Hot water supply device, hot water supply method, and water treatment device

Abstract

The present invention provides a hot water supply device including a water purification filter that purifies raw water, a heating unit into which purified water filtered by the water purification filter flows and heats the purified water to a first preheating temperature to produce preheated water, or generates hot water by heating one of stockpiled water, which is a stored state of purified water or preheated water, to a target temperature higher than the first preheating temperature, a preheating tank in which the preheated water is stored as stockpiled water, a flow path switching unit that switches the direction of the flow path between the heating unit and the preheating tank, and a control unit that controls the heating unit and the flow path switching unit.

Description

[Technical field]

[0001] The present invention relates to a hot water supplying device, its control method, and water treatment device, and in particular to a hot water supplying device, its control method, and water treatment device that heats purified water to a first preheating temperature and stores it, and then heats the stockpiled water stored at the first preheating temperature to a target temperature when hot water is discharged, thereby reducing the heating time when hot water is discharged due to the stockpiled water that has been preheated and stored, enabling efficient use of electricity, and increasing the amount of hot water, thereby providing an abundant supply of hot water at the temperature desired by the user. [Background technology]

[0002] Generally, a water purifier removes contaminants from raw water through a water purification filter to produce purified water. In particular, in the case of a direct water type water purifier that does not have a buffer tank, such a water purifier is equipped with an instantaneous heating module to supply hot water. The instantaneous heating module controls the heating temperature according to the flow rate of the supplied purified water and the applied power. That is, in order to increase the heating temperature, the power must be increased or the flow rate of the purified water must be reduced. At this time, since the power is set within a certain range for each device, the temperature control of the direct water type water purifier is largely dependent on the flow rate of the purified water. Therefore, in general, the flow rate of the purified water flowing into the instantaneous heating module is reduced to heat the purified water to a target temperature. However, this leads to a decrease in the amount of hot water output, causing customer dissatisfaction.

[0003] A hybrid instant hot water device including a preheating heater disclosed in Japanese Patent Publication No. 2020-026943 by Water Stand Co., Ltd. supplies hot water of 90°C or higher by selectively driving multiple heaters to additionally heat preheated water. This allows hot water of 90°C or higher to be supplied sufficiently and quickly, reducing the power required for heating and allowing stable operation. However, this requires the provision of an additional heater for preheating, which not only increases manufacturing costs but also increases the overall size of the hot water device and complicates the structure. Summary of the Invention [Problem to be solved by the invention]

[0004] In order to solve the problems of the prior art as described above, the hot water supply device, its control method, and water treatment device according to the present invention heat purified water to a first preheating temperature and store it, and then heat the stockpiled water stored at the first preheating temperature to a target temperature when hot water is discharged. By doing so, the heating time when hot water is discharged is reduced by the stockpiled water that has been preheated, allowing efficient use of electricity, and the amount of hot water is increased, thereby providing an abundant supply of hot water at the temperature desired by the user.

[0005] The hot water supply device, its control method, and water treatment device according to the embodiments of the present invention aim to miniaturize the entire device and reduce manufacturing costs by generating hot water using a built-in heating unit without a separate pre-heater to prevent a decrease in the hot water flow rate.

[0006] The hot water supply device, its control method, and water treatment device according to the embodiments of the present invention are capable of maintaining the temperature of the stored water at a constant temperature by detecting a drop in the temperature of the stored water, discharging the stored water, heating purified water, and re-storing the stored water heated to the first pre-heating temperature, thereby increasing the amount of hot water output and improving user satisfaction.

[0007] The hot water supply device, its control method, and water treatment device of the embodiments of the present invention are equipped with a temperature sensor that detects the temperature of the stored water, thereby enabling immediate response to changes in the temperature of the stored water, and therefore aims to ensure the reliability of the temperature of the stored water.

[0008] The hot water supply device, its control method, and water treatment device of the embodiments of the present invention aim to improve power efficiency by maintaining a constant amount of power required to heat to a target temperature in the heating section by repeatedly discharging and re-storing stored water at regular time intervals.

[0009] The hot water supply device, its control method, and water treatment device according to the embodiments of the present invention are provided with a heater that heats a preheating tank to maintain the stored water at a first preheating temperature, thereby eliminating the process of discharging and re-storing the stored water, thereby reducing unnecessary consumption of raw water and efficiently using resources.

[0010] The hot water supply device, its control method, and water treatment device according to the embodiments of the present invention aim to reduce power consumption by minimizing reheating of the heating unit for replenishing the stockpile water by equipping the preheating tank with a heat-insulating material or by placing heat-insulating material around the outer periphery of the preheating tank.

[0011] The hot water supply device, its control method, and water treatment device of the embodiments of the present invention aim to automate the mode-specific flow path configuration by controlling the flow path switching unit and the heating unit to switch the flow path depending on the preheating mode and the hot water discharge mode.

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

[0013] In order to solve the above problems, the hot water supply device of the present invention includes a water purification filter that purifies raw water; a heating unit into which purified water filtered by the water purification filter flows and heats the purified water to a first preheating temperature to generate preheated water, or heats one of the reserve water, which is a storage state of the purified water or the preheated water, to a target temperature higher than the first preheating temperature to generate hot water; a preheating tank in which the preheated water is stored as the reserve water; a flow path switching unit that switches the direction of a flow path between the heating unit and the preheating tank; and a control unit that controls the heating unit and the flow path switching unit, wherein the control unit controls the heating unit in a preheating mode to heat the purified water flowing into the heating unit from the water purification filter to the first preheating temperature to generate the preheated water, controls the flow path switching unit to cause the preheated water generated by the heating unit to flow into the preheating tank, and controls the flow path switching unit to cause the reserve water to flow into the heating unit in a hot water discharge mode, and controls the heating unit to heat the reserve water flowing into the heating unit from the preheating tank to the target temperature to generate the hot water.

[0014] In a hot water supply device according to an embodiment of the present invention, the device further includes a temperature sensor provided in the pre-heating tank for detecting a temperature of the reserve water, and when the temperature of the reserve water is equal to or lower than a first pre-heating temperature, the control unit controls the heating unit to heat the purified water to the first pre-heating temperature to generate the pre-heated water, and controls the flow path switching unit so that the pre-heated water generated by the heating unit flows into the pre-heating tank and the reserve water stored in the pre-heating tank is discharged to the outside.

[0015] In a hot water supply device according to an embodiment of the present invention, the control unit controls the heating unit to heat the purified water to the first preheating temperature at preset time intervals to generate the preheated water, and controls the flow path switching unit so that the preheated water generated by the heating unit flows into the preheating tank and the reserve water stored in the preheating tank is discharged to the outside.

[0016] In the hot water supply device according to an embodiment of the present invention, the device further includes a heater provided along an outer periphery of the pre-heating tank, and the control unit controls the heater to heat the pre-heating tank so that the stored water maintains the first pre-heating temperature.

[0017] In a hot water supply device according to an embodiment of the present invention, the control unit is characterized in that it controls the heater to heat the preheating tank at regular time intervals or to heat the stored water when the temperature of the stored water is lower than the first preheating temperature.

[0018] In the hot water supply device according to the embodiment of the present invention, the pre-heating tank is made of a heat-insulating material or has a heat-insulating case disposed around its outer periphery.

[0019] In a hot water supply device according to an embodiment of the present invention, the preheating tank is provided with a first opening and a second opening at an upper end thereof, and the second opening is provided with a capillary tube extending to the bottom side of the preheating tank.

[0020] In a hot water supply device according to an embodiment of the present invention, the control unit controls the flow path switching unit so that in the preheating mode, the preheated water flows into the preheating tank through the first opening and the stored water is discharged to the outside through the capillary tube and the second opening, and in the hot water discharge mode, the control unit controls the flow path switching unit so that the purified water flows into the preheating tank through the capillary tube and the second opening and the stored water is discharged to the heating unit side through the first opening.

[0021] In a hot water supply device according to an embodiment of the present invention, the flow path switching unit includes a first valve disposed on a first flow path from the water purification filter side toward the heating unit and opening and closing the first flow path so that the purified water flows into the heating unit; a second valve disposed on an input side of the heating unit and opening and closing a second flow path branched off from the first flow path so that one of the purified water or the reserve water flows into the heating unit; a third valve disposed on a third flow path from an output side of the heating unit toward the pre-heating tank and opening and closing the third flow path so that the pre-heated water flows into the pre-heating tank; and a fourth valve disposed on a fourth flow path branched off from the third flow path and connected to the second flow path so that the purified water or the reserve water flows from the pre-heating tank to the pre-heating tank. the pre-heating tank includes a fourth valve that opens and closes the fourth flow path so that one of the waters flows into the heating unit; a fifth valve that is disposed on a fifth flow path toward a drain valve for discharging the stored water from the pre-heating tank to the outside and opens and closes the fifth flow path so that the stored water is discharged to the drain valve; a sixth valve that is disposed on a sixth flow path from the water purification filter side to the pre-heating tank and opens and closes the sixth flow path so that the purified water flows into the pre-heating tank; and an eighth valve that is disposed on an eighth flow path from the output side of the heating unit to an extraction valve for extracting one of the hot water or the purified water and opens and closes the eighth flow path so that the hot water is extracted to the extraction valve.

[0022] In the hot water supply device according to an embodiment of the present invention, the flow path switching unit is characterized in that it further includes a 9th valve arranged on a 9th flow path branched from the first flow path toward the extraction valve and configured to open and close the 9th flow path so that the purified water is extracted to the extraction valve.

[0023] The hot water supply device according to the embodiment of the present invention further includes a seventh flow path connecting the pre-heating tank to a branch point of the third flow path and the fourth flow path.

[0024] The water treatment device according to the present invention includes a hot water supply device as described above; and a housing in which the hot water supply device is built-in, and the preheating tank is provided at a plurality of positions where moisture is generated within the housing.

[0025] In a water treatment device according to an embodiment of the present invention, the pre-heating tank is made of a thermally conductive material, and the control unit controls the heating unit to heat the purified water to a second pre-heating temperature higher than the first pre-heating temperature in order to remove moisture generated in the vicinity of the pre-heating tank due to heat emitted from the pre-heating tank.

[0026] In a water treatment device according to an embodiment of the present invention, the control unit controls the heating unit to heat the purified water to the second preheating temperature to generate the preheated water when the temperature of the reserve water stored in any one of the plurality of preheating tanks is lower than the first preheating temperature, and controls the flow path switching unit so that the preheated water generated by the heating unit flows into the corresponding preheating tank and the reserve water stored in the corresponding preheating tank is discharged to the outside.

[0027] The hot water supply method of the present invention is characterized by including a step of supplying purified water filtered by a water purification filter to a heating unit by a flow path switching unit; a step of heating the purified water to a first preheating temperature by the heating unit to generate preheated water; a step of supplying the generated preheated water to a preheating tank by the flow path switching unit; a step of storing the preheated water as reserve water by the preheating tank; a step of determining by a control unit whether hot water outlet is input; a step of supplying the reserve water to the heating unit by the flow path switching unit when hot water outlet is input; a step of heating the reserve water to a target temperature by the heating unit to generate hot water; and a step of discharging the generated hot water to an extraction valve by the flow path switching unit.

[0028] In a hot water supply method according to an embodiment of the present invention, the storing step further includes a step of determining by the control unit whether the temperature of the stockpiled water is below a first pre-heating temperature or a predetermined time has elapsed; if the determination result indicates that the temperature of the stockpiled water is below the first pre-heating temperature or a predetermined time has elapsed, a step of heating the purified water to the first pre-heating temperature by the heating unit to regenerate the pre-heated water; a step of re-supplying the regenerated pre-heated water to the pre-heating tank by the flow path switching unit; and a step of discharging the stockpiled water stored in the pre-heating tank to the outside by the flow path switching unit.

[0029] In the hot water supply method according to an embodiment of the present invention, the storing step further includes a step of heating the pre-heating tank by a heater provided along an outer periphery of the pre-heating tank so that the stored water maintains the first pre-heating temperature. Effect of the Invention

[0030] The hot water supply device, its control method, and water treatment device of the present invention heat purified water to a first preheating temperature and store it, and then heat the stockpiled water stored at the first preheating temperature to a target temperature when hot water is discharged.By doing so, the preheated and stored stockpiled water reduces the heating time when hot water is discharged, allowing for efficient use of electricity, and increases the amount of hot water, thereby providing an abundant supply of hot water at the temperature desired by the user.

[0031] The hot water supply device, its control method, and water treatment device according to the embodiments of the present invention generate hot water using a built-in heating unit without a separate pre-heater to prevent a decrease in the hot water flow rate, thereby providing the effect of miniaturizing the entire device and reducing manufacturing costs.

[0032] The hot water supply device, its control method, and water treatment device according to the embodiments of the present invention can maintain the temperature of the stored water at a constant temperature by detecting a drop in the temperature of the stored water, discharging the stored water, heating purified water, and re-storing the stored water heated to the first pre-heating temperature, thereby increasing the amount of hot water output and improving user satisfaction.

[0033] The hot water supply device, its control method, and water treatment device according to the embodiments of the present invention are equipped with a temperature sensor that detects the temperature of the stored water, thereby enabling immediate response to changes in the temperature of the stored water, thereby providing the effect of ensuring the reliability of the temperature of the stored water.

[0034] The hot water supply device, its control method, and water treatment device according to the embodiments of the present invention provide the effect of improving power efficiency by repeatedly discharging and re-storing stored water at regular time intervals, thereby maintaining a constant amount of power required to heat the heating section to a target temperature.

[0035] The hot water supply device, its control method, and water treatment device according to the embodiments of the present invention are provided with a heater that heats a preheating tank to maintain the stored water at a first preheating temperature, thereby eliminating the need to discharge and re-store the stored water and reducing unnecessary consumption of raw water, thereby providing the effect of using resources efficiently.

[0036] The hot water supply device, its control method, and water treatment device according to the embodiments of the present invention provide an effect of minimizing reheating of the heating unit for replenishing the reserve water and reducing power consumption by equipping the preheating tank with a heat insulating material or by placing heat insulating material around the outer periphery of the preheating tank.

[0037] The hot water supply device, its control method, and water treatment device according to the embodiments of the present invention provide the effect of automating the flow path configuration for each mode by controlling the flow path switching unit and the heating unit to switch the flow path depending on the preheating mode and the hot water discharge mode. [Brief description of the drawings]

[0038] [Figure 1]1 is a configuration diagram of a hot water supply device according to a first embodiment of the present invention. [Diagram 2] FIG. 4 is a cross-sectional view of a first modified example of the preheating tank of the hot water supply apparatus according to the first embodiment of the present invention. [Diagram 3] FIG. 4 is a cross-sectional view of a second modified example of the preheating tank of the hot water supply apparatus according to the first embodiment of the present invention. [Figure 4] 1 is a block diagram of a hot water supply device according to a first embodiment of the present invention. [Diagram 5] 3 is a flowchart of a hot water supply method according to a first embodiment of the present invention. [Figure 6] 4 is a flowchart of a reserve water storage procedure in the hot water supply method according to the first embodiment of the present invention. [Figure 7] FIG. 2 is a diagram showing a flow path configuration in a preheating mode of the hot water supply method according to the first embodiment of the present invention. [Figure 8] 1 is a configuration diagram showing a flow path configuration in a hot water discharge mode of a hot water supply method according to a first embodiment of the present invention. FIG. [Figure 9] FIG. 11 is a configuration diagram of a water treatment device according to a second embodiment of the present invention. [Figure 10] FIG. 5 is a block diagram of a water treatment device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may be embodied in various different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts that are not related to the description are omitted, and the same reference numerals are used throughout the specification to refer to the same or similar components.

[0040] The embodiments of the present invention are provided to more completely explain the present invention to those having ordinary skill in the art, and the embodiments described below may be modified into various other forms, and the scope of the present invention is not limited to the following embodiments. Rather, these embodiments are provided to more faithfully and completely explain the present invention and to fully convey the idea of ​​the present invention to those skilled in the art.

[0041] Hereinafter, embodiments of the present invention will be described with reference to the drawings, which are schematic illustrations of embodiments of the present invention. In the drawings, for example, variations in the shapes shown may be expected due to manufacturing techniques and / or tolerances. Thus, embodiments of the present invention should not be construed as being limited to the specific shapes of regions illustrated herein, but should include variations in shapes that occur during manufacturing, for example.

[0042] FIG. 1 is a configuration diagram of a hot water supplying apparatus according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of a first modified example of a preheating tank of the hot water supplying apparatus according to the first embodiment of the present invention, and FIG. 3 is a cross-sectional view of a second modified example of the preheating tank of the hot water supplying apparatus according to the first embodiment of the present invention.

[0043] Referring to FIG. 1, a hot water supplying device 100 according to a first embodiment of the present invention may include water purification filters 111-113, a preheating tank 120, a temperature sensor 130, a heating unit 140, and valves V1-V10.

[0044] The hot water supplying device 100 according to the first embodiment is a device for generating hot water by heating purified water or raw water to a target temperature, and may be a water purifier, but is not limited thereto. In addition, the hot water supplying device 100 is not particularly limited to a direct water type or a tank type.

[0045] The water purification filters 111 to 113 may generate purified water by filtering raw water supplied from the outside. The first filter 111 may be a pre-treatment filter that removes organic compounds and residual chlorine contained in the raw water. The second filter 112 may be a filtration filter that filters the raw water using a reverse osmosis (RO) method or the like. The third filter 113 may be a post-treatment filter that removes gas, odor, residual chlorine, and the like.

[0046] The preheating tank 120 may have a first opening 121a and a second opening 121b at an upper end thereof, the first opening 121a may be connected to a seventh flow path L7, and the second opening 121b may be connected to a fifth branch point J5. Here, the fifth branch point J5 may be branched into a fifth flow path L5 and a sixth flow path L6, and the seventh flow path L7 may be connected between the first opening 121a and the fourth branch point J4. At this time, the second opening 121b may be provided with a capillary tube 122 extending to the bottom side of the preheating tank 120.

[0047] In the preheating mode, the preheated water heated by the heating unit 140 can flow into the first opening 121a through the third flow path L3 and the seventh flow path L7. Here, the preheated water can be stored as reserve water in the preheating tank 120. The third flow path L3 can connect between the sixth branch point J6 and the fourth branch point J4.

[0048] In addition, in the hot water discharge mode, the pre-heating tank 120 can receive purified water filtered by the water purification filters 111-113. At this time, the purified water flowing into the pre-heating tank 120 can flow into the lower side of the pre-heating tank 120 through the capillary tube 122. Here, the temperature of the purified water flowing into the pre-heating tank 120 can increase due to the heat of the reserved water or the internal heat of the pre-heating tank 120. In addition, since the purified water flows into the lower side of the pre-heating tank 120, the reserved water stored in the pre-heating tank 120 has a higher temperature than the purified water flowing into the pre-heating tank 120, and therefore can be discharged to the seventh flow path L7 through the first opening 121a.

[0049] Referring to FIG. 2, the preheat tank 120 ’The pre-heating tank 120 may further include a heater 124 provided along the outer periphery. As an example, the heater 124 may be a coil wound around the outer periphery of the pre-heating tank 120, but is not limited thereto. ’ is made of a thermally conductive material and can transfer heat transferred from the heater 124 to the reserved water stored in the pre-heating tank 120. Therefore, the reserved water can be maintained at a constant temperature.

[0050] As a result, the hot water supply device 100 according to an embodiment of the present invention maintains the stored water at a constant temperature, eliminating the need to discharge and re-store the stored water in order to maintain the stored water at a constant temperature, thereby reducing unnecessary consumption of raw water and enabling efficient use of resources.

[0051] Referring to FIG. 3, the preheat tank 120 ” A thermal insulation case 126 may be disposed around the outer periphery of the preheating tank 120. ” In this case, the pre-heating tank 120 can prevent the heat of the water stored therein from being released to the outside.

[0052] Therefore, the hot water supply device 100 according to the embodiment of the present invention can minimize reheating of the heating unit 140 for replenishing the reserved water, thereby reducing power consumption.

[0053] 1 again, the temperature sensor 130 may be provided in the pre-heating tank 120 to sense the temperature of the stored water. As an example, the temperature sensor 130 may be provided at the top of the pre-heating tank 120, but is not particularly limited to this location.

[0054] The heating unit 140 may have an input end connected to the second flow path L2 and an output end connected to the sixth branch point J6. Here, the second flow path L2 may connect between the third branch point J3 and the heating unit 140. The sixth branch point J6 may branch into the third flow path L3 and the eighth flow path L8.

[0055] In the preheating mode, the heating unit 140 may receive purified water filtered by the water purification filters 111 to 113, and heat the purified water to a first preheating temperature to generate preheated water. In the hot water outlet mode, the heating unit 140 may heat the reserve water stored in the preheating tank 120 to a target temperature to generate hot water. Here, the target temperature may be a hot water outlet temperature and may be higher than the first preheating temperature. In this case, the heating unit 140 may generate hot water by heating the purified water that is refilled in the preheating tank 120 and then flows in from the preheating tank 120 to the target temperature. That is, the heating unit 140 may first heat the reserve water stored in the preheating tank 120, and then heat the purified water that flows in via the preheating tank 120.

[0056] As a result, the hot water supplying apparatus 100 according to the embodiment of the present invention does not require a separate pre-heater to prevent a decrease in the flow rate of hot water, so that the hot water supplying apparatus 100 as a whole can be made smaller and manufacturing costs can be reduced.

[0057] Here, the heating unit 140 and the valves V1 to V10 can be controlled by a control unit 180 as described later.

[0058] The first valve V1 is disposed on the first flow path L1 from the water purification filters 111-113 side toward the heating unit 140, and can open and close the first flow path L1 so that purified water discharged from the water purification filters 111-113 flows into the heating unit 140. Here, the first flow path L1 can connect between the first branch point J1 and the second branch point J2. At this time, the first valve V1 can be provided on one side of the first branch point J1. Here, the first branch point J1 can branch into the first flow path L1 and the sixth flow path L6. The second branch point J2 can branch into the first flow path L1 and the ninth flow path L9.

[0059] The second valve V2 is disposed on the input side of the heating unit 140 on the second flow path L2 and may open or close the second flow path L2 so that one of the purified water or the reserved water flows into the heating unit 140 via the third branch point J3. Here, the third branch point J3 may branch into the second flow path L2 and a fourth flow path L4. The second valve V2 may be a flow rate control valve.

[0060] The third valve V3 is disposed on the third flow path L3 extending from the output side of the heating unit 140 toward the preheating tank 120, and can open and close the third flow path L3 so that the preheated water heated by the heating unit 140 flows into the preheating tank 120 via the fourth branch point J4. Here, the fourth branch point J4 can be branched into a seventh flow path L7 and a fourth flow path L4.

[0061] The fourth valve V4 is disposed on a fourth flow path L4 extending from the pre-heating tank 120 toward the heating unit 140, and can open and close the fourth flow path L4 so that one of the purified water or the reserved water flows from the pre-heating tank 120 into the heating unit 140. Here, the fourth flow path L4 can connect between the fourth branch point J4 and the third branch point J3.

[0062] The fifth valve V5 is disposed on a fifth flow path L5 leading to a seventh valve V7 for discharging the stored water from the pre-heating tank 120 to the outside, and can open and close the fifth flow path L5 so that the stored water is discharged to the seventh valve V7 via a seventh branch point J7. Here, the fifth flow path L5 can connect between the fifth valve V5 and the seventh branch point J7, and the seventh branch point J7 can branch into the fifth flow path L5 and an eighth flow path L8.

[0063] The sixth valve V6 is disposed on a sixth flow path L6 extending from the water purification filters 111-113 side toward the pre-heating tank 120, and can open and close the sixth flow path L6 so that purified water flows into the pre-heating tank 120 via the first branch point J1. Here, the sixth flow path L6 can connect between the first branch point J1 and the fifth branch point J5.

[0064] The seventh valve V7 is disposed on one side of the eighth branch point J8 and can be opened and closed to discharge hot water through the eighth flow path L8, discharge purified water through the ninth flow path L9, or discharge reserved water through the fifth flow path L5. The seventh valve V7 can be a drain valve. The eighth branch point J8 can be branched into the ninth flow path L9 and the tenth flow path L10. The tenth flow path L10 can be connected between the seventh branch point J7 and the eighth branch point J8.

[0065] The eighth valve V8 is disposed on an eighth flow path L8 leading to a tenth valve V10 for extracting one of hot water or purified water from an output side of the heating unit 140, and may open or close the eighth flow path L8 so that hot water is extracted to the tenth valve V10. The eighth flow path L8 may connect between the eighth valve V8 and the seventh branch point J7.

[0066] The ninth valve V9 is disposed on the ninth flow path L9 branched from the first flow path L1 by the second branch point J2 toward the tenth valve V10, and can open and close the ninth flow path L9 so that purified water is extracted to the tenth valve V10. Here, the ninth flow path L9 can be connected between the second branch point J2 and the eighth branch point J8. The ninth valve V9 can be a purified water valve.

[0067] The tenth valve V10 is disposed on one side of the eighth branch point J8 and can be opened and closed to extract hot water through the eighth flow path L8 or purified water through the ninth flow path L9. The tenth valve V10 may be an extraction valve.

[0068] FIG. 4 is a block diagram of the hot water supply device according to the first embodiment of the present invention.

[0069] Referring to FIG. 4, the hot water supplying device 100 according to the first embodiment may further include a flow path switching unit 150, a timer 170 and a control unit 180.

[0070] Here, the heater 160 may be the heater 124 installed around the outer periphery of the preheating tank 120 as shown in FIG.

[0071] The flow path switching unit 150 is for switching the direction of the flow path between the heating unit 140 and the pre-heating tank 120, and may include valves V1 to V10 as shown in FIG. 1. The flow path switching unit 150 may be controlled by the control unit 180 to form one of paths for purified water, pre-heated water, or reserved water according to the operation mode. Here, in the pre-heating mode, the first valve V1 to the third valve V3 may be opened, and the fourth valve V4 to the tenth valve V10 may be closed. At this time, when the reserved water is discharged, the fifth valve V5 and the seventh valve V7 may be opened, and the first valve V1 to the fourth valve V4, the sixth valve V6, and the eighth valve V8 to the tenth valve V10 may be closed. In the hot water discharge mode, the sixth valve V6, the fourth valve V4, the second valve V2, the eighth valve V8 and the tenth valve V10 may be opened, and the first valve V1, the third valve V3, the fifth valve V5, the seventh valve V7 and the ninth valve V9 may be closed. In addition, in the purified water discharge mode, the first valve V1, the ninth valve V9 and the tenth valve V10 may be opened, and the second valve V2 to the eighth valve V8 may be closed.

[0072] As a result, the hot water supply device 100 according to the embodiment of the present invention can automate the configuration of flow paths for preheating purified water and generating hot water using stored water.

[0073] The timer 170 can provide time information for re-storing the reserved water in the pre-heating tank 120 or for heating the pre-heating tank 120. As an example, the timer 170 is built into the control unit 180 and can count the time set by the control unit 180.

[0074] The control unit 180 may be configured to control the operations of the temperature sensor 130, the heating unit 140, and the valves V1 to V10. Here, the operation of the temperature sensor 130 means being input to the control unit 180. The operation of the heating unit 140 means being driven by the control unit 180. The operation of the valves V1 to V10 means being opened and closed by the control unit 180. The control unit 180 may be a microprocessor built into the hot water supply device 100.

[0075] In the preheating mode, the control unit 180 can control the heating unit 140 to generate preheated water by heating the purified water flowing from the water purification filters 111-113 to the heating unit 140 to a first preheating temperature. At this time, the control unit 180 can control the flow path switching unit 150 so that the purified water discharged from the water purification filters 111-113 flows into the heating unit 140 and the preheated water generated by the heating unit 140 flows into the preheating tank 120. Here, the first preheating temperature is a stage prior to hot water discharge and may be lower than the hot water target temperature.

[0076] In the hot water discharge mode, the control unit 180 may control the heating unit 140 to generate hot water by heating the reserved water flowing from the pre-heating tank 120 to the heating unit 140 to a target temperature. In this case, the control unit 180 may control the flow path switching unit 150 so that the reserved water flows from the pre-heating tank 120 to the heating unit 140 and the hot water generated in the heating unit 140 is discharged through the eighth flow path L8 and the tenth valve V10. As an example, the target temperature may be 90° C. or higher.

[0077] As a result, the hot water supply device 100 according to an embodiment of the present invention uses stored water preheated to a first preheat temperature when heating to supply hot water. As a result, the preheated and stored stored water reduces the heating time when supplying hot water, allowing for efficient use of electricity, and increases the amount of hot water, allowing for abundant supply of hot water at the temperature desired by the user.

[0078] The control unit 180 can control the pre-stored water to be re-stored depending on whether or not there is a drop in the temperature of the pre-stored water stored in the pre-heating tank 120. Here, re-storing the pre-stored water means storing new pre-heated water in the pre-heating tank 120 as the pre-stored water and discharging the pre-stored water stored in the pre-heating tank 120 to the outside.

[0079] As a result, the hot water supply device 100 according to the embodiment of the present invention can maintain the temperature of the reserve water stored in the pre-heating tank 120 at a constant temperature, so there is no need to reduce the flow rate in the heating section 140 when generating hot water, and therefore the amount of hot water output can be increased, improving user satisfaction.

[0080] As an example, the control unit 180 may control the reserve water to be re-stored when the temperature of the reserve water is equal to or lower than the first pre-heating temperature. That is, the control unit 180 may control the heating unit 140 to heat the purified water discharged from the water purification filters 111-113 to the first pre-heating temperature to regenerate pre-heated water when the temperature of the reserve water sensed by the temperature sensor 130 is equal to or lower than the first pre-heating temperature. At this time, the control unit 180 may control the flow path switching unit 150 so that the purified water discharged from the water purification filters 111-113 flows into the heating unit 140, the pre-heated water generated by the heating unit 140 flows into the pre-heating tank 120 as reserve water, and the reserve water previously stored due to the inflow of new pre-heated water is discharged to the outside from the pre-heating tank 120.

[0081] As a result, the hot water supply device 100 according to the embodiment of the present invention can immediately respond to changes in the temperature of the stored water, thereby ensuring the reliability of the temperature of the stored water, and therefore ensuring the reliability of preventing a reduction in the amount of hot water output.

[0082] As another example, the control unit 180 may control the reserve water to be re-stored at every preset time. That is, the control unit 180 may control the heating unit 140 to heat the purified water discharged from the water purification filters 111-113 to the first pre-heating temperature to regenerate pre-heated water when the time preset in the timer 170 has elapsed. At this time, the control unit 180 may control the flow path switching unit 150 so that the purified water discharged from the water purification filters 111-113 flows into the heating unit 140, the pre-heated water generated by the heating unit 140 flows into the pre-heating tank 120 as reserve water, and the reserve water stored in the pre-heating tank 120 is discharged to the outside.

[0083] As a result, the hot water supply device 100 according to an embodiment of the present invention can improve power efficiency by maintaining a constant amount of power required to heat the stored water to a target temperature in the heating unit 140 without using additional power due to a decrease in the temperature of the stored water.

[0084] At this time, the control unit 180 can control the flow path switching unit 150 to configure a flow path for reserved water, preheated water, or purified water for the preheating tank 120 according to the operation mode.

[0085] For example, in the preheating mode, the control unit 180 may control the flow path switching unit 150 so that the preheated water heated by the heating unit 140 flows into the preheating tank 120 through the first opening 121a. Here, in the case of re-storing the stored water, the control unit 180 may control the flow path switching unit 150 so that the stored water below the first preheating temperature is discharged to the outside through the capillary tube 122 and the second opening 121b of the preheating tank 120.

[0086] In the hot water discharge mode, the control unit 180 can control the flow path switching unit 150 so that the reserve water stored in the pre-heating tank 120 is discharged to the heating unit 140 side through the first opening 121a. At this time, the control unit 180 can control the flow path switching unit 150 so that the purified water flows into the pre-heating tank 120 through the capillary tube 122 and the second opening 121b.

[0087] In the purified water discharge mode, the control unit 180 can control the flow path switching unit 150 so that the purified water filtered by the purified water filters 111 to 113 is discharged to the outside through the tenth valve V10.

[0088] Meanwhile, the control unit 180 may control the pre-heating tank 120 to maintain the first pre-heating temperature. For example, if a heater 124 is provided around the outside of the pre-heating tank 120, the control unit 180 may control the heater 124 to heat the pre-heating tank so that the reserve water stored in the pre-heating tank 120 maintains the first pre-heating temperature. In this case, the control unit 180 may control the heater 124 to heat the pre-heating tank 120 at regular time intervals, or to heat the pre-heating tank 120 when the temperature of the reserve water detected by the temperature sensor 130 is lower than the first pre-heating temperature.

[0089] The hot water supply method of the present invention will be described below with reference to Figs.

[0090] Figure 5 is a flowchart of a hot water supply method according to a first embodiment of the present invention, Figure 6 is a flowchart of a reserve water storage procedure in the hot water supply method according to the first embodiment of the present invention, Figure 7 is a configuration diagram showing the flow path configuration in the preheating mode of the hot water supply method according to the first embodiment of the present invention, and Figure 8 is a configuration diagram showing the flow path configuration in the hot water outlet mode of the hot water supply method according to the first embodiment of the present invention.

[0091] The hot water supply method 200 of the present invention can include steps of heating purified water to generate preheated water (S210 and S220), storing the preheated water as reserve water (S230 and S240), and heating the reserve water to provide hot water when hot water is discharged (S250 to S280).

[0092] 5, first, the flow path switching unit 150 supplies purified water filtered by the water purification filters 111-113 to the heating unit 140 (step S210). At this time, the flow path switching unit 150 may form the first path C1 of Fig. 7. That is, the purified water filtered by the water purification filters 111-113 may flow into the heating unit 140 through the first flow path L1 and the second flow path L2.

[0093] Next, the heating unit 140 heats the incoming purified water to a first preheating temperature to generate preheated water (step S220). Here, the first preheating temperature may be lower than a target temperature for generating hot water.

[0094] Next, the flow path switching unit 150 supplies the preheated water generated in the heating unit 140 to the preheating tank 120 (step S230). At this time, the flow path switching unit 150 can supply the preheated water to the preheating tank 120 through the first path C1 of Fig. 7. That is, the preheated water heated in the heating unit 140 can flow into the preheating tank 120 through the third flow path L3 and the seventh flow path L7.

[0095] Next, the pre-heating tank 120 stores the pre-heated water flowing from the heating unit 140 as reserve water (step S240). Here, the pre-heated water flowing into the pre-heating tank 120 may be called reserve water. At this time, as described below, the hot water supply device 100 may maintain the temperature of the reserve water stored in the pre-heating tank 120 at a first pre-heat temperature. As an example, a heater 124 provided along the outer periphery of the pre-heating tank 120 may heat the pre-heating tank 120 so that the reserve water maintains the first pre-heat temperature.

[0096] Next, the control unit 180 determines whether hot water is to be output (step S250). At this time, the control unit 180 can determine whether hot water is to be output depending on whether the tenth valve V10 is open or closed or whether hot water is selected by a selection unit (not shown). If hot water is not to be output as a result of the determination in step S250, the control unit 180 waits until hot water is output.

[0097] If it is determined in step S250 that hot water discharge is input, the flow path switching unit 150 supplies the reserved water stored in the pre-heating tank 120 to the heating unit 140 (step S260). At this time, the flow path switching unit 150 may configure the third path C3 of Fig. 8. That is, the reserved water stored in the pre-heating tank 120 may flow into the heating unit 140 through the fourth flow path L4 and the second flow path L2.

[0098] 8 so that the purified water flows into the pre-heating tank 120. That is, the purified water filtered by the water purification filters 111-113 can flow into the pre-heating tank 120 through the sixth flow path L6. Here, the purified water can flow into the lower side of the pre-heating tank 120 through the capillary tube 122 of the pre-heating tank 120. Accordingly, the reserved water, which has a higher temperature than the purified water that flows into the pre-heating tank 120, can be discharged to the seventh flow path L7 through the first opening 121a.

[0099] Next, the heating unit 140 heats the reserved water flowing from the pre-heating tank 120 to a target temperature to generate hot water (step S270). For example, the target temperature may be 90° C. or higher. At this time, when the heating of the reserved water is completed, the heating unit 140 may heat the purified water flowing from the pre-heating tank 120 in addition to the reserved water.

[0100] Next, the flow path switching unit 150 extracts the hot water by discharging the hot water generated in the heating unit 140 through the tenth valve V10 (step S280). At this time, the flow path switching unit 150 can discharge the hot water through the third path C3 of Fig. 8. That is, the hot water generated in the heating unit 140 can be extracted to the tenth valve V10 through the eighth flow path L8 and the tenth flow path L10.

[0101] Meanwhile, the reserved water storage procedure 240 of the hot water supply method of the present invention may include a step of detecting a temperature drop of the reserved water (S241) and a step of discharging and re-storing the reserved water (S243-S243).

[0102] 6, first, after pre-heated water is supplied to the pre-heating tank 120 (step S230), the control unit 180 determines whether the temperature of the reserved water stored in the pre-heating tank 120 has decreased (step S241). As an example, the control unit 180 may determine whether the temperature of the reserved water sensed by the temperature sensor 130 is equal to or lower than the first pre-heating temperature. As another example, the control unit 180 may determine whether the temperature of the reserved water has decreased depending on whether a preset time has elapsed.

[0103] If it is determined in step S241 that the temperature of the reserved water has not decreased, the control unit 180 may continuously detect whether the temperature of the reserved water has decreased. Here, if the temperature of the reserved water has not decreased, it may be that the temperature of the reserved water detected by the temperature sensor 130 exceeds the first pre-heating temperature or that a preset time has not elapsed.

[0104] If it is determined in step S241 that the temperature of the reserved water has decreased, the heating unit 140 heats the purified water to the first pre-heating temperature to regenerate pre-heated water (step S242). Here, the temperature of the reserved water may be decreased when the temperature of the reserved water sensed by the temperature sensor 130 is equal to or lower than the first pre-heating temperature, or when a preset time has elapsed.

[0105] At this time, the flow path switching unit 150 can form the first path C1 of Fig. 7. That is, purified water filtered by the water purification filters 111 to 113 can be re-supplied to the heating unit 140 through the first flow path L1 and the second flow path L2.

[0106] Next, the flow path switching unit 150 re-supplies the preheated water regenerated in the heating unit 140 to the preheating tank 120 (step S243). Here, the flow path switching unit 150 may supply the preheated water to the preheating tank 120 through the first path C1 of Fig. 7. That is, the preheated water reheated in the heating unit 140 may re-flow into the preheating tank 120 through the third path L3 and the seventh path L7.

[0107] Next, the flow path switching unit 150 discharges the reserved water stored in the pre-heating tank 120 to the outside (step S244). At this time, the flow path switching unit 150 may form the second path C2 of Fig. 7. That is, the reserved water whose temperature has been lowered by the inflow of new pre-heated water may be discharged to the seventh valve V7 through the fifth flow path L5 and the tenth flow path L10.

[0108] Next, the control unit 180 proceeds to step S250 to determine whether hot water is being discharged.

[0109] The above-mentioned method may be implemented by the hot water supplying apparatus 100 as shown in Fig. 1, and may be implemented in a software program for performing the above-mentioned steps. In this case, the program may be stored in a computer-readable recording medium or transmitted by a computer data signal combined with a carrier wave through a transmission medium or a communication network. In this case, the computer-readable recording medium may include any kind of recording device in which data readable by a computer system is stored.

[0110] FIG. 9 is a configuration diagram of a water treatment device according to a second embodiment of the present invention, and FIG. 10 is a block diagram of the water treatment device according to the second embodiment of the present invention.

[0111] 9 and 10, the water treatment device 300 according to the second embodiment may include a housing 310, a pre-heating tank 320, a temperature sensor 330, a heating unit 340, a flow path switching unit 350, a heater 360, a timer 370, and a control unit 380. Here, the water treatment device 300 according to the second embodiment includes a plurality of pre-heating tanks 320, and the configuration except for the configuration for heating purified water is the same as that of the hot water supply device 100 according to the first embodiment, so a detailed description thereof will be omitted here.

[0112] The water treatment device 300 according to the second embodiment is for removing moisture generated in the housing 310 by using heat generated in the pre-heating tank 320, and may include a plurality of pre-heating tanks 320. Here, the water treatment device 300 is not particularly limited to a water purifier.

[0113] The housing 310 may be an exterior case of the water treatment device 300. That is, the housing 310 may house the hot water supply device 100 as shown in FIG.

[0114] The pre-heating tanks 320 may be provided at a plurality of positions where moisture is generated within the housing 310. Here, the pre-heating tanks 320 may be made of a thermally conductive material so as to have an excellent heat generating function using stored water. At this time, since a plurality of pre-heating tanks 320 are provided, the pre-heating tanks 320 may have a smaller volume than the pre-heating tank 120 of Fig. 1. As an example, the pre-heating tanks 320 may be provided relatively narrow and thin depending on the positions where moisture is generated within the housing 310.

[0115] The control unit 380 can control the heating unit 340 to heat the purified water to a second pre-heating temperature higher than the first pre-heating temperature in order to remove moisture generated around the pre-heating tank 320 due to heat emitted from the pre-heating tank 320. That is, the reserved water stored in the pre-heating tank 320 must have a higher temperature than the pre-heating tank 120 of FIG. 1 in order to remove moisture from the housing 310 by emitting heat.

[0116] At this time, when the temperature of the reserved water stored in any one of the plurality of pre-heating tanks 320 is equal to or lower than the first pre-heating temperature, the control unit 380 may re-store the reserved water in the corresponding pre-heating tank 320. Here, if the temperature of the reserved water stored in the pre-heating tank 320 is equal to or lower than the first pre-heating temperature, the temperature of the reserved water stored in the pre-heating tank 320 is maintained at least at the first pre-heating temperature since the reduction in the warm water caused by heating using the reserved water cannot be sufficiently prevented. That is, the control unit 180 may control the flow path switching unit 150 so that the purified water filtered by the water purification filters 311 to 313 is re-flowed into the heating unit 340 and the reserved water stored in the pre-heating tank 320 is discharged to the outside. In addition, the control unit 180 may control the heating unit 340 so that the re-flowed purified water is heated to the second pre-heating temperature to generate pre-heated water, and may control the flow path switching unit 350 so that the pre-heated water generated by the heating unit 340 flows into the corresponding pre-heating tank 320.

[0117] As a result, the water treatment device 300 according to the embodiment of the present invention can remove moisture from the housing 310 using heat from the pre-heating tank 120 that stores reserve water without having a separate heat generating means, thereby maintaining performance and improving service life. In addition, the water treatment device 300 can increase the capacity of reserve water by including a plurality of pre-heating tanks 120, thereby more effectively preventing a decrease in hot water discharge.

[0118] [Table 1]

[0119] The above table shows the hot water output depending on the preheated water temperature measured through an experiment. In this experiment, the target water output temperature was set to 90°C, and a 2400W heater was used as the instantaneous water heater. As shown in the table, when the preheated water temperature is 20°C, the hot water output is 0.47LPM (liters per minute), but when the preheated water temperature is 60°C, the hot water output is 1.08LPM (liters per minute), which is a 2.3-fold increase in output. Therefore, by adding a preheating tank and maintaining an appropriate preheated water temperature, the hot water extraction volume can be significantly increased.

[0120] Although one embodiment of the present invention has been described above, the concept of the present invention is not limited to the embodiment presented in this specification, and a person skilled in the art who understands the concept of the present invention may easily propose other embodiments by adding, changing, deleting, or adding components within the scope of the same concept, which may also be considered to fall within the scope of the concept of the present invention. [Industrial Applicability]

[0121] The hot water supply device, the control method thereof, and the water treatment device of the present invention can be embodied in various home appliances used in homes or industrial sites and in controllers for controlling these appliances, and therefore have industrial applicability.

Claims

1. Water filters to purify raw water; a heating unit which receives purified water filtered by the water purification filter, heats the purified water to a first preheating temperature to generate preheated water, or heats one of the purified water and reserve water, which is a storage state of the preheated water, to a target temperature higher than the first preheating temperature to generate hot water; a preheating tank in which the preheated water is stored as the reserve water; A flow path switching unit that switches the direction of a flow path between the heating unit and the preheating tank; and A control unit that controls the heating unit and the flow path switching unit, The control unit is In a preheating mode, the heating unit is controlled so as to heat the purified water flowing from the water purification filter into the heating unit to the first preheating temperature to generate the preheated water, and the flow path switching unit is controlled so that the preheated water generated by the heating unit flows into the preheating tank. This hot water supply device is characterized in that, in a hot water discharge mode, the flow path switching unit is controlled so that the stored water flows into the heating unit, and the heating unit is controlled so that the stored water flowing into the heating unit from the preheating tank is heated to the target temperature to generate the hot water.

2. A temperature sensor is provided in the preheating tank to detect the temperature of the stored water; The hot water supply device described in claim 1, characterized in that when the temperature of the stored water is below a first pre-heating temperature, the control unit controls the heating unit to heat the purified water to the first pre-heating temperature to generate the pre-heated water, and controls the flow path switching unit so that the pre-heated water generated by the heating unit flows into the pre-heating tank and the stored water stored in the pre-heating tank is discharged to the outside.

3. The hot water supply device of claim 1, characterized in that the control unit controls the heating unit to heat the purified water to the first preheating temperature at predetermined time intervals to generate the preheated water, and controls the flow path switching unit so that the preheated water generated by the heating unit flows into the preheating tank and the reserve water stored in the preheating tank is discharged to the outside.

4. The preheating tank further includes a heater disposed along an outer periphery thereof, The hot water supply device according to claim 1 , wherein the control unit controls the heater to heat the preheating tank so that the stored water maintains the first preheating temperature.

5. The hot water supply device according to claim 4, wherein the control unit controls the heater to heat the preheating tank at regular time intervals or to heat the stored water when the temperature of the stored water is lower than the first preheating temperature.

6. The hot water supply device according to claim 1, wherein the preheating tank is made of a heat insulating material or has a heat insulating material disposed around its outer periphery.

7. The preheating tank has a first opening and a second opening at an upper end thereof, The hot water supply device according to claim 1 , wherein the second opening is provided with a capillary tube extending to a bottom side of the preheating tank.

8. The control unit is In the preheating mode, the flow path switching unit is controlled so that the preheated water flows into the preheating tank through the first opening and the reserved water is discharged to the outside through the capillary tube and the second opening. The hot water supply device according to claim 7, characterized in that in a heating mode, the flow path switching unit is controlled so that the purified water flows into the preheating tank through the capillary tube and the second opening, and the stored water is discharged to the heating unit side through the first opening.

9. The flow path switching unit is a first valve that is disposed on a first flow path extending from the water purification filter toward the heating unit and opens and closes the first flow path so that the purified water flows into the heating unit; a second valve disposed on an input side of the heating unit and configured to open and close a second flow path branched from the first flow path so that one of the purified water or the reserved water flows into the heating unit; a third valve disposed on a third flow path extending from the output side of the heating unit toward the preheating tank and configured to open and close the third flow path so that the preheated water flows into the preheating tank; a fourth valve disposed on a fourth flow path branched from the third flow path portion and coupled to the second flow path, and configured to open and close the fourth flow path so that one of the purified water and the reserved water from the preheating tank flows into the heating portion; a fifth valve that is disposed on a fifth flow path leading to a drain valve for discharging the stored water from the pre-heating tank to the outside and opens and closes the fifth flow path so that the stored water is discharged to the drain valve; a sixth valve that is disposed on a sixth flow path extending from the water purification filter to the pre-heating tank and opens and closes the sixth flow path so that the purified water flows into the pre-heating tank; and an eighth valve disposed on an eighth flow path from the output side of the heating unit toward an extraction valve for extracting one of the hot water or the purified water, and opening and closing the eighth flow path so that the hot water is extracted to the extraction valve.

10. The flow path switching unit is The hot water supply device according to claim 9, further comprising a ninth valve arranged on a ninth flow path branched from the first flow path toward the extraction valve, and opening and closing the ninth flow path so that the purified water is extracted to the extraction valve.

11. The hot water supply device according to claim 10, further comprising a seventh flow path connecting the preheating tank to a branch point of the third flow path and the fourth flow path.

12. A hot water supply device according to any one of claims 1 to 11; and The hot water supply device includes a housing, The water treatment device according to claim 1, wherein the preheating tank is provided at a plurality of positions where moisture is generated within the housing.

13. The preheating tank is made of a thermally conductive material, The water treatment device according to claim 12, wherein the control unit controls the heating unit to heat the purified water to a second preheating temperature higher than the first preheating temperature in order to remove moisture generated in the vicinity of the preheating tank due to heat emitted from the preheating tank.

14. The water treatment device according to claim 13, characterized in that, when the temperature of the reserve water stored in any one of the plurality of pre-heating tanks is equal to or lower than the first pre-heating temperature, the control unit controls the heating unit to heat the purified water to the second pre-heating temperature to generate the pre-heated water, and controls the flow path switching unit so that the pre-heated water generated by the heating unit flows into the corresponding pre-heating tank and the reserve water stored in the corresponding pre-heating tank is discharged to the outside.

15. supplying purified water filtered by the water purification filter to the heating unit by the flow path switching unit; heating the purified water to a first preheating temperature by a heating unit to generate preheated water; supplying the generated preheated water to a preheating tank by the flow path switching unit; storing the preheated water as reserve water by the preheating tank; and determining by the control unit whether hot water outlet is input; supplying the stored water to the heating unit by the flow path switching unit when hot water discharge is input; Heating the stored water to a target temperature by the heating unit to generate hot water; and A hot water supply method comprising the step of discharging the generated hot water to an extraction valve by the flow path switching unit.

16. The storing step includes: determining, by the control unit, whether the temperature of the stored water is equal to or lower than a first pre-heating temperature or whether a preset time has elapsed; heating the purified water to the first preheating temperature by the heating unit to regenerate the preheated water if the temperature of the reserved water is equal to or lower than a first preheating temperature or if a preset time has elapsed; re-supplying the regenerated preheated water to the preheat tank by the flow path switching unit; and The method of claim 15, further comprising discharging the reserved water stored in the pre-heating tank to the outside by the flow path switching unit.

17. The storing step includes:

16. The method of claim 15, further comprising: heating the pre-heating tank by a heater provided along an outer periphery of the pre-heating tank so that the stored water maintains the first pre-heating temperature.

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