Method and apparatus for controlling number of cascade boilers

Abstract

A method for controlling the number of cascade boilers, according to one embodiment of the present disclosure, comprises the steps of: calculating the average heat capacity of boilers when a heating operation has begun; determining whether the average heat capacity is greater than or equal to a preset first reference heat capacity, and calculating the difference between a set heating temperature and a heating supply water temperature if the average heat capacity is greater than or equal to the first reference heat capacity; and determining the number of additional boilers to be additionally operated on the basis of the difference between the set heating temperature and the heating supply water temperature.

Description

Cascade boiler number control method and device thereof

[0001] [Cross-reference with related applications]

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0187940, filed December 21, 2023, the entire contents of which are incorporated herein by reference.

[0003] The present disclosure relates to a technology for controlling the number of cascade boilers, and more specifically, to a method for controlling the number of cascade boilers and a device therefor, which determine the number of boilers in operation in order to supply heating heat capable of responding to the heating load in a cascade system that operates heating with two or more boilers.

[0004] A boiler cascade system can consist of up to 32 units, for example, one master boiler and 31 slave boilers. Each boiler in the cascade system individually controls its heat output to match the heating supply water temperature to the heating setpoint when heating is requested.

[0005] The master boiler calculates the average heat by collecting the heat of itself and the slave boilers, and if the average heat is maintained above the preset first reference heat, for example, the Unit ON heat, for a certain period of time, it determines that the heating supply heat is insufficient and adds (turns ON) one slave boiler at a time.

[0006] On the other hand, if the average heat quantity remains below the preset second reference heat quantity, for example, the Unit OFF heat quantity, for a certain period of time, the heating supply heat quantity is judged to be excessive and the slave boilers are removed (turned OFF) one by one.

[0007] In the case of the condition where heating is first started (initial heating operation), the heating supply water temperature is significantly lower than the heating setting temperature, and the maximum amount of heat that can be supplied by the cascade system must be supplied. However, since the number of slave boilers to be added / removed is fixed at 1, as the total number of installed units increases, the time required to add up to the maximum number of units to be operated at the time of initial heating operation increases, which inevitably leads to a decrease in performance in terms of heating speed.

[0008] Additionally, if slave boilers are added / removed one by one even when the heating load increases / decreases rapidly, the performance in terms of heating load response speed will inevitably deteriorate.

[0009] The technical problem of the present disclosure is to provide a method and device for controlling the number of cascade boilers, which determine the number of boilers in operation in order to supply heating heat capable of responding to the heating load in a cascade system that operates heating with two or more boilers.

[0010] The technical problem of the present disclosure is to provide a method and device for controlling the number of cascade boilers that can actively determine the number of additional boilers based on the total number of boilers and the temperature difference.

[0011] A method for controlling the number of cascade boilers according to one embodiment of the present disclosure includes the steps of calculating an average heat amount of boilers when heating operation starts; determining whether the average heat amount is equal to or greater than a first reference heat amount set in advance, and calculating a difference between a heating set temperature and a heating supply water temperature when the average heat amount is equal to or greater than the first reference heat amount; and determining an additional number of boilers to be additionally operated based on the difference between the heating set temperature and the heating supply water temperature.

[0012] According to one embodiment, the step of determining the number of additional boilers may determine the number of additional boilers as 1 if the difference between the heating set temperature and the heating supply water temperature is less than the first difference value, determine the number of additional boilers as a first ratio of the total number of boilers if the difference between the heating set temperature and the heating supply water temperature is greater than or equal to the first difference value and less than or equal to the second difference value, and determine the number of additional boilers as a second ratio of the total number of boilers if the difference between the heating set temperature and the heating supply water temperature is greater than or equal to the second difference value.

[0013] According to one embodiment, the first ratio may include 10 to 20%, and the second ratio may include 25 to 35%.

[0014] Furthermore, a method for controlling the number of cascade boilers according to an embodiment of the present disclosure may further include a step of determining whether the average heat quantity is less than a preset second reference heat quantity when the average heat quantity is less than the first reference heat quantity, and determining the number of boilers to be removed for stopping operation when the average heat quantity is less than the second reference heat quantity.

[0015] According to one embodiment, the step of determining the number of additional boilers may determine the number of additional boilers by additionally considering at least one of a heat control speed of each of the entire boilers, an overshoot allowable level of the heating supply water temperature, and a preset number control stability.

[0016] A cascade boiler control device according to another embodiment of the present disclosure includes a determination unit that determines whether the average heat quantity of the boilers is equal to or greater than a first preset reference heat quantity when heating operation starts; a calculation unit that calculates the difference between a heating set temperature and a heating supply water temperature when the average heat quantity is equal to or greater than the first reference heat quantity; and a determination unit that determines the number of additional boilers to be additionally operated based on the difference between the heating set temperature and the heating supply water temperature.

[0017] According to one embodiment, the determination unit may determine the number of additional boilers as 1 if the difference between the heating set temperature and the heating supply water temperature is less than the first difference value, determine the number of additional boilers as a first ratio of the total number of boilers if the difference between the heating set temperature and the heating supply water temperature is greater than or equal to the first difference value and less than or equal to the second difference value, and determine the number of additional boilers as a second ratio of the total number of boilers if the difference between the heating set temperature and the heating supply water temperature is greater than or equal to the second difference value.

[0018] According to one embodiment, the first ratio may include 10 to 20%, and the second ratio may include 25 to 35%.

[0019] According to one embodiment, the judgment unit determines whether the average heat quantity is less than a preset second reference heat quantity when the average heat quantity is less than the first reference heat quantity, and the judgment unit can determine the number of boilers to be removed to stop operation when the average heat quantity is less than the second reference heat quantity.

[0020] According to one embodiment, the decision unit may determine the number of additional boilers by additionally considering at least one of a heat control speed of each of the entire boilers, an overshoot allowable level of the heating supply water temperature, and a preset logarithmic control stability.

[0021] According to the present disclosure, in a cascade system that operates heating with two or more boilers, the number of boilers in operation can be determined to supply heating heat that can respond to the heating load.

[0022] According to the present disclosure, by actively determining the number of additional boilers based on the total number of boilers and the temperature difference, the heating energy supply speed and the heating load response speed can be improved, and the heating control stability can be improved.

[0023] Figure 1 illustrates an example diagram for explaining a cascade system.

[0024] FIG. 2 is a flowchart illustrating an operation of a cascade boiler number control method according to an embodiment of the present disclosure.

[0025] FIG. 3 illustrates an operation flowchart of one embodiment of step S240 of FIG. 2.

[0026] Figure 4 is an example diagram illustrating a method for determining the number of additional boilers according to temperature difference.

[0027] Figure 5 shows an example of calculating the number of additional boilers based on the total number of boilers.

[0028] FIG. 6 is an exemplary diagram comparing initial heating performance according to load conditions by a method according to an embodiment of the present disclosure.

[0029] FIG. 7 is an exemplary diagram comparing performance according to load fluctuations by a method according to an embodiment of the present disclosure.

[0030] FIG. 8 is a block diagram illustrating a configuration of a cascade boiler number control device according to another embodiment of the present disclosure.

[0031] FIG. 9 is a block diagram of a computing system for executing a cascade boiler number control method according to an embodiment of the present disclosure.

[0032] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present disclosure. However, the present disclosure may be implemented in various different forms and is not limited to the embodiments described herein.

[0033] In describing embodiments of the present disclosure, detailed descriptions of known configurations or functions will be omitted if they are deemed to obscure the gist of the present disclosure. Furthermore, portions unrelated to the description of the present disclosure in the drawings have been omitted, and similar portions have been designated with similar reference numerals.

[0034] In the present disclosure, when a component is said to be "connected," "coupled," or "connected" to another component, this may include not only a direct connection, but also an indirect connection in which another component exists in between. Furthermore, when a component is said to "include" or "have" another component, unless otherwise specifically stated, this does not exclude the other component, but rather implies that the other component may be included.

[0035] In this disclosure, terms such as first, second, etc. are used solely to distinguish one component from another, and do not limit the order or importance of components unless specifically stated otherwise. Accordingly, within the scope of this disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

[0036] In this disclosure, distinct components are used only to clearly illustrate their respective characteristics and do not necessarily imply separation. That is, multiple components may be integrated into a single hardware or software unit, or a single component may be distributed into multiple hardware or software units. Therefore, even if not specifically mentioned, such integrated or distributed embodiments are also included within the scope of this disclosure.

[0037] In the present disclosure, the components described in various embodiments are not necessarily essential components, and some may be optional components. Therefore, embodiments comprising a subset of the components described in one embodiment are also within the scope of the present disclosure. Furthermore, embodiments including other components in addition to the components described in various embodiments are also within the scope of the present disclosure.

[0038] In the present disclosure, expressions of positional relationships used in the present specification, such as top, bottom, left, right, etc., are described for convenience of explanation, and when the drawings illustrated in the present specification are viewed in reverse, the positional relationships described in the specification may be interpreted in the opposite way.

[0039] In the present disclosure, each of the phrases "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" may include any one of the items listed together in the corresponding phrase, or all possible combinations thereof.

[0040] The embodiments of the present disclosure aim to improve the heating energy supply speed and heating load response speed, and to improve heating control stability, by actively determining the number of boilers in operation for supplying heating heat capable of responding to the current heating load in a cascade system based on the difference between the current set temperature and the heating supply water temperature.

[0041] Figure 1 illustrates an example diagram for explaining a cascade system.

[0042] As illustrated in Fig. 1, the cascade system may be composed of one master boiler and at least one slave boiler, and may be configured with up to 31 slave boilers.

[0043] The master boiler calculates the average heat by collecting the heat of itself and the slave boilers, and if the average heat is maintained above the preset first reference heat, for example, the Unit ON heat, for a certain period of time, it determines that the heating supply heat is insufficient, calculates the difference between the heating set temperature and the heating supply water temperature, and determines the number of additional boilers to supply heating energy based on the difference between the heating set temperature and the heating supply water temperature.

[0044] Here, the method by which the master boiler calculates the average heat capacity is a technical matter that can be understood by those skilled in the art, so a detailed explanation is omitted.

[0045] In some embodiments, the master boiler may determine the number of additional boilers based on the temperature difference, by comparing the temperature difference with a preset temperature difference range, and determining a certain percentage of the total number of boilers as the number of additional boilers. This is described in detail in FIGS. 4 and 5.

[0046] In an embodiment, the master boiler may determine the number of additional boilers based on the temperature difference, and then operate the additional boilers to quickly supply heating energy, and may control the operation of the additional boilers to be performed for a certain period of time, for example, 5 seconds, and to sequentially turn off the additional boilers one by one for the remaining period of time, for example, 5 seconds. Here, the certain period of time for supplying heating energy to the additional boilers and the certain period of time for sequentially turning off the additional boilers may be determined by a business operator or individual providing the technology of the present disclosure.

[0047] Furthermore, the master boiler can control the heating supply to be maintained if the heating supply water temperature remains at the heating set temperature after the additional boilers have been operated for a certain period of time and the difference between the heating set temperature and the heating supply water temperature is recalculated, and if the heating supply water temperature rises within a certain range from the heating set temperature, the heating supply heat is judged to be excessive and the additional boilers are turned off one by one at certain time intervals. In addition, if the heating supply water temperature rises beyond a certain range from the heating set temperature, the additional boilers can be turned off one by one at a preset number of times.

[0048] FIG. 2 is a flowchart illustrating an operation flowchart for a cascade boiler number control method according to an embodiment of the present disclosure, and illustrates an operation flowchart in a master boiler.

[0049] Referring to FIG. 2, a method for controlling the number of cascade boilers according to an embodiment of the present disclosure calculates the average heat amount of the boilers when heating operation starts, and determines whether the average heat amount is equal to or greater than a preset first reference heat amount, for example, Unit ON heat amount (S210, S220).

[0050] Here, the Unit ON calorie can be 60% of the calorie, and the Unit ON calorie is not necessarily limited or restricted to 60%.

[0051] As a result of the judgment in step S220, if it is determined that the average heat amount is greater than the first reference heat amount, the difference between the heating set temperature and the heating supply water temperature is calculated, and the number of additional boilers to be operated is determined based on the difference between the heating set temperature and the heating supply water temperature (S230, S240).

[0052] On the other hand, if the average calorie is less than the first reference calorie as a result of the judgment in step S220, it is determined whether the average calorie is less than the preset second reference calorie, for example, the Unit OFF calorie (S250).

[0053] Here, the Unit OFF calorie can be 30% of the calorie, and the Unit OFF calorie is not necessarily limited or restricted to 30%.

[0054] As a result of the judgment in step S250, if it is determined that the average heat quantity is less than the first reference heat quantity and less than the second reference heat quantity, one boiler is removed from the number of boilers currently in operation, that is, one boiler is turned off, and the process of calculating the average heat quantity is performed again. If it is determined that the average heat quantity is less than the first reference heat quantity and more than the second reference heat quantity, the number of boilers currently in operation is maintained, and the process of calculating the average heat quantity is performed again (S260, S270).

[0055] According to an embodiment, step S240 may determine the number of additional boilers by using the temperature difference between the heating set temperature and the heating supply water temperature, and the preset first difference value and the second difference value. For example, step S240 determines the number of additional boilers for supplying heating energy as 1 when the temperature difference between the heating set temperature and the heating supply water temperature is less than the preset first difference value, for example, 2 degrees, as illustrated in FIG. 3, and determines whether the temperature difference is greater than or equal to the first difference value and less than the second difference value when the temperature difference between the heating set temperature and the heating supply water temperature is greater than or equal to the first difference value (S310, S320, S330).

[0056] In some embodiments, the first difference value may be 2 degrees, the second difference value may be a value between 5 and 12 degrees, and the default value of the second difference value may be set to 5 degrees.

[0057] As a result of the judgment in step S330, if the temperature difference between the heating set temperature and the heating supply water temperature is greater than or equal to the first difference value and less than or equal to the second difference value, the number of additional boilers for supplying heating energy is determined to be equal to the first ratio of the total number of boilers, and if the temperature difference between the heating set temperature and the heating supply water temperature is greater than or equal to the second difference value, the number of additional boilers for supplying heating energy is determined to be equal to the second ratio of the total number of boilers (S340, S350).

[0058] Here, the first ratio may range from 10 to 20%, and the second ratio may range from 25 to 35%. Of course, the first and second ratios are not limited to the above-described ranges and may be determined based on factors such as the total number of boilers and the installation environment of the cascade system.

[0059] For example, as shown in FIG. 4, if the first difference value is 2 degrees, the second difference value is set to “set value + 2 degrees,” and the temperature difference between the heating set temperature and the heating supply water temperature is less than 2 degrees, 1 boiler is determined as the number of additional boilers, if the temperature difference is 2 degrees or more but less than “set value + 2 degrees,” 15% of the total number of installed boilers (total number of boilers) is determined as the number of additional boilers, and if the temperature difference is “set value + 2 degrees” or more, 30% of the total number of installed boilers can be determined as the number of additional boilers.

[0060] That is, step S240 can increase the additional logarithm as the temperature difference is calculated to be large, and can decrease the additional logarithm as the temperature difference is calculated to be small.

[0061] If more than the appropriate number of boilers is added in step S240, unstable control results may occur, such as overshoot of the heating supply water temperature, frequent repetition of adding / removing boilers, and increased time required to converge to a stable temperature and stable number of boilers. Therefore, step S240 may determine the number of additional boilers by considering the heat control speed of each boiler, the allowable level of overshoot of the heating supply water temperature, and the stability of the boiler control, which may be derived through experiments, etc. As described above, the determination ratio of the additional boilers (% of the total number of boilers) may be changed at any time, and therefore, the determination ratio of the additional boilers defined in the method of the present disclosure is not limited to a fixed value.

[0062] In addition, step S240 has an increased probability of being added to 30% of the total number of installations as the setting value for determining the second difference value decreases, which can improve the heating energy supply speed in an environment where the heating load is relatively large or in a condition where the heating load increases rapidly.

[0063] On the other hand, step S240 has an increased probability of being added to 15% of the total number of installations as the setting value for determining the second difference value increases, which can improve heating control stability in an environment where the heating load is relatively small or in a condition where the heating load increases somewhat gradually.

[0064] If the heating supply water temperature is close to the heating setting temperature, the heating load can be judged to be small, and if additional slave boilers are required, they can be added in smaller numbers. If the heating supply water temperature is far from the heating setting temperature, the heating load can be judged to be large, and if additional slave boilers are required, they can be added in larger numbers.

[0065] Fig. 5 is an example diagram showing the calculation of the number of additional boilers according to the total number of boilers. As shown in Fig. 5, the cascade system can be installed up to 32 times, and the number of additional boilers to be operated can be calculated according to the number of installed boilers. For example, the master boiler can be determined as the number of additional boilers to be operated from 1 to a maximum of 5 by applying a 15% rate to the total number of installed boilers when the temperature difference is 2 degrees or more but less than the "set value + 2 degrees", and can be determined as the number of additional boilers to be operated from 1 to a maximum of 10 by applying a 30% rate to the total number of installed boilers when the temperature difference is "set value + 2 degrees" or more. Figure 5 is calculated by rounding up the additional operating number according to the applied ratio, and the rounding up or down of the calculated value can be determined by the business operator or individual providing the technology of the present disclosure, and the rounding up or down can be different depending on whether the total number of installations is small or large, and the applied setting value, application ratio, etc. can also be different.

[0066] FIG. 6 is an example diagram comparing the initial heating performance according to load conditions by a method according to an embodiment of the present disclosure, and is an example diagram comparing the performance by the existing method of adding one at a time (mass production control) and the method of the present disclosure (improvement control).

[0067] As shown in Fig. 6, the existing method (mass production control) uses a method of adding one unit at a time according to the load, so it can be seen that the time to reach the heating temperature and the time to reach the final stable logarithm are longer than the method of the present disclosure (improved control).

[0068] That is, it can be seen that the method of the present disclosure (improvement control) has a heating temperature reaching time that is on average 23% faster (4.3 times faster) than the existing method (mass production control), and a final stable logarithm reaching time that is on average 27% faster (3.7 times faster) than the existing method (mass production control).

[0069] FIG. 7 is an example diagram comparing performance according to load fluctuations by a method according to an embodiment of the present disclosure, and is an example diagram comparing performances of rapid load fluctuations and gentle load fluctuations by the existing method of adding one at a time (mass production control) and the method of the present disclosure (improvement control).

[0070] As shown in Fig. 7, it can be seen that the temperature recovery speed of the conventional method (mass production control) is longer than that of the method of the present disclosure (improved control) when the load changes abruptly from 10% to 50% or from 10% to 90%.

[0071] That is, it can be seen that the method of the present disclosure (improvement control) has a temperature recovery speed of 38% (2.6 times faster) on average compared to the existing method (mass production control) when the load increases rapidly, and there is no significant difference from the existing method (mass production control) when the load decreases rapidly / slowly increases and decreases.

[0072] In this way, the cascade boiler number control method according to the embodiment of the present disclosure can determine the number of boilers to be operated in order to supply heating heat that can respond to the heating load in a cascade system that operates heating with two or more boilers.

[0073] In addition, the cascade boiler number control method according to the embodiment of the present disclosure can improve the heating energy supply speed and heating load response speed and enhance heating control stability by actively determining the number of additional boilers based on the total number of boilers and the temperature difference.

[0074] FIG. 8 is a block diagram showing a configuration of a cascade boiler number control device according to another embodiment of the present disclosure, and is a block diagram showing a configuration of a device performing the methods of FIGS. 1 to 7.

[0075] Referring to FIG. 8, a cascade boiler control device (800) according to another embodiment of the present disclosure includes a judgment unit (810), a calculation unit (820), a decision unit (830), and a storage unit (840).

[0076] The storage unit (840) is a means for storing all data related to the technology of the present disclosure, and can store information on each boiler of the cascade system, heating set temperature data, heating supply water temperature data, and algorithms related to the technology.

[0077] When heating operation starts, the judgment unit (810) determines whether the average heat amount of the boilers is greater than or equal to the first preset standard heat amount.

[0078] According to an embodiment, the judgment unit (810) may determine whether the average heat amount is less than a preset second reference heat amount if the average heat amount is less than a first reference heat amount.

[0079] The calculation unit (820) calculates the difference between the heating set temperature and the heating supply water temperature when the average heat amount is greater than or equal to the first reference heat amount.

[0080] According to an embodiment, the calculation unit (820) may also calculate the average heat amount of the boilers.

[0081] The decision unit (830) determines the number of additional boilers to be operated based on the difference between the heating set temperature and the heating supply water temperature.

[0082] According to an embodiment, the decision unit (830) may determine the number of additional boilers as 1 if the difference between the heating set temperature and the heating supply water temperature is less than the first difference value, determine the number of additional boilers as a first ratio of the total number of boilers if the difference between the heating set temperature and the heating supply water temperature is greater than or equal to the first difference value and less than or equal to the second difference value, and determine the number of additional boilers as a second ratio of the total number of boilers if the difference between the heating set temperature and the heating supply water temperature is greater than or equal to the second difference value.

[0083] Here, the first ratio may include 10 to 20%, and the second ratio may include 25 to 35%.

[0084] According to an embodiment, the decision unit (830) may determine the number of boilers to be removed to stop operation when the average heat amount is less than the second reference heat amount. For example, the decision unit may determine the number of boilers to be removed to be 1 so that 1 boiler is turned off when the average heat amount is less than the second reference heat amount.

[0085] According to an embodiment, the decision unit (830) may determine the number of additional boilers by additionally considering at least one of the heat control speed of each of the entire boilers, the overshoot allowable level of the heating supply water temperature, and the preset logarithmic control stability.

[0086] Although the description is omitted in the device according to another embodiment of the present disclosure, the device according to another embodiment of the present disclosure may include all the contents described in the method of FIGS. 1 to 7, which is obvious to a person skilled in the art engaged in the technical field of the present disclosure.

[0087] FIG. 9 is a block diagram of a computing system for executing a cascade boiler number control method according to an embodiment of the present disclosure.

[0088] Referring to FIG. 9, the cascade boiler control method according to an embodiment of the present disclosure described above may also be implemented through a computing system. The computing system (1000) may include at least one processor (1100), memory (1300), a user interface input device (1400), a user interface output device (1500), storage (1600), and a network interface (1700) connected via a system bus (1200).

[0089] The processor (1100) may be a central processing unit (CPU) or a semiconductor device that executes processing on instructions stored in memory (1300) and / or storage (1600). The memory (1300) and storage (1600) may include various types of volatile or non-volatile storage media. For example, the memory (1300) may include a read-only memory (ROM) (1310) and a random access memory (RAM) (1320).

[0090] Accordingly, the steps of a method or algorithm described in connection with the embodiments disclosed herein may be implemented directly in hardware, a software module, or a combination of the two executed by the processor (1100). The software module may reside in a storage medium (i.e., memory (1300) and / or storage (1600)), such as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM. An exemplary storage medium is coupled to the processor (1100), such that the processor (1100) can read information from, and write information to, the storage medium. Alternatively, the storage medium may be integral with the processor (1100). The processor (1100) and the storage medium may reside within an application-specific integrated circuit (ASIC). The ASIC may reside within a user terminal. Alternatively, the processor (1100) and the storage medium may reside as discrete components within the user terminal.

[0091] The above description is merely an illustrative description of the technical idea of ​​the present disclosure, and those skilled in the art to which the present disclosure pertains will appreciate that various modifications and variations may be made without departing from the essential characteristics of the present disclosure. Therefore, the embodiments disclosed in the present disclosure are not intended to limit the technical idea of ​​the present disclosure but to explain it, and the scope of the technical idea of ​​the present disclosure is not limited by these embodiments. The scope of protection of the present disclosure should be interpreted by the claims below, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of rights of the present disclosure.

Claims

1. Step of calculating the average heat output of the boilers when heating operation starts; A step of determining whether the average heat amount is greater than or equal to a preset first reference heat amount, and calculating the difference between the heating set temperature and the heating supply water temperature if the average heat amount is greater than or equal to the first reference heat amount; and A step for determining the number of additional boilers to be operated based on the difference between the above heating set temperature and the above heating supply water temperature. A method for controlling the number of cascade boilers, comprising:

2. In paragraph 1, The step of determining the number of additional boilers is: If the difference between the above heating setting temperature and the above heating supply water temperature is less than the first difference value, the number of additional boilers is determined as 1, If the difference between the above heating setting temperature and the above heating supply water temperature is greater than or equal to the first difference value and less than or equal to the second difference value, the number of additional boilers is determined as the first ratio of the total number of boilers, A method for controlling the number of cascade boilers, wherein the number of additional boilers is determined as a second ratio of the total number of boilers when the difference between the heating set temperature and the heating supply water temperature is greater than or equal to the second difference value.

3. In paragraph 2, The above first ratio includes 10 to 20%, A method for controlling the number of cascade boilers, wherein the second ratio comprises 25 to 35%.

4. In paragraph 1, If the average heat amount is less than the first reference heat amount, a step of determining whether the average heat amount is less than the second reference heat amount set in advance, and if the average heat amount is less than the second reference heat amount, a step of determining the number of boilers to be removed to stop operation. A method for controlling the number of cascade boilers, comprising:

5. In paragraph 1, The step of determining the number of additional boilers is: A method for controlling the number of cascade boilers, wherein the number of additional boilers is determined by additionally considering at least one of the heat control speed of each of the entire boilers, the overshoot allowable level of the heating supply water temperature, and the preset logarithmic control stability.

6. A judgment unit that determines whether the average heat output of the boilers is greater than the preset first standard heat output when heating operation begins; A calculation unit that calculates the difference between the heating set temperature and the heating supply water temperature when the above average heat amount is greater than or equal to the first reference heat amount; and A decision unit that determines the number of additional boilers to be operated based on the difference between the above heating set temperature and the above heating supply water temperature. A cascade boiler control device, comprising:

7. In paragraph 6, The above decision-making body, If the difference between the above heating setting temperature and the above heating supply water temperature is less than the first difference value, the number of additional boilers is determined as 1, If the difference between the above heating setting temperature and the above heating supply water temperature is greater than or equal to the first difference value and less than or equal to the second difference value, the number of additional boilers is determined as the first ratio of the total number of boilers, A cascade boiler number control device, which determines the number of additional boilers as a second ratio of the total number of boilers when the difference between the heating set temperature and the heating supply water temperature is greater than or equal to the second difference value.

8. In paragraph 7, The above first ratio includes 10 to 20%, The second ratio is a cascade boiler control device comprising 25 to 35%.

9. In paragraph 6, The above judgment committee, If the above average calorie is less than the first reference calorie, it is determined whether the above average calorie is less than the preset second reference calorie, The above decision-making body, A cascade boiler number control device that determines the number of boilers to be removed to stop operation when the above average heat amount is less than the above second reference heat amount.

10. In paragraph 6, The above decision-making body, A cascade boiler number control device that determines the number of additional boilers by additionally considering at least one of the heat control speed of each of the entire boilers, the overshoot allowable level of the heating supply water temperature, and the preset number control stability.

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