CN111912117A - Constant temperature control method of gas water heater - Google Patents
Constant temperature control method of gas water heater Download PDFInfo
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- CN111912117A CN111912117A CN202010790267.0A CN202010790267A CN111912117A CN 111912117 A CN111912117 A CN 111912117A CN 202010790267 A CN202010790267 A CN 202010790267A CN 111912117 A CN111912117 A CN 111912117A
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 117
- 238000000034 method Methods 0.000 title claims abstract description 28
- 238000010438 heat treatment Methods 0.000 claims description 68
- 238000005070 sampling Methods 0.000 claims description 43
- 238000004364 calculation method Methods 0.000 claims description 40
- 238000007599 discharging Methods 0.000 claims description 6
- 238000006243 chemical reaction Methods 0.000 abstract description 5
- 238000003287 bathing Methods 0.000 abstract description 4
- 239000007789 gas Substances 0.000 description 27
- 238000002485 combustion reaction Methods 0.000 description 4
- 230000001186 cumulative effect Effects 0.000 description 3
- 238000013459 approach Methods 0.000 description 2
- 239000002737 fuel gas Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
- F24H9/00—Details
- F24H9/20—Arrangement or mounting of control or safety devices
- F24H9/2007—Arrangement or mounting of control or safety devices for water heaters
- F24H9/2035—Arrangement or mounting of control or safety devices for water heaters using fluid fuel
Abstract
The invention discloses a constant temperature control method of a gas water heater, wherein the constant temperature control method in the embodiment is applied to the gas water heater, so that the heat conversion relation is calculated through the acquisition of the heat energy conversion relation, the PID algorithm fuzzy control is used for the control deviation of the preset target temperature, and the opening degree of a gas proportional valve is controlled to enable the outlet water temperature to be close to the preset target temperature, so that the constant temperature control of the gas water heater is realized. The method is simple and reliable, and the temperature of the outlet water can reach a constant value, thereby bringing good bathing experience to users.
Description
Technical Field
The invention relates to the technical field of water heaters, in particular to a constant temperature control method of a gas water heater.
Background
In the related art, most of gas water heaters are subject to water pressure, air pressure and difference of various components, so that the temperature of outlet water is often suddenly cooled and suddenly heated, and bad bathing experience of users is caused. Therefore, the constant temperature problem of the outlet water temperature of the gas water heater becomes a technical problem to be solved urgently in the existing gas water heater.
Disclosure of Invention
The invention aims to solve at least one of the problems in the prior related art to a certain extent, and therefore, the invention provides a constant temperature control method of a gas water heater, which is simple and reliable and can make the outlet water temperature reach a constant value, thereby bringing good bathing experience to users.
The above purpose is realized by the following technical scheme:
a thermostatic control method of a gas water heater comprises the following steps:
starting the gas water heater and igniting successfully;
collecting a water flow value Q of the gas water heater;
calculating the water flow value Q to obtain heating energy E0, and heating according to the calculated heating energy E0;
calculating the water flow value Q to obtain the current sampling period;
judging whether the PID operation exceeds the preset period regulation times K and TGo out>TTarget+ K or TGo out>TTarget-K；
If so, eliminating the PID data and continuing heating according to the heating energy E0;
if not, performing PID operation on each sampling period to obtain an Ep operation value, an Ei operation value and an Ed operation value, and simultaneously calculating PID operation parameters to obtain EPIDA value;
will calculate the obtained EPIDThe value is compared with a preset coefficient, and whether to reduce the heating energy or increase the heating energy is determined according to the comparison result.
In some embodiments, the heating energy E0 is calculated by the following calculation formula: e0 ═ Q × Δ T, where Q is the current water flow value and Δ T is the amount of temperature change.
In some embodiments, the sampling period is calculated by the following calculation formula: hSampling＝HHeating of/Q/F, wherein HSamplingFor a sampling period, HHeating ofAnd in the heating period, Q is the current water flow value, and F is the preset sampling frequency.
In some embodiments, the heating period HHeating ofThe calculation is carried out by the following calculation formula: hHeating ofI is the time required for the cold water at the water inlet end to be heated to the hot water at the water outlet end, and Q is the current water flow value.
In some embodiments, the P operation specifically includes:
the sampling period is calculated through P to obtain an Ep calculation value, wherein Ep is Err multiplied by Kp/100, Err is an energy deviation value, and Kp is a first preset threshold value.
In some embodiments, the I operation specifically includes:
the sampling period is calculated by I to obtain an Ei calculation value, Ei ═ TAt present–TLast time) Q is Ki/100, wherein TAt presentFor the current heating temperature, TLast timeKi is the second preset threshold value for the last heating temperature.
In some embodiments, the D operation specifically includes:
until T is reached in the case of a number of successive preset period adjustments KGo outMaximum value-TGo outMinimum value<First set value and TGo outSatisfy TTargetPlus or minus a second set value, simultaneously Ep<A third set value;
and the sampling period is operated by D to obtain an Ed operation value, wherein the Ed is Kd (accumulated Err value/K)/100, Kd is a third preset threshold, the accumulated Err value is a preset period adjustment time K times Ep accumulated value/preset period adjustment time K, and K is a preset period adjustment time.
In some embodiments, the E isPIDThe value is calculated by the following calculation formula: ePIDEp + Ei + Ed, where Ep is the Ep calculation, Ei is the Ei calculation, and Ed is the Ed calculation.
In some embodiments, the Err is calculated by the following calculation: err ═ TDischarging water-TTarget) Q, wherein TDischarging waterAs the outlet water temperature value, TTargetAnd Q is a current water flow value for a preset target temperature value.
In some embodiments, the E to be calculatedPIDComparing the value with a first preset coefficient, and determining whether to reduce the heating energy according to the comparison result, wherein the step of reducing the heating energy specifically comprises the following steps:
judging the calculated EPIDWhether the value is greater than a preset coefficient;
if so, reducing the heating energy and returning to continue calculating the current sampling period;
if not, increasing the heating energy and returning to continue calculating the current sampling period.
Compared with the prior art, the invention at least comprises the following beneficial effects:
1. the constant temperature control method of the gas water heater is simple and reliable, and can enable the outlet water temperature to reach a constant value, thereby bringing good bathing experience to users.
Drawings
FIG. 1 is a schematic flow chart illustrating a method for controlling gear-shifting according to an embodiment of the present invention;
FIG. 2 is a graph of sample period versus water flow rate in an embodiment of the present invention;
FIG. 3 is a table of control parameters in an embodiment of the present invention.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, shall fall within the scope of the claims of the present invention.
As shown in fig. 1 to 3, the present embodiment provides a thermostatic control method for a gas water heater, in which the thermostatic control method in the present embodiment is applied to the gas water heater to calculate a heat conversion relationship through collection of a heat energy conversion relationship, fuzzy control is performed on a control deviation of a preset target temperature by using a PID algorithm, and an opening degree of a gas proportional valve is controlled to make an outlet water temperature approach the preset target temperature, so that the gas water heater realizes thermostatic control.
The constant temperature control method of the gas water heater specifically comprises the following steps:
and step S101, starting the gas water heater and igniting successfully.
In the embodiment, the gas water heater is in a standby state, ignition is started after a water flow signal is detected, a constant temperature control program can be entered after ignition is successful, and if no water flow signal is detected, the valve is closed to stop heating.
And S102, collecting a water flow value Q of the gas water heater.
In step S103, the water flow rate value Q is calculated to obtain heating energy E0, and heating is performed according to the calculated heating energy E0.
In the present embodiment, the heating energy E0 is calculated by the following calculation formula: e0 is Q × Δ T, where Q is the current water flow rate and Δ T is the temperature change, i.e., Δ T is the change in the temperature of the water after heat absorption.
And step S104, calculating the water flow value Q to obtain the current sampling period.
In this embodiment, the sampling period is calculated by the following calculation formula: hSampling＝HHeating of/Q/F, wherein HSamplingFor a sampling period, HHeating ofFor a heating period, Q is the current water flow value, F is the preset sampling times, and H is the heating periodHeating ofThe calculation is carried out by the following calculation formula: hHeating ofI is the time required for the cold water at the water inlet end to be heated to the hot water at the water outlet end, and Q is the current water flow value.
In this embodiment, cold water at the water inlet end enters the fins of the heat exchanger to exchange heat, the length of each coil is 30cm, and the cold water flows out to the position of the water outlet end, that is, the length of each coil is 30cm, cold water flows in from the water inlet end and outputs hot water from the water outlet end, the passing length of the water flow is 180cm in total, and the inner diameter of the water pipe is 10.9mm, so that the water storage volume from the water inlet end to the water outlet end can be calculated to be 0.56L, and when the water flow is 8L/min, the time I required for heating the cold water at the water inlet end to the hot water at the water outlet end is (0.56/8) × 60 ═ 4.2 s. This time is inversely related to the water flow, i.e. HHeating of33.6/Q, so the water flow is in inverse proportion to the sampling period, that is, the smaller the water flow is, the larger the sampling period is, when the preset sampling times are 10, 10 points are taken at the position between the water inlet end and the water outlet end for each heating period to control, and then the sampling period H isSamplingThen is HSampling3.36/8/10s, i.e. HSampling＝0.042。
Step S105, judging whether PID operation exceeds the preset period regulation times K and TGo out>TTarget+ K or TGo out>TTarget-K；
If yes, the process goes to step S115, PID data is eliminated, and heating is continued according to heating energy E0;
if not, the process proceeds to step S125, and performs PID calculation on each sampling period to obtain Ep calculation value, Ei calculation value, and Ed calculation value, and meanwhile calculates PID calculation parameters to obtain EPIDThe value is obtained.
In the present embodiment, TGo outFor the real-time detected outlet water temperature, TTargetFor presetting the target temperature value, the preset period adjustment number K is preferably 20, but is not limited to the above value, and other more suitable values may be selected according to actual needs. If the preset period adjustment time K is 20, then when the PID operation exceeds the preset period adjustment time K and TGo out>TTarget+20, so an abnormal overshoot is considered; or when the PID operation exceeds the preset period regulation times K and T is reachedGo out>TTargetAt-20, a low key is considered to be present.
In this embodiment, the sampling period is calculated by P to obtain an Ep calculation value, where Ep is Err × Kp/100, where Err is an energy deviation value and Kp is a first preset threshold, and Err is calculated by the following calculation formula: err ═ TDischarging water-TTarget) Q, wherein TDischarging waterAs the outlet water temperature value, TTargetIn the present embodiment, the first preset threshold value Kp is preferably 10, and the larger the first preset threshold value Kp is, the faster the response is, but the overshoot is more, if the target value is larger, the compensation control heating value is larger.
In this embodiment, since P is calculated, when the control load is increased, the outlet water temperature and the actual control are performedThe heating temperature has large hysteresis, so I operation is required to be added for carrying out advance estimation operation, the hysteresis of control is eliminated, overshoot is prevented, and the sampling period obtains the operation value of Ei through the I operation, wherein Ei is (T)At present–TLast time) Q is Ki/100, wherein TAt presentFor the current heating temperature, TLast timeFor the last heating temperature, Ki is a second preset threshold, in this embodiment, Ki is 20, and the larger the value of Ki is, the more the delay will be, but the target value cannot be reached for a long time.
In the present embodiment, when the P operation value is too small or equal to 0, the outlet water temperature may be kept 1 ℃ from the target temperature. In this embodiment, the D operation specifically includes:
until T is reached in the case of a number of successive preset period adjustments KGo outMaximum value-TGo outMinimum value<First set value and TGo outSatisfy TTargetPlus or minus a second set value, simultaneously Ep<A third set value;
the sampling period is calculated by D to obtain an Ed calculation value, Ed ═ Kd (Err cumulative value/K)/100, where Kd is a third preset threshold, in the embodiment in the market, the third preset threshold Kd is preferably 5 × Kp, the Err cumulative value is a preset period adjustment number K times Ep cumulative value/preset period adjustment number K, and K is a preset period adjustment number.
Thus, EPIDThe value is calculated by the following calculation formula: ePIDAnd (2) setting the sum to Ep + Ei + Ed, wherein Ep is an Ep calculation value, Ei is an Ei calculation value, Ed is an Ed calculation value, and Ep, Ei and Ed are all distinguished in positive and negative.
Step S106, judging the calculated EPIDWhether the value is greater than a preset coefficient;
if yes, the method goes to step S116, reduces the heating energy and returns to step S104 to continue calculating the current sampling period;
if not, the process proceeds to step S126, where the heating energy is increased and the process returns to step S104 to continue calculating the current sampling period.
In the present embodiment, the predetermined coefficient is preferably 0, but not limited to the above value, and may be determined according to the factOther more suitable values are selected as required, and the preset coefficient is taken as 0 in this embodiment for example, and the other values are not described again. When the predetermined coefficient is 0, then the resulting E will be calculatedPIDThe value is compared with 0 if Epid<When the temperature is 0, the current state is in a low state, and the heating energy Epid is increased; if Epid>0, the current state is in overshoot and the heating energy Epid is reduced. In this embodiment, the calculated EPIDAnd comparing the value with a preset coefficient, determining whether to reduce heating energy or increase heating energy according to a comparison result, and calculating the current gear and the current value of the proportional valve through conversion so as to control the opening of the gas proportional valve until the outlet water temperature is close to the target temperature, thereby realizing constant temperature control of the gas water heater.
In this embodiment, the heat conservation model of the gas water heater is hot water heating heat, i.e. gas combustion heat-heat dissipation heat. The heating heat of the hot water can be represented by the formula E ═ CM Δ T, i.e. E ^ Q × Δ T, and in addition, the effective energy of the part of the gas combustion energy-heat dissipation heat can be regarded as being in a direct proportion relation with the gas proportional valve.
The energy level E ═ Q ×. Δ T is set, and from this, the proportion E ∈ B can be obtained.
A PID control model: q, TInto、TTargetFor known quantity, the proportion B is obtained from the proportional relation, and T is obtainedGo outBy setting the control deviation Err to TGo out-TTargetPID operations are performed to continuously correct the B ratio so that Err approaches 0.
In this embodiment, the constant temperature model shows that the combustion heat system is regarded as a whole, only the input of the fuel gas is concerned, the output of the temperature and the flow rate are controlled and input through the output difference to form closed-loop control, so that the fuel gas system has certain adaptivity, but the delay constant of the temperature sensor, the degree of charge of the flame combustion, the gas purity, the gas pressure stability and the like all affect the control stability of the system, such as: the temperature sensor delay constant (thermal inertia, hysteresis) was 1.8S.
In this embodiment, as shown in fig. 3, a gas water heater fire grate is described by taking 2-4-6 segments as an example, then PH in fig. 3 is the maximum load of the whole machine, that is, the opening degree of the proportional valve is the maximum at this time, PL is the maximum load of the whole machine, that is, the opening degree of the proportional valve is the maximum at this time, and all parameters in fig. 3 need to be entered into a controller program for load calculation, so as to realize accurate control of the opening degree and the segment gear of the proportional valve. In the program control in this embodiment, the energy level is used as the control object, and if the current Q × Δ T is 2000, the gear is first selected to be 2, and then the proportional valve current is proportional to the energy level, so as to obtain the proportional valve current as (2000 + 880)/(2160 + 880) × (186 + 120) + 120.
What has been described above are merely some embodiments of the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the inventive concept thereof, and these changes and modifications can be made without departing from the spirit and scope of the invention.
Claims (10)
1. A thermostatic control method of a gas water heater is characterized by comprising the following steps:
starting the gas water heater and igniting successfully;
collecting a water flow value Q of the gas water heater;
calculating the water flow value Q to obtain heating energy E0, and heating according to the calculated heating energy E0;
calculating the water flow value Q to obtain the current sampling period;
judging whether the PID operation exceeds the preset period regulation times K and TGo out>TTarget+ K or TGo out>TTarget-K；
If so, eliminating the PID data and continuing heating according to the heating energy E0;
if not, performing PID operation on each sampling period to obtain an Ep operation value, an Ei operation value and an Ed operation value, and simultaneously calculating PID operation parameters to obtain EPIDA value;
will calculate the obtained EPIDThe value is compared with a preset coefficient, and whether to reduce the heating energy or increase the heating energy is determined according to the comparison result.
2. The thermostatic control method of a gas water heater as claimed in claim 1, wherein the heating energy E0 is calculated by the following calculation formula: e0 ═ Q × Δ T, where Q is the current water flow value and Δ T is the amount of temperature change.
3. The thermostatic control method of a gas water heater according to claim 1, wherein the sampling period is calculated by the following calculation formula: hSampling＝HHeating of/Q/F, wherein HSamplingFor a sampling period, HHeating ofAnd in the heating period, Q is the current water flow value, and F is the preset sampling frequency.
4. Thermostatic control method for a gas water heater according to claim 3, characterized in that said heating period HHeating ofThe calculation is carried out by the following calculation formula: hHeating ofI is the time required for the cold water at the water inlet end to be heated to the hot water at the water outlet end, and Q is the current water flow value.
5. The thermostatic control method of a gas water heater according to claim 1, wherein the P-operation specifically comprises:
the sampling period is calculated through P to obtain an Ep calculation value, wherein Ep is Err multiplied by Kp/100, Err is an energy deviation value, and Kp is a first preset threshold value.
6. The thermostatic control method of a gas water heater according to claim 5, wherein the I operation specifically comprises:
the sampling period is calculated by I to obtain an Ei calculation value, Ei ═ TAt present–TLast time) Q is Ki/100, wherein TAt presentFor the current heating temperature, TLast timeKi is the second preset threshold value for the last heating temperature.
7. The thermostatic control method of a gas water heater according to claim 6, wherein the D operation specifically comprises:
until T is reached in the case of a number of successive preset period adjustments KGo outMaximum value-TGo outMinimum value<First set value and TGo outSatisfy TTargetPlus or minus a second set value, simultaneously Ep<A third set value;
and the sampling period is operated by D to obtain an Ed operation value, wherein the Ed is Kd (accumulated Err value/K)/100, Kd is a third preset threshold, the accumulated Err value is a preset period adjustment time K times Ep accumulated value/preset period adjustment time K, and K is a preset period adjustment time.
8. The thermostatic control method of a gas water heater according to claim 7, wherein E is the temperature of the gas water heaterPIDThe value is calculated by the following calculation formula: ePIDEp + Ei + Ed, where Ep is the Ep calculation, Ei is the Ei calculation, and Ed is the Ed calculation.
9. The thermostatic control method of a gas water heater as claimed in claim 5, wherein the Err is calculated by the following calculation formula: err ═ TDischarging water-TTarget) Q, wherein TDischarging waterAs the outlet water temperature value, TTargetAnd Q is a current water flow value for a preset target temperature value.
10. The thermostatic control method for a gas water heater according to claim 1, wherein said E obtained by calculationPIDComparing the value with a first preset coefficient, and determining whether to reduce the heating energy according to the comparison result, wherein the step of reducing the heating energy specifically comprises the following steps:
judging the calculated EPIDWhether the value is greater than a preset coefficient;
if so, reducing the heating energy and returning to continue calculating the current sampling period;
if not, increasing the heating energy and returning to continue calculating the current sampling period.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113340003A (en) * | 2021-06-17 | 2021-09-03 | 东莞市艾瑞科热能设备有限公司 | Gas water heater and control method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113340003A (en) * | 2021-06-17 | 2021-09-03 | 东莞市艾瑞科热能设备有限公司 | Gas water heater and control method thereof |
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