Patent Application
20240418404
This application claims the benefit of priority to Korean Patent Application No. 10-2023-0078234, filed in the Korean Intellectual Property Office on Jun. 19, 2023, the entire contents of which are incorporated herein by reference.
The present disclosure relates to a hot water supply apparatus and a hot water control method therefor.
Generally, hot water supply apparatuses are apparatuses that heat direct water to a predetermined temperature in a short period of time and supplies the heated direct water so that a user may conveniently use the heated direct water. Examples of the hot water supply apparatuses may include boilers and water heaters.
As an example, when the user requests supply of hot water, a combination boiler may include a primary heat exchanger that heats heating water by combusting a fuel through a burner and a secondary heat exchanger that generates hot water by exchanging heat between the heating water heated by the primary heat exchanger and the direct water.
In the combination boiler, a temperature of the heating water supplied from the primary heat exchanger may be increased depending on performance of the secondary heat exchanger.
In this case, the temperature of the heating water is highest at a time point at which supply starts after the heat exchange in the primary heat exchanger is completed, and when the temperature of the heating water supplied from the primary heat exchanger is higher than a boiling point, boiling noise may occur, and the heat exchange is unstable, thereby reducing performance and stability of products.
In the related art, to solve the above problem, an overheating preventing function of limiting the combustion when the temperature of the heating water is higher than or equal to a specific temperature is applied. However, in this case, satisfaction of the user who receives hot water is decreased due to turning-off of the combustion.
In addition, a method of operating the boiler without turning off the combustion by limiting the temperature of the supply water within a range in which the temperature of the heating water is not greater than a specific temperature is used. However, in this method, the combustion is switched to an OFF state as the temperature of the heating water is increased even after the temperature of the supply water is limited due to a temperature reaction rate delay of the heating water.
The present disclosure has been made to solve the above-mentioned problems occurring in the prior art while advantages achieved by the prior art are maintained intact.
An aspect of the present disclosure provides a hot water supply apparatus that predicts a temperature of supply water as quickly as a delay time for a temperature reaction rate of heating water based on a temperature of return water and thus enables hot water to be supplied without turning off combustion even during supply water temperature limiting control, and a hot water control method therefor.
Another aspect of the present disclosure provides a hot water supply apparatus that calculates correction values for a combustion heat amount and a circulation flow rate, applies an average value of the correction values, predicts a temperature of supply water, and thus improves prediction accuracy for the temperature of the supply water in a stable state while combustion is performed in the hot water supply apparatus, and a hot water control method therefor.
The technical problems to be solved by the present disclosure 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 disclosure pertains.
According to an aspect of the present disclosure, there is provided a hot water supply apparatus including a first heat exchanger that heats heating water using heat obtained by combusting a fuel by a burner and a second heat exchanger that generates hot water by exchanging heat between supply water supplied by the first heat exchanger and direct water, the hot water supply apparatus including a first temperature sensor that is installed on a first flow path through which the supply water supplied by the first heat exchanger flows to the second heat exchanger and measures a temperature of the supply water, a second temperature sensor that is 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 measures a 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 preforms hot water control based on the predicted temperature of the supply water.
In an embodiment, the controller may predict the temperature of the supply water based on a combustion heat amount of the first heat exchanger, a circulation flow rate 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 a temperature reaction delay time until a change in the temperature of the return water is reflected on the temperature of the supply water.
In an embodiment, the controller may perform supply water temperature limiting control when the predicted temperature of the supply water is greater than a preset reference temperature.
In an embodiment, the controller may set the reference temperature to the temperature of the supply water measured by the first temperature sensor when performing the supply water temperature limiting control and perform a combustion heat amount control operation based on the reference temperature.
In an embodiment, the hot water supply apparatus may further include a mixing valve that is 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 adjusts a flow rate of the direct water to adjust a temperature of the hot water discharged through the fourth flow path.
In an embodiment, the controller may perform a supply water temperature limiting control when the predicted temperature of the supply water is greater than a preset reference temperature and control an opening rate of the mixing valve such that the temperature of the hot water is maintained at a target temperature while performing a supply water temperature limiting control operation.
In an embodiment, while performing the supply water temperature limiting control operation, the controller may control an outlet temperature of the second heat exchanger to a temperature higher than the temperature of the hot water adjusted by the mixing valve.
In an embodiment, while combustion is performed by the burner, 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 period of time, the controller may calculate a correction value for a combustion heat amount of the first heat exchanger and a circulation flow rate of the supply water and the return water flowing along the first flow path and the second flow path.
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 combustion heat amount of the first heat exchanger, and the circulation flow rate.
In an embodiment, the controller may predict the temperature of the supply water based on a correction average value of the correction values calculated in each stable state.
In an embodiment, the controller may predict the temperature of the supply water based on a value obtained by reflecting the correction average value on the combustion heat amount of the first heat exchanger and the circulation flow rate and the temperature of the return water.
In an embodiment, the controller may predict the temperature of the supply water based on the correction average value when usage conditions of the hot water supply apparatus are changed or when next combustion is performed by the burner.
In an embodiment, the controller may predict the temperature of the supply water based on the correction average value when an output of a predetermined heat amount or more is generated in the first heat exchanger.
According to another aspect of the present disclosure, there is a hot water control method for a hot water supply apparatus including a first heat exchanger that heats heating water using heat obtained by combusting a fuel by a burner and a second heat exchanger that generates hot water by exchanging heat between supply water supplied by the first heat exchanger and direct water, the hot water control method including measuring a 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 through which the return water flows to the first heat exchanger, predicting a 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.
In an embodiment, the predicting of the temperature of the supply water may include predicting the temperature of the supply water based on the combustion heat amount 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 change in the temperature of the return water is reflected on the temperature of the supply water.
In an embodiment, the performing of the hot water control may include performing supply water temperature limiting control when the predicted temperature of the supply water is greater than a preset reference temperature, and setting the reference temperature to the temperature of the supply water measured by the first temperature sensor when performing the supply water temperature limiting control and performing a combustion heat amount control operation based on the reference temperature.
In an embodiment, the performing of the hot water control may further include controlling 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 such that the temperature of the hot water is maintained at a target temperature when performing the supply water temperature limiting control.
In an embodiment, the predicting of the temperature of the supply water may further include calculating a correction value for the combustion heat amount of the first heat exchanger and the 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 period of time while combustion is performed by the burner, and predicting the temperature of the supply water based on a correction average value of the correction values calculated in each stable state.
The above and other objects, features and advantages of the present disclosure will be more apparent from the following detailed description taken in conjunction with the accompanying drawings:
Hereinafter, some embodiments of the present disclosure will be described in detail with reference to the exemplary drawings. In adding reference numerals to components of each drawing, it should be noted that identical or equivalent components are designated by an identical numeral even when they are displayed on other drawings. Further, in describing the embodiment of the present invention, a detailed description of the related known configuration or function will be omitted when it is determined that it interferes with the understanding of the embodiment of the present invention.
In describing the components of the embodiment according to the present invention, terms such as first, second, A, B, (a), (b), and the like may be used. These terms are merely intended to distinguish one component from other components, and the terms do not limit the nature, order, or sequence of the components. Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Referring to
The first heat exchanger 20 heats heating water using heat obtained by combusting a fuel by a burner and supplies the heated heating water, that is, supply water to the second heat exchanger 30. The second heat exchanger 30 generates hot water through heat exchange between the supply water and direct water and supplies the generated hot water to a user. As an 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.
A first flow path, through which the supply water is moved, may be formed between the first heat exchanger 20 and the second heat exchanger 30. Accordingly, the first flow path is a heating 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 is used to generate the hot water. A first temperature sensor 11 that measures a temperature of the supply water may be installed on the first flow path. As an example, the first temperature sensor 11 may be installed on an outlet side of the first heat exchanger 20.
A second flow path that returns the supply water supplied through the first flow path may be connected to the second heat exchanger 30. Thus, the second heat exchanger 30 performs heat exchange with the direct water using the supply water and discharges the supply water cooled by the heat exchange to the second flow path.
As the second flow path is connected to the first heat exchanger 20 via an 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.
A second temperature sensor 13 that measures a temperature of return water may be installed on the second flow path. As an example, the second temperature sensor 13 may be installed on an outlet side of the second heat exchanger 30.
The expansion tank 40 receives water, which is to be used as the 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 the return water discharged after the hot water is generated by the second heat exchanger 30.
The expansion tank 40 is provided to accommodate a change in a volume according to a change in a temperature of the heating water. The expansion tank 40 may be disposed on the second flow path to constitute a portion of the closed flow path and may accommodate the change in the volume of the heating water flowing along the closed flow path. The expansion tank 40 may be of a closed type and may be provided with a flexible diaphragm therein. When the temperature is changed or the heating water is input or output in a state in which the expansion tank 40 is filled with the heating water, an internal pressure of the expansion tank 40 may be changed at the same time. The water accommodated 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 that smoothly supply the heat water to the first heat exchanger 20 may be installed on an outlet side of the expansion tank 40 on the second flow path.
Although not illustrated in
Meanwhile, a third flow path into which the direct water flows and a 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 through the heat exchange with the supply water, and the hot water generated in this case may be discharged to the fourth flow path and supplied to the user. Here, a third temperature sensor 15 that measures a temperature of the direct water supplied to the second heat exchanger 30 may be installed on the third flow path, and a fourth temperature sensor 17 that measures a temperature of the hot water discharged from the second heat exchanger 30 may be installed on the fourth flow path.
As illustrated in
In this case, a mixing valve 50 that adjusts a 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 through the mixing valve 50, the direct water having the adjusted flow rate is joined to the fourth flow path, and thus, the temperature of the hot water discharged along the fourth flow path may be adjusted by the direct water. In this case, the fourth temperature sensor 17 may measure the temperature of the hot water, which is adjusted by the direct water.
Further, a fifth temperature sensor 19 that measures an outlet temperature 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.
Referring to
The controller 110 may control the supply of the hot water by controlling operations of the first heat exchanger 20, the second heat exchanger 30, an expansion valve, and the burner (not illustrated) based on the information detected by a temperature sensor 10 and a flow rate sensor 60. Here, the temperature sensor 10 may include at 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 illustrated in
Among the heating water circulating through the closed flow path, the supply water that is heated by the first heat exchanger 20 flows into the second heat exchanger along the first flow path, and the return water that is 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.
In the closed flow path, a temperature reaction delay occurs in the heating water in the expansion tank 40 and the first heat exchanger 20, and the supply water having a temperature corresponding to a target value through the temperature reaction delay is output from the first heat exchanger 20.
As illustrated in
When the temperature of the supply water supplied from the first heat exchanger 20 is greater than a reference temperature, supply water temperature limiting control is performed, and thus problematic situations may be prevented from occurring due to overheating. However, as illustrated in
To prevent this, the controller 110 may predict the temperature of the supply water in consideration of a delay speed for the temperature reaction rate and thus may perform the supply water temperature limiting control without stopping the combustion.
Accordingly, the controller 110 predicts the temperature of the supply water based on the temperature of the return water in consideration of the temperature reaction delay in the heating water in the expansion tank 40 and the first heat exchanger 20. [Equation 1] refers to an equation of predicting the temperature of the supply water based on the temperature of the return water.
In [Equation 1], a combustion heat amount means a combustion heat amount of the first heat exchanger 20, and a circulation flow rate means a flow rate previously measured by the flow rate sensor. Further, the temperature of the return water means the temperature of the return water, which is measured by the second temperature sensor 13. Here, “60” is a numerical value that matches a time unit between the heat amount unit [Kcal/h] and the flow rate unit [Liter per minute (LPM)].
In this way, when predicting the temperature of the supply water based on the temperature of the return water, the controller 110 may predict the temperature of the supply water as quickly as a delay time for the temperature reaction rate in the expansion tank 40 or the first heat exchanger 20 and thus may perform the supply water temperature limiting control without stopping the combustion.
However, errors may occur in the combustion heat amount of the first heat exchanger 20 according to a combustion condition. Further, in a model in which a flow rate sensor is not provided in a boiler, foreign substances are accumulated on the flow path through which the heating water is circulated or lime is accumulated in the first heat exchanger 20. Thus, as a circulation flow rate of the product is changed, it may be difficult to secure a constant circulation flow rate.
To this end, the controller 110 may calculate a correction value for the combustion heat amount and the circulation flow rate, predict the temperature of the supply water by reflecting the calculated correction value, and thus minimize the errors.
Accordingly, [Equation 2] refers to an equation of calculating the correction value for the combustion heat amount and the circulation flow rate.
In [Equation 2], a combustion heat amount means a combustion heat amount of the first heat exchanger 20, and a circulation flow rate means a flow rate previously measured by the flow rate sensor. Further, the temperature of the supply water means a temperature measured by the first temperature sensor 11, and the temperature of the return water means a temperature measured by the second temperature sensor 13.
Here, the correction value is adapted to improve accuracy of the predicted temperature of the supply water and may be calculated in a state in which the temperature of the supply water, the temperature of the return water, the combustion, and the like are maintained for a certain period of time, that is, in a stable state. In this case, the controller 110 may calculate a correction value in each stable state and may reflect an average value of the calculated correction values to the equation of predicting the temperature of the supply water.
Accordingly, [Equation 3] refers to an equation of predicting the temperature of the supply water by reflecting the correction average value.
In [Equation 3], a combustion heat amount means a combustion heat amount of the first heat exchanger 20, and a circulation flow rate means a flow rate previously measured by the flow rate sensor. Further, the correction ed average value means an average value of the correction values calculated by [Equation 2] in each stable state, and the temperature of the return water means a temperature measured by the second temperature sensor 13.
Accordingly, the controller 110 may predict the temperature of the supply water with reference to [Equation 1] in normal times and predict the temperature of the supply water with reference to [Equation 3] on which the previously calculated correction average value is reflected when usage conditions such as a usage flow rate are changed or during next combustion.
However, since errors occur in the combustion heat amount according to an output range for each product, the controller 110 may predict the temperature of the supply water with reference to [Equation 3] on which the correction average value is reflected only at output that is greater than a predetermined heat amount.
The controller 110 performs the supply water temperature limiting control operation when the temperature of the supply water, which is predicted through [Equation 1] or [Equation 3], is greater than the reference temperature.
When performing the supply water temperature limiting control operation, the controller 110 sets the reference temperature to the temperature of the supply water and performs combustion heat amount control based on the temperature of the hot water to discharge the hot water having a temperature desired by the user. In this case, as the reference temperature is set to the temperature of the supply water, even when the temperature is smaller than the temperature desired by the user, the combustion may be continuously performed within a safe range. Accordingly, control switching is performed before the temperature of the supply water is actually increased according to the delay time for the temperature reaction rate, and thus the combustion may be prevented from stopping unnecessarily.
As in the embodiment of
An operation flow of the hot water supply apparatus according to the present disclosure as described above will be described in more detail below.
First, referring to
The hot water supply apparatus identifies whether the predicted temperature of the supply water, which is calculated in operation S120, is greater than a preset reference temperature while the combustion is formed. When the calculated predicted temperature of the supply water is not greater than the preset reference temperature, the hot water supply apparatus may continuously perform operations S110 to S120. In this case, the hot water supply apparatus may perform combustion heat amount control based on the temperature of the hot water while the combustion is performed.
Meanwhile, when the calculated predicted temperature of the supply water is greater than the preset reference temperature (S130), the hot water supply apparatus performs the supply water temperature limiting control (S140).
The hot water supply apparatus sets the reference temperature to the temperature of the supply water during the supply water temperature limiting control in operation S140. In this case, the hot water supply apparatus performs the combustion heat amount control based on the temperature of the hot water based on a reset reference temperature to discharge the hot water having a temperature desired by the user. In this case, as the reference temperature is set to the temperature of the supply water, even when the temperature is lower than the temperature desired by the user, the combustion may be continuously performed within a safe range. Accordingly, control switching is performed before the temperature of the supply water is actually increased according to the delay time for the temperature reaction rate, and thus the combustion may be prevented from stopping unnecessarily.
Referring to
In operation S230, a method of calculating the correction value for the combustion heat amount and the circulation flow rate refers to [Equation 2] described above. In this case, the hot water supply apparatus repeatedly performs operations S210 to S230 while the combustion is performed and calculates the correction value for correcting the predicted temperature of the supply water in each stable state in which the temperature of the supply water, the temperature of the return water, the combustion, and the like are maintained constant for a predetermined time.
However, in the hot water supply apparatus, the correction value calculated in operation S230 is not directly applied to the calculation of the predicted temperature of the supply water. Further, when the usage conditions such as the usage flow rate are changed or during next combustion, an average value of the correction values calculated in operation S230, that is, the correction average value, is calculated, and the predicted temperature of the supply water is calculated by reflecting the correction average value.
Further, in the hot water supply apparatus, in consideration of the fact that an output range is different for each heat exchanger and an error occurs in the combustion heat amount when the output is greater than or equal to a certain level, when the output having a predetermined heat amount or more is generated, the predicted temperature of the supply water may be calculated by reflecting the correction average value calculated in operation S230.
According to an embodiment of the present disclosure, a temperature of supply water is predicted as quickly as a delay time for a temperature reaction rate of heating water based on a temperature of return water, and thus even during the supply water temperature limiting control, hot water may be supplied without turning off combustion.
Further, according to the embodiment of the present disclosure, in a stable state while combustion is performed in the hot water supply apparatus, correction values for a combustion heat amount and a circulation flow rate are calculated, an average value of the correction values is applied, a temperature of supply water is predicted, and thus prediction accuracy for the temperature of the supply water may be improved.
The above description is merely illustrative of the technical spirit of the present disclosure, and those skilled in the art to which the present disclosure belongs may make various modifications and changes without departing from the essential features of the present disclosure.
Thus, the embodiments disclosed in the present disclosure are not intended to limit the technology spirit of the present disclosure, but are intended to describe the present disclosure, and the scope of the technical spirit of the present disclosure is not limited by these embodiments. The scope of protection of the present disclosure should be interpreted by the appended claims, and all technical spirits within the scope equivalent thereto should be interpreted as being included in the scope of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2023-0078234 | Jun 2023 | KR | national |
