Hot water supply apparatus and hot water control method therefor

Abstract

A hot water supply apparatus according to an embodiment of the present invention comprises: a first heat exchanger that heats hot water; a second heat exchanger generating hot water; a first temperature sensor installed on a first flow path through which the supply water supplied by the first heat exchanger flows to the second heat exchanger, and measuring a temperature of the supply water; a second temperature sensor installed on a second flow path through which return water of the supply water cooled after heat exchange with the second heat exchanger flows to the first heat exchanger, and measuring the temperature of the return water; and a controller that predicts the temperature of the supply water based on the temperature of the return water measured by the second temperature sensor, and performs hot water control based on the predicted temperature of the supply water.

Description

Technical Field

[0001] The invention relates to a hot water supply device and a hot water control method used for the device. Background Art

[0002] Generally speaking, a hot water supply device is a device that heats direct water to a predetermined temperature in a short period of time and supplies the heated direct water so that a user can conveniently use the heated direct water. Examples of the hot water supply device may include a boiler and a water heater.

[0003] For example, when a user requests hot water supply, the combination boiler may include a first stage heat exchanger that heats heating water by burning fuel through a burner, and a second stage heat exchanger that generates hot water by exchanging heat between heating water heated by the first stage heat exchanger and direct water.

[0004] In the combination boiler, the temperature of the heating water supplied from the first-stage heat exchanger may be increased according to the performance of the second-stage heat exchanger.

[0005] In this case, the temperature of the heating water is highest at the moment when the supply starts after completing the heat exchange in the first-stage heat exchanger, and when the temperature of the heating water supplied from the first-stage heat exchanger is higher than the boiling point, boiling noise may occur and the heat exchange is unstable, thereby reducing the performance and stability of the product.

[0006] In the related art, in order to solve the above problems, an overheating prevention function that limits combustion when the temperature of the heated water is higher than or equal to a specific temperature is applied. However, in this case, the satisfaction of the user receiving the hot water may be reduced due to the burning heated water.

[0007] In addition, a method of operating the boiler without shutting off the combustion by limiting the temperature of the supply water within a range where the temperature of the heating water is not higher than a specific temperature is used. However, in this method, since the temperature reaction rate of the heating water is delayed, even if the temperature of the supply water is limited, the combustion is switched to the OFF state as the temperature of the heating water increases. Summary of the invention

[0008] The present invention is made to solve the above-mentioned problems in the prior art, while the advantages achieved by the prior art are completely retained.

[0009] One aspect of the present invention provides a hot water supply device and a hot water control method for the device, which predicts the temperature of supply water as quickly as the delay time of the temperature reaction rate of heating water based on the temperature of return water, thereby being able to supply hot water without cutting off combustion even during supply water temperature limit control.

[0010] Another aspect of the present invention provides a hot water supply device and a hot water control method for the device, wherein the hot water supply device calculates correction values ​​of the amount of combustion heat and the circulation flow rate, applies the average value of the correction values, and predicts the temperature of the supply water, thereby improving the prediction accuracy of the temperature of the supply water in a steady state when combustion is performed in the hot water supply device.

[0011] The technical problems to be solved by the present invention are not limited to the aforementioned problems, and any other technical problems not mentioned herein will be clearly understood from the following description by those skilled in the art to which the present invention belongs.

[0012] According to one aspect of the present invention, there is provided a hot water supply device, which includes: a first heat exchanger that uses heat obtained by burning fuel in a burner to heat heating water; and a second heat exchanger that produces hot water by performing heat exchange between supply water supplied by the first heat exchanger and direct water, the hot water supply device includes: a first temperature sensor that is installed on a first flow path where supply water supplied by the first heat exchanger flows to the second heat exchanger, and measures the temperature of the supply water; a second temperature sensor that is installed on a second flow path where return water of the supply water cooled after heat exchange with the second heat exchanger flows to the first heat exchanger, and measures the temperature of the return water; and a controller that predicts the temperature of the supply water based on the temperature of the return water measured by the second temperature sensor, and performs hot water control based on the predicted temperature of the supply water.

[0013] In an embodiment, the controller can predict the temperature of the supply water based on the amount of combustion heat of the first heat exchanger, the circulation flow rates of the supply water and the return water flowing along the first flow path and the second flow path, and the temperature of the return water before the temperature reaction delay time until the temperature change of the return water is reflected in the temperature of the supply water.

[0014] In an embodiment, the controller may perform the supplied water temperature limit control when the predicted supplied water temperature is higher than a preset reference temperature.

[0015] In an embodiment, the controller may set a reference temperature to the temperature of the supplied water measured by the first temperature sensor when performing the supplied water temperature limit control, and perform the amount of combustion heat control operation based on the reference temperature.

[0016] In an embodiment, the hot water supply device may further include a mixing valve, which is installed on a bypass flow path connecting a third flow path in which direct water flows into the second heat exchanger and a fourth flow path in which hot water generated by the second heat exchanger is discharged, and adjusts the flow rate of the direct water to adjust the temperature of the hot water discharged through the fourth flow path.

[0017] In an embodiment, the controller may perform supply water temperature limit control when the predicted supply water temperature is higher than a preset reference temperature, and control the opening rate of the mixing valve while performing the supply water temperature limit control operation so that the temperature of the hot water is maintained at a target temperature.

[0018] In an embodiment, the controller may control the outlet temperature of the second heat exchanger to a temperature higher than the temperature of the hot water adjusted by the mixing valve when performing the supply water temperature limit control operation.

[0019] In an embodiment, the controller can calculate the amount of combustion heat of the first heat exchanger and the correction value of the circulation flow rate of the supply water and the return water flowing along the first flow path and the second flow path while the temperature of the supply water and the temperature of the return water are maintained in a constant stable state for a predetermined time while the burner performs combustion.

[0020] In an embodiment, the controller may calculate the correction value based on the temperature of the supply water, the temperature of the return water, the amount of combustion heat of the first heat exchanger, and the circulation flow rate.

[0021] In an embodiment, the controller may predict the temperature of the supply water based on a corrected average of the correction values ​​calculated in each stable state.

[0022] In an embodiment, the controller may predict the temperature of the supply water based on a value obtained by reflecting the corrected average value on the amount of combustion heat and the circulation flow rate of the first heat exchanger and the temperature of the return water.

[0023] In an embodiment, the controller may predict the temperature of the supplied water based on the corrected average value when the use condition of the hot water supply device changes or when the burner performs the next combustion.

[0024] In an embodiment, the controller may predict the temperature of the supply water based on the corrected average value when an output of a predetermined amount of heat or more is generated in the first heat exchanger.

[0025] According to another aspect of the present invention, there is a hot water control method for a hot water supply device, the hot water supply device comprising: a first heat exchanger which heats heating water using heat obtained by burning fuel in a burner; and a second heat exchanger which produces hot water by performing heat exchange between supply water supplied by the first heat exchanger and direct water, the hot water control method comprising: measuring the temperature of return water of the supply water cooled after heat exchange with the second heat exchanger using a temperature sensor installed on a flow path of the return water flowing to the first heat exchanger, predicting the temperature of the supply water based on the temperature of the return water measured by the temperature sensor, and performing hot water control based on the predicted temperature of the supply water.

[0026] In an embodiment, predicting the temperature of the supply water may include predicting the temperature of the supply water based on the amount of combustion heat of the first heat exchanger, the circulation flow rate of the supply water flowing from the first heat exchanger to the second heat exchanger along the first flow path and the return water flowing from the second heat exchanger to the first heat exchanger along the second flow path, and the temperature of the return water before a temperature reaction delay time until the temperature change of the return water is reflected in the temperature of the supply water.

[0027] In an embodiment, performing hot water control may include: when the predicted supply water temperature is higher than a preset reference temperature, performing supply water temperature limit control, and setting the reference temperature to the temperature of supply water measured by the first temperature sensor when performing the supply water temperature limit control, and performing a combustion heat amount control operation based on the reference temperature.

[0028] In an embodiment, performing hot water control may also include: controlling the opening rate of a mixing valve installed on a bypass flow path connecting a third flow path through which water directly flows into the second heat exchanger and a fourth flow path through which hot water generated by the second heat exchanger is discharged, so that the temperature of the hot water is maintained at a target temperature when performing supply water temperature limit control.

[0029] In an embodiment, predicting the temperature of the supply water may also include: while the burner is performing combustion, while the temperature of the supply water and the temperature of the return water are maintained in a constant stable state for a predetermined time, calculating the amount of combustion heat of the first heat exchanger and the correction value of the circulation flow rate of the supply water flowing through the first flow path and the return water flowing through the second flow path; and predicting the temperature of the supply water based on the corrected average value of the correction values ​​calculated in each stable state. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and other objects, features and advantages of the present invention will become more apparent through the following detailed description in conjunction with the accompanying drawings:

[0031] Figure 1 is a view showing a configuration of a hot water supply apparatus according to an embodiment of the present invention;

[0032] Figure 2 is a view showing a configuration of a hot water supply apparatus according to another embodiment of the present invention;

[0033] Figure 3 is a view showing a control structure of a hot water supply device according to an embodiment of the present invention;

[0034] Figure 4 is a schematic diagram for describing the delay speed of the temperature reaction rate according to an embodiment of the present invention;

[0035] Figure 5is a schematic diagram for reference in describing the operating effect of the hot water supply device according to the embodiment of the present invention; and

[0036] Figure 6 and Figure 7 is a flowchart illustrating an operation flow of a hot water control method for a hot water supply apparatus according to an embodiment of the present invention. DETAILED DESCRIPTION

[0037] Some embodiments of the present invention will be described in detail below with reference to the exemplary drawings. When adding reference numerals to the components of the various figures, it should be noted that the same or equivalent components are represented by the same reference numerals even if they are shown in other figures. In addition, when describing the embodiments of the present invention, when it is determined that the detailed description of the relevant known configuration or function will interfere with the understanding of the embodiments of the present invention, its detailed description will be omitted.

[0038] When describing components according to embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only used to distinguish one component from other components, and these terms do not limit the nature, order or sequence of the components. Unless otherwise defined, all terms (including technical terms and scientific terms) used in this document have the same meaning as those generally understood by ordinary technicians in the field to which the present invention belongs. It will also be understood that terms such as terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technical field, and will not be interpreted in an idealized or overly formal sense unless explicitly defined as such in this document.

[0039] Figure 1 is a view showing a configuration of a hot water supply apparatus according to an embodiment of the present invention, Figure 2 2 is a view showing a configuration of a hot water supply device according to another embodiment of the present invention. Figure 1 and Figure 2 The hot water supply device of the embodiment may correspond to a combination boiler.

[0040] refer to Figure 1 and Figure 2 , the hot water supply device may include a first heat exchanger 20 and a second heat exchanger 30 .

[0041] The first heat exchanger 20 heats the heating water using the heat obtained by burning the fuel in the burner, and supplies the heated heating water, i.e., supply water, to the second heat exchanger 30. The second heat exchanger 30 generates hot water through heat exchange between the supply water and the direct water and supplies the generated hot water to the user. For example, the first heat exchanger 20 may be a sensible heat exchanger, and the second heat exchanger 30 may be a hot water heat exchanger.

[0042] A first flow path through which the supply water moves may be formed between the first heat exchanger 20 and the second heat exchanger 30. Therefore, the first flow path is a heated water supply flow path, and the supply water heated by the first heat exchanger 20 is supplied to the second heat exchanger 30 through the first flow path and used to generate hot water. A first temperature sensor 11 for measuring the temperature of the supply water may be installed on the first flow path. For example, the first temperature sensor 11 may be installed on the outlet side of the first heat exchanger 20.

[0043] The second flow path returning the supply water supplied through the first flow path may be connected to the second heat exchanger 30. Therefore, the second heat exchanger 30 performs heat exchange with direct water using the supply water and discharges the supply water cooled by the heat exchange to the second flow path.

[0044] Since the second flow path is connected to the first heat exchanger 20 via the expansion tank 40, a closed flow path circulating through the first heat exchanger 20 and the second heat exchanger 30 is formed by the first flow path and the second flow path.

[0045] A second temperature sensor 13 for measuring the temperature of the return water may be installed on the second flow path. For example, the second temperature sensor 13 may be installed on the outlet side of the second heat exchanger 30.

[0046] The expansion tank 40 receives water to be used as heating water from the second heat exchanger 30 through the second flow path. In this case, the water supplied from the second heat exchanger 30 is return water discharged after the second heat exchanger 30 generates hot water.

[0047] The expansion tank 40 is configured to accommodate volume changes according to temperature changes of the heated water. The expansion tank 40 may be disposed on the second flow path to constitute a part of the closed flow path and may accommodate volume changes of the heated water flowing along the closed flow path. The expansion tank 40 may be a closed type and may be provided with a flexible diaphragm therein. When the temperature changes or the heated water is input or output in a state where the expansion tank 40 is full of heated water, the internal pressure of the expansion tank 40 may change simultaneously. The water contained in the expansion tank 40 may be provided to the first heat exchanger 20 along the second flow path. In this case, a circulation pump 45 for smoothly supplying hot water to the first heat exchanger 20 may be installed on the outlet side of the expansion tank 40 on the second flow path.

[0048] Although in Figure 1 and Figure 2 Although not shown in the figure, a flow sensor for measuring the flow rate of water circulating in the closed flow path may be additionally installed on the first flow path and / or the second flow path.

[0049] Meanwhile, the third flow path into which the direct water flows and the fourth flow path through which the hot water generated by the heat exchange is discharged may be connected to the second heat exchanger 30. The direct water flowing into the second heat exchanger 30 through the third flow path may be heated by heat exchange with the supply water, in which case the generated hot water may be discharged to the fourth flow path and supplied to the user. Here, the third temperature sensor 15 for measuring the temperature of the direct water supplied to the second heat exchanger 30 may be installed on the third flow path, and the fourth temperature sensor 17 for measuring the temperature of the hot water discharged from the second heat exchanger 30 may be installed on the fourth flow path.

[0050] like Figure 2 As shown, in a hot water supply device according to another embodiment, a bypass flow path may be connected between a third flow path for supplying direct water to the second heat exchanger 30 and a fourth flow path for discharging hot water. Here, a portion of the direct water flowing through the third flow path may flow into the second heat exchanger 30 and be heated, and another portion thereof may flow into the fourth flow path through the bypass flow path.

[0051] In this case, a mixing valve 50 for adjusting the flow rate of the direct water passing through the bypass flow path may be additionally installed on the bypass flow path. When the flow rate of the direct water passing through the bypass flow path is adjusted by the mixing valve 50, the direct water with the adjusted flow rate flows into the fourth flow path, so that the temperature of the hot water discharged along the fourth flow path can be adjusted by the direct water. In this case, the fourth temperature sensor 17 may measure the temperature of the hot water adjusted by the direct water.

[0052] In addition, a fifth temperature sensor that measures the outlet temperature 19 of the second heat exchanger 30 may be additionally included on the outlet side of the second heat exchanger 30 on the fourth flow path.

[0053] Figure 3 is a view showing a control structure of a hot water supply apparatus according to an embodiment of the present invention.

[0054] refer to Figure 3 The hot water supply device may further include a controller 110 that performs overall functions related to the supply of hot water. Here, the controller 110 may be a hardware device such as a processor or a central processing unit (CPU) or a program executed by the processor.

[0055] The controller 110 may control the supply of hot water by controlling the operation of the first heat exchanger 20, the second heat exchanger 30, the expansion valve, and the burner (not shown) based on the information detected by the temperature sensor 10 and the flow sensor 60. Here, the temperature sensor 10 may include Figure 1 and Figure 2At least one of the first temperature sensor 11 , the second temperature sensor 13 , the third temperature sensor 15 , the fourth temperature sensor 17 and the fifth temperature sensor 19 shown.

[0056] In the heating water circulating in the closed flow path, the supply water heated by the first heat exchanger 20 flows into the second heat exchanger 30 along the first flow path, and the return water cooled after heat exchange with the second heat exchanger 30 flows into the first heat exchanger 20 via the expansion tank 40 along the second flow path.

[0057] In the closed flow path, the heating water in the expansion tank 40 and the first heat exchanger 20 may experience a temperature response delay, and the supply water having a temperature corresponding to the target value after the temperature response delay is output from the first heat exchanger 20 .

[0058] Figure 4 Schematic diagram showing the temperature reaction rate delay operation according to an embodiment of the present invention. Figure 4 , reference numeral 411 represents a graph showing changes in supply water temperature, and reference numeral 415 represents a graph showing changes in return water temperature.

[0059] like Figure 4 As shown, it can be seen that when the return water temperature increases or decreases, the supply water temperature increases or decreases after the return water temperature is delayed by a predetermined time.

[0060] When the temperature of the supply water supplied from the first heat exchanger 20 is higher than the reference temperature, the supply water temperature limit control is performed, so that a problem due to overheating can be prevented. Figure 4 As shown, when the temperature reaction rate is delayed, even if the current state is switched to the supply water temperature limit control, there is a possibility that the combustion stops due to the subsequent temperature increase.

[0061] To prevent this, the controller 110 may predict the temperature of the supplied water in consideration of the delay speed of the temperature reaction rate, so that the supplied water temperature limit control may be performed without stopping the combustion.

[0062] Therefore, the controller 110 predicts the supply water temperature based on the return water temperature in consideration of the temperature reaction delay of the heating water in the expansion tank 40 and the first heat exchanger 20. [Equation 1] is an equation for predicting the supply water temperature based on the return water temperature.

[0063] Supply water temperature = {combustion heat / (circulation flow rate × 60)} + return water temperature

[0064] [Equation 1]

[0065] In [Equation 1], the amount of combustion heat refers to the amount of combustion heat of the first heat exchanger 20, and the circulation flow rate refers to the flow rate previously measured by the flow sensor. In addition, the return water temperature refers to the return water temperature measured by the second temperature sensor 13. Here, "60" is a value that matches the time unit between the unit of the amount of heat [kcal / hour] and the unit of the flow rate [liter per minute (LPM)].

[0066] In this way, when predicting the supply water temperature based on the return water temperature, the controller 110 can predict the supply water temperature as fast as the delay time of the temperature reaction rate in the expansion tank 40 or the first heat exchanger 20, thereby performing supply water temperature limit control without stopping combustion.

[0067] However, the amount of combustion heat of the first heat exchanger 20 may have an error depending on the combustion conditions. In addition, in a model in which a flow sensor is not provided in the boiler, foreign matter may accumulate on a flow path through which heating water circulates, or lime may accumulate in the first heat exchanger 20. Therefore, as the circulation flow rate of the product changes, it may be difficult to ensure a constant circulation flow rate.

[0068] To this end, the controller 110 may calculate correction values ​​of the amount of combustion heat and the circulation flow rate, and predict the temperature of the supplied water by reflecting the calculated correction values, thereby minimizing the error.

[0069] Therefore, [Equation 2] is an equation for calculating the amount of combustion heat and the correction value of the circulation flow rate.

[0070] Correction value = (supply water temperature

[0071] - return water temperature) ÷ {combustion heat ÷ (circulation flow rate × 60)}

[0072] [Equation 2]

[0073] In [Equation 2], the amount of combustion heat refers to the amount of combustion heat of the first heat exchanger 20, and the circulation flow rate refers to the flow rate previously measured by the flow sensor. In addition, the supply water temperature refers to the temperature measured by the first temperature sensor 11, and the return water temperature refers to the temperature measured by the second temperature sensor 13.

[0074] Here, the correction value is suitable for improving the accuracy of the predicted supply water temperature, and can be calculated in a state where the supply water temperature, return water temperature, combustion, etc. are maintained for a certain period of time, that is, in a stable state. In this case, the controller 110 can calculate the correction value in each stable state, and can reflect the average value of the calculated correction values ​​in the equation of the predicted supply water temperature.

[0075] Therefore, [Equation 3] is an equation for predicting the supply water temperature by reflecting the corrected average value.

[0076] Supply water temperature

[0077] = {combustion heat ÷ (circulation flow × 60) 1 × corrected average value

[0078] + Return water temperature

[0079] [Equation 3]

[0080] In [Equation 3], the amount of combustion heat refers to the amount of combustion heat of the first heat exchanger 20, and the circulation flow rate refers to the flow rate previously measured by the flow sensor. In addition, the correction average value refers to the average value of the correction value calculated by [Equation 2] in each stable state, and the return water temperature refers to the temperature measured by the second temperature sensor 13.

[0081] Therefore, the controller 110 can predict the temperature of the supplied water by referring to [Equation 1] at ordinary times, and predict the temperature of the supplied water by referring to [Equation 3] reflecting the corrected average value calculated previously when usage conditions such as usage flow rate change or during the next combustion.

[0082] However, since the amount of combustion heat may have an error according to the output range of each product, the controller 110 may predict the temperature of the supplied water with reference to [Equation 3] which reflects the corrected average value only when the output is greater than a predetermined amount of heat.

[0083] When the supplied water temperature predicted by [Equation 1] or [Equation 3] is higher than the reference temperature, the controller 110 performs the supplied water temperature limit control operation.

[0084] When the supply water temperature limit control operation is performed, the controller 110 sets the reference temperature to the temperature of the supply water, and performs the amount control of the combustion heat based on the temperature of the hot water to discharge the hot water having the user's desired temperature. In this case, since the reference temperature is set to the temperature of the supply water, even if the temperature is lower than the user's desired temperature, the combustion can be continuously performed within a safe range. Therefore, according to the delay time of the temperature reaction rate, the control switching is performed before the supply water temperature actually increases, so that the combustion can be prevented from being stopped unnecessarily.

[0085] like Figure 2 In the embodiment, in the case of the hot water supply device including the mixing valve 50, the temperature of the supplied water may differ according to the outlet temperature of the second heat exchanger 30. Therefore, the controller 110 may control so that the temperature measured by the fifth temperature sensor 19 installed on the outlet side of the second heat exchanger 30 on the fourth flow path is higher than the temperature of the hot water whose temperature is adjusted by the mixing valve 50, that is, the temperature measured by the fourth temperature sensor 17.

[0086] Figure 51 is a schematic diagram for describing the operation effect of the hot water supply device according to an embodiment of the present invention. Figure 5 In the embodiment of the invention, in the hot water supply device including the mixing valve 50, when the temperature of the supply water predicted by [Equation 1] or [Equation 3] is higher than the reference temperature and the supply water temperature limit control operation is performed, the controller 110 can perform the amount of combustion heat control while setting the reference temperature as the temperature of the supply water, and thus the amount of combustion heat can be reduced due to the decrease in the reference temperature. In addition, when performing the supply water temperature limit control operation, the controller 110 can reduce the temperature of the supply water by controlling the opening rate of the mixing valve 50 while maintaining the temperature of the hot water at the target temperature.

[0087] The operation process of the hot water supply device according to the present invention is described in more detail below.

[0088] Figure 6 and Figure 7 is a flowchart illustrating an operation flow of a hot water control method for a hot water supply apparatus according to an embodiment of the present invention.

[0089] First, refer to Figure 6 , the hot water supply device calculates the predicted supply water temperature (S120) while performing combustion (S110). In operation S120, the hot water supply device may calculate the predicted supply water temperature based on the return water temperature. The method of calculating the predicted supply water temperature based on the return water temperature refers to the above [Equation 1].

[0090] The hot water supply device identifies whether the predicted supply water temperature calculated in operation S120 is greater than a preset reference temperature when combustion is formed. When the calculated predicted supply water temperature is not greater than the preset reference temperature, the hot water supply device may continue to perform operations S110 to S120. In this case, the hot water supply device may perform a quantity control of combustion heat based on the temperature of the hot water when performing combustion.

[0091] Meanwhile, when the calculated predicted supply water temperature is higher than the preset reference temperature (S130), the hot water supply apparatus performs supply water temperature limit control (S140).

[0092] In operation S140, the hot water supply device sets the reference temperature to the temperature of the supply water during the supply water temperature limit control. In this case, the hot water supply device performs the amount control of the combustion heat based on the temperature of the hot water based on the reset reference temperature to discharge the hot water having the temperature desired by the user. In this case, since the reference temperature is set to the temperature of the supply water, even if the temperature is lower than the temperature desired by the user, the combustion can be continuously performed within the safety range. Therefore, according to the delay time of the temperature reaction rate, the control switching is performed before the supply water temperature actually increases, so that the combustion can be prevented from being stopped unnecessarily.

[0093] refer to Figure 7 , when performing combustion (S210), when the temperature of the supply water, the temperature of the return water, the combustion, etc. are maintained constant within a predetermined time (S220), the hot water supply device calculates the correction value of the amount of combustion heat and the circulation flow rate (S230). Here, the correction value is a value for minimizing the error value of the predicted supply water temperature when the amount of combustion heat or the circulation flow rate is not maintained constant.

[0094] In operation S230, the method of calculating the correction value of the amount of combustion heat and the circulation flow rate refers to [Equation 2] described above. In this case, the hot water supply device repeatedly performs operations S210 to S230 while performing combustion, and calculates a correction value for correcting the predicted supply water temperature in each stable state where the supply water temperature, return water temperature, combustion, etc. are maintained constant for a predetermined time.

[0095] However, in the hot water supply device, the correction value calculated in operation S230 is not directly applied to the calculation of the predicted supply water temperature. In addition, when the use conditions such as the use flow rate change or during the next combustion, the average value of the correction value calculated in operation S230, that is, the correction average value, is calculated, and the predicted supply water temperature is calculated by reflecting the correction average value.

[0096] In addition, in the hot water supply equipment, considering that the output range of each heat exchanger is different, and when the output is greater than or equal to a certain level, an error will occur in the amount of combustion heat. Therefore, when an output with a predetermined amount of heat or more is generated, the predicted supply water temperature can be calculated by reflecting the corrected average value calculated in operation S230.

[0097] According to the embodiment of the present invention, the supply water temperature is predicted as fast as the delay time of the temperature reaction rate of heating water based on the return water temperature, so hot water can be supplied without shutting off combustion even during supply water temperature limit control.

[0098] In addition, according to an embodiment of the present invention, in a stable state when combustion is performed in a hot water supply device, correction values ​​of the amount of combustion heat and the circulation flow rate are calculated, and the average value of the correction values ​​is applied to predict the supply water temperature, thereby improving the prediction accuracy of the supply water temperature.

[0099] The above description is merely an illustration of the technical spirit of the present invention, and those skilled in the art to which the present invention belongs may make various modifications and changes without departing from the essential features of the present invention.

[0100] Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but are intended to describe the present invention, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the attached claims, and all technical spirits within the equivalent scope thereof should be interpreted as included within the scope of the present invention.

[0101] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0078234 filed in the Korean Intellectual Property Office on June 19, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. A hot water supply device, comprising: a first heat exchanger configured to heat heating water using heat obtained by burning fuel in the burner; and a second heat exchanger configured to generate hot water by exchanging heat between supply water supplied by the first heat exchanger and direct water, the hot water supply device comprising: a first temperature sensor installed on a first flow path of the supply water supplied from the first heat exchanger to the second heat exchanger and configured to measure a temperature of the supply water; a second temperature sensor installed on a second flow path of the return water of the supply water cooled after heat exchange with the second heat exchanger flowing toward the first heat exchanger and configured to measure a temperature of the return water; A controller is configured to predict the temperature of the supply water based on the temperature of the return water measured by the second temperature sensor, and is configured to perform hot water control based on the predicted temperature of the supply water.

2. The hot water supply device according to claim 1, wherein: The controller predicts the temperature of the supply water based on the amount of combustion heat of the first heat exchanger, the circulation flow rate of water flowing along the first flow path and the second flow path, and the temperature of the return water before a temperature reaction delay time until a temperature change of the return water is reflected in the temperature of the supply water.

3. The hot water supply device according to claim 2, wherein: The controller performs supply water temperature limit control when the predicted temperature of the supply water is higher than a preset reference temperature.

4. The hot water supply device according to claim 3, wherein: The controller sets the reference temperature to the temperature of the supplied water measured by the first temperature sensor when performing the supplied water temperature limit control, and performs a combustion heat amount control operation based on the reference temperature.

5. The hot water supply device according to claim 1, further comprising: a mixing valve installed on a bypass flow path connecting a third flow path through which the direct water flows into the second heat exchanger and a fourth flow path through which the hot water generated by the second heat exchanger is discharged, and configured to adjust the flow rate of the direct water to adjust the temperature of the hot water discharged through the fourth flow path.

6. The hot water supply device according to claim 5, wherein: The controller performs supply water temperature limit control when the predicted temperature of the supply water is higher than a preset reference temperature, and controls an opening rate of the mixing valve while performing the supply water temperature limit control so that the temperature of the hot water is maintained at a target temperature.

7. The hot water supply device according to claim 6, wherein: When performing the supply water temperature limit control, the controller controls the outlet temperature of the second heat exchanger to a temperature higher than the temperature of the hot water adjusted by the mixing valve.

8. The hot water supply device according to claim 1, wherein: The controller calculates the amount of combustion heat of the first heat exchanger and the correction value of the circulation flow rate of water flowing along the first flow path and the second flow path while the temperature of the supply water and the temperature of the return water are maintained in a constant stable state for a predetermined time while the burner performs combustion.

9. The hot water supply device according to claim 8, wherein: The controller calculates the correction value based on a temperature of the supply water, a temperature of the return water, an amount of the combustion heat of the first heat exchanger, and the circulation flow rate.

10. The hot water supply device according to claim 8, wherein: The controller predicts the temperature of the supply water based on a corrected average value of correction values ​​calculated in each steady state.

11. The hot water supply device according to claim 10, wherein: The controller predicts the temperature of the supply water based on a value obtained by reflecting the corrected average value on the amount of the heat of combustion and the circulation flow rate of the first heat exchanger and the temperature of the return water.

12. The hot water supply device according to claim 10, wherein: When a use condition of the hot water supply device changes or the burner performs next combustion, the controller predicts the temperature of the supply water based on the corrected average value.

13. The hot water supply device according to claim 10, wherein: The controller predicts the temperature of the supply water based on the corrected average value when an output of a predetermined amount of heat or more is generated in the first heat exchanger.

14. A hot water control method for a hot water supply device, the hot water supply device comprising: a first heat exchanger configured to heat heating water using heat obtained by burning fuel in the burner; and a second heat exchanger configured to generate hot water by exchanging heat between supply water supplied by the first heat exchanger and direct water, the hot water control method comprising: measuring the temperature of the return water using a temperature sensor installed on a flow path of the return water of the supply water cooled after heat exchange with the second heat exchanger flowing to the first heat exchanger; predicting the temperature of the supply water based on the temperature of the return water measured by the temperature sensor; as well as Hot water control is performed based on the predicted temperature of the supply water.

15. The hot water control method according to claim 14, wherein: Predicting the temperature of the supply water includes predicting the temperature of the supply water based on the amount of combustion heat of the first heat exchanger, the circulation flow rate of the supply water flowing from the first heat exchanger to the second heat exchanger along a first flow path and the return water flowing from the second heat exchanger to the first heat exchanger along a second flow path, and the temperature of the return water before a temperature reaction delay time until a temperature change of the return water is reflected in the temperature of the supply water.

16. The hot water control method according to claim 15, wherein: Executing the hot water control includes: When the predicted temperature of the supplied water is higher than a preset reference temperature, performing supplied water temperature limit control; and When the supplied water temperature limit control is performed, the reference temperature is set to the temperature of the supplied water measured by the temperature sensor installed on the first flow path, and an amount control operation of combustion heat is performed based on the reference temperature.

17. The hot water control method according to claim 16, wherein: Executing the hot water control further includes: An opening rate of a mixing valve installed on a bypass flow path connecting a third flow path through which the direct water flows into the second heat exchanger and a fourth flow path through which the hot water generated by the second heat exchanger is discharged is controlled so that the temperature of the hot water is maintained at a target temperature when the supply water temperature limit control is performed.

18. The hot water control method according to claim 15, wherein: Predicting the temperature of the supply water further includes: calculating, while the burner performs combustion, a correction value of the amount of combustion heat of the first heat exchanger and a circulation flow rate of the supply water flowing through the first flow path and the return water flowing through the second flow path in a stable state in which the temperature of the supply water and the temperature of the return water are maintained constant for a predetermined time; and The temperature of the supply water is predicted based on a corrected average value of the correction values ​​calculated in each steady state.

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