Gas water heating equipment and preheating circulation control method thereof

Abstract

The invention provides gas water heating equipment and a preheating cycle control method thereof. The method comprises the steps that when a preheating circulation mode is triggered, a preheating circulation pump is started immediately; after the preheating circulating pump runs for a preset prolonged time period, the preheating return water temperature starts to be detected; and if the detected preheating return water temperature is larger than the first temperature threshold value, the preheating circulating pump stops running. The preheating circulating pump is immediately started when the preheating circulating mode is triggered, and the preheating return water temperature is delayed to be detected, so that the problem that the preheating circulating function is not started due to the fact that the room temperature of an equipment installation space is too high can be effectively avoided.

Description

Technical Field

[0001] This disclosure relates to the field of gas-fired water heating equipment control, and in particular to a gas-fired water heating equipment and its preheating circulation control method. Background Technology

[0002] Gas-fired water heating systems typically include gas water heaters and gas boilers. Gas water heaters supply hot water for domestic purposes such as drinking and bathing; while gas boilers, in addition to providing domestic hot water, can be connected to radiators installed indoors to provide central heating. Normally, users turn on the mixing tap when they need hot water, which activates the gas water heating system. For a short period after startup, cold water stored in the pipes is discharged, affecting the user experience. To avoid this problem, current gas water heating systems usually have a preheating circulation mode, which circulates the cold water in the preheating pipes when the user is not using hot water, ensuring that hot water is available immediately upon turning on the tap.

[0003] Currently, most users install gas-fired water heaters in the kitchen. In summer, the temperature in the kitchen is high, and the water temperature in the equipment and the water circuit in the kitchen is also high. This causes the detection device inside the equipment to detect the temperature of the preheating circulating water to also detect the return water temperature, which is consistently higher than the start temperature of the preheating circulating pump, thus preventing the preheating circulation function from being activated. Summary of the Invention

[0004] To overcome the problems existing in the prior art, this disclosure provides a gas-fired hot water equipment and a preheating circulation control method thereof.

[0005] A first aspect of this disclosure provides a preheating circulation control method for a gas-fired water heater. The gas-fired water heater includes a casing, a burner, a main heat exchanger, and a preheating circulation pump disposed within the casing, and a bathroom inlet pipe, a bathroom outlet pipe, and a preheating return pipe extending out of the casing; wherein a preheating return water temperature detection device is provided in the preheating return water pipe. The method includes:

[0006] When the preheating circulation mode is triggered, the preheating circulation pump is started immediately;

[0007] After the preheating circulation pump has been running for a predetermined extended period of time, the preheating return water temperature is monitored.

[0008] If the detected preheated return water temperature is greater than the first temperature threshold, the preheating circulation pump will stop running.

[0009] In some embodiments, if the detected preheated return water temperature is less than or equal to a first temperature threshold, the preheating circulation pump continues to operate; the preheated return water temperature continues to be detected, and when the preheated return water temperature is greater than or equal to a second temperature threshold, the preheating circulation pump stops operating, wherein the second temperature threshold is greater than the first temperature threshold.

[0010] In some embodiments, the predetermined extended time period is determined based on the average flow rate of the preheating circulation pump during operation, the extension length of the external water supply pipeline connected to the preheating return water pipeline within the space where the equipment is located, and the diameter of the external water supply pipeline.

[0011] In some embodiments, the predetermined extension period is between 14 and 35 seconds.

[0012] A second aspect of this disclosure provides a computer-readable storage medium having instructions stored thereon that, when executed by a processor, implement the method steps described above.

[0013] A third aspect of this disclosure provides a computer program product including a computer program that, when executed by a processor, implements the method steps described above.

[0014] A fourth aspect of this disclosure provides a gas-fired water heating device, which includes a housing, a burner, a main heat exchanger, and a preheating circulation pump disposed within the housing, a bathroom inlet pipe, a bathroom outlet pipe, and a preheating return pipe extending out of the housing, and a controller; wherein a preheating return water temperature detection device is provided in the preheating return water pipe. The controller is configured to...

[0015] When the preheating circulation mode is triggered, the preheating circulation pump is started immediately;

[0016] After the preheating circulation pump has been running for a predetermined extended period of time, the preheating return water temperature is monitored.

[0017] If the detected preheated return water temperature is greater than the first temperature threshold, the preheating circulation pump will stop running.

[0018] In some embodiments, the controller is further configured to: if the detected preheated return water temperature is less than or equal to a first temperature threshold, to continue operating the preheating circulation pump and continue detecting the preheated return water temperature, and to stop operating the preheating circulation pump when the preheated return water temperature is greater than or equal to a second temperature threshold, wherein the second temperature threshold is greater than the first temperature threshold.

[0019] In some embodiments, the predetermined extended time period is determined based on the average flow rate of the preheating circulation pump during operation, the extension length of the external water supply pipeline connected to the preheating return water pipeline within the space where the equipment is located, and the diameter of the external water supply pipeline.

[0020] In some embodiments, the predetermined extension period is between 14 and 35 seconds.

[0021] In some embodiments, the gas-fired water heater further includes a plate heat exchanger, a heating water pump, and heating return and outlet pipes extending out of the housing.

[0022] The technical solutions provided by one or more embodiments of this disclosure may include the following beneficial effects: by immediately starting the preheating circulation pump when the preheating circulation mode is triggered and delaying the detection of the preheating return water temperature, the problem of the preheating circulation function not starting due to excessively high room temperature in the equipment installation space can be effectively avoided. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic block diagram of a gas-fired water heater connected to a hot water system according to one embodiment of the present disclosure;

[0025] Figure 2 This is a flowchart of a control method for a preheating cycle in one embodiment of a gas-fired hot water equipment;

[0026] Figure 3 This is a flowchart of a preheating cycle control method for a gas-fired water heater in another embodiment. Detailed Implementation

[0027] The embodiments shown will now be described in detail with reference to the accompanying drawings. However, these embodiments do not represent all embodiments consistent with this disclosure, and any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the scope of protection claimed in the appended claims.

[0028] Gas-fired water heating equipment uses combustible gases as fuel, such as natural gas, city gas, liquefied petroleum gas, and biogas, to provide heat to meet users' domestic needs. Examples include gas-fired water heaters that provide domestic hot water, and dual-purpose gas-fired boilers that can simultaneously provide domestic hot water and heating. The following description uses a gas-fired boiler as an example to illustrate the methods and equipment disclosed herein; however, it is clear that the methods and equipment disclosed herein are not limited to this.

[0029] like Figure 1The hot water system shown in one embodiment of this disclosure includes a gas-fired water heater connected to a water point (such as a mixing valve faucet) 90 via a cold water pipe 91 and a hot water pipe 92. A return water pipe 93 connects the gas-fired water heater and the hot water pipe 92. The aforementioned water pipes located outside the equipment can be formed by connecting several water pipes to create a water flow path. There can be multiple water points, each connected to a cold water pipe and a hot water pipe. In this embodiment, water point 90 is the water point furthest or relatively farthest from the gas-fired water heater among several water points. When the gas-fired water heater operates in bathroom mode, i.e., supplying domestic hot water, cold water and hot water are supplied to water point 90 via the cold water pipe 91 and hot water pipe 92 respectively, mixed, and then output. When the gas-fired water heater operates in preheating circulation mode, the water output by the equipment flows back into the equipment via the hot water pipe 92 and the return water pipe 93. Thus, the hot water pipe 92, the return water pipe 93, and the corresponding pipes within the equipment form a preheating loop, ensuring that the water is circulated and heated without cooling down. In some embodiments, a short pipe can be connected between the cold water pipe 91 and the hot water pipe 92 near the water point 90 via two tee fittings. In this way, even if the user did not pre-lay a return water pipe during home renovation, a short pipe can be connected between the cold and hot water pipes at a water point far from the gas water heater (such as under the sink) to achieve the preheating circulation function.

[0030] like Figure 1 The specific embodiment shown is a gas-fired hot water device, which includes a casing 10, a burner 11, a main heat exchanger 12, a flue gas exhaust device 13, and a water circuit module housed within the casing 10. In this embodiment, the casing 10 can be assembled from several panels. The burner 11 can be an atmospheric burner, which typically includes burner units, such as several burner plates (not shown) arranged side by side. Each burner plate is provided with a gas-air mixing channel, in which gas supplied through a gas delivery pipeline mixes with primary air and is then delivered to the flame holes located at the top of the burner plate for combustion to generate hot flue gas. Since the structure and arrangement of the burner plates are well known to those skilled in the art, the applicant will not elaborate further here. The main heat exchanger 12 is usually located above the burner 11, and it can be a finned tube heat exchanger, i.e., the heat exchanger shell is provided with multiple fins, and a hot water suction pipe (not shown) meanders through these fins. The heat carried by the hot flue gas generated by the combustion of burner 11 is absorbed by the fins and further transferred to the water flowing through the hot water intake pipe. The heated water is then output through corresponding pipes. The exhaust system 13 is typically installed on the main heat exchanger 12 and includes a fume hood and an exhaust pipe located on top of the hood. The flue gas generated by combustion (containing waste gases such as carbon monoxide and nitrogen oxides) is collected by the fume hood and discharged to the outside through the exhaust pipe.

[0031] The water circuit module is installed on the bottom plate of the outer casing. It includes a heating return water pipe 21, a bathroom inlet water pipe 22, a bathroom outlet water pipe 23, a heating outlet water pipe 24, and a preheating return water pipe 25 extending from the bottom plate of the outer casing. The bathroom inlet water pipe 22 and the preheating return water pipe 25 are arranged in parallel. The heating return water pipe and the heating outlet water pipe are connected to the radiator or underfloor heating pipe (not shown) installed indoors through pipes to form a heating circuit. The bathroom inlet water pipe 22 is connected to the cold water pipe 91, and the bathroom outlet water pipe 23 is connected to several water points (such as water point 90) in the user's home through the hot water pipe 92 to supply domestic hot water. In this embodiment, the preheating return water pipe 25 is connected to the return water pipe 93 to form part of the preheating circuit. Thus, the water flowing out of the bathroom outlet water pipe 23 passes through the hot water pipe 92 and the return water pipe 93 and flows into the preheating return water pipe 25 to circulate the water in the preheating circuit.

[0032] The water circuit module also includes a heating water pump 31, a preheating circulation pump 32, a three-way valve 40, and a plate heat exchanger 50. A circulating water circuit flows sequentially through the heating water pump 31, the main heat exchanger 12, and the plate heat exchanger 50, returning to the heating water pump 31. The plate heat exchanger 50 is connected to the bathroom water circuit and the circulating water circuit, which include the bathroom inlet pipe 22 and the bathroom outlet pipe 23, thereby achieving heat exchange between the two water circuits. The three-way valve 40 is installed in the heating circuit and the circulating water circuit, allowing selective flow between the heating return and the circulating water circuit. The preheating circulation pump 32 is installed in the preheating return water pipe 25. Furthermore, the preheating return water pipe 25 is equipped with a preheating return water temperature detection device 62, such as a negative temperature coefficient thermistor. In some embodiments, a water flow sensor 61 is installed in the water circuit between the connection between the bathroom inlet pipe 22 and the preheating return water pipe 25 and the plate heat exchanger 50. Other gas-fired water heating equipment, such as gas water heaters, does not include heating-related components and pipes, such as heating water pump 31, three-way valve 40, plate heat exchanger 50, heating return water pipe 21 and heating outlet water pipe 24, etc.

[0033] A controller 19 is disposed within the housing 10 for detecting and controlling the operation of various components and circuit devices within the gas-fired water heater. The controller 19 may be a control circuit comprising a processor, memory, and several electronic components connected in a specific wiring configuration. The processor may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. In this embodiment, the processor is the control center of the gas-fired water heater, connecting various parts of the equipment via various interfaces and lines. For example, the controller is electrically or wirelessly connected to the heating water pump 31, the preheating circulation pump 32, the three-way valve 40, the water flow sensor 61, and the preheating return water temperature detection device 62.

[0034] Memory can be used to store instructions for any application or method that operates on the processor, as well as various types of data. The processor implements the various functions of the gas-fired water heater by running or executing programs or instructions stored in memory and by calling data stored in memory. Memory can contain any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (PROM), magnetic storage, flash memory, solid-state memory, magnetic disk or optical disk, etc.

[0035] Figure 2 The following describes the steps of a preheating cycle control method in one embodiment, and the execution of these method steps by the controller 19 will be described in detail below.

[0036] The preheating circulation mode is triggered (step 701). In some embodiments, the preheating circulation mode may be activated during a fixed time period, such as between 4 PM and 6 PM. The start time of the fixed time period can be arbitrarily set by the user through the device's control panel, remote control, or associated mobile application. In other embodiments, the preheating circulation mode can also be manually activated by the user at any time through the above control methods. When the preheating circulation mode is triggered, the controller 19 outputs voltage to the preheating circulation pump 32 to immediately start the preheating circulation pump (step 702). In the prior art, the controller 19 obtains the return water temperature data in real time through a preheating return water temperature detection device, such as reading the resistance value of a negative temperature coefficient thermistor. However, in the embodiments of this disclosure, the controller 19 does not immediately obtain the return water temperature data, but waits for a predetermined extended time period Sd (step 703). If the predetermined extended time period Sd has not arrived, the preheating circulation pump 32 continues to run (step 705); and when the preheating circulation pump 32 has run for the predetermined extended time period Sd, it begins to detect the preheating return water temperature Tr (step 704).

[0037] The predetermined extension time period Sd is determined based on the average flow rate of the preheating circulation pump 32 during operation, the extension length of the external water pipe connected to the preheating return water pipe within the space where the equipment is located, and the diameter of the external water pipe. For example, if a household water pipe uses a 6-point pipe (DN20 pipe), its standard inner diameter is 19.05mm, then the volume of water in a 1m long 6-point pipe is approximately 0.285L. If the average flow rate of the preheating circulation pump 32 during operation is 6L / min, then the length of water flowed by the circulation pump 32 in one minute is approximately 21m. Depending on the house type, the extension length of the external water pipe connected to the preheating return water pipe 25 (such as the return water pipe 93 in this embodiment) within the space where the equipment is located (such as the kitchen in this embodiment) is approximately between 5 and 12m. Accordingly, the predetermined extension time period can be set between 14 and 35 seconds.

[0038] If the detected preheated return water temperature Tr is greater than the first temperature threshold T1 (step 706), where the first temperature threshold T1 can be the start-up temperature that triggers the preheating cycle, such as 31°C, then the preheating circulation pump 32 stops operating (step 708). Conversely, if the detected preheated return water temperature is less than or equal to the first temperature threshold T1, then the preheating circulation pump continues to operate (step 707), and the preheated return water temperature continues to be detected. When the preheated return water temperature is greater than or equal to the second temperature threshold T2, the preheating circulation pump 32 stops operating. The second temperature threshold T2 being greater than the first temperature threshold T1 typically indicates that the temperature of the preheated circulating water is sufficiently high, such as 37°C, so the preheating circulation pump 32 can be stopped.

[0039] By immediately starting the preheating circulation pump when the preheating circulation mode is triggered and delaying the detection of the preheating return water temperature, the problem of the preheating circulation function not starting due to excessively high room temperature in the equipment installation space can be effectively avoided.

[0040] Figure 3 The steps of a preheating cycle control method in another embodiment are shown below, and the execution of these method steps by the controller 19 is described in detail below.

[0041] The equipment operates in preheating circulation mode. In some embodiments, the preheating circulation mode can be activated during a fixed time period, such as between 4 PM and 6 PM, or it can be activated 24 hours a day. When the previous preheating cycle ends and the preheating circulation pump 32 stops running (step 801), the controller 19 does not immediately acquire the return water temperature data, but waits for a predetermined interruption time Sb (step 802). If the predetermined interruption time Sb has not been reached, it continues to wait; and when the predetermined interruption time Sb has elapsed, it begins to detect the preheated return water temperature Tr (step 803). The predetermined interruption time Sb is set to avoid the problem that the preheating circulation pump 32 will start frequently due to the low room temperature in the equipment installation space, which may further lead to frequent interruptions in heating (once the preheating circulation pump 32 starts, the heating water pump 31 stops running). Therefore, the interruption time Sb should not be set too short or too long, because if the preheating cycle interval is too long, the preheated water temperature in the water pipe will drop too much, thus failing to achieve the preheating effect. Therefore, the predetermined blocking time Sb can be set between 5 and 15 minutes, preferably between 8 and 12 minutes, such as 8 minutes, 10 minutes, 12 minutes, etc.

[0042] Subsequently, it is determined whether the preheated return water temperature Tr is less than or equal to the first temperature threshold T1, i.e., the starting temperature that triggers the preheating circulation pump (step 804). If so, it indicates that the water temperature in the water pipe is low, and the water flow sensor 61 is used to further determine whether there is water flow through the bathroom inlet pipe 22 (step 805). If there is no water flow, the preheating circulation pump 32 is started (step 806), thus avoiding interruption of the user's need for domestic hot water due to triggering the preheating circulation pump. As the preheating circulation pump 32 is running, the preheated return water temperature is continuously monitored, and it is determined whether the preheated return water temperature Tr is greater than or equal to the second temperature threshold T2, or whether the current operation of the preheating circulation pump exceeds the set time (step 806). If either of the above two conditions is met, the preheating circulation pump 32 is stopped (step 808); otherwise, the preheating circulation pump 32 continues to run (step 809). As mentioned above, the second temperature threshold T2 is greater than the first temperature threshold T1. When the preheating circulation pump 32 is running, if a user turns on the tap to use domestic hot water, the circulating water temperature may fail to reach the second temperature threshold T2 for an extended period. During this time, the heating function will be unavailable. Therefore, a set time can be introduced to interrupt the preheating circulation in a timely manner. This set time is determined based on the circulation time of the preheating loop, which includes the preheated return water pipe, and is typically between 3 and 15 minutes. For example, experimental measurements show that for small apartments, the preheating loop is approximately 50 meters long, requiring about 3 minutes of circulation time; for medium-sized apartments, the preheating loop is approximately 70 meters long, requiring about 6 minutes of circulation time; for large apartments, the preheating loop is approximately 160 meters long, requiring about 13 minutes of circulation time; and for buildings such as villas, the circulation time of the preheating loop is generally around 15 minutes.

[0043] By setting a blocking time after the previous preheating cycle ends to delay the acquisition of the preheated return water temperature, the problem of frequent start-up of the preheating circulation pump due to low room temperature in the equipment installation space can be effectively avoided, which may further lead to frequent interruptions in heating.

[0044] All or part of the steps in the methods of the above-disclosed embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or some intermediate form. The readable storage medium can contain any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (PROM), magnetic storage, flash memory, solid-state memory, magnetic disk, or optical disk, etc.

[0045] It should be understood that the methods and apparatus disclosed above can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. The division of units in the controller is only a logical functional division; in actual implementation, there may be other division methods. For example, multiple units may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the connections between the components, parts, and units discussed above can be electrical, mechanical, or other forms of connection; they can be direct connections or indirect connections through interfaces, etc.; they can be wired connections or wireless connections.

[0046] Furthermore, the units described above as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; some or all of the units can be selected to achieve the purpose of the disclosed embodiments according to actual needs. Additionally, the functional units in the above embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated units described above can be implemented in hardware or in a combination of hardware and software functional units.

[0047] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A preheating circulation control method for a gas-fired water heater, the gas-fired water heater comprising a shell, a burner, a main heat exchanger and a preheating circulation pump disposed within the shell, and a bathroom water inlet pipe, a bathroom water outlet pipe and a preheating return pipe extending out of the shell; The preheated return water pipeline is equipped with a preheated return water temperature detection device; its characteristic is that... The method includes: When the preheating circulation mode is triggered, the preheating circulation pump is started immediately; After the preheating circulation pump has been running for a predetermined extended period of time, the preheating return water temperature is monitored. If the detected preheated return water temperature is greater than the first temperature threshold, the preheating circulation pump will stop running.

2. The method according to claim 1, characterized in that: If the detected preheated return water temperature is less than or equal to the first temperature threshold, the preheating circulation pump continues to run; the preheated return water temperature continues to be detected, and when the preheated return water temperature is greater than or equal to the second temperature threshold, the preheating circulation pump stops running, wherein the second temperature threshold is greater than the first temperature threshold.

3. The method according to claim 1, characterized in that: The predetermined extension time period is determined based on the average flow rate of the preheating circulation pump during operation, the extension length of the external water supply pipeline connected to the preheating return water pipeline within the space where the equipment is located, and the diameter of the external water supply pipeline.

4. The method according to claim 1, 2 or 3, characterized in that: The predetermined extension period is between 14 and 35 seconds.

5. A computer-readable storage medium having instructions stored thereon, characterized in that: When the instructions are executed by the processor, they implement the steps of the method as described in any one of claims 1-4.

6. A computer program product comprising a computer program, characterized in that: When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1-4.

7. A gas-fired hot water device, characterized in that: The gas-fired water heater includes a casing, a burner, a main heat exchanger, and a preheating circulation pump housed within the casing, a bathroom inlet pipe, a bathroom outlet pipe, and a preheating return pipe extending out of the casing, and a controller; wherein a preheating return water temperature detection device is provided in the preheating return water pipe; the controller is configured to... When the preheating circulation mode is triggered, the preheating circulation pump is started immediately; After the preheating circulation pump has been running for a predetermined extended period of time, the preheating return water temperature is monitored. If the detected preheated return water temperature is greater than the first temperature threshold, the preheating circulation pump will stop running.

8. The gas-fired hot water equipment according to claim 7, characterized in that: The controller is further configured to, if the detected preheated return water temperature is less than or equal to a first temperature threshold, continue to operate the preheating circulation pump and continue to detect the preheated return water temperature, and stop operating the preheating circulation pump when the preheated return water temperature is greater than or equal to a second temperature threshold, wherein the second temperature threshold is greater than the first temperature threshold.

9. The gas-fired hot water equipment according to claim 7, characterized in that: The predetermined extension time period is determined based on the average flow rate of the preheating circulation pump during operation, the extension length of the external water supply pipeline connected to the preheating return water pipeline within the space where the equipment is located, and the diameter of the external water supply pipeline.

10. The gas-fired hot water equipment according to claim 7, 8 or 9, characterized in that: The predetermined extension period is between 14 and 35 seconds.

11. The gas-fired hot water equipment according to claim 7, characterized in that: Gas-fired water heating equipment also includes plate heat exchangers, heating water pumps, and heating return and outlet water pipes extending from the outer casing.

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