into communication with each other.

[0042] The pump (40), the fourth flow path (P4) of the first water heat exchanger (23), and the sixth flow path (P6) of the second water heat exchanger (26) are connected in this order to the main flow path (50).

[0043] The hot water supply flow path (51) includes an inflow pipe (51a) and an outflow pipe (51b). The internal heat exchanger (42) is connected between the inflow pipe (51a) and the outflow pipe (51b).

[0044] A utilization-side heat exchanger (6) of the heater (5) is connected to the heater flow path (52). The utilization-side heat exchanger (6) heats the air in a target space (indoor space). The utilization-side heat exchanger (6) is configured as a fin-and-tube heat exchanger or a radiant panel. The utilization-side heat exchanger (6) is configured as an air heat exchanger that directly heats the air in the target space, or a floor heating heat exchanger that heats the floor of the target space.

[0045] The hot water supply unit (20) includes a supply pipe (52a) and a return pipe (52b) as some of elements of the heater flow path (52). The supply pipe (52a) is a flow path through which hot water heated by the first water heat exchanger (23) and the second water heat exchanger (26) is to be supplied to the utilization-side heat exchanger (6). The return pipe (52b) is a flow path through which water that has dissipated heat in the utilization-side heat exchanger (6) is to be returned to the main flow path (50).

[0046] The hot water supply unit (20) further includes, as device elements of the water circuit (W), a heater unit (54) and an expansion tank (55). The heater unit (54) is provided on the main flow path (50) to supplementarily heat water in the water circuit (W). The expansion tank (55) communicates with the main flow path (50), and mitigates the rise in water pressure in the water circuit (W).(2) Structure of Hot Water Supply Unit

[0047] The structure of the hot water supply unit (20) will be described with reference to FIGS. 1 to 4. In the following description, the terms for directions such as "upper," "lower," "front," "back," "right," and "left" refer to the directions of the arrows in FIG. 2.(2-1) Casing

[0048] As illustrated in FIG. 2, the hot water supply system (1) includes a casing (60) disposed in an indoor space (I). The indoor space (I) is a space formed inside a building, and includes not only a habitable space but also a non-habitable space, such as a corridor, a basement, a warehouse, or a garage. The casing (60) is placed on the floor surface of the indoor space (I). The casing (60) has the shape of a hollow box. The casing (60) has a rectangular parallelepiped outer shape. The height of the casing (60) in the upper-lower direction is greater than the front-to-back length and the left-to-right width of the casing (60). The casing (60) includes a top panel (61), a bottom plate (62), a front panel (63), a back plate (64), a right plate (65), and a left plate (66). The top panel (61) forms an upper surface of the casing (60), and the bottom plate (62) forms a lower surface of the casing (60). The front panel (63) forms a front surface of the casing (60), which is a first side surface thereof, and the back plate (64) forms a back surface of the casing (60), which is a second side surface thereof. The right plate (65) forms a right surface of the casing (60), which is a third side surface of the casing (60), and the left plate (66) forms a left surface of the casing (60), which is a fourth side surface of the casing (60).

[0049] A partition plate (67) is provided in the casing (60). The partition plate (67) partitions the interior of the casing (60) in the upper-lower direction. Specifically, the partition plate (67) separates the interior of the casing (60) into a first space (S1) and a second space (S2). The first space (S1) is formed in a lower portion of the casing (60). The second space (S2) extends from an intermediate portion to an upper portion of the casing (60). The first space (S1) and the second space (S2) have a rectangular parallelepiped shape. The height of the second space (S2) is greater than the height of the first space (S1). The tank (41) is disposed in the second space (S2).

[0050] In the state where the casing (60) is placed, an adequately large work space (S3) is provided in front of the casing (60). The lower portion of the front panel (63) of the casing (60) has an access port (A). An opening / closing lid (68) serving as a portion of the front panel (63) is detachably attached to the access port (A). An operator can access the first space (S1) in the casing (60) from the work space (S3) through the access port (A).(2-2) Layout of Devices in First Space

[0051] FIG. 3 illustrates the arrangement relationship among the devices including a refrigerant unit (U) and an electric component unit (71). FIG. 3 schematically illustrates pipes connecting the devices together and junctions of these pipes. Thus, the positions and shapes of these pipes and these junctions are not limited to those illustrated in FIG. 3. The above-described devices of the hot water supply unit (20) are disposed in the first space (S1). As illustrated in FIG. 3, the refrigerant unit (U) including the first refrigerant circuit (R1) is disposed in the first space (S1). The refrigerant unit (U) includes the entire first refrigerant circuit (R1) as a closed circuit. The refrigerant unit (U) includes, as the constituent devices of the first refrigerant circuit (R1), the first compressor (21), the refrigerant heat exchanger (22), the first expansion valve (24), and the first water heat exchanger (23).

[0052] The refrigerant unit (U) is closer to the front panel (63) than to the back plate (64). The refrigerant unit (U) is closer to the left plate (66) than to the right plate (65). The first compressor (21) is disposed near the access port (A). The first compressor (21) is positioned to be visible from the outside of the casing (60) through the access port (A) with the opening / closing lid (68) removed. The refrigerant unit (U) is located below the tank (41). The refrigerant unit (U) overlaps with the tank (41) in the vertical direction.

[0053] The refrigerant heat exchanger (22) and the first water heat exchanger (23) are disposed behind the first compressor (21). In this embodiment, the refrigerant heat exchanger (22) is disposed to the right of the first water heat exchanger (23). The first expansion valve (24) is disposed between the refrigerant heat exchanger (22) and the first compressor (21) or between the first water heat exchanger (23) and the first compressor (21).

[0054] The hot water supply unit (20) includes a support (70) configured to support the refrigerant unit (U). The support (70) is located below the refrigerant unit (U), and supports the support (70) from below. The support (70) is configured to be able to be pulled out of the access port (A) along the bottom plate (62). It is preferable that the bottom plate (62) is provided with a guide member configured to guide the support (70) in the front-back direction.

[0055] The electric component unit (71) is provided in the first space (S1). The electric component unit (71) is disposed below the tank (41). The electric component unit (71) overlaps with the tank (41) in the vertical direction.

[0056] The electric component unit (71) includes a control board for controlling the devices of the hot water supply unit (20). The electric component unit (71) is disposed near the access port (A). The electric component unit (71) is positioned to be visible from the outside of the casing (60) through the access port (A) with the opening / closing lid (68) removed.

[0057] The second water heat exchanger (26) is disposed behind the electric component unit (71). The first on-off valve (35) and the second on-off valve (36) are disposed between the second water heat exchanger (26) and the electric component unit (71). The first pipe (31) and the third pipe (33) serving as refrigerant pipes are disposed around the second water heat exchanger (26). The first pipe (31) and the third pipe (33) pass through the partition plate (67), and extend through the first space (S1) in the vertical direction.

[0058] The first space (S1) includes a connection space (75) behind the electric component unit (71). The connection space (75) is formed near the front side of the first space (S1). A first connection portion (C1), a second connection portion (C2), a third connection portion (C3), and a fourth connection portion (C4) are disposed in the connection space (75).

[0059] The first connection portion (C1) and the second connection portion (C2) form water-side connection portions configured to detachably connect the first water heat exchanger (23) and the water circuit (W) together. As illustrated in FIG. 1, the first connection portion (C1) connects a water pipe near the inlet of the fourth flow path (P4) of the first water heat exchanger (23) and the water circuit (W) together. The second connection portion (C2) connects a water pipe near the outlet of the fourth flow path (P4) of the first water heat exchanger (23) and the water circuit (W) together. The first connection portion (C1) is closer to the front panel (63) than to the back plate (64). The second connection portion (C2) is closer to the front panel (63) than to the back plate (64). The first connection portion (C1) and the second connection portion (C2) are arranged side by side in the left-right direction along the back surface of the electric component unit (71). The first connection portion (C1) and the second connection portion (C2) may directly connect the first water heat exchanger (23) and the water circuit (W) together, or may indirectly connect the first water heat exchanger (23) and the water circuit (W) together through a pipe.

[0060] The third connection portion (C3) and the fourth connection portion (C4) form heating medium-side connection portions configured to detachably connect the refrigerant heat exchanger (22) and the second refrigerant circuit (R2) together. As illustrated in FIG. 1, the third connection portion (C3) connects a refrigerant pipe on the gas side of the second flow path (P2) of the refrigerant heat exchanger (22) and the second refrigerant circuit (R2) together. The third connection portion (C3) is closer to the front panel (63) than to the back plate (64). The fourth connection portion (C4) connects a refrigerant pipe on the liquid side of the second flow path (P2) of the refrigerant heat exchanger (22) and the second refrigerant circuit (R2) together. The fourth connection portion (C4) is disposed behind the third connection portion (C3). The third connection portion (C3), like the fourth connection portion (C4), may be closer to the front panel (63) than to the back plate (64). The third connection portion (C3) and the fourth connection portion (C4) may directly connect the refrigerant heat exchanger (22) and the second refrigerant circuit (R2) together, or may indirectly connect the refrigerant heat exchanger (22) and the second refrigerant circuit (R2) together through a pipe.

[0061] The first space (S1) includes the constituent devices of the water circuit (W) behind the refrigerant unit (U) and the connection space (75). A water circuit space (76) is formed. The water circuit space (76) is formed near the back side of the first space (S1). The pump (40), the heater unit (54), the three-way valve (53), and the expansion tank (55) are disposed in the water circuit space (76). The inflow pipe (51a), the outflow pipe (51b), the supply pipe (52a), and the return pipe (52b) serving as water pipes are disposed in the water circuit space (76).

[0062] The inflow pipe (51a) and the outflow pipe (51b) pass through the partition plate (67), and are connected to the internal heat exchanger (42) in the tank (41). The supply pipe (52a) and the return pipe (52b) pass through the partition plate (67), and extend through the first space (S1) in the vertical direction.

[0063] Although not shown, the other devices of the water circuit (W) are disposed in the first space (S1). The other devices include a valve for drainage, a ball valve, a flow rate sensor, and a filter. It is preferable that the other devices are positioned to be closer to the front panel (63) than to the back plate (64).(2-3) Layout of Connection Portions For Top Panel

[0064] As illustrated in FIGS. 2 and 4, the top panel (61) is provided with a first refrigerant coupling (81), a second refrigerant coupling (82), a first water coupling (83), a second water coupling (84), a third water coupling (85), and a fourth water coupling (86). These couplings are located outside the casing (60). These couplings couple the pipes inside the casing (60) to pipes outside the casing (60).

[0065] Specifically, the first pipe (31) is connected to the lower end of the first refrigerant coupling (81), and the third pipe (33) is connected to the root end of the second refrigerant coupling (82). The water supply pipe (43) is connected to the lower end of the first water coupling (83), the hot water delivery pipe (44) is connected to the lower end of the second water coupling (84), the supply pipe (52a) is connected to the lower end of the third water coupling (85), and the return pipe (52b) is connected to the lower end of the fourth water coupling (86).

[0066] After installing the casing (60) in the indoor space (I), the operator connects pipes outside the casing (60) to the associated couplings. Specifically, a gas-side first connection pipe (91) that is joined to the outdoor unit (10) is connected to the upper end of the first refrigerant coupling (81). A liquid-side second connection pipe (92) that is joined to the outdoor unit (10) is connected to the upper end of the second refrigerant coupling (82). A first water pipe (93) for water supply is connected to the upper end of the first water coupling (83). A second water pipe (94) for hot water supply is connected to the upper end of the second water coupling (84). A third water pipe (95) near the inlet of the heater (5) is connected to the upper end of the third water coupling (85). A fourth water pipe (96) near the outlet of the heater (5) is connected to the upper end of the fourth water coupling (86).

[0067] The first water coupling (83), the second water coupling (84), the third water coupling (85), and the fourth water coupling (86) form first outer connection portions, and the first refrigerant coupling (81) and the second refrigerant coupling (82) form second outer connection portions. The second outer connection portions (81, 82) are closer to the front panel (63), which is the first side surface, than the first outer connection portions (83, 84, 85, 86) are. The second outer connection portions (81, 82) are closer to the front panel (63) than to the back plate (64), which is the second side surface (64). The first refrigerant coupling (81) and the second refrigerant coupling (82) are arranged in the left-right direction along the front panel (63). The first water coupling (83), the second water coupling (84), the third water coupling (85), and the fourth water coupling (86) are arranged in the left-right direction along the back plate (64). These water couplings are arranged at equal intervals.(3) Operation

[0068] In operation of the hot water supply system (1), the second refrigerant circuit (R2) performs a subcritical cycle or a supercritical cycle, and the first refrigerant circuit (R1) simultaneously performs a subcritical cycle. The second refrigerant circuit (R2) operates by switching between a first operation and a second operation. The water circuit (W) operates by switching between a third operation and a fourth operation.

[0069] In the first operation, the four-way switching valve (14) is in the first state, the first on-off valve (35) is in an open state, and the second on-off valve (36) is in a closed state. In the first operation, the refrigerant compressed by the second compressor (11) dissipates heat in the second water heat exchanger (26) and the refrigerant heat exchanger (22), is decompressed by the second expansion valve (13), and evaporates in the outdoor heat exchanger (12).

[0070] In the second operation, the four-way switching valve (14) is in the first state, the first on-off valve (35) is in a closed state, and the second on-off valve (36) is in an open state. In the first operation, the refrigerant compressed by the second compressor (11) bypasses the second water heat exchanger (26), dissipates heat in the refrigerant heat exchanger (22), is decompressed by the second expansion valve (13), and evaporates in the outdoor heat exchanger (12).

[0071] In the first refrigerant circuit (R1), the refrigerant compressed by the first compressor (21) dissipates heat in the first water heat exchanger (23), is decompressed by the first expansion valve (24), and evaporates in the refrigerant heat exchanger (22).

[0072] In the third operation, the three-way valve (53) is in the first state. In the third operation, water transported by the pump (40) is heated only in the first water heat exchanger (23) or in both the second water heat exchanger (26) and the first water heat exchanger (23). The heated water dissipates heat to water in the hot water storage space (41a) through the internal heat exchanger (42). As a result, hot water is produced in the tank (41).

[0073] In the fourth operation, the three-way valve (53) is in the second state. In the fourth operation, the water transported by the pump (40) is heated only in the first water heat exchanger (23) or in both the second water heat exchanger (26) and the first water heat exchanger (23). The heated water dissipates heat to the air in the target space through the utilization-side heat exchanger (6) of the heater (5). As a result, the target space is heated.(4) Operator's Tasks

[0074] The operator transports the hot water supply unit (20) to the spot, and then installs the hot water supply unit (20) in the indoor space (I). At this time, the refrigerant unit (U) and the tank (41) are housed in the casing (60) of the hot water supply unit (20). Since no water has been supplied into the tank (41), the tank (41) is empty. The weight of the hot water supply unit (20) is relatively greater than the weight of the tank (41).

[0075] The refrigerant unit (U) is disposed in the first space (S1) below the tank (41). This lowers the center of gravity of the hot water supply unit (20). Thus, the operator can easily perform a transportation task and an installation task for the hot water supply unit (20). Since the casing (60) has a height in its upper-lower direction greater than the length in its front-back direction or the width in its left-right direction, lowering the center of gravity of the casing (60) in the vertical direction greatly contributes to improving workability.

[0076] In addition, other devices different from those of the refrigerant unit (U) are disposed below the tank (41). Thus, the center of gravity of the hot water supply unit (20) can be further lowered. The other devices include the second water heat exchanger (26), the electric component unit (71), the pump (40), the three-way valve (53), the heater unit (54), the expansion tank (55), a valve for drainage, a ball valve, a flow rate sensor, and a filter.

[0077] The operator connects the pipes to the associated couplings on the top panel (61) after installing the hot water supply unit (20) in the indoor space (I). Specifically, the operator connects the first connection pipe (91) to the first refrigerant coupling (81), and connects the second connection pipe (92) to the second refrigerant coupling (82). A task for connecting these refrigerant pipes is more difficult than a task for connecting the water pipes. This is because the refrigerant pipes require more stringent countermeasures than the water pipes. Since the first refrigerant coupling (81) and the second refrigerant coupling (82) are closer to the front panel (63) than the water couplings (83, 84, 85, 86) are, the operator can easily perform a task for connecting the refrigerant pipes from the work space (S3).

[0078] The refrigerant couplings (81, 82) are closer to the front panel (63) than to the back plate (64), and the water couplings (83, 84, 85, 86) are closer to the back plate (64) than to the front panel (63). This increases the distance between the refrigerant couplings (81, 82) and the water couplings (83, 84, 85, 86). Thus, the task for connecting the pipes to the associated couplings can be easily performed.

[0079] The operator can bring the refrigerant unit (U) out of the casing (60) to maintain the refrigerant unit (U). Specifically, the operator in the work space (S3) detaches the opening / closing lid (68) from the casing (60) to expose the access port (A). The operator disconnects the first connection portion (C1), the second connection portion (C2), the third connection portion (C3), and the fourth connection portion (C4) through the access port (A). As a result, the refrigerant unit (U) is separated from the water circuit (W) and the second refrigerant circuit (R2). Also in this state, the first refrigerant circuit (R1) of the refrigerant unit (U) remains closed. Thus, the risk of leakage of the flammable refrigerant from the first refrigerant circuit (R1) is lower than if the refrigerant unit (U) is separated inside the first refrigerant circuit (R1). Since the refrigerant in the second refrigerant circuit (R2) is carbon dioxide, no serious problem occurs even if the refrigerant leaks from the second refrigerant circuit (R2).

[0080] The operator moves the support (70) forward through the access port (A). This allows the refrigerant unit (U) to be taken out of the casing (60) together with the support (70) through the access port (A). The operator maintains the refrigerant unit (U) not in the indoor space (I) but in an outdoor space. Thus, even if the flammable refrigerant leaks from the first refrigerant circuit (R1), problems caused by the leakage can be reduced. After the maintenance of the refrigerant unit (U), the operator returns the refrigerant unit (U) and the support (70) to their original positions. Thereafter, the operator again connects the first connection portion (C1), the second connection portion (C2), the third connection portion (C3), and the fourth connection portion (C4) to the refrigerant unit (U).(5) Advantages of Embodiments

[0081] (5-1) The refrigerant unit (U) is disposed below the tank (41). This configuration can lower the center of gravity of the hot water supply unit (20). Thus, the operator can simply perform the transportation task and the installation task for the hot water supply unit (20).

[0082] The electric component unit (71) disposed below the tank (41) further lowers the center of gravity of the hot water supply unit (20).

[0083] (5-2) The front panel (63) has the access port (A) for the first space (S1) in which the refrigerant unit (U) is housed. The hot water supply unit (20) includes the support (70) supporting the refrigerant unit (U) and being able to be taken in and out through the access port (A). This configuration allows the operator to take the refrigerant unit (U) out of the casing (60). The operator can maintain the refrigerant unit (U) after moving the refrigerant unit (U) to the outdoor space. This can reduce the risk caused by the leakage of the flammable refrigerant.

[0084] (5-3) The refrigerant unit (U) includes the water-side connection portions (C1, C2) that detachably connect the first water heat exchanger (23) and the water circuit (W) together, and the heating medium-side connection portions (C3, C4) that detachably connect the refrigerant heat exchanger (22) and the second refrigerant circuit (R2) together. According to this configuration, disconnecting these connection portions (C1, C2, C3, C4) allows the refrigerant unit (U) to be taken out of the casing (60) while the first refrigerant circuit (R1) remains closed. This can reduce the leakage of the flammable refrigerant when the refrigerant unit (U) is to be taken out.

[0085] (5-4) The water-side connection portions (C1, C2) are closer to the front panel (63) than to the back plate (64). Thus, the operator can simply perform the task for disconnecting or connecting the water-side connection portions (C1, C2). The heating medium-side connection portion (strictly, the third connection portion) is closer to the front panel (63) than to the back plate (64). Thus, the operator can simply perform the task for disconnecting or connecting the third connection portion (C3).

[0086] (5-5) The second outer connection portions (81, 82) are closer to the first side surface (63) than the first outer connection portions (83, 84, 85, 86) are. Thus, the operator can easily perform the task for connecting the refrigerant pipes to the associated second outer connection portions (81, 82).

[0087] The second outer connection portions (81, 82) are closer to the front panel (63) than to the back plate (64). The first outer connection portions (83, 84, 85, 86) are closer to the front panel (63) than to the back plate (64). According to this configuration, the second outer connection portions (81, 82) are apart from the first outer connection portions (83, 84, 85, 86) in the front-back direction. This enlarges the space around each of the second outer connection portions (81, 82) and the first outer connection portions (83, 84, 85, 86). Thus, the operator can easily perform the tasks for connecting the refrigerant pipes to the associated second outer connection portions (81, 82) and for connecting the water pipes to the associated first outer connection portions (83, 84, 85, 86).(6) Variations

[0088] The foregoing embodiments may be modified as follows. Differences from the above embodiments will be described below.(6-1) First Variation

[0089] As illustrated in FIG. 5, a hot water supply unit (20) of a first variation includes a shielding member (98). The shielding member (98) is disposed near the front side of the first space (S1). The shielding member (98) is disposed between the refrigerant unit (U) and the connection space (75). The shielding member (98) shields the third connection portion (C3) and the fourth connection portion (C4) from the first refrigerant circuit (R1). The shielding member (98) is formed in the shape of a plate in which the left-right direction serves as the plate thickness direction. The shielding member (98) extends from near the front end of the casing (60) to an intermediate position in the casing (60) in the front-back direction as viewed from above. The upper end of the shielding member (98) is located above the upper end of the first compressor (21). The shielding member (98) of this variation is integrated with the support (70). A lower portion of the shielding member (98) is continuous with the support (70). The shielding member (98) may be separate from the support (70).

[0090] At the third connection portion (C3) and the fourth connection portion (C4), a task of connecting pipes by brazing or welding and a task of separating pipes by cutting are required. Such tasks may cause sparks to fly toward the first refrigerant circuit (R1). The shielding member (98) shields the third connection portion (C3) and the fourth connection portion (C4) from the first refrigerant circuit (R1). This can keep sparks from flying toward the first refrigerant circuit (R1). As a result, the risk of ignition of the flammable refrigerant can be reduced.(6-2) Second Variation

[0091] As illustrated in FIG. 6, a hot water supply system (1) of a second variation includes a primary circulation circuit (100) serving as a heating medium circuit, instead of the second refrigerant circuit (R2) of the embodiment. The primary circulation circuit (100) is filled with a heating medium, such as water or an antifreeze solution. A configuration of a portion of the primary circulation circuit (100) in the hot water supply unit (20) is the same as that of the embodiment. The primary circulation circuit (100) includes a circulation pump (101) and an underground heat exchanger (102) as constituent devices installed in an outdoor space. The circulation pump (101) circulates the heating medium in the primary circulation circuit (100). The underground heat exchanger (102) is a heat transfer tube that transfers heat in the ground to the heating medium, and is helical, for example. The heating medium heated by the underground heat exchanger (102) dissipates heat in the refrigerant heat exchanger (22), and is used to produce hot water in the tank (41).(7) Other Embodiments

[0092] The hot water supply system (1) may be a system that supplies hot water from the tank (41) only to the heater (5).

[0093] The hot water supply unit (20) does not have to include the second water heat exchanger (26). In this case, the second refrigerant circuit (R2) is configured such that the second water heat exchanger (26), the bypass pipe (34), the first on-off valve (35), and the second on-off valve (36) are omitted.

[0094] The water heated by the first water heat exchanger (23) may be directly collected in the tank (41). In other words, the tank (41) may store water directly heated by the first refrigerant.

[0095] The support (70) may have a box shape that houses the refrigerant unit (U). In this case, a side plate of the support (70) may form the shielding member (98) of the first variation.

[0096] The refrigerant unit (U) and the electric component unit (71) do not always have to overlap with the tank (41) in the vertical direction. The refrigerant unit merely needs to be located below the lower end of the tank (41). The electric component unit (71) may be disposed in the second space (S2). Since the partition plate (67) shields the electric component unit (71) from the third connection portion (C3) and the fourth connection portion (C4), the flying of sparks toward the electric component unit during a task such as brazing or welding can be suppressed.

[0097] The connection space (75) does not have to be formed behind the electric component unit (71), and may be formed, for example, above, in front of, or to a side of, the electric component unit (71).

[0098] The first connection portion (C1), the second connection portion (C2), the third connection portion (C3), and the fourth connection portion (C4) may be located near the access port (A). The first connection portion (C1), the second connection portion (C2), the third connection portion (C3), and the fourth connection portion (C4) may be arranged side by side in the left-right direction.

[0099] The heating medium-side connection portions (C3, C4) and the water-side connection portions (C1, C2) may be provided on a side surface of the casing (60).

[0100] An expansion mechanism is not necessarily an expansion valve, and may be a capillary tube or an expander.(8) Other Descriptions

[0101] While the embodiments and variations thereof have been described above, it will be understood that various changes in form and details may be made without departing from the spirit and scope of the claims. The embodiments, the variations thereof, and the other embodiments may be combined and replaced with each other without deteriorating intended functions of the present disclosure.

[0102] The expressions such as "first," "second," "third," . . . , described above are used to distinguish the terms to which these expressions are given, and do not limit the number and order of the terms.INDUSTRIAL APPLICABILITY

[0103] As can be seen from the foregoing description, the present disclosure is useful for a hot water supply unit.DESCRIPTION OF REFERENCE CHARACTERS

[0104] 20Hot Water Supply Unit 21First Compressor (Compressor) 22Refrigerant Heat Exchanger (Second Heat Exchanger) 23First Water Heat Exchanger (First Heat Exchanger) 24First Expansion Valve (Decompression Mechanism) 41Tank 60Casing 63Front Panel (First Side Surface) 64Back Plate (Second Side Surface) 70Support 71Electric Component Unit 81, 82Second Outer Connection Portion 83, 84, 85, 86First Outer Connection Portion 91, 92Refrigerant Pipe 93, 94, 95, 96Water Pipe 98Shielding Member AAccess Port C1, C2Water-Side Connection Portion C3, C4Heating Medium-Side Connection Portion IIndoor Space R1First Refrigerant Circuit (Refrigerant Circuit) R2Second Refrigerant Circuit (Heating Medium Circuit) 100Primary Circulation Circuit (Heating Medium Circuit) S1First Space URefrigerant Unit WWater Circuit

Claims

1. A hot water supply unit comprising: a refrigerant unit (U) including a refrigerant circuit (R1) that performs a refrigeration cycle using a first refrigerant that is a flammable refrigerant; a tank (41) configured to store water directly or indirectly heated by the first refrigerant; and a casing (60) disposed in an indoor space (I) and configured to house the refrigerant unit (U) and the tank (41), the refrigerant circuit (R1) including: a compressor (21); a first heat exchanger (23) configured to exchange heat between the first refrigerant in the refrigerant circuit (R1) and water in a water circuit (W); a decompression mechanism (24); and a second heat exchanger (22) configured to exchange heat between the first refrigerant in the refrigerant circuit (R1) and a heating medium in a heating medium circuit (R2, 100), the refrigerant unit (U) being disposed below the tank (41).

2. The hot water supply unit of claim 1, wherein the casing (60) has a first side surface (63) having an access port (A) for a first space (S1) in which the refrigerant unit (U) is housed, and a second side surface (64) located on a side of the casing (60) opposite to the first side surface (63), and the hot water supply unit further includes a support (70) configured to support the refrigerant unit (U) and to be able to be taken in and out through the access port (A).

3. The hot water supply unit of claim 2, wherein the refrigerant unit (U) includes a water-side connection portion (C1, C2) configured to detachably connect the first heat exchanger (23) and the water circuit (W) together, and a heating medium-side connection portion (C3, C4) configured to detachably connect the second heat exchanger (22) and the heating medium circuit (R2, 100) together.

4. The hot water supply unit of claim 3, wherein the water-side connection portion (C1, C2) is closer to the first side surface (63) than to the second side surface (64).

5. The hot water supply unit of claim 3 or 4, wherein the heating medium-side connection portion (C3, C4) is closer to the first side surface (63) than to the second side surface (64).

6. The hot water supply unit of any one of claims 2 to 5, further comprising: a first outer connection portion (83, 84, 85, 86) provided outside the casing (60) and to which a water pipe (93, 94, 95, 96) of the water circuit (W) is connected; and a second outer connection portion (81, 82) provided outside the casing (60) and to which a refrigerant pipe (91, 92) of the heating medium circuit (R2, 100) is connected, wherein the second outer connection portion (81, 82) is closer to the first side surface (63) than the first outer connection portion (83, 84, 85, 86).

7. The hot water supply unit of claim 6, wherein the second outer connection portion (81, 82) is closer to the first side surface (63) than to the second side surface (64), and the first outer connection portion (83, 84, 85, 86) is closer to the second side surface (64) than to the first side surface (63).

8. The hot water supply unit of any one of claims 3 to 5, further comprising: a shielding member (98) configured to shield the heating medium-side connection portion (C3, C4) and the refrigerant circuit (R1) from each other.

9. The hot water supply unit of any one of claims 1 to 8, further comprising: an electric component unit (71) housed in the casing (60), wherein the electric component unit (71) is disposed below the tank (41).

10. The hot water supply unit of any one of claims 1 to 9, wherein the heating medium circuit (R2, 100) is a second refrigerant circuit (R2) that performs a refrigeration cycle using a second refrigerant.

Images