JP2014070812A - Temperature adjustment water supply machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce electric power and time required for scale removal in a scale removal operation using an electrolyzer.SOLUTION: A temperature adjustment water supply machine includes: an electrolyzer 41 that includes a water heat exchanger 21 for heating water, a container 47 and an electrode pair 49 provided in the container 47, and removes a scale component contained in water sent to the water heat exchanger 21; and a control unit 32. The control unit 32 executes a normal operation that precipitates the scale component contained in water by performing electrification to the electrode pair 49, and a scale removal operation that inverts the polarity of the electrode pair 49 from the state of the normal operation and performs electrification to the electrode pair 49 for a predetermined period at a current value higher than a current value at the normal operation.

Description

  TECHNICAL FIELD The present invention relates to a temperature-controlled water supply device such as a heat pump water heater, a heat pump hot water heater, a combustion hot water heater, an electric water heater, a cooling tower and the like provided with an electrolyzer.

  Tap water and groundwater contain components (scale components) such as calcium ions and magnesium ions that cause scales. Therefore, in a temperature-controlled water supply device such as a water heater, scales such as calcium salt (for example, calcium carbonate) and magnesium salt may be deposited. In the water heat exchanger of the temperature-controlled water supply machine, water is heated and the temperature of the water is increased, so that scale is particularly likely to precipitate. If the scale is deposited and deposited on the inner surface of the pipe in the water heat exchanger, there may be a problem that the heat transfer performance of the water heat exchanger is lowered or the flow path of the pipe is narrowed.

  Therefore, in order to prevent scale from adhering in the water heat exchanger, a technique for removing scale components by electrolysis has been proposed. When electrolysis is performed, a scale such as calcium carbonate is deposited on the cathode side. A part of the deposited scale remains in water, while the other part adheres to the electrode (cathode) surface. When scale adheres to the electrode surface, the electrical resistance increases, so the removal efficiency of scale components in water decreases. Further, when the amount of scale adhesion on the electrode surface increases, there is a possibility of causing clogging between the electrodes. The scale adhering to the electrode surface is usually dissolved and removed from the electrode surface by reversing the polarity of the electrode pair and energizing.

Japanese Patent No. 4447148 JP 2006-027825 A

  However, energization for a long time (for example, about several tens of minutes) is required to dissolve most of the scale attached to the electrode surface and remove the scale from the electrode surface. As a result, a large amount of power is required. .

  An object of the present invention is to reduce power and time required for scale removal in scale removal operation using an electrolyzer.

  (1) The temperature controlled water supply machine of the present invention comprises a water heat exchanger (21) for heating water, a container (47), and an electrode pair (49) provided in the container (47). And an electrolyzer (41) for removing scale components contained in the water sent to the water heat exchanger (21), and a controller (32). The control unit (32) reverses the polarity of the electrode pair (49) from the state of the normal operation, the normal operation of energizing the electrode pair (49) to deposit the scale component contained in the water, The scale removal operation is performed in which the electrode pair (49) is energized for a predetermined time with a current value higher than the current value during the normal operation.

  In this configuration, in the scale removal operation, the electrode pair (49) is energized with a current value higher than the current value during the normal operation. For example, compared with the case where the scale removal operation is performed with the same current value as during the normal operation. Thus, the scale can be dissolved mainly (dissolved in water) at the interface between the scale and the electrode surface. The scale on which the dissolution reaction is preferentially generated at the interface with the electrode surface is likely to drop off from the electrode surface in a needle-like or sheet-like state (a relatively large lump state). That is, in this configuration, the scale can be peeled off from the electrode surface without dissolving most of the portions other than the interface while the scale is melted mainly at the interface. Therefore, the scale removal operation is executed at the same current value as in normal operation, and the time required for the scale removal operation can be greatly shortened as compared with the case where most of the scale adhering to the electrode surface is melted. It also leads to a reduction in power required for scale removal operation.

  (2) In the temperature-controlled water supply device, when the current value during the scale removal operation is a value within the range of 2 to 20 times the current value during the normal operation, the scale and the electrode surface The reaction for intensively dissolving the scale at the interface can be effectively advanced.

  (3) In the said temperature control water supply machine, it is preferable that the said predetermined time of a scale removal driving | operation is 60 second or less. Thereby, the electric power and time which a scale removal driving | operation requires can be reduced effectively. In addition, when the predetermined time is 60 seconds or less, the scale can be prevented from being excessively dissolved in water, so that the state in which the concentration of the scale component in the water in the container (47) is low can be maintained. Furthermore, as described above, when the current value during the scale removal operation is a value within the range of 2 to 20 times the current value during the normal operation, the electrode surface can be used even if the predetermined time is 60 seconds or less. Therefore, if the predetermined time is set to a time exceeding 60 seconds, a wasteful time that does not contribute to the scale peeling may occur.

  (4) In the temperature-controlled water supply machine, the control unit (32) is configured to provide water in the container (47) in order to promote removal of scale from the electrode surface during the scale removal operation or after the scale removal operation. It is preferable to execute the control to form the flow of As for the scale of the electrode surface, the adhesion force to the electrode surface is considerably reduced by energization of the electrode pair (49) in the scale removal operation. Therefore, the external force resulting from the movement of water is applied to the scale, thereby facilitating the scale from falling off the electrode surface.

  (5) In the temperature-controlled water supply machine, the electrolyzer (41) further includes a vibration imparting means (61) for promoting the removal of the scale from the electrode surface, and the control unit (32) is In addition, during the scale removal operation or after the scale removal operation, the vibration imparting means (61) may perform control for directly or indirectly transmitting vibration to the scale. As for the scale on the surface of the electrode, the adhesion force to the electrode surface is considerably reduced by energization of the electrode pair (49) in the scale removal operation. Accordingly, the vibration is directly or indirectly transmitted to the scale by the vibration applying means (61), thereby facilitating the drop-off of the scale from the electrode surface.

  As described above, according to the present invention, the power and time required for scale removal can be reduced in the scale removal operation using the electrolyzer.

It is a lineblock diagram showing the heat pump water heater concerning one embodiment of the present invention. It is a perspective view which shows the electrolyzer used for the said heat pump water heater. (A) is sectional drawing when the said electrolyzer is cut | disconnected by the plane parallel to a perpendicular direction, (B) is sectional drawing when the said electrolyzer is cut | disconnected by the plane parallel to a horizontal direction. is there. (A), (B) is a chart which shows the time-dependent change of the scale component density | concentration (hardness) in a normal driving | operation and scale removal driving | operation, (A) has shown the example of control in the said embodiment, (B) Shows a control example in the reference example. (A)-(C) has shown the change of the mode of the scale in the normal driving | operation and scale removal driving | operation of the said embodiment. (A) And (B) is a photograph which shows the state from which the acicular or sheet-like scale peeled from the electrode in the scale removal driving | operation in the said embodiment. (A)-(C) has shown the change of the mode of the scale in the normal driving | operation and scale removal driving | operation of a reference example. (A) is the schematic which shows the modification 1 of the said electrolyzer, (B) is the schematic which shows the modified example 2 of the said electrolyzer, (C) is the said electrolyzer. It is the schematic which shows the modification 3. It is the schematic which shows the structure of the cooling tower provided with the said electrolyzer, a combustion type water heater, or an electric water heater.

  Hereinafter, a temperature-controlled water supply device (device for supplying temperature-controlled water) according to an embodiment of the present invention will be described with reference to the drawings. Examples of the temperature-controlled water supply machine include a heat pump water heater, a heat pump hot water heater, a combustion hot water heater, an electric water heater, a cooling tower, and the like. Hereinafter, the heat pump water heater will be mainly described.

<Heat pump water heater>
As shown in FIG. 1, the heat pump water heater 11 according to the present embodiment includes a refrigerant circuit 10a and a hot water storage circuit 10b. The refrigerant circuit 10a includes a compressor 19, a water heat exchanger 21, an electric expansion valve 23 as an expansion mechanism, an air heat exchanger 25, and a refrigerant pipe connecting them. The hot water storage circuit 10b includes a tank 15, a pump 31, an electrolyzer 41, a water heat exchanger 21, and water conduits 27 and 29 for connecting them. The water heat exchanger 21 has two flow paths, one flow path is connected to the refrigerant circuit 10a, and the other flow path is connected to the hot water storage circuit 10b. The operation of the refrigerant circuit 10a and the hot water storage circuit 10b is controlled by the control unit 32.

  The compressor 19, the water heat exchanger 21, the electric expansion valve 23, and the air heat exchanger 25 are provided in the heat pump unit 13. The tank 15 and the pump 31 are provided in the hot water storage unit 17. The water conduits 27 and 29 include a water inlet pipe 27 that sends water from the tank 15 to the water heat exchanger 21, and a hot water outlet pipe 29 that returns water heated by exchanging heat with the water heat exchanger 21 to the tank 15.

  The pump 31 is for sending water in the hot water storage circuit 10a. In the present embodiment, the pump 31 is provided in the incoming water pipe 27, but the arrangement position of the pump 31 is not limited to this. By the operation of the pump 31, the water in the tank 15 flows out from the lower part of the tank 15 to the incoming water pipe 27, is sent in the order of the incoming water pipe 27, the water heat exchanger 21 and the hot water outlet pipe 29, and returns to the upper part of the tank 15.

  In the present embodiment, carbon dioxide is used as the refrigerant circulating in the refrigerant circuit 10a, but the present invention is not limited to this. The refrigerant circulating in the refrigerant circuit 10a exchanges heat with water circulating in the hot water storage circuit 10b in the water heat exchanger 21 to heat the water, and heat exchange with outside air in the air heat exchanger 25 absorbs heat from the outside air. To do.

  A water supply pipe 37 and a hot water supply pipe 35 are connected to the tank 15. The hot water supply pipe 35 is connected to the upper part of the tank 15. The hot water supply pipe 35 is for taking out hot water stored in the tank 15 and supplying hot water to a bathtub or the like. The water supply pipe 37 is connected to the bottom of the tank 15. The water supply pipe 37 is for supplying low-temperature water into the tank 15 from a water supply source. As a water supply source for supplying water to the tank 15, for example, tap water or ground water such as well water can be used. The water heater 11 of the present embodiment is a transient water heater that does not return the hot water supplied from the hot water supply pipe 35 to the tank 15, but is not limited thereto.

  The electrolyzer 41 is for removing scale components contained in the water sent to the water heat exchanger 21. The electrolyzer 41 is provided at a position upstream of the water heat exchanger 21 in the water inlet pipe 27 at a position downstream of the pump 31. Details of the electrolyzer 41 will be described later.

  The control unit 32 is configured by, for example, a microcomputer having a central processing unit 33, a memory 34, and the like. The memory 34 stores a schedule for a boiling operation (normal operation) for boiling water in the tank 15, an operation condition for a scale removal operation described later, and the like. The control unit 32 executes the normal operation based on the schedule, and executes the scale removal operation after the normal operation. The normal operation may be executed as necessary even at a time other than the scheduled time. It is preferable that the normal operation is scheduled to be executed, for example, at night time when the amount of water used is low, or when the electricity rate is low, but is not limited thereto.

  During normal operation, scale deposits and adheres to the surface of the electrode functioning as the cathode in the electrolysis apparatus 41. The scale removal operation is performed to remove scale attached to the electrode surface. The scale removal operation may be executed immediately after the end of the normal operation, or may be executed after a time after the end of the normal operation. In the scale removal operation, the control unit 32 reverses the polarity of the electrode pair 49 (see FIG. 3A) and energizes the electrode pair 49 to remove the scale from the electrode surface. Details of the normal operation and the scale removal operation will be described later.

  The heat pump water heater 11 of the present embodiment is a transient water heater. In the transient hot water heater 11, the water (hot water) supplied from the hot water supply pipe 35 is used by the user and does not return to the tank 15. Accordingly, the same amount of water supplied from the tank 15 through the hot water supply pipe 35 is supplied to the tank 15 from the water supply source through the water supply pipe 37. That is, the tank 15 is frequently replenished with water containing scale components from a water supply source such as tap water or well water, and the amount of replenishment is also large. Therefore, in the case of a transient heat pump water heater, it is necessary to remove scale components more efficiently than a circulating cooling water circulation device or a circulating water heater.

  Next, the operation of the heat pump water heater 11 will be described. In the normal operation of boiling water in the tank 15, the control unit 32 drives the compressor 19 of the heat pump unit 13 to adjust the opening degree of the electric expansion valve 23 and drives the pump 31 of the hot water storage unit 17. Thereby, as shown in FIG. 1, low-temperature water in the tank 15 is sent to the water heat exchanger 21 through the inlet pipe 27 from the water outlet provided at the bottom of the tank 15, and is heated in the water heat exchanger 21. The The heated high-temperature water is returned into the tank 15 from a water inlet provided in the upper part of the tank 15 through the hot water supply pipe 29. Thereby, hot water is stored in the tank 15 in order from the upper part.

<Electrolysis device>
FIG. 2 is a perspective view showing the electrolyzer 41. 3A is a cross-sectional view of the electrolyzer 41 cut along a plane parallel to the vertical direction, and FIG. 3B is a cross-sectional view of the electrolyzer 41 cut along a plane parallel to the horizontal direction. is there. The electrolyzer 41 includes a container 47 having a water inlet 43 and a water outlet 45, and a plurality of electrodes 51 and 52 accommodated in the container 47. The plurality of electrodes 51 and 52 include a plurality of first electrodes 51 and a plurality of second electrodes 52.

  The plurality of first electrodes 51 and the plurality of second electrodes 52 are arranged in one direction (electrode thickness direction) such that the first electrodes 51 and the second electrodes 52 are alternately arranged. Adjacent electrodes 51 and 52 constitute an electrode pair 49. A plurality of electrodes 51 and 52 are connected to a power source 53 so that one electrode of the electrode pair 49 functions as an anode and the other electrode functions as a cathode. As the power source 53, for example, a DC power source is used. In the present embodiment, the plurality of first electrodes 51 and the plurality of second electrodes 52 are connected in parallel to the power source 53, but are not limited thereto.

  As shown in FIG. 3B, the electrolysis apparatus 41 includes a reversing mechanism 63 for reversing the polarity of each electrode pair 49. The reversing mechanism 63 is controlled by the control unit 32. The reversing mechanism 63 includes a contact switching unit 71 and a contact switching unit 72, and the polarity of the electrodes 51 and 52 can be reversed by switching the contact of the contact switching unit 71 and the contact switching unit 72. it can. Specifically, when the reversing mechanism 63 is in the state shown on the left side in FIG. 3B, the plurality of first electrodes 51 are connected to the negative electrode of the power source 53, and the plurality of second electrodes 52 are connected to the positive electrode of the power source 53. On the other hand, when the reversing mechanism 63 is in the state shown on the right side in FIG. 3B, the plurality of first electrodes 51 are connected to the positive electrode of the power source 53, and the plurality of second electrodes 52 are connected to the negative electrode of the power source 53.

  Each electrode is formed of a material excellent in corrosion resistance. Examples of the material mainly constituting each electrode include platinum and titanium. Specifically, it is as follows. For example, it is preferable that at least the surface of each electrode is formed of a material whose main component is platinum. Specifically, a mode in which the entirety of each electrode is formed of a material mainly composed of platinum (a material such as platinum or a platinum alloy) can be exemplified. Each electrode is made of an electrode body made of a material having a higher ionization tendency than platinum (that is, a material that is more easily oxidized than platinum in water), and a material mainly containing platinum on the surface of the electrode body (platinum) And a coating layer formed of a material such as a platinum alloy. Examples of the material for the electrode main body include materials mainly composed of titanium (materials such as titanium and titanium alloys). In addition, each electrode may be formed of, for example, a material mainly composed of titanium (a material such as titanium or a titanium alloy) as a material that is more easily oxidized than platinum but relatively excellent in corrosion resistance. In the electrolysis apparatus 41 in which the scale removal operation for reversing the polarity of the electrode pair 49 is performed as in the present embodiment, it is preferable that the anode material and the cathode material are the same.

  As the shape of each electrode, for example, various shapes such as a plate shape and a rod shape can be adopted, but in this embodiment, a plate shape is adopted. Thereby, the surface area of each electrode can be increased. In the present embodiment, the plurality of first electrodes 51 and the plurality of second electrodes 52 are arranged in parallel to each other, and are arranged at intervals in the thickness direction of the electrodes. The gap between the electrodes functions as a flow path through which water flows. In the present embodiment, the plurality of first electrodes 51 and the plurality of second electrodes 52 are arranged so that a meandering flow path in which water flows while meandering in the container 47 is not limited thereto.

  As shown in FIGS. 2 and 3A and 3B, the container 47 has a substantially rectangular parallelepiped shape constituted by six wall portions. These wall portions form a water flow space through which water flows. The six wall parts include a first wall part 471, a second wall part 472, a third wall part 473, a fourth wall part 474, a fifth wall part 475, and a sixth wall part 476.

  Although the water inlet 43 of the container 47 is provided in the lower part of the 1st wall part 471, and the water outlet 45 is provided in the upper part of the 2nd wall part 472, it is not limited to this. The water inlet 43 is connected to the water inlet pipe 27 located on the pump 31 side, and the water outlet 45 is connected to the water inlet pipe 27 located on the water heat exchanger 21 side. Water sent to the electrolyzer 41 through the water inlet pipe 27 by the pump 31 flows into the water flow space inside the container 47 from the water inlet 43. The water that has flowed into the water flow space flows toward the downstream side of the water flow, and is discharged from the water outlet 45 to the outside of the container 47.

  During normal operation of boiling water in the tank 15, a voltage is applied to the electrode pair 49 of the electrolyzer 41, and a current having a predetermined current value flows. During normal operation, the scale component contained in the water is deposited as a scale on the cathodes of the electrode pair 49 until the water flowing into the container 47 from the water inlet 43 flows out of the container 47 through the water outlet 45. In normal operation, water from which the scale component has been removed in the electrolyzer 41 is sent to the water heat exchanger 21, and water is heated by exchanging heat with the refrigerant in the water heat exchanger 21. The scale adhering to the electrode surface in the normal operation is removed from the electrode surface by executing the scale removal operation.

  Hereinafter, the scale removal operation which is a feature of the present embodiment will be described in detail while comparing with the normal operation. In the following description, in the reference example compared with the present embodiment, the current value of the scale removal operation is set to the same value as the current value of the normal operation.

<Scale removal operation>
In the present embodiment, the control unit 32 reverses the polarity of the electrode pair 49 from the normal operation state by energizing the electrode pair 49 to deposit the scale component contained in the water, and the current during the normal operation. The scale removal operation is performed in which the electrode pair 49 is energized for a predetermined time with a current value (second current value) higher than the value (first current value).

  The second current value during the scale removal operation is not particularly limited as long as the second current value is higher than the first current value during the normal operation. However, the second current value is within a range of 2 to 20 times the first current value. The value is preferred.

  When an electrode having a coating layer formed on the surface of the electrode body (for example, an electrode having a coating layer mainly composed of platinum on the surface of an electrode body mainly composed of titanium) is used, the current value If the thickness is excessively high, the life of the coating layer may be reduced. Even when such an electrode is used, when the upper limit value of the second current value is set as described above, it is possible to prevent the life of the electrode from being shortened.

  FIG. 4A is a chart showing the change over time in the scale component concentration (hardness) when the normal operation and the scale removal operation are executed in the heat pump water heater 11 of the present embodiment. FIG. 4B is a chart showing the change over time in the scale component concentration (hardness) when the normal operation and the scale removal operation are executed in the heat pump water heater of the reference example. In the control examples shown in FIGS. 4A and 4B, the case where the electrode pair 49 is energized while water is circulated through the container 47 in the scale removal operation is illustrated, but the present invention is not limited to this. In the scale removal operation, the electrode pair 49 may be energized with the flow of water to the container 47 stopped.

  In the present embodiment, since the second current value of the scale removal operation is set to a value larger than the first current value of the normal operation, as can be seen by comparing FIG. 4A and FIG. In the removal operation, the predetermined time (energization time) in which the current of the second current value flows through the electrode pair 49 is shorter than that in the reference example.

  Specifically, the energization time is preferably set to, for example, 60 seconds or less, and more preferably set to 30 seconds or less (for example, 10 seconds to 30 seconds). In the present embodiment, if the second current value is set to a higher value, the energization time can be set to a very short time of about several seconds (1 second to less than 10 seconds).

  FIGS. 5A to 5C show changes in the scale state in the normal operation and the scale removal operation of the present embodiment. FIG. 5A is a schematic diagram showing an electrode with a scale attached in a normal operation, and FIG. 5B shows a state where the polarity of the electrode pair 49 is reversed and energization is started in the scale removal operation. FIG. 5C is a schematic diagram illustrating a state in which a needle-like or sheet-like scale is peeled from an electrode in a scale removal operation. FIGS. 6A and 6B are photographs showing a state where the needle-like or sheet-like scale is peeled from the electrode in the scale removal operation in the present embodiment. The experimental results shown in FIGS. 6A and 6B show that when the second current value of the scale removal operation is set to 10 times the first current value of the normal operation and the energization time is set to 5 seconds. belongs to.

  As shown in FIGS. 5 (A) to 5 (C) and FIGS. 6 (A) and 6 (B), in this embodiment, in the scale removal operation, the electrode pair 49 has a shorter current than the normal operation as described above. By energizing for a period of time, the scale is concentrated in the vicinity of the interface between the electrode surface and the scale, while the scale in the form of needles, sheets, etc. before the scale other than in the vicinity of the electrode interface is hardly dissolved. Fall off (peel) from the electrode surface. Therefore, the power and time required for the scale removal operation can be reduced as compared with the reference example. The scale removal operation is performed at an appropriate frequency before the scale adhering to the electrode surface in a normal operation becomes dense. As a result, the above-described reaction that occurs predominantly at the interface between the electrode surface and the scale can occur not only at the periphery of the electrode but also at the entire electrode surface. The scale removal operation may be performed, for example, once to a plurality of times a day, for example, once every a plurality of days.

  In the present embodiment, when energization of the scale removal operation is started, the concentration of scale components in the water in the container 47 tends to increase due to dissolution of the scale from the electrode surface, as indicated by C1 in FIG. is there. However, in the present embodiment, in the scale removal operation, the scale near the interface is preferentially dissolved in water, and the scale other than the vicinity of the interface is maintained in a precipitated state, so that the concentration of scale components in the water in the container 47 increases. Is suppressed as compared with the reference example shown in FIG.

  As described above, the increase in the concentration of the scale component in water during the scale removal operation is suppressed, so that the adhesion of the scale to the electrode functioning as the cathode during the scale removal operation is also suppressed. That is, the next normal operation can be resumed with almost no scale attached to the cathode surface. Thereby, the fall of the scale removal efficiency of the next normal driving | operation can be suppressed, and it can suppress that the cycle of normal driving | operation becomes short.

  In the present embodiment, after the energization of the scale removal operation is stopped, the water in the container 47 used for the scale removal operation is not sent to the water heat exchanger 21 but is drained upstream of the water heat exchanger 21. (For example, the water replacement operation in FIG. 4A). That is, until the concentration of the scale component in the water in the container 47 in FIG. 4 (A) is, for example, equal to or lower than the concentration indicated by the inlet concentration line, The water is discharged without being sent to the water heat exchanger 21. The “inlet concentration” in FIG. 4A is the concentration of the scale component in the water supplied from the water inlet 43 into the container 47.

  As a method for draining the water in the container 47 without sending it to the hydrothermal exchanger 21 after the energization stop of the scale removal operation, for example, the following two methods can be mentioned. In the first draining method, after energization of the scale removal operation is stopped, the water in the container 47 is drained out of the system through the drain port 46 provided at the bottom of the container 47 shown in FIG. The drain port 46 is opened and closed by an on-off valve 48, for example. After the water in the container 47 is drained, the on-off valve 48 is closed, the container 47 is filled again with water, and normal operation is performed.

  In the second drainage method, drainage branched from a water conduit (inlet pipe) 27 between the water outlet 45 of the container 47 and the water heat exchanger 21 shown in FIG. Water in the container 47 is drained out of the system through the path 44. The drainage channel 44 can be opened and closed by a switching mechanism 42. Examples of the switching mechanism 42 include a switching valve provided at a branch portion between the drainage channel 44 and the water inlet pipe 27. Other examples of the switching mechanism 42 include open / close valves provided in the drainage channel 44 and the water inlet pipe 27, for example. In FIG. 3A, the drainage channel 44 is provided in the vicinity of the water outlet 45, but is not limited thereto. For example, the drainage channel 44 may be provided in the vicinity of the water heat exchanger 21, or may be provided in an intermediate portion between the water outlet 45 and the water heat exchanger 21.

  In addition, in the electrolyzer 41 shown to FIG. 3 (A), the drain outlet 46 and the on-off valve 48, the drain channel 44, and the switching mechanism 42 do not need to be provided. Moreover, since the drainage method is not limited to these, when other drainage methods other than these are adopted, the drainage port 46 and the on-off valve 48, the drainage channel 44, and the switching mechanism 42 can be omitted.

  Moreover, in this embodiment, even if the water after the scale removal operation to be discharged flows into the heat exchanger 21, the increase in the scale component is small, so that heat exchange is performed compared to the conventional operation. Scale adhesion in the vessel can be suppressed.

  As described above, in this embodiment, in the scale removal operation, a method of energizing the electrode pair 49 without circulating water in the container 47 and a method of energizing the electrode pair 49 while circulating water in the container 47 are used. And can be selected.

  In the latter case, that is, when the electrode pair 49 is energized while flowing water through the container 47 in the scale removal operation, water having an “inlet concentration” from the water inlet 43 to the container 47 is energized while the electrode pair 49 is energized. Supplied and water having an increased scale component concentration flows out from the water outlet 45. In this embodiment, even in the latter case, since the energization time is very short as described above, the amount of water used for the scale removal operation is very small compared to the reference example. However, the water in the container 47 during the scale removal operation is not sent to the water heat exchanger 21 but is drained through, for example, the drainage channel 44 on the upstream side of the water heat exchanger 21.

  In the present embodiment, the former control, that is, control for energizing the electrode pair 49 without flowing water through the container 47 in the scale removal operation may be employed. In this case, the electrode pair 49 can be energized with almost no flow of water in the container 47. Accordingly, since there is almost no movement of water near the surface of the electrode (anode) to which the scale is attached, a low pH state is maintained near the surface of the electrode (anode) while the electrode pair 49 is energized. The lower the pH is, the more easily the scale dissolves in water. Therefore, the scale tends to dissolve mainly at the interface between the scale and the electrode surface.

  Further, when a high current is passed through the electrode pair 49 as in the present embodiment, the scale is evenly dissolved on the entire electrode surface. On the other hand, when a low current is passed through the electrode pair 49 as in the reference example, variations tend to occur in the portion where the scale melts on the electrode surface. Also from this, in this embodiment, since the adhesion force of the scale can be weakened as a whole at the interface between the electrode surface and the scale as compared with the reference example, the scale is in a lump state such as a needle shape or a sheet shape. Can be peeled off.

  Further, the reference example in which the scale removal operation is performed with the same current value as that in the normal operation has the following problems. 7A to 7C show changes in the scale state in the normal operation and the scale removal operation of the reference example. FIG. 7A is a schematic view showing an electrode with a scale attached in a normal operation, and FIG. 7B shows a state where the polarity of the electrode pair 49 is reversed and energization is started in the scale removal operation. FIG. 7C is a schematic diagram illustrating a state in which the attached scale is gradually dissolved and the scale removal operation is completed. In the reference example, the current value of the scale removal operation is set to the same first current value as the current value of the normal operation.

  In the reference example, the electrode which functions as a cathode during normal operation and has a scale attached becomes an anode by reversing the polarity, and the attached scale gradually dissolves in water. In the scale removal operation of the reference example, the scale is not dissolved in the vicinity of the interface between the electrode surface and the scale as in this embodiment, but the entire thickness direction of the scale is gradually dissolved in water (FIG. 7 ( B)). Therefore, in the reference example, since it takes a long time for the scale to be removed from the electrode surface, it is necessary to set the energization time for the scale removal operation to be long as shown in FIG. About 1 hour)).

  In the reference example, even if the current value of the scale removal operation is the same as that of the normal operation, it takes a long time until the energization of the scale removal operation is completed. Increases compared to the present embodiment.

  In the reference example, most of the scale adhering to the anode in the scale removal operation is dissolved in the water in the container, so that the concentration of the scale component in the water is high (see C2 in FIG. 4B). . Accordingly, the amount of scale attached to the electrode surface functioning as the cathode during the scale removal operation increases (see FIG. 7C). That is, the next normal operation is resumed with many scales attached to the cathode surface. As a result, the scale removal efficiency of the next normal operation is likely to be reduced, and the operable time per one normal operation is shortened.

  In the reference example, the concentration of the scale component in the water in the container is high, so the water in the container used for the scale removal operation is not sent to the water heat exchanger after the scale removal operation is stopped. It must be drained upstream from the exchanger.

  In the scale removal operation of the reference example, a method of energizing the electrode pair without circulating water in the container and a method of energizing the electrode pair while circulating water in the container can be selected.

  In the latter case, that is, when energizing the electrode pair while circulating water in the container in the scale removal operation, in the reference example, it is necessary to continue flowing water for a long time until the energization of the scale removal operation is completed. Very much water is needed.

  The main features of the present embodiment are as described above. Examples of the control that promotes the removal of the scale from the electrode surface during the scale removal operation or after the scale removal operation are as follows.

  The control unit 32 may execute control for forming a flow of water in the container 47 in order to promote the drop-off of the scale from the surface of the electrode during energization or after the energization of the electrode pair 49 in the scale removal operation. Good. As a method of forming the water flow, for example, as shown in FIG. 3A, the water in the container 47 is drained by opening an openable / closable drain port 46 provided at the bottom of the container 47 or the like. A method is mentioned. According to this method, the water in the container 47 moves downward as the water is drained, so that an external force is applied to the scale on the surface of the electrode by the movement of the water. Since the scale of the electrode surface is considerably reduced in the adhesion force to the electrode surface due to the energization of the electrode pair 49, the drop off of the scale from the electrode surface is promoted by the external force due to the movement of water.

  In addition, when drainage of water is executed after the energization of the scale removal operation is stopped and water is supplied again into the container 47, all the water in the container 47 is replaced with “inlet concentration” water. The concentration of scale components in water can be reduced to “inlet concentration”. Therefore, normal operation can be resumed immediately after the water is replaced.

  In addition, as another method for forming the flow of water, there is a method in which water is allowed to flow into the container 47 from the water inlet 43 and water is sequentially discharged from the water outlet 45 to the outside of the container 47. According to this method, when water flows through the water flow path between the electrodes 51 and 52, the water moves along the electrode surface, so that an external force is applied to the scale on the surface of the electrode by the movement of the water. And the drop-off of the scale from the electrode surface is promoted by the external force resulting from the movement of water.

  It should be noted that the scale drop acceleration control from the electrode surface as described above is particularly effective when the electrode pair 49 is energized in a state where the flow of water to the container 47 is stopped in the scale removal operation.

(Modification 1)
The electrolyzer 41 is not necessarily limited to having a meandering flow path as shown in FIG. 3 (A), and may be an electrolyzer 41 as in Modification 1 shown in FIG. 8 (A), for example. As shown in FIG. 8A, the electrolyzer 41 includes a container 47 having a water inlet 43 and a water outlet 45, and a first electrode 51 and a second electrode 52 accommodated in the container 47. Since this electrolyzer 41 does not have a meandering flow path, the water flowing into the container 47 from the water inlet 43 flows in the container 47 from the water inlet 43 toward the water outlet 45 at random to some extent, The scale component is removed in the process of passing through the gap between adjacent electrodes in the middle of flowing toward the 45 side. Also in the first modification, the above-described normal operation and scale removal operation are performed.

  In the first modification, similarly to the embodiment shown in FIG. 3A, after the energization of the scale removal operation is stopped, for example, the water in the container 47 is drained through the drain port 46 or the drainage channel 44, and then the normal operation is performed. Executed.

  In Modification 1, a reversing mechanism similar to the reversing mechanism 63 shown in FIG. 3B is provided, but the reversing mechanism is not shown in FIG. 8A (FIG. 8B). The same).

(Modification 2)
FIG. 8B shows an electrolyzer 41 of the second modification. The electrolyzer 41 further includes a vibration applying means 61 for promoting the removal of the scale from the surfaces of the electrodes 51 and 52. In the scale removal operation, the control unit 32 performs control for directly or indirectly transmitting vibration to the scale by the vibration applying unit 61. As a result, scale removal from the surfaces of the electrodes 51 and 52 is promoted.

  Specific examples of the vibration applying means 61 include a device that applies ultrasonic vibration to the container 47, the water in the container 47, the electrodes 51 and 52, and the like. Another example of the vibration applying means 61 is a device that strikes the electrodes 51 and 52 with a hammer (not shown).

  Also in the modified example 2, as in the embodiment shown in FIG. 3A, after the energization of the scale removal operation is stopped, the water in the container 47 is drained through the drain port 46 or the drainage channel 44, and then the normal operation is performed. Executed.

  In addition, you may provide the vibration provision means 61 in the electrolyzer 41 which has a meandering flow path shown to FIG. 3 (A).

(Modification 3)
FIG. 8C shows an electrolyzer 41 of the third modification. As shown in FIG. 8C, the electrolyzer 41 includes a container 47 having a water inlet 43 and a water outlet 45, and a first electrode 51 and a second electrode 52 accommodated in the container 47. In this modification 3, each electrode is arrange | positioned in parallel with the direction through which water flows. Specifically, each electrode is arranged in a posture parallel to or substantially parallel to a direction from the first wall portion 471 provided with the water inlet 43 to the second wall portion 472 provided with the water outlet 45. The first wall portion 471 and the second wall portion 472 are arranged in parallel to each other.

  The water that has flowed into the container 47 from the water inlet 43 flows through the gap between the first electrode 51 and the second electrode 52 and flows in the container 47 toward the water outlet 45 side. The scale component in the water is removed in the process of passing through the gap between the adjacent electrodes 51 and 52 while the water flows to the water outlet 45 side. Also in the third modification, the above-described normal operation and scale removal operation are performed.

  In the modified example, after the energization of the scale removal operation is stopped, the water in the container 47 is drained through a drain port or a drainage channel (not shown) similar to that shown in FIG. Executed.

  As described above, in the present embodiment, in the scale removal operation, the electrode pair 49 is energized with a current value higher than the current value during the normal operation. For example, the scale removal operation is executed with the same current value as during the normal operation. Compared with the case where it is done, the scale can be dissolved mainly (dissolved in water) at the interface between the scale and the electrode surface. The scale where the dissolution reaction has occurred predominantly at the interface tends to fall off from the electrode surface in a needle-like or sheet-like state (a relatively large lump state). That is, in this configuration, the scale can be peeled off from the electrode surface without dissolving most of the portions other than the interface while the scale is melted mainly at the interface. Therefore, the scale removal operation is executed at the same current value as in normal operation, and the time required for the scale removal operation can be greatly shortened as compared with the case where most of the scale adhering to the electrode surface is melted. It also leads to a reduction in power required for scale removal operation.

  Further, in this embodiment, even if a scale that has fallen out of the electrode surface in a needle-like or sheet-like state (a relatively large lump state) flows into the hydrothermal exchanger 21, this scale is not a calcium salt ( For example, it is a precipitate such as calcium carbonate) or a magnesium salt, so that it is less likely to adhere to the hydrothermal exchanger 21 than the scale component.

  In the present embodiment, when the current value during the scale removal operation is a value within the range of 2 to 20 times the current value during the normal operation, the scale is focused on the interface between the scale and the electrode surface. The reaction to be dissolved in can be effectively advanced.

  In the present embodiment, when the energization time of the scale removal operation is 60 seconds or less, the power and time required for the scale removal operation can be effectively reduced.

  Moreover, in this embodiment, the control part 32 performs control which forms the flow of water in the container 47 in order to accelerate | stimulate the drop-off | omission of the scale from an electrode surface during scale removal operation or after scale removal operation. preferable. As for the scale of the electrode surface, the adhesion force to the electrode surface is considerably reduced by energizing the electrode pair 49 in the scale removal operation. Therefore, the external force resulting from the movement of water is applied to the scale, thereby facilitating the scale from falling off the electrode surface.

  Further, as in Modification 2, the control unit 32 may perform control for directly or indirectly transmitting vibration to the scale by the vibration applying unit 61 during or after the scale removal operation. As for the scale on the surface of the electrode, the adhesion force to the electrode surface is considerably reduced by energizing the electrode pair 49 in the scale removal operation. Accordingly, the vibration is directly or indirectly transmitted to the scale by the vibration applying means 61, thereby facilitating the removal of the scale from the electrode surface.

  Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the spirit of the present invention.

  In the above embodiment, the case where the plurality of electrodes 51 and 52 form a meandering flow path that meanders in the vertical direction in the container 47 is exemplified, but the present invention is not limited to this. For example, the form which forms the meandering flow path in which the some electrodes 51 and 52 meander in other directions, such as a horizontal direction, in the container 47 may be sufficient. In order to obtain a meandering flow path meandering in the horizontal direction, for example, in the electrolysis apparatus 41 shown in FIGS. 3A and 3B, the fifth wall portion 475 is located below and the sixth wall portion 476 is located above. What is necessary is just to arrange | position so that it may be located in.

  In the said embodiment, the case where the electrolyzer 41 is provided in the inflow piping 27 located downstream from the pump 31 and upstream from the water heat exchanger 21 in the water flow path of the heat pump water heater 11 is given as an example. However, the present invention is not limited to this. The electrolyzer 41 may be provided upstream of the water heat exchanger 21 in the water flow path. Specifically, the electrolyzer 41 may be provided, for example, in the incoming water pipe 27 upstream of the pump 31, or may be provided in the water supply pipe 37 that supplies water to the tank 15 from the water supply source. Good.

  In the embodiment, the case where the container 47 has a substantially rectangular parallelepiped shape has been described as an example. However, the present invention is not limited to this. The container 47 may have a prismatic shape other than a rectangular parallelepiped or a cylindrical shape.

  Moreover, in the said embodiment, although the transient hot water heater was mentioned as an example and demonstrated, it is not limited to this. The present invention can also be applied to, for example, a water heater of a type in which a part of water (hot water) supplied from the hot water supply pipe 35 is returned to the tank 15 again.

  Moreover, in the said embodiment, although the case where the temperature control water supply machine was the heat pump water heater 11 was illustrated, it is not limited to this. As a temperature control water supply machine, it is applicable also to the other use which needs to remove a scale component, for example, a heat pump hot water heater, a combustion type hot water heater, an electric water heater, a cooling tower, etc.

  In the heat pump hot water heater, for example, in the configuration diagram shown in FIG. 1, high-temperature water stored in the tank 15 is used for heating and the like.

  As shown in FIG. 9, the combustion water heater includes an electrolyzer 41 and a water heat exchanger 21 </ b> A provided on the downstream side of the electrolyzer 41. In the combustion type water heater, water is heated using thermal energy obtained by burning fuel gas or the like in the water heat exchanger 21A.

  Further, as shown in FIG. 9, the electric water heater includes an electrolysis device 41 and a water heat exchanger 21 </ b> A provided on the downstream side of the electrolysis device 41. In the electric water heater, water is heated using electric energy in the water heat exchanger 21A.

  For example, as shown in FIG. 9, the cooling tower includes an electrolyzer 41 and a water heat exchanger 21 </ b> A provided on the downstream side of the electrolyzer 41. In the cooling tower, water is heated in the water heat exchanger 21A by exchanging heat generated by other devices with a fluid that has been conveyed.

DESCRIPTION OF SYMBOLS 11 Heat pump water heater 21 Water heat exchanger 33 Control part 41 Electrolyzer 47 Container 49 Electrode pair 51,52 Electrode 53 Power supply 61 Vibration imparting means 63 Inversion mechanism

Claims (5)

A water heat exchanger (21) for heating the water;
An electrolysis apparatus (5) having a container (47) and an electrode pair (49) provided in the container (47), for removing scale components contained in water sent to the hydrothermal exchanger (21) 41),
A control unit (32),
The control unit (32)
A normal operation of energizing the electrode pair (49) to deposit a scale component contained in water;
The polarity removal operation of reversing the polarity of the electrode pair (49) from the normal operation state and energizing the electrode pair (49) for a predetermined time with a current value higher than the current value during the normal operation is performed. Temperature control water supply machine.   The temperature-controlled water supply device according to claim 1, wherein the current value during the scale removal operation is a value within a range of 2 to 20 times the current value during the normal operation.   The temperature-controlled water supply machine according to claim 1 or 2, wherein the predetermined time is 60 seconds or less.   The said control part (32) performs control which forms the flow of water in the said container (47) in order to accelerate | stimulate the drop-off | omission of the scale from the said surface during the said scale removal operation | movement or after a scale removal operation | movement. Item 4. The temperature-controlled water supply device according to any one of items 1 to 3. The electrolyzer (41) further includes vibration imparting means (61) for promoting the removal of the scale from the surface,
The said control part (32) performs control which transmits a vibration to the said scale directly or indirectly by the said vibration provision means (61) during the said scale removal driving | operation or after a scale removal driving | operation. The temperature-controlled water supply machine according to claim 1.