A method for evaluating low-nitrogen economic operation of gas-fired heating water boilers

Abstract

The present invention discloses a method for evaluating the low-nitrogen economic operation of a gas-fired heating water heater, comprising the following steps: determining a single evaluation index; calculating the single evaluation index used to evaluate each gas-fired heating water heater to obtain the values ​​of each single evaluation index and performing standardization to obtain the standardized values ​​of the single evaluation index; using the standardized values ​​of the single evaluation index to construct a calculation model of the classification index evaluation index of each gas-fired heating water heater and the weight of the single evaluation index in each classification index evaluation index; constructing the weights of the three classification index evaluation indicators of the cost index, energy consumption index and operation index of each gas-fired heating water heater, and obtaining the economic index and low-nitrogen economic index of each gas-fired heating water heater by calculation; and evaluating the low-nitrogen operation performance of the water heater. The method can classify the overall low-nitrogen economic operation of the product.

Description

Technical Field

[0001] The invention relates to an operation control method for a heating water heater, in particular to a low-nitrogen economic operation evaluation method for a gas-fired heating water heater. Background Art

[0002] At present, the common low-nitrogen technologies for gas heating water boilers include full premixed combustion, water-cooled low-nitrogen combustion, increasing the number of single-chip burners, and concentrated and diluted combustion. When gas heating water boilers use different low-nitrogen technologies, their key components are configured differently. x The economic cost varies with the content.

[0003] The Chinese patent with publication number CN111861101A discloses "a method for evaluating the operating performance of a gas-fired heating water boiler based on principal component analysis". It combines the structural characteristics, combustion characteristics and operating performance of the gas-fired heating water boiler to determine the factors affecting its operating performance; collects test data of the factors affecting the operating performance of multiple gas-fired heating water boilers to form a test set and obtains an evaluation matrix; performs data standardization on the test data of each influencing factor to obtain a standardized evaluation matrix; determines the correlation coefficients between the influencing factors based on the standardized evaluation matrix and its transposed matrix to obtain a correlation coefficient matrix; determines a new comprehensive evaluation index to obtain an operating performance evaluation model; selects appropriate samples to verify the rationality of the evaluation model, and finally determines the comprehensive ranking of the test samples.

[0004] In 2019, the paper "Operation Performance Evaluation of Gas Heating Water Boilers Based on Principal Component Analysis" was published in Volume 39, Issue 3, Pages 29-34 of "Gas and Heat" magazine. It proposed a method based on the operating performance indicators of gas heating water boilers, using principal component analysis to construct an evaluation model for the operating performance of gas heating water boilers.

[0005] The above patents and papers only focus on ordinary atmospheric gas heating water heaters, and only select the combustion characteristics of gas heating water heaters during normal operation, including thermal efficiency, exhaust gas temperature, O2, CO, CO2, NO in the flue gas. x It fails to comprehensively consider the low nitrogen and economy of all types of gas heating water boilers (including ordinary atmospheric type, water-cooled low nitrogen type, secondary heat exchange condensing type, and full premixed condensing type), fails to include the various costs of gas heating water boilers in the economic evaluation, and fails to classify the operating performance of gas heating water boilers into different levels. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an accurate, quantitative and effective gas heating water heater low nitrogen economic operation evaluation method which uses a model to calculate the specific value of the low nitrogen economy of the gas heating water heater.

[0007] A method for evaluating low-nitrogen economic operation of a gas-fired heating water heater of the present invention comprises the following steps:

[0008] Step 1: Determine a single evaluation indicator, which includes key costs, additional costs, maintenance costs, operating costs, fuel costs, electricity costs, NO x Volume fraction conversion value and CO volume fraction conversion value;

[0009] The key cost mentioned here refers to the purchase cost of key components of the gas heating water heater related to the heat load;

[0010] The additional cost mentioned refers to the purchase cost of gas heating water heater components that are not related to the heat load;

[0011] The maintenance cost mentioned refers to the cost of replacing components of the gas heating water heater;

[0012] The operating cost mentioned above refers to the cost that affects the user's use when a combustion failure occurs during the operation of the gas heating water heater;

[0013] Fuel cost refers to the cost of fuel consumed by a gas heating water heater per unit time;

[0014] The NO x The volume fraction conversion value and the volume fraction conversion value of CO refer to the NO in the flue gas emitted by the gas heating water boiler. x The volume fraction conversion value and the volume fraction conversion value of CO;

[0015] Step 2: Calculate the single evaluation index used to evaluate each gas heating water heater to obtain the value of each single evaluation index:

[0016] Step 3: Standardize the values ​​of the single evaluation indexes of all gas-fired heating water heaters used for evaluation to obtain standardized values ​​of the single evaluation indexes;

[0017] Step 4: Use the standardized value of a single evaluation index to construct a calculation model for the classification index evaluation index of each gas heating water heater, divide the standardized single evaluation index into four types of index evaluation indicators, namely cost index, energy consumption index, operation index, and low nitrogen index, and construct the weight of the single evaluation indicator in each classification index evaluation indicator;

[0018] Step 5: Construct the weights of the three classification index evaluation indicators of cost index, energy consumption index and operation index for each gas heating water heater;

[0019] Step 6: Construct a mathematical model of the economic index of the gas heating water heater according to the weights of the three classification index evaluation indicators of the cost index, energy consumption index and operation index of each gas heating water heater, and obtain the economic index of each gas heating water heater by calculation;

[0020] Step 7: construct a low-nitrogen economic index mathematical model of each gas-fired heating water heater according to the low-nitrogen index and economic index of each gas-fired heating water heater, and obtain the low-nitrogen economic index of each gas-fired heating water heater by calculation;

[0021] Step 8: Quantitatively evaluate the low nitrogen operation performance of all gas-fired heating water heaters used for evaluation:

[0022] The low nitrogen economic index values ​​of all gas heating water heaters under evaluation are ranked from low to high. The smaller the low nitrogen economic index value, the higher the low nitrogen economy.

[0023] Step 9. Use cluster analysis to conduct a qualitative evaluation of the low-nitrogen operation of all gas-fired heating water heaters used for evaluation, and divide the gas-fired heating water heaters into products of different levels.

[0024] Advantages of the present invention:

[0025] 1. The present invention determines the low-nitrogen economic evaluation index, provides a calculation model for each index, and conducts evaluation and analysis based on this.

[0026] 2. The present invention establishes a mathematical model for evaluating the low-nitrogen economic efficiency of a gas-fired heating water heater, and conducts evaluation and analysis based on this model.

[0027] 3. The present invention provides a scientific, accurate and quantitative evaluation method, which can calculate the real and specific low-nitrogen economic index based on the actual product information of the gas heating water boiler through an evaluation mathematical model, and sort them according to the index value.

[0028] 4. The present invention provides a scientific and effective classification method. Based on the low-nitrogen economic index of gas-fired heating water boilers, the economic values ​​can be scientifically and effectively divided into different categories, and the overall low-nitrogen economic operation of the product can be classified.

[0029] 5. The present invention can replace subjective judgment based on human experience. It can provide a specific low-nitrogen economy index value at the level of a single gas heating water boiler, and can provide a specific low-nitrogen economy classification at the level of all gas heating water boilers. Compared with subjective judgment based on human experience, this method is more scientific, accurate, quantitative and effective. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0031] Figure 1 The present invention is a flow chart of a method for evaluating low-nitrogen economic operation of a gas-fired heating water boiler.

[0032] Figure 2 It is an evaluation index of a low-nitrogen economic operation evaluation method for a gas-fired heating water boiler according to the present invention. DETAILED DESCRIPTION

[0033] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in the present application have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0034] Reference Figure 1 and Figure 2 The present invention provides a method for evaluating low-nitrogen economic operation of a gas-fired heating water heater, comprising the following steps:

[0035] Step 1: Determine a single evaluation indicator, which includes key costs, additional costs, maintenance costs, operating costs, fuel costs, electricity costs, NO x Volume fraction conversion value and CO volume fraction conversion value;

[0036] The key costs mentioned refer to the purchase costs of key components of the gas heating water heater related to the heat load, such as: burners, heat exchangers, condensing heat exchangers and other key components related to the heat load.

[0037] The additional cost mentioned above refers to the purchase cost of gas heating water heater components that are not related to the heat load. For gas heating water heaters that use different low-nitrogen technologies or different types and configurations, in addition to the key components related to the rated heat load, other components that are not related to the rated heat load, such as gas valves, fans, water pumps, wind pressure switches / wind pressure sensors, condensate collection devices, etc., also affect the low-nitrogen economical operation of the gas heating water heater. The purchase cost of these components can be regarded as additional costs.

[0038] The maintenance cost mentioned refers to the cost of replacing components of the gas heating water heater, including key components and additional components used in the gas heating water heater.

[0039] The operating cost refers to the cost that affects the user's use when a combustion failure occurs during the operation of the gas heating water heater. Gas heating water heaters of different types and configurations may have combustion problems during operation. The combustion problems mainly include flame separation, ignition difficulties, and easy flameout and shutdown under partial load of domestic hot water. These problems directly affect the user's comfort experience and are also indirect factors affecting the low-nitrogen economic operation of gas heating water heaters.

[0040] Fuel cost refers to the cost of fuel consumed by a gas-fired heating water heater per unit time. Thermal efficiency is the effective utilization rate of fuel. For a gas-fired heating water heater with the same rated heat load, the higher the thermal efficiency, the less fuel cost is consumed and the higher the economy is. The main indicator that reflects the economic performance of a gas-fired heating water heater during operation is operating efficiency. The thermal efficiencies of different types of gas-fired heating water heaters under different operating conditions vary greatly, so thermal efficiency is used as an indicator to reflect fuel cost.

[0041] The electricity consumption cost is used as an evaluation indicator because the fans, water pumps and other components in the gas heating water boiler can be divided into variable frequency and fixed frequency. The power consumption is different when the gas heating water boiler uses fixed frequency fans and water pumps with different rated power, or when the gas heating water boiler uses variable frequency fans and water pumps, the power consumption under different heat load conditions is also different.

[0042] The NO x The volume fraction conversion value and the volume fraction conversion value of CO refer to the NO in the flue gas emitted by the gas heating water boiler. x The volume fraction conversion value and the volume fraction conversion value of CO.

[0043] NO in flue gas in the above evaluation indicators x and CO reflect the evaluation indicators of low nitrogen of gas heating water boiler; key cost, additional cost, maintenance cost, operating cost, fuel cost, electricity consumption cost, etc. reflect the evaluation indicators of economic operation of gas heating water boiler.

[0044] Step 2: Calculate the single evaluation index used to evaluate each gas heating water heater to obtain the value of each single evaluation index:

[0045] The calculation model of the key costs is as follows:

[0046] (j1=1,2,...,n1)

[0047] Among them, F i1 is the key cost of the i-th gas heating water boiler; n1 is the total number of key components of the i-th gas heating water boiler; Takes 0 or 1, =0 means that the i-th gas heating water boiler does not use the j1-th key component, =1 means the i-th gas heating water boiler uses the j1-th key component, is the purchase cost of the j1st key component of the i-th gas-fired hot water boiler; Q i is the rated heat load of the i-th gas-fired heating water boiler.

[0048] An example is as follows: The key component used in the secondary heat exchange condensing gas heating water heater is the secondary heat exchange condensing heat exchanger, and the non-condensing gas heating water heater does not use this key component; if the rated heat load of the first gas heating water heater is 26kW, the burner is used as the second key component of the gas heating water heater, and its purchase cost is 450 yuan, then 1,2 =1,M 1,2 =450, Q1=26.

[0049] The calculation model of additional costs is as follows:

[0050] (j2=1,2,...,n2)

[0051] Among them, F i2 is the additional cost of the i-th gas heating water heater; n2 is the total number of additional components of the i-th gas heating water heater; Takes 0 or 1, =0 means that the i-th gas heating water heater does not use the j2-th additional component, =1 means the i-th gas heating water boiler uses the j2-th additional component, is the purchase cost of the j2nd additional component of the i-th gas heating water boiler.

[0052] An example is as follows: A fully premixed condensing gas heating water heater uses an additional component: a condensate collection device, and a non-condensing gas heating water heater does not use this additional component; if the wind pressure switch is used as the third additional component of the gas heating water heater, and the second gas heating water heater uses the wind pressure switch, the purchase cost is 80 yuan, then β 2,3 =1,N 2,3 =80.

[0053] The calculation model of maintenance cost is as follows:

[0054] (j3=1,2,...,n3)

[0055] Among them, F i3 is the maintenance cost of the i-th gas heating water heater; n3 is the total number of replacement parts for the i-th gas heating water heater; Takes 0 or 1, =0 means that the i-th gas heating water heater has not replaced the j3-th component, =1 means that the i-th gas heating water heater has replaced the j3-th component; The cost of replacing the j3rd component for the i-th gas heating water boiler.

[0056] An example is as follows: The gas valve is regarded as the fifth component to be replaced in a gas-fired hot water boiler. The third gas-fired hot water boiler has its gas valve replaced, and the replacement cost is 400 yuan. Then χ 3,5 =1, R 3,5 =400.

[0057] The calculation model of operating costs is as follows:

[0058] (j4=1,2,...,n4)

[0059] Among them, F i4 is the operating cost of the i-th gas heating water heater; n4 is the total number of problems that may occur in the i-th gas heating water heater; Takes 0 or 1, =0 means that the i-th gas heating water heater will not have the j4th problem. =1 means the i-th gas heating water heater may have the j4th problem; is the probability of the j4th problem occurring.

[0060] An example is given below: Taking the flame-off problem as the first common problem of gas-fired heating water heaters, the probability of the fourth water-cooled low-nitrogen gas-fired heating water heater having the flame-off problem is 30%, then ε 4,1 =1,P 4,1 =30.

[0061] The calculation model of fuel cost is as follows:

[0062] (j5=1,2,...,n5)

[0063] Among them, F i5 is the fuel cost of the i-th gas-fired heating water heater; n5 is the total number of operating states evaluated for the i-th gas-fired heating water heater; is the heating circulating water flow or domestic hot water flow of the i-th gas-fired heating water boiler in the j5th operating state, in m 3 / h; is the water density of the inlet or return water of the i-th gas-fired heating water heater in the j5th operating state, in kg / m 3 ; is the outlet water temperature of the i-th gas-fired heating water heater in the j5th operating state, in °C; is the inlet or return water temperature of the i-th gas-fired heating water heater in the j5th operating state, in °C; is the gas flow rate of the i-th gas-fired heating water boiler in the j5th operating state, in m 3 / h; is the lower calorific value of the gas used for combustion in the j5th operating state of the i-th gas-fired heating water boiler at the reference state of 15°C and 101.325 kPa, in MJ / m 3 .

[0064] The calculation model of power consumption cost is as follows:

[0065] (j6=1,2,...,n 61 , =1,2,...,n 62 )

[0066] Among them, F i6 is the electricity consumption cost of the i-th gas heating water heater; n 61 The total number of fixed-frequency power-consuming components used by the i-th gas-fired heating water boiler; n 62 The total number of variable frequency power-consuming components used by the i-th gas heating water heater; Takes 0 or 1, =0 means that the i-th gas heating water heater does not use the j6-th fixed-frequency power-consuming component, =1 means that the i-th gas heating water boiler uses the j6-th fixed-frequency power-consuming component; Takes 0 or 1, =0 means the i-th gas heating water heater is not in use A kind of frequency conversion power-consuming components, =1 means the i-th gas heating water boiler uses the A fixed frequency power-consuming component; is the rated power of the fixed-frequency power-consuming components; It is the rated power of the power-consuming components of the frequency conversion.

[0067] An example is as follows: the fan is regarded as the first power-consuming component of the gas heating water heater, and the water pump is regarded as the second power-consuming component. The sixth gas heating water heater uses a variable frequency fan and a fixed frequency water pump. The rated power of the variable frequency fan is 35W, and the rated power of the fixed frequency water pump is 90W. Then φ 6,1 =0,ψ 6,1 =1, =35;φ 6,2 =1,ψ 6,2 =0,W6,2 =90.

[0068] NO x The calculation model of volume fraction conversion value is as follows:

[0069] (j7=1,2,...,n7)

[0070]

[0071] Among them, F i7 is the NO in the flue gas of the i-th gas heating water boiler under different heat load conditions x The weighted conversion value of the volume fraction, in mg / (kW·h); n7 is the total number of heat load states evaluated for the i-th gas heating water boiler; is the NO in the flue gas of the i-th gas-fired hot water boiler under the j7th heat load state x The weight of is the NO in the flue gas of the i-th gas-fired hot water boiler under the j7th heat load state x The actual measured value of volume fraction, in mg / (kW·h); is the air humidity content of the i-th gas-fired hot water boiler when it is evaluated under the j7th heat load state, in g / kg; is the ambient air temperature of the i-th gas-fired hot water boiler evaluated under the j7th heat load state, in °C.

[0072] As an embodiment: the heat load state can be divided into 70% rated heat load, 60% rated heat load, 40% rated heat load, and 20% rated heat load. When the 20% rated heat load is less than the minimum heat load of the gas heating water heater, the minimum heat load of the gas heating water heater replaces the 20% rated heat load, and the corresponding weights are 0.15, 0.25, 0.3, and 0.3 respectively; f(s i,j7 ) is the NO in the flue gas of the i-th gas heating water boiler under the j7th heat load state x Volume fraction conversion value, unit is mg / (kW·h).

[0073] The calculation model of the CO volume fraction conversion value is as follows:

[0074] (j7=1,2,...,n7)

[0075] Among them, F i8 is the CO volume fraction conversion value in the flue gas under different heat load states of the i-th gas heating water boiler; n7 is the total number of heat load states evaluated for the i-th gas heating water boiler; is the weight of the volume fraction of CO in the flue gas under the j7th heat load state of the i-th gas heating water boiler, and is the weight of the volume fraction of NO in the flue gas under the j7th heat load state x The weight values ​​are the same; is the measured value of CO volume fraction in flue gas of the i-th gas-fired hot water boiler under the j7th heat load state, is the measured value of the CO2 volume fraction in the flue gas of the i-th gas-fired hot water boiler under the j7th heat load state.

[0076] Step 3: Standardize the values ​​of the single evaluation index of all gas-fired heating water heaters used for evaluation to obtain the standardized values ​​of the single evaluation index. The specific process can be as follows:

[0077] Step 301, standardize the data of six single evaluation indicators, namely, key cost, additional cost, maintenance cost, operation cost, fuel cost and electricity cost of all gas heating water heaters used for evaluation, respectively, and the calculation formula is as follows:

[0078] When the value of a single evaluation index is positive, it is calculated according to the following formula:

[0079] (j=1,2,3,4,5,6)

[0080] When the value of a single evaluation index is negative, it is calculated according to the following formula:

[0081] (j=1,2,3,4,5,6)

[0082] Step 302: The NO of all gas-fired heating water heaters used for evaluation is x The values ​​of the two single evaluation indicators, CO and , are standardized respectively, and the calculation formula is as follows:

[0083] (j=7,8)

[0084] Among them, z ij is the standardized value of the jth single evaluation index of the i-th gas heating water heater after standardization. ij is the value of the j-th single evaluation index of the i-th gas heating water boiler, F min,j is the minimum value of the jth single evaluation index among all gas-fired heating water heaters used for evaluation; F max,j It is the maximum value of the jth type of single evaluation index among all gas heating water heaters used for evaluation.

[0085] Step 4: Use the standardized value of a single evaluation index to construct a calculation model for the classification index evaluation index of each gas heating water heater. The standardized single evaluation index is divided into four types of index evaluation indicators, namely cost index, energy consumption index, operation index, and low nitrogen index. The weight of the single evaluation indicator in each classification index evaluation indicator is constructed. The specific calculation process of the weight is as follows:

[0086] For the cost index, the normalized value z based on the key cost i1 , Standardized value of additional cost z i2 and the normalized value of maintenance cost z i3 , the calculation process is as follows:

[0087] Step 401, calculate the entropy value of a single evaluation index, the formula is as follows:

[0088] (j=1,2,3)

[0089] Among them, e j is the entropy value of a single evaluation index, n is the number of gas heating water heaters to be evaluated, z ij is the value of the jth single evaluation index of the i-th gas heating water boiler.

[0090] Step 402, calculate the weight of each single evaluation index, the formula is as follows:

[0091] (j=1,2,3)

[0092] Among them, w j is the weight of the jth single evaluation indicator, m is the number of single evaluation indicators, m=3.

[0093] Step 403, construct a cost index mathematical model, the formula is as follows:

[0094] (j=1,2,3)

[0095] Among them, y i1 is the cost index of the i-th gas heating water boiler.

[0096] The energy consumption index is based on the normalized value of fuel cost z i5 and the normalized value of electricity cost z i6 , normalize the value z by the fuel cost i5 and the normalized value of electricity cost z i6 Replace z in the formula of step 401 ij Then, the energy consumption index y is calculated according to step 401 to step 404. i2 ;

[0097] The operating index is based on the normalized value of operating costs z i4 , normalize the value z with the operating cost i4 Replace z in the formula of step 401 ij Then, the operation index y is calculated according to steps 401 to 404. i3 ;

[0098] Low nitrogen index v i Based on NO x Normalized value z i7 and CO normalized value z i8 , use NO x Normalized value z i7 and CO normalized value z i8 Replace z in the formula of step 401 ij Then, the low nitrogen index v is calculated according to step 401 to step 404. i .

[0099] Step 5: construct the weights of the three classification index evaluation indicators of cost index, energy consumption index and operation index of each gas heating water heater. The specific calculation process of the weights is as follows:

[0100] Step 501, based on the cost index y of step 4 i1 , Energy consumption index y i2 and operation index y i3 , calculate the entropy value of each classification index evaluation indicator, the formula is as follows:

[0101] (j'=1,2,3)

[0102] Among them, e j’ is the entropy value of each classification index evaluation index, n is the number of gas heating water heaters evaluated, y ij’ It is the value of the j'th classification index evaluation indicator of the i-th gas heating water boiler.

[0103] Step 502, calculate the weight of each classification index evaluation indicator, the formula is as follows:

[0104] (j'=1,2,3)

[0105] Among them, w j’ is the weight of the j'th classification index evaluation indicator, m' is the number of classification index evaluation indicators, m'=3.

[0106] Step 6: Construct a mathematical model of the economic index of gas-fired heating water heaters based on the weights of the three classification index evaluation indicators of cost index, energy consumption index and operation index of each gas-fired heating water heater. The economic index of each gas-fired heating water heater is obtained by calculation. The formula is as follows:

[0107] (j'=1,2,3)

[0108] Among them, k i is the economic index of the i-th gas heating water boiler.

[0109] Step 7: According to the low nitrogen index and economic index of each gas-fired heating water heater, a mathematical model of the low nitrogen economic index of each gas-fired heating water heater is constructed. The low nitrogen economic index of each gas-fired heating water heater is obtained by calculation. The formula is as follows:

[0110]

[0111] Among them, K i is the low nitrogen economic index of the i-th gas heating water boiler.

[0112] Step 8: Quantitatively evaluate the low nitrogen operation performance of all gas-fired heating water heaters used for evaluation:

[0113] The low nitrogen economic index K for all gas heating water heaters evaluated i The values ​​are sorted from low to high, and the low nitrogen economic index K i The smaller the value, the higher the low-nitrogen economy.

[0114] Step 9. Use cluster analysis method (see Multivariate Statistical Analysis, pages 34-55. Science Press, publication date March 1, 2024) to conduct a qualitative evaluation of the low-nitrogen operation of all gas-fired heating water heaters used for evaluation, and divide the gas-fired heating water heaters into products of different levels. The specific process can be:

[0115] Step 801, randomly select the K of l gas heating water heaters i The value is taken as the initial center K cen,t (t=1,2,...,l), calculate the K of each gas heating water boiler i Value and l initial centers K cen,t (t=1,2,...,l) distance.

[0116] The distance calculation formula is:

[0117] (t=1,2,...,l)

[0118] Among them, d(K i ,K cen,t) is the i-th gas heating water heater K i The value is the same as the t-th initial center K cen,t , n is the total number of gas heating water heaters, and l is the total number of initial centers selected.

[0119] Step 802: according to the calculated distance value d(K i ,K cen,t ), classify gas heating water boilers.

[0120] As an example: randomly select 3 initial centers, the first gas heating water heater K1 to K cen,1 , K cen,2 , K cen,3 The distances are 0.5, 0.4, and 0.7 respectively. According to the rule that each gas heating water heater is assigned to the initial center closest to the gas heating water heater, the first gas heating water heater is assigned to the category based on the second initial center. i ,K cen,t ) can be classified, and each category can be defined as C1, C2, ..., C l .

[0121] Step 803, calculate the K of gas heating water heaters in all categories respectively i The average value of the value is determined as the new center, and the calculation is repeated for each gas heating water heater K i The distance to each new center is calculated, and each gas heating water heater is assigned to the center closest to it again, and then classified according to the distance.

[0122] Step 804, repeating steps 801 to 804 until the center no longer changes.

[0123] Step 805, each type of gas heating water heater K completed in step 804 i Values ​​as a set C.

[0124] As an example: if there are 5 gas heating water boilers participating in the low nitrogen operation evaluation, after the above process, the gas heating water boilers are divided into three categories, C1={K1, K3}, C2={K2, K5}, C3={K4}.

[0125] Step 806: Based on the K i The average value K avg Gas heating water heaters can be divided into three levels of products, such as low nitrogen high economy, low nitrogen moderate economy, and low nitrogen poor economy. avg The smaller it is, the higher the low-nitrogen economy, that is, it is a gas-fired heating hot water boiler with high low-nitrogen economy.

[0126] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for evaluating low-nitrogen economic operation of a gas-fired heating water boiler, characterized in that The following steps are involved: Step 1: Determine a single evaluation indicator, which includes key costs, additional costs, maintenance costs, operating costs, fuel costs, electricity costs, NO x Volume fraction conversion value and CO volume fraction conversion value; The key cost mentioned here refers to the purchase cost of key components of the gas heating water heater related to the heat load; The additional cost mentioned refers to the purchase cost of gas heating water heater components that are not related to the heat load; The maintenance cost mentioned refers to the cost of replacing components of the gas heating water heater; The operating cost mentioned above refers to the cost that affects the user's use when a combustion failure occurs during the operation of the gas heating water heater; Fuel cost refers to the cost of fuel consumed by a gas heating water heater per unit time; The NO x The volume fraction conversion value and the volume fraction conversion value of CO refer to the NO in the flue gas emitted by the gas heating water boiler. x The volume fraction conversion value and the volume fraction conversion value of CO; Step 2: Calculate the single evaluation index used to evaluate each gas heating water heater to obtain the value of each single evaluation index: the calculation models of the values ​​of each single evaluation index are as follows: The calculation model of the key costs is as follows: Among them, F i1 is the key cost of the i-th gas heating water boiler; n1 is the total number of key components of the i-th gas heating water boiler; Takes 0 or 1, It means that the i-th gas heating water boiler does not use the j1-th key component. represents the i-th gas heating water boiler using the j1-th key component, is the purchase cost of the j1st key component of the i-th gas-fired hot water boiler; Q i is the rated heat load of the i-th gas-fired heating water boiler; The calculation model of additional costs is as follows: Among them, F i2 is the additional cost of the i-th gas heating water heater; n2 is the total number of additional components of the i-th gas heating water heater; Takes 0 or 1, It means that the i-th gas heating water boiler does not use the j2-th additional component. It means that the i-th gas heating water boiler uses the j2-th additional component. is the purchase cost of the j2nd additional component of the i-th gas heating water boiler; The calculation model of maintenance cost is as follows: Among them, F i3 is the maintenance cost of the i-th gas heating water heater; n3 is the total number of replacement parts for the i-th gas heating water heater; Takes 0 or 1, It means that the i-th gas heating water heater has not replaced the j3-th component. It means that the j3th component has been replaced on the i-th gas heating water boiler; The cost of replacing the j3rd component for the i-th gas heating water boiler; The calculation model of operating costs is as follows: Among them, F i4 is the operating cost of the i-th gas heating water heater; n4 is the total number of problems that may occur in the i-th gas heating water heater; Takes 0 or 1, This means that the i-th gas heating water boiler will not have the j4th problem. It means that the i-th gas heating water heater may have the j4th problem; is the probability of the j4th problem occurring; The calculation model of fuel cost is as follows: Among them, F i5 is the fuel cost of the i-th gas-fired heating water heater; n5 is the total number of operating states evaluated for the i-th gas-fired heating water heater; is the heating circulating water flow or domestic hot water flow of the i-th gas-fired heating water boiler in the j5th operating state, in m 3 / h; is the water density of the inlet or return water of the i-th gas-fired heating water heater in the j5th operating state, in kg / m 3 ; is the outlet water temperature of the i-th gas-fired heating water heater in the j5th operating state, in °C; is the inlet or return water temperature of the i-th gas-fired heating water heater in the j5th operating state, in °C; is the gas flow rate of the i-th gas-fired heating water boiler in the j5th operating state, in m 3 / h; is the lower calorific value of the gas used for combustion in the j5th operating state of the i-th gas-fired heating water boiler at the reference state of 15°C and 101.325 kPa, in MJ / m 3 ; The calculation model of power consumption cost is as follows: Among them, F i6 is the electricity consumption cost of the i-th gas heating water heater; n 61 The total number of fixed-frequency power-consuming components used by the i-th gas-fired heating water boiler; n 62 The total number of variable frequency power-consuming components used by the i-th gas heating water heater; Takes 0 or 1, It means that the i-th gas heating water boiler does not use the j6-th fixed-frequency power-consuming component. It means that the i-th gas heating water boiler uses the j6-th fixed-frequency power-consuming component; Takes 0 or 1, It means that the i-th gas heating water boiler does not use the j'6th variable frequency power-consuming component. =1 means that the i-th gas heating water boiler uses the j'6th type of fixed-frequency power-consuming component; is the rated power of the fixed-frequency power-consuming components; is the rated power of the frequency conversion power-consuming components; NO x The calculation model of volume fraction conversion value is as follows: Among them, F i7 is the NO in the flue gas of the i-th gas heating water boiler under different heat load conditions x The weighted conversion value of the volume fraction, in mg / (kW·h); n7 is the total number of heat load states evaluated for the i-th gas heating water boiler; is the NO in the flue gas of the i-th gas-fired hot water boiler under the j7th heat load state x The weight of is the NO in the flue gas of the i-th gas-fired hot water boiler under the j7th heat load state x The actual measured value of volume fraction, in mg / (kW·h); is the air humidity content of the i-th gas-fired hot water boiler when it is evaluated under the j7th heat load state, in g / kg; is the ambient air temperature of the i-th gas-fired hot water boiler evaluated under the j7th heat load state, in °C; The calculation model of the CO volume fraction conversion value is as follows: Among them, F i8 is the CO volume fraction conversion value in the flue gas under different heat load states of the i-th gas heating water boiler; n7 is the total number of heat load states evaluated for the i-th gas heating water boiler; is the weight of the volume fraction of CO in the flue gas under the j7th heat load state of the i-th gas heating water boiler, and is the weight of the volume fraction of NO in the flue gas under the j7th heat load state x The weight values ​​are the same; is the measured value of CO volume fraction in flue gas of the i-th gas-fired hot water boiler under the j7th heat load state, is the measured value of CO2 volume fraction in flue gas of the i-th gas-fired hot water boiler under the j7th heat load state; Step 3: Standardize the values ​​of the single evaluation index of all gas-fired heating water heaters used for evaluation to obtain the standardized values ​​of the single evaluation index; the specific process is as follows: Step 301, standardize the data of six single evaluation indicators, namely, key cost, additional cost, maintenance cost, operation cost, fuel cost and electricity cost of all gas heating water heaters used for evaluation, respectively, and the calculation formula is as follows: When the value of a single evaluation index is positive, it is calculated according to the following formula: When the value of a single evaluation index is negative, it is calculated according to the following formula: Step 302: The NO of all gas-fired heating water heaters used for evaluation is x The values ​​of the two single evaluation indicators, CO, are standardized respectively, and the calculation formula is as follows: Among them, z ij is the standardized value of the jth single evaluation index of the i-th gas heating water heater after standardization; F ij is the value of the j-th single evaluation index of the i-th gas heating water boiler, F min,j is the minimum value of the jth single evaluation index among all gas-fired heating water heaters used for evaluation; F max,j It is the maximum value of the single evaluation index of the jth category among all gas-fired heating water heaters used for evaluation; Step 4: Use the standardized value of a single evaluation index to construct a calculation model for the classification index evaluation index of each gas heating water heater. The standardized single evaluation index is divided into four types of index evaluation indicators, namely cost index, energy consumption index, operation index, and low nitrogen index. The weight of the single evaluation indicator in each classification index evaluation indicator is constructed; the specific calculation process is as follows: For the cost index, the normalized value z based on the key cost i1 , Standardized value of additional cost z i2 and the normalized value of maintenance cost z i3 , the calculation process is as follows: Step 401, calculate the entropy value of a single evaluation index, the formula is as follows: Among them, e j is the entropy value of a single evaluation index, n is the number of gas heating water heaters to be evaluated, z ij is the value of the jth single evaluation index of the i-th gas heating water boiler; Step 402, calculate the weight of each single evaluation index, the formula is as follows: Among them, w j is the weight of the jth single evaluation index, m is the number of single evaluation indicators, m = 3; Step 403, construct a cost index mathematical model, the formula is as follows: Among them, y i1 is the cost index of the i-th gas heating water heater; The energy consumption index is based on the normalized value of fuel cost z i5 and the normalized value of electricity cost z i6 , normalize the value z by the fuel cost i5 and the normalized value of electricity cost z i6 Replace z in the formula of step 401 ij Then, the energy consumption index y is calculated according to step 401 to step 404. i2 ; The operating index is based on the normalized value of operating costs z i4 , normalize the value z with the operating cost i4 Replace z in the formula of step 401 ij Then, the operation index y is calculated according to steps 401 to 404. i3 ; Low nitrogen index v i Based on NO x Normalized value z i7 and CO normalized value z i8 , use NO x Normalized value z i7 and CO normalized value z i8 Replace z in the formula of step 401 ij Then, the low nitrogen index v is calculated according to step 401 to step 404. i ; Step 5: Construct the weights of the three classification index evaluation indicators of cost index, energy consumption index and operation index for each gas heating water heater; Step 6: Construct an economic index mathematical model of the gas heating water heater according to the weights of the three classification index evaluation indicators of cost index, energy consumption index and operation index of each gas heating water heater, and obtain the economic index of each gas heating water heater by calculation; Step 7: construct a low-nitrogen economic index mathematical model of each gas-fired heating water heater according to the low-nitrogen index and economic index of each gas-fired heating water heater, and obtain the low-nitrogen economic index of each gas-fired heating water heater by calculation; Step 8: Quantitatively evaluate the low nitrogen operation performance of all gas-fired heating water heaters used for evaluation: The low nitrogen economic index values ​​of all gas heating water heaters under evaluation are ranked from low to high. The smaller the low nitrogen economic index value, the higher the low nitrogen economy. Step 9. Use cluster analysis to conduct a qualitative evaluation of the low-nitrogen operation of all gas-fired heating water heaters used for evaluation, and divide the gas-fired heating water heaters into products of different levels.

2. The method for evaluating low-nitrogen economic operation of a gas-fired heating water heater according to claim 1, characterized in that: The specific calculation process of the weight in step 5 is as follows: Step 501, based on the cost index y of step 4 i1 , Energy consumption index y i2 and operation index y i3 , calculate the entropy value of each classification index evaluation indicator, the formula is as follows: Among them, e j’ is the entropy value of each classification index evaluation index, n is the number of gas heating water heaters evaluated, y ij’ is the value of the j'th classification index evaluation indicator of the i-th gas heating water boiler; Step 502, calculate the weight of each classification index evaluation indicator, the formula is as follows: Among them, w j’ is the weight of the j'th classification index evaluation indicator, m' is the number of classification index evaluation indicators, m'=3.

3. The low-nitrogen economic operation evaluation method for gas-fired heating water heater according to claim 2 is characterized in that: The formula for calculating the economic efficiency index of each gas heating water heater in step 6 is as follows: Among them, k i is the economic index of the i-th gas heating water boiler.

4. The method for evaluating low-nitrogen economic operation of a gas-fired heating water heater according to claim 3, characterized in that: The formula for calculating the low nitrogen economic index of each gas-fired heating water heater in step 7 is as follows: Among them, K i is the low nitrogen economic index of the i-th gas heating water boiler.

5. The method for evaluating low-nitrogen economic operation of a gas-fired heating water heater according to claim 4, characterized in that: The specific process of step nine is as follows: Step 801, randomly select the K of l gas heating water heaters i The value is taken as the initial center K cen,t (t=1,2,...,l), calculate the K of each gas heating water boiler i Value and l initial centers K cen,t (t=1,2,...,l) distance; The distance calculation formula is: Among them, d(K i ,K cen,t ) is the i-th gas heating hot water boiler K i The value is the same as the t-th initial center K cen,t The distance, n is the total number of gas heating water heaters, l is the total number of selected initial centers; Step 802: according to the calculated distance value d(K i ,K cen,t ), classify gas heating water heaters; Step 803, calculate the K of gas heating water heaters in all categories respectively i The average value of the value is determined as the new center, and the calculation is repeated for each gas heating water heater K i The distance to each new center is calculated, and each gas heating water heater is assigned to the center closest to it again, and then classified according to the distance; Step 804, repeating steps 801 to 804 until the center no longer changes; Step 805, each type of gas heating water heater K completed in step 804 i Values ​​as a set C; Step 806: Based on the K i The average value K avg Size, gas heating water heaters are divided into different levels of products, K avg The smaller it is, the higher the low-nitrogen economy, that is, it is a gas-fired heating hot water boiler with high low-nitrogen economy.

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