A heating room temperature regulation method based on temperature estimation

Abstract

This invention discloses a heating room temperature control method based on temperature estimation, belonging to the field of heating room temperature control technology. Starting with the calculated relationship between room temperature, water temperature, and air temperature at a given heating load obtained from a single on-site measurement, this invention eliminates the need for continuous room temperature measurement by installing a room temperature data logger within the heating load. It accurately estimates the calculated relationship between room temperature, water temperature, and air temperature at subsequent time points using a reference method. Furthermore, given the air temperature, it can estimate both the actual room temperature based on the actual water temperature and the target water temperature based on the target room temperature. By controlling the actual water temperature to the target water temperature, the goal of controlling the actual room temperature to the target room temperature is achieved. This invention not only avoids the limitations of current heating room temperature control methods that rely on accurate room temperature data acquisition, which is often subject to human interference, but also benefits from the relatively easy measurement and control of water temperature, making it more feasible and economical in practical applications.

Description

Technical Field

[0001] This invention provides a heating room temperature control method based on temperature estimation, which relates to the field of heating room temperature control. Background Technology

[0002] Currently, the regulation and control of room temperature in heating systems, whether manual or electric, requires the installation of room temperature monitoring devices in users' homes. The collected room temperature data is used as the basis for regulation, lowering the room temperature for users with high temperatures and raising the room temperature for users with low temperatures to achieve a balanced distribution and automatic control of room temperature. While this method of room temperature regulation is technically feasible, in practice, many users believe that higher room temperature is better and are extremely uncooperative with heating companies' efforts to regulate room temperature. They often interfere with the room temperature monitoring devices by deliberately obstructing them or changing their location, making it difficult for heating companies to obtain the true room temperature of users, thus significantly reducing the effectiveness of room temperature regulation. Summary of the Invention

[0003] To address the difficulty in obtaining user room temperature data in current heating room temperature control methods, this invention provides a heating room temperature control method based on temperature estimation. The aim is to achieve effective control of user room temperature without the need for installing room temperature data acquisition devices and with minimal in-home temperature data collection.

[0004] To achieve the above objectives, the present invention employs the following technical solution: First, by conducting an on-site measurement of the user's room temperature and water temperature, the calculated relationship between the room temperature, water temperature, and air temperature at the measurement point is obtained (hereinafter referred to as "temperature coefficient," denoted by K). T After indicating the actual water temperature, the temperature coefficient at each subsequent time point is estimated using the reference method. This eliminates the need to install a room temperature acquisition device in the user's room. With the air temperature known, the actual room temperature can be estimated based on the actual water temperature at each subsequent time point, and the target water temperature can be estimated based on the target room temperature at each subsequent time point. By controlling the actual water temperature to the target water temperature, the goal of controlling the actual room temperature to the target room temperature can be achieved.

[0005] Although the present invention is slightly inferior to the current technical solutions in terms of control precision, the error is still within the acceptable range of room temperature control. Furthermore, the present invention is more feasible because it does not require the installation of a room temperature acquisition device, and it is also more economical because it does not require the installation of pressure gauges, flow meters, or heat meters.

[0006] The following section will provide a detailed explanation of the heating room temperature control method based on temperature estimation, which is based on the present invention, from aspects such as the calculation formula of the temperature coefficient, influencing factors, curve characteristics, acquisition method, temperature estimation, correction and recovery, and verification experiments.

[0007] 1. Formula for calculating temperature coefficient.

[0008] Under ideal thermal equilibrium, assuming the outdoor air temperature (hereinafter referred to as "air temperature", denoted by T) is... 气 (represented by) remains constant, for a fixed indoor temperature (hereinafter referred to as "room temperature", denoted by T) 室 (This is expressed as a constant), and there will always be a fixed average temperature of the supply and return water (hereinafter referred to as "water temperature", denoted by T). 水 This corresponds to the relationship between air temperature, room temperature, and water temperature for a given heating load. If we understand the calculated relationship between air temperature, room temperature, and water temperature for a given heating load, it's equivalent to understanding the correspondence between the target room temperature and the target water temperature at a fixed air temperature. Therefore, by adjusting the water temperature to the target temperature, we can achieve the goal of adjusting the room temperature to the target room temperature, without necessarily installing a room temperature acquisition device within the heating load before adjusting the room temperature. We define the calculated relationship between the water temperature, room temperature, and air temperature of the heating load as a temperature coefficient, denoted by K. T express.

[0009] The aforementioned heating load forms include rooms, houses, units, buildings, communities, factories, heat exchange stations, etc. The heating load characteristics are divided into inherent heating characteristics and variable heating characteristics. Inherent heating characteristics include the inherent heating characteristics of the building itself, such as insulation level, heat transfer coefficient, air leakage coefficient, apartment type, orientation, area, floor level, whether it is a detached house, whether it is situated on a hillside, whether it has a roof, whether it is on the ground floor, and whether it has a basement—characteristics that generally do not change over time. Variable heating characteristics include heating characteristics that may change over a period of time, such as radiator type, radiator obstruction level, floor paving material, the number of adjacent heating loads above and below, the number of adjacent heating loads to the left and right, the performance and location of measuring meters, the daily number of people and their activity intensity, and whether other radiators are frequently used.

[0010] In winter, to maintain a stable room temperature, a thermal balance must be maintained under those conditions, meaning that heat gain equals heat loss. For typical residential buildings and industrial buildings with low heat generation, heat gain primarily considers the heat dissipation Q from the radiator surface. 散热 Solar radiation heat Q 辐射 Human body and daily life heat dissipation Q 生活 The heat loss mainly considers the heat loss Q of the building envelope. 围护 The heat consumption Q of heating the cold air intrusion 冷风 The heat transfer Q to surrounding houses without heating 传热 .

[0011] Heat gained = heat lost Q 散热 +Q 辐射 +Q 生活 =Q 围护 +Q 冷风 +Q 传热 To simplify the calculation and highlight the main contradiction, we will first perform the following processing: Q辐射 Because sunlight is weaker in winter, even on sunny days, Q 辐射 The value is also relatively small and can be ignored; Q 生活 Because the value is small, and on-site temperature measurements are generally taken during the day, Q 生活 The value is also low and can be ignored; Q 冷风 Although the value is relatively large, it is proportional to the indoor and outdoor temperature difference and can be calculated based on the heat transfer coefficient K of the building envelope. 维护 Correction factor ф 冷风 To simplify the process; Q 传热 The practical effect is to increase the heat dissipation area of ​​the maintenance structure, which can be calculated based on the heat dissipation area F of the maintenance structure. 维护 Correction factor ф 传热 To simplify the process; Winter winds are generally not strong, so the effect of wind on the heat transfer coefficient of the building envelope can be ignored. After the above simplification, the above equation becomes Q. 散热 =Q 围护 +Q 冷风 +Q 传热 That is, K 散热器 F 散热器 (T) 水 -T 室 ) = (1 + ф 冷风 )K 围护 (1+ф) 传热 )F 围护 (T) 室 -T 气 ) (T) 水 -T 室 ) / (T 室 -T 气 ) = ((1+ф) 冷风 )K 围护 (1+ф) 传热 )F 围护 ) / (K 散热器 F 散热器 ) In the formula, T 水 Water temperature, which is the average temperature of the supply and return water for the heating load, equal to (supply water temperature + return water temperature) / 2; T 室 The room temperature is the indoor temperature corresponding to the heating load. It can be the room temperature at a representative point or the average of the room temperatures at multiple points. T 气 Temperature can be the outdoor temperature released by the meteorological bureau or measured by the bureau itself, or it can be the corrected composite outdoor temperature. K围护 : The overall heat transfer coefficient of the building envelope; F 围护 The outdoor heat dissipation area of ​​the building envelope; K 散热器 The heat transfer coefficient of the outer surface of a radiator (including geothermal heating); F 散热器 The heat dissipation area of ​​the outer surface of a radiator (including geothermal heating); Under ideal operating conditions, when the inherent heating characteristics and variable heating characteristics of the heating load remain unchanged, K 围护 F 围护 K 散热器 F 散热器 ф 冷风 ф 传热 It should be a constant value, i.e. (T) 水 -T 室 ) / (T 室 -T 气 The temperature coefficient is a constant. We define the formula for calculating the temperature coefficient as (water temperature - room temperature) / (room temperature - air temperature), i.e., K. T = (T 水 -T 室 ) / (T 室 -T 气 Under ideal operating conditions, the temperature coefficient should be a constant.

[0012] 2. Factors affecting the temperature coefficient.

[0013] Factors affecting the temperature coefficient can be categorized into two types: variable factors and fluctuating factors. Variable factors refer to the inherent heating characteristics and variable heating characteristics, while fluctuating factors mainly include water temperature, air temperature, wind force, wind direction, and sunshine duration, which fluctuate frequently. Variable factors determine the magnitude of the average temperature coefficient and the width of its fluctuation range, while fluctuating factors determine the direction and magnitude of the real-time fluctuations in the temperature coefficient.

[0014] 3. Curve characteristics of temperature coefficient.

[0015] 3.1 Fluctuation: Although the temperature coefficient is theoretically a constant value, in actual applications, due to the asynchronous changes in air temperature, water temperature, and room temperature caused by the thermal inertia of the heating load, coupled with the influence of factors such as solar radiation, wind force and direction, and domestic heat dissipation, the measured temperature coefficient fluctuates every moment. Therefore, the first characteristic of the temperature coefficient curve is fluctuation.

[0016] 3.2 Stability: Although the temperature coefficient fluctuates under the influence of fluctuation factors, if the inherent heating characteristics and variable heating characteristics of the heating load remain unchanged, its fluctuation mainly fluctuates around the average value. The fluctuation range is relatively narrow and the fluctuation trend is close to horizontal, which reflects the second curve characteristic of the temperature coefficient: stability.

[0017] When regulating room temperature based on heating load, this is often achieved by adjusting valve openings or changing the inverter's operating frequency to alter the flow rate, thereby changing the water temperature. While changes in water temperature may temporarily affect the temperature coefficient, because water temperature is a fluctuating factor, after a period of time, as the room temperature stabilizes, the temperature coefficient and the temperature estimation deviation will "return" to the level before the water temperature change. This stable characteristic of the temperature coefficient allows for the estimation of the current room temperature before the flow rate change, and also for the estimation of the target water temperature after the flow rate change without correction.

[0018] 3.3 Similarity. In a quality-regulated heating system, the water temperature and room temperature of each user exhibit a clear synchronous rise and fall characteristic. That is, as the temperature of the hot water supplied by the heat source increases or decreases, the water temperature and room temperature of each user will also rise or fall synchronously. This synchronous rise and fall characteristic is reflected in the similarity of the curve shapes on the graph. The subsequent verification experiments will prove that in a quality-regulated heating system, not only do the room temperature and water temperature curve shapes show this similarity under different heating loads, but the temperature coefficient curve shape also shows this similarity, which is the third curve characteristic of the temperature coefficient—similarity. The closer the inherent heating characteristics and variable heating characteristics of the heating load are, the more similar the curve shapes of their room temperature, water temperature, and temperature coefficient.

[0019] Experiments have verified that the similarity of the curves for water temperature, room temperature, and temperature coefficient can be expressed by the similarity of the difference or ratio between two parameters. The difference refers to the difference between the two parameters at the same point in time; similar differences mean that the differences between the two parameters at different points in time are similar. The ratio refers to the ratio of a parameter at adjacent points in time; similar ratios mean that the ratios of the same parameter at adjacent points in time are similar. The similarity of the curves for room temperature and temperature coefficient is as follows: Figure 5 and Figure 6 The temperature and temperature coefficient curves for rooms 7 and 8 show that the distance between the two curves varies very little, clearly indicating that they rise and fall together.

[0020] 3.4 Translation. In a quality-regulated heating system, after the inherent or variable heating characteristics of the heating load change, even if the air and water temperatures remain constant, the room temperature will change, and naturally, the temperature coefficient will also change. At the same time, because the changed temperature coefficient must maintain the similarity of its curve shape to the temperature coefficient of the heating load with unchanged heating characteristics, the changed temperature coefficient curve will show an overall upward or downward translation relative to the unchanged temperature coefficient curve. This is the fourth characteristic of the temperature coefficient curve—translation.

[0021] 4. Methods for obtaining the temperature coefficient.

[0022] There are two methods for obtaining the temperature coefficient: the reference method and the constant value method.

[0023] The reference method is based on the similarity of temperature coefficient curves for different heating loads in a quality-regulated heating system. First, room temperature and water temperature monitoring devices are installed on some representative heating loads, and the temperature coefficients are calculated in real time. Then, the temperature coefficients of other similar heating loads are estimated by using the reference method.

[0024] The constant value method is used when there is little similarity between heating loads or no heating load to refer to. It utilizes the stable characteristics of the temperature coefficient curve to directly or empirically correct the temperature coefficient of a normal load measured on-site once as the temperature coefficient for subsequent time points.

[0025] The reference method can omit a large amount of complex calculations and can reflect the influence of fluctuations in air temperature, water temperature, sunshine, wind direction, and wind force on the temperature coefficient in real time, thus obtaining the temperature coefficient quickly and accurately. Compared with the reference method, the biggest drawback of the constant value method is that it cannot accurately reflect the influence of changes in water temperature and meteorological parameters on the temperature coefficient, and naturally, the accuracy of the estimation is not as good as that of the reference method.

[0026] 4.1 Instructions for the reference method.

[0027] Step (4.1.1) Establish a standard heating load. The standard heating load (hereinafter referred to as "standard load") is selected from the ordinary heating load (hereinafter referred to as "ordinary load"). It is required to have representativeness of the inherent heating characteristics, stability of the variable heating characteristics, few interference factors, good user cooperation, at least one room temperature acquisition device, and, depending on the situation, also supply water temperature and return water temperature monitoring and transmission devices, electric flow regulation devices, and centralized or distributed control systems.

[0028] Step (4.1.2) Establishing a reference relationship. The load form of the ordinary load and the standard load must be the same, their inherent heating characteristics and variable heating characteristics should be as close as possible, and they must both be in the same single-source heating network or, although in a multi-source heating network, be supplied by the same heat source. A many-to-many reference relationship can be established between the ordinary load and the standard load, but only one set of reference relationships can be in use for an ordinary load, while multiple sets of reference relationships can be in use for a standard load simultaneously.

[0029] Step (4.1.3) Measure the normal load. When the heating system is in quality regulation mode and operating stably, perform an on-site measurement of the room temperature and water temperature under the normal load and calculate the temperature coefficient. At the same time, record the room temperature, water temperature, and temperature coefficient of the standard load at the time of the on-site measurement of the normal load. Each on-site measurement is a calibration and correction of the temperature estimate. If possible, perform an on-site measurement of the normal load at intervals and start the estimation again from the new measurement time and data. This can further improve the accuracy of the estimation.

[0030] Step (4.1.4) Set the starting time point. Set the starting time point according to the time of the normal load field measurement, and generate the next time point according to the user-defined fixed time interval.

[0031] Step (4.1.5) Estimate the room temperature, water temperature, and temperature coefficient at the second time point of normal load. Based on the measured room temperature, water temperature, and temperature coefficient at the start time of normal load, and referring to the room temperature, water temperature, and temperature coefficient at the start time and the second time point of standard load, estimate the room temperature, water temperature, and temperature coefficient at the second time point of normal load using the same difference algorithm or the same comparison algorithm.

[0032] Step (4.1.6) Estimate the room temperature, water temperature, and temperature coefficient at the third time point of normal load. Based on the room temperature, water temperature, and temperature coefficient estimated at the second time point of normal load, and referring to the room temperature, water temperature, and temperature coefficient at the second and third time points of standard load, estimate the room temperature, water temperature, and temperature coefficient at the third time point of normal load using the same difference algorithm or the same comparison algorithm.

[0033] Step (4.1.7) Repeat step (4.1.6) to estimate the room temperature, water temperature and temperature coefficient at the fourth, fifth, sixth and so on time points of normal load, until the normal load is measured on-site again, and start the estimation again from the new measured time and value.

[0034] 4.2 Explanation of the same difference algorithm in the reference method.

[0035] The same difference algorithm assumes that the difference between the measured or estimated room temperature, water temperature, and temperature coefficient of the normal load at the current time point and the room temperature, water temperature, and temperature coefficient of the standard load at the current time point is equal to the difference between the room temperature, water temperature, and temperature coefficient of the normal load to be estimated at the next time point and the room temperature, water temperature, and temperature coefficient of the standard load at the next time point. This allows the estimation of the room temperature, water temperature, and temperature coefficient of the normal load at the next time point and all subsequent time points.

[0036] For example, given the measured room temperature A at time 1 under normal load A... 1， And the room temperatures at standard load time points 1, 2, and 3 are B1, B2, and B, respectively. 3， Estimate the room temperatures A2 and A3 at time points 2 and 3 under normal load A. Based on the assumption of the difference algorithm A1-B1=A2-B2=A3-B3, the formulas for calculating A2 are: A2=A1-B1+B2, and A3=A2-B2+B3. A3 can then be calculated accordingly. n .

[0037] 4.3 Explanation of the year-on-year calculation method in the reference method.

[0038] The year-on-year calculation method assumes that the ratio of the room temperature, water temperature, and temperature coefficient measured or estimated at the current time point under normal load to the room temperature, water temperature, and temperature coefficient to be estimated at the next time point is the same as the ratio of the room temperature, water temperature, and temperature coefficient at adjacent time points under the same standard load. This method is used to estimate the room temperature, water temperature, and temperature coefficient at the next time point and subsequent time points under normal load.

[0039] For example, given the measured temperature coefficient A at point 1 under normal load A... 1， And the temperature coefficients at standard load time points 1, 2, and 3 are B1, B2, and B, respectively. 3， Estimate the temperature coefficients A2 and A3 at time points 2 and 3 under normal load A. Based on the assumptions of the proportional calculation method A1 / A2 = B1 / B2 and A2 / A3 = B2 / B3, the formulas for calculating A2 are: A2 = A1 × B2 ÷ B1, and A3 is: A3 = A2 × B3 ÷ B2. A3 can then be calculated accordingly. n .

[0040] 5. Temperature estimation of temperature coefficient.

[0041] Temperature estimation can be categorized by temperature into room temperature estimation and water temperature estimation, and by method into direct reference method and temperature coefficient method. The direct reference method estimates the room or water temperature under normal load by directly using a reference method. The temperature coefficient method first estimates the temperature coefficient at the current time using a reference method or a fixed value method, and then estimates the water or room temperature at the current time based on the measured or estimated room or water temperature at the current time.

[0042] In the control of room temperature during heating, temperature estimation mainly involves the following two situations.

[0043] 5.1 Estimate the current room temperature under normal load. This can be done using the direct reference method or the temperature coefficient method. The main purpose is to understand the room temperature under normal load to determine if adjustment is necessary.

[0044] 5.2 Estimate the target water temperature for normal load. Only the temperature coefficient method can be used. The main purpose is to determine the target water temperature at each time point based on the target room temperature set for each time point under normal load.

[0045] 6. Correction and recovery of temperature coefficient.

[0046] When the inherent or variable heating characteristics of a heating load change, the average values ​​of room temperature, water temperature, and temperature coefficient will also change, and the curves will shift upward or downward. To maintain the consistency of the estimation accuracy before and after the change, it is necessary to correct the estimated room temperature, water temperature, and temperature coefficient after the change. There are three ways to correct these values.

[0047] Correction method (6.1) After the inherent heating characteristics or variable heating characteristics of normal load and standard load change respectively or simultaneously, the correction can be carried out by re-measuring the normal load and establishing a new reference relationship based on the measured value.

[0048] Correction method (6.2): ​​If the inherent heating characteristics or variable heating characteristics of the standard load change, the changes in the average values ​​of room temperature, water temperature and temperature coefficient at the same time interval before and after the change can be statistically analyzed (increase is positive, decrease is negative). The room temperature, water temperature and temperature coefficient at each time point after the change of the standard load are then subtracted from the above changes before being included in the estimation. This is equivalent to "eliminating" the impact of the change in the inherent heating characteristics or variable heating characteristics of the standard load on the room temperature, water temperature and temperature coefficient.

[0049] Correction Method (6.3): If the inherent heating characteristics or variable heating characteristics of the normal load change, the changes in the average room temperature, water temperature, and temperature coefficient of the standard load after the change can be estimated by statistically simulating the change in the normal load (increase is positive, decrease is negative). This change is then added to the estimated room temperature, water temperature, and temperature coefficient at each time point after the change in the normal load, effectively "reflecting" the impact of the change in the inherent or variable heating characteristics of the normal load on its room temperature, water temperature, and temperature coefficient. If the normal load uses a differential calculation method, the change needs to be added to the estimated room temperature, water temperature, and temperature coefficient at each time point after the change in the normal load for correction. If the normal load uses a proportional calculation method, the change only needs to be added to the estimated room temperature, water temperature, and temperature coefficient at a selected time point after the change in the normal load.

[0050] 7. Verification experiment of temperature coefficient.

[0051] like Figure 1 As shown, this verification experiment selected two adjacent households, A and B, on the 24th floor (out of 33 floors) of Unit 1 in a residential building in Heping District, Shenyang City. Household A faces north and south, with the western side facing the mountain, and temperature monitoring devices were placed in rooms 1 to 6. Household B faces south, is a middle unit, and does not face the mountain, and temperature monitoring devices were placed in rooms 7 to 10. In terms of decoration, the living room and bathroom floors of both households are tiled, while the floors of the other rooms are ordinary solid wood flooring.

[0052] Data was collected from 10:00 AM to 8:00 PM on February 28th, March 1st, and March 2nd, 2023. Indoor temperature in each room, supply and return water temperatures for households A and B (from heat meters in the inlet wells), and real-time air temperature from the weather network were recorded every hour. After data collection was completed at 8:00 PM on February 28th, the opening of the return water ball valve for household A was reduced from fully open to approximately one-third and maintained until the end of the experiment. The valve opening for household B was not adjusted. For ease of explanation, Figure 2 The document only lists the daily statistical data of air temperature, water temperature, room temperature, and temperature coefficient for representative units A (houses 1, 3, and 6) and B (houses 7, 8, and 10). Figure 3 This table shows the estimation deviation of room temperature using different algorithms and similarities between different rooms in the reference method. The estimation starting point (i.e., the actual measurement time) for ordinary houses in the table is 10:00 AM on February 28th. The estimation deviation is equal to the absolute value of the difference between the estimated value and the measured value. The smaller the estimation deviation, the higher the accuracy of the estimation.

[0053] The main purpose of this experiment is to verify the relevant conclusions of the reference method for temperature estimation.

[0054] Conclusion (7.1) The closer the heating characteristics of ordinary load and standard load are, the more similar their room temperature, water temperature and temperature coefficient curves are, the smaller the deviation of the reference method temperature estimation and the higher the accuracy.

[0055] like Figure 4 and Figure 5 As shown, Figure 3 The rooms in group 3 (7-8) showed strong similarity, and their room temperature and temperature coefficient curves were also quite similar. The difference between the estimated room temperature and the measured room temperature using the temperature coefficient method was only 0.18℃. Figure 3 The similarity between rooms 10-8 in Group 4 is relatively weak, and the linearity of their room temperature and temperature coefficient curves differs significantly. The deviation between the estimated room temperature and the measured room temperature using the temperature coefficient method and the difference algorithm is 0.76℃.

[0056] Conclusion (7.2) from Figure 3 As can be seen, the temperature coefficient method is generally more accurate than the direct reference method, but it requires knowledge of the water temperature during estimation. The accuracy of the same-difference and same-comparison algorithms within the reference method is generally comparable.

[0057] Conclusion (7.3) When the inherent heating characteristics and variable heating characteristics of normal load and standard load differ too much or there is no standard load, the stable characteristics of the temperature coefficient curve can be used to directly or after correction based on experience the temperature coefficient of normal load measured on site once as the temperature coefficient of subsequent time points.

[0058] exist Figure 3In the data, although the deviations of the constant value method (0.65, 0.57, 0.43) were greater than those of the equal difference method (0.32, 0.18, 0.27) in groups 1, 3, and 5 where room similarity was strong, the deviations of the constant value method (0.34, 0.37, 0.67) were smaller than those of the equal difference method (0.67, 0.76, 0.87) in groups 2, 4, and 7 where room similarity was weak, the deviations of the constant value method (0.34, 0.37, 0.67) were smaller than those of the equal difference method (0.67, 0.76, 0.87). This indicates that when there is no standard load available for reference on site, the temperature coefficient method of the constant value method can be used temporarily for temperature estimation.

[0059] Conclusion (7.4): The water temperature change caused by the change in flow rate is a fluctuating factor, not a variable factor, for the temperature coefficient. The temperature coefficient estimated at the current point in time can be used not only to estimate the current room temperature before the flow rate change, but also directly to estimate the target water temperature after the flow rate change without correction.

[0060] In the verification experiment, after the valve of household A was partially closed, the water temperature and room temperature of household A continued to decrease (see details). Figure 6 However, after a significant change over one day, the measured temperature coefficient for Household A returned to the level of 31 days prior to the valve being closed on the 2nd, as the room temperature stabilized (see details). Figure 2 and Figure 7 This indicates that water temperature is a fluctuating factor and will not cause a shift in the temperature coefficient curve. Therefore, it can be directly used for estimating the target water temperature at subsequent time points without any correction.

[0061] Conclusion (7.5) The temperature coefficient obtained by the same difference algorithm or the same comparison algorithm in the reference method can accurately reflect the influence of fluctuation factors such as air temperature, radiation, wind direction, and wind force on the temperature coefficient. Therefore, the target water temperature calculated by the above temperature coefficient also includes the influence of the above fluctuation factors, and its value is closer to the actual target water temperature. The expected room temperature that can be achieved is also closer to the set target room temperature.

[0062] Figure 8 An analysis table is provided to estimate the temperature coefficient using both the reference method and the constant value method, and then to estimate the target water temperature based on the target room temperature of 26.35℃. The reference method can "reflect" the influence of fluctuating factors such as air temperature, radiation, wind direction, and wind force on the temperature coefficient. Figure 9 As shown, although the estimated target water temperature 1 and predicted room temperature 1 do not match the measured water temperature and room temperature well, the predicted room temperature 1 matches the target room temperature of 26.35℃ well (with an average deviation of 0.18℃), indicating that the room temperature control is also effective. The constant value method, compared with the reference method, cannot "reflect" the influence of fluctuations in air temperature, radiation, wind direction, and wind force on the temperature coefficient. Figure 10As shown, although the estimated target water temperature 2 and the predicted room temperature 2 are in good agreement with the measured water temperature and room temperature, the predicted room temperature 2 is in poor agreement with the target room temperature of 26.35℃ (with an average deviation of 0.28℃), indicating that the room temperature control effect is also poor. Attached Figure Description

[0063] Figure 1 This is a distribution map of room temperature measurement points for households A and B in the verification experiment of this invention.

[0064] Figure 2 This is a daily statistical analysis of the experimental data from the verification experiment of this invention.

[0065] Figure 3 This is the laboratory temperature estimation deviation analysis table for the verification of this invention.

[0066] Figure 4 These are the room temperature curves of experimental chambers 7, 8, and 10 used in the verification experiment of this invention.

[0067] Figure 5 These are the temperature coefficient curves of chambers 7, 8, and 10 in the verification experiment of this invention.

[0068] Figure 6 These are the room temperature curves of experimental chambers 6 and 10 in this invention.

[0069] Figure 7 These are the temperature coefficient curves of chambers 6 and 10 in the verification experiment of this invention.

[0070] Figure 8 This invention is a verification experimental chamber 7 temperature coefficient method for estimating target water temperature analysis table.

[0071] Figure 9 This invention verifies the curves of the target water temperature 1 and the expected room temperature 1 estimated by the reference method in the experimental chamber 7.

[0072] Figure 10 This invention verifies the curves of the target water temperature 2 and the expected room temperature 2 estimated by the constant value method in the experimental chamber 7.

[0073] Figure 11 These are four specific embodiments of the present invention. Detailed Implementation

[0074] like Figure 11 As shown, the present invention has four implementation methods: accurate estimation of load room temperature, rapid adjustment of load room temperature, autonomous control of room temperature under partial load, and autonomous control of room temperature under full load. The first three implementation methods are mainly applied in quality-regulated heating systems, including quality-regulated heating systems that change flow rate in stages, while the fourth implementation method is mainly applied in quantity-regulated heating systems.

[0075] 1. Accurately estimate the room temperature under load.

[0076] If the direct reference method is used to estimate room temperature, at least one on-site measurement of room temperature is required for a normal load, while a room temperature acquisition device can be installed indoors for a standard load. If the temperature coefficient method is used to estimate room temperature, in addition to the direct reference method mentioned above, a movable pipe wall thermometer is required for temporary water temperature measurement for a normal load, and a water temperature monitoring device is required for continuous water temperature measurement for a standard load.

[0077] 1.1 Estimating room temperature using the direct reference method.

[0078] Step (1.1.1) Measure the room temperature at the current time under normal load on site.

[0079] Step (1.1.2) uses the reference method to estimate the room temperature at each subsequent time point under normal load.

[0080] 1.2 Temperature coefficient method for estimating room temperature.

[0081] Step (1.2.1) Measure the room temperature and water temperature at the current time under normal load and calculate the temperature coefficient.

[0082] Step (1.2.2) uses the reference method to estimate the temperature coefficient at each subsequent time point under normal load.

[0083] Step (1.2.3) Use a mobile pipe wall thermometer or water temperature monitoring device to temporarily or continuously measure the water temperature at various time points after normal load.

[0084] Step (1.2.4) Based on the estimated temperature coefficient and measured water temperature at each subsequent time point of the normal load, estimate the room temperature at each subsequent time point of the normal load.

[0085] 2. Quickly adjust the room temperature under load.

[0086] Based on the specific implementation method of "accurately estimating the room temperature under load", if some ordinary loads have manual flow adjustment devices and standard loads have water temperature monitoring devices, then the room temperature of these ordinary loads can be quickly adjusted to the target room temperature. The specific steps are as follows.

[0087] Step (2.1) Measure the room temperature and water temperature at the current time and calculate the temperature coefficient at the current time; or, if the on-site measurement has been completed, the temperature coefficient at the current time can be estimated by using the reference method.

[0088] Step (2.2) Estimate the target water temperature at the current time based on the temperature coefficient at the current time and the target room temperature at the current time.

[0089] Step (2.3): If the deviation between the measured or estimated current water temperature and the target water temperature (the deviation is the absolute value of the difference, the same below, will not be repeated) is greater than or equal to the action value, the system will adjust the current water temperature to the target water temperature, calculate the target opening of the manual flow regulating device based on the working flow characteristic curve of the manual flow regulating device, and execute it. Otherwise, the manual flow regulating device does not need to be adjusted.

[0090] After step (2.4) N, repeat steps (2.1) to (2.3). N is an integer greater than or equal to 1, which is set by the user. The same applies below and will not be repeated.

[0091] 3. Partial load autonomous control of room temperature.

[0092] Based on the specific implementation method of "rapidly adjusting the room temperature of the load", if some ordinary loads can upgrade the manual flow regulating device to an electric flow regulating device and add a water temperature monitoring device, a data transmission system, and a centralized or decentralized control system, then these ordinary loads can autonomously control the room temperature according to the self-set room temperature control strategy. The specific operation steps are as follows.

[0093] Step (3.1) A typical load autonomously sets a room temperature control strategy, that is, determines the target room temperature at each time point within a control cycle. Considering that there is a heat dissipation and temperature rise process between the water temperature and the room temperature, the target room temperature should be set several time points in advance based on the actual heating load. The target room temperature for the following typical load room temperature control strategies can all be set several time points in advance based on the actual heating load, and will not be repeated.

[0094] Step (3.2) Estimate the temperature coefficient of the normal load at the current time point by on-site measurement or reference method.

[0095] Step (3.3) Calculate the target water temperature at the current time based on the estimated normal load temperature coefficient and the target room temperature at the current time, and record it as the calculated target water temperature at the current time.

[0096] Step (3.4) At each time point, the difference (positive or negative) between the target water temperature at the previous time point and the water temperature at the current time point needs to be calculated and recorded as the "water temperature difference" at each time point.

[0097] Step (3.5) adds the cumulative value of the "water temperature difference" from the previous M time points (including the current time point) to the target water temperature calculated in step (3.3) for the current time point, thereby obtaining the execution target water temperature for the current time point. This ensures that even if the adjustment at a certain time point is not in place, the average water temperature can be made as close as possible to the average target water temperature, thus achieving a balance in the overall heat supply. M is an integer starting from 1, which can be set by the user.

[0098] Step (3.6) uses an electric flow regulating device to adjust the actual water temperature to the target room temperature and maintain it.

[0099] From step (3.7) to the next time point, repeat steps (3.2) to (3.6) to control the actual water temperature at each subsequent time point to the target water temperature, thereby achieving the purpose of controlling the actual room temperature at each subsequent time point to the target room temperature.

[0100] 4. All loads can autonomously control room temperature.

[0101] Based on the specific implementation method of "partial load autonomous room temperature control", if the standard load is equipped with an electric flow regulating device, and all ordinary loads have an electric flow regulating device, a water temperature monitoring device, a data transmission system, and a centralized or decentralized control system, all ordinary loads can achieve the goal of autonomous room temperature control according to the room temperature control strategy of the reference standard load or the room temperature control strategy set autonomously. The specific operation steps are as follows.

[0102] Step (4.1) Standard load autonomously controls room temperature. Each standard load follows the autonomously set room temperature control strategy, directly using the collected room temperature as the control object, and ensuring that the room temperature conforms to the autonomously set room temperature control strategy through water temperature control.

[0103] Step (4.2) forms multiple quality regulation subsystems. When the room temperature control strategy for normal load is the same as that for standard load, the normal load calculates the target water temperature at each time point according to the actual water temperature of the reference standard load using the reference method, and then adjusts the water temperature to the target room temperature and maintains it through the electric flow regulating device. In fact, multiple quality regulation subsystems are formed with the standard load as the unit.

[0104] Step (4.3) The water quality regulation subsystem autonomously controls the room temperature under normal load. When the room temperature control strategy of the normal load is different from the reference standard load, steps (3.2) to (3.7) are repeated to control the actual water temperature at each subsequent time point to the target water temperature, thereby achieving the purpose of controlling the actual room temperature at each subsequent time point to the target room temperature.

[0105] Based on the specific embodiments described in this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

Claims

1. A heating room temperature control method based on temperature estimation, characterized in that: In a temperature-regulating heating system, the relationship between room temperature, water temperature, and air temperature at the measurement point is first obtained through on-site measurement of the room and water temperatures under the heating load. This relationship is hereinafter referred to as the "temperature coefficient" and is expressed in K. T This means that the temperature coefficients at subsequent time points are estimated using the reference method; The temperature coefficient is calculated as (water temperature - room temperature) / (room temperature - air temperature), i.e., K. T = (T 水 -T 室 ) / (T 室 -T 气 ); In the formula: Water temperature, using T 水 The average temperature of the supply and return water for the heating load is equal to (supply water temperature + return water temperature) / 2. The water temperature is measured using a fixed contact temperature sensor or a temporary moving pipe wall thermometer. Room temperature, using T 室 This indicates the indoor temperature for the corresponding heating load, which is either the room temperature at a representative point or the average of room temperatures at multiple points. Temperature, expressed in T 气 This indicates the outdoor temperature, which is either the outdoor temperature released by the meteorological bureau or the outdoor temperature measured by the bureau itself, or the corrected composite outdoor temperature. The heating characteristics of the heating load are divided into inherent heating characteristics and variable heating characteristics. Inherent heating characteristics refer to the inherent heating characteristics of the building itself that do not change over time, while variable heating characteristics refer to the heating characteristics that change over a period of time. The reference method steps in the quality-regulating heating system are as follows: Step (1.1) Establish standard heating load: The standard heating load is hereinafter referred to as "standard load" and the ordinary heating load is hereinafter referred to as "ordinary load". The standard load is selected from the ordinary load and is required to have the representativeness of the inherent heating characteristics, the stability of the variable heating characteristics, few interference factors, good user cooperation, and at least one room temperature acquisition device. Depending on the specific implementation method, it is also required to have a monitoring device for supply water temperature and return water temperature, an electric flow regulation device, a data transmission system, and a centralized or decentralized control system. Step (1.2) Establishing a reference relationship: The load forms of ordinary load and standard load must be the same, and they must be in the same single heat source heat network or, although in a multi-heat source heat network, be supplied by the same heat source to establish a reference relationship; many-to-many reference relationships can be established between ordinary load and standard load, but only one set of reference relationships can be in use for an ordinary load, while multiple sets of reference relationships can be in use for a standard load at the same time. Step (1.3) Measure the normal load: When the heating system is in quality regulation mode and operating stably, take a field measurement of the room temperature and water temperature of the normal load and calculate the temperature coefficient. At the same time, record the room temperature, water temperature and temperature coefficient of the standard load at the time of the field measurement of the normal load. Each field measurement is a calibration and correction of the temperature estimation. The normal load can be measured at intervals, and the estimation can be restarted from the time and data of the new measurement. This can further improve the accuracy of the estimation. Step (1.4) Set the starting time point: Set the starting time point according to the time of the ordinary load field measurement, and generate the next time point according to the user-defined fixed time interval; Step (1.5) Estimate the room temperature, water temperature and temperature coefficient at the second time point of normal load: Based on the measured room temperature, water temperature and temperature coefficient at the start time of normal load, and with reference to the room temperature, water temperature and temperature coefficient at the start time and the second time point of standard load, estimate the room temperature, water temperature and temperature coefficient at the second time point of normal load using the same difference algorithm or the same comparison algorithm. Step (1.6) Estimate the room temperature, water temperature and temperature coefficient at the third time point of normal load: Based on the room temperature, water temperature and temperature coefficient estimated at the second time point of normal load, refer to the room temperature, water temperature and temperature coefficient at the second and third time points of standard load, and use the same difference algorithm or the same comparison algorithm to estimate the room temperature, water temperature and temperature coefficient at the third time point of normal load. Step (1.7) Repeat step (1.6) to estimate the room temperature, water temperature and temperature coefficient at the fourth, fifth, sixth and so on time points of normal load, until the normal load is measured on site again, and start the estimation again from the new measurement time and value. This eliminates the need to install room temperature acquisition devices within the heating load. With the air temperature known, the actual room temperature can be estimated based on the actual water temperature at each subsequent time point, and the target water temperature can be estimated based on the target room temperature at each subsequent time point. By controlling the actual water temperature to the target water temperature, the goal of controlling the actual room temperature to the target room temperature can be achieved.

2. The heating room temperature control method based on temperature estimation according to claim 1, characterized in that: The heating load forms include rooms, houses, units, buildings, communities, factories, and heat exchange stations. The heating characteristics of the heating load are divided into inherent heating characteristics and variable heating characteristics. Inherent heating characteristics include the inherent heating characteristics of the house itself, which do not change over time, such as insulation level, heat transfer coefficient, air leakage coefficient, house type, orientation, area, floor, whether it is a detached house, whether it is adjacent to a mountain, whether it is on the roof, whether it is on the ground floor, and whether it has a basement. Variable heating characteristics include the type of radiator, the degree of radiator obstruction, the ground paving material, the number of adjacent loads above and below, the number of adjacent loads to the left and right, the performance and location of measuring meters, the daily number of people and their activity intensity, and whether other radiators are frequently added. These are heating characteristics that will change over time.

3. The heating room temperature control method based on temperature estimation according to claim 1, characterized in that: The factors affecting the temperature coefficient are divided into two categories: variable factors and fluctuation factors. Variable factors refer to the inherent heating characteristics and variable heating characteristics, while fluctuation factors mainly include water temperature, air temperature, wind force, wind direction, and sunshine that fluctuate frequently. Variable factors determine the magnitude of the average value of the temperature coefficient and the width of the fluctuation range, while fluctuation factors determine the direction and value of the real-time fluctuation of the temperature coefficient.

4. The heating room temperature control method based on temperature estimation according to claim 1, characterized in that... The reference method includes two algorithms: same difference and same year. The equal difference algorithm assumes that the difference between the measured or estimated room temperature, water temperature, and temperature coefficient of the current ordinary load and the room temperature, water temperature, and temperature coefficient of the current standard load is equal to the difference between the estimated room temperature, water temperature, and temperature coefficient of the ordinary load at the next time point and the standard load at the next time point. The difference between room temperature, water temperature, and temperature coefficient under quasi-load conditions is used to estimate the room temperature, water temperature, and temperature coefficient at the next time point and subsequent time points under normal load conditions. The year-on-year calculation method estimates the room temperature, water temperature, and temperature coefficient of the normal load at the next time point by assuming that the ratio of the room temperature, water temperature, and temperature coefficient measured or estimated at the current time point to the room temperature, water temperature, and temperature coefficient to be estimated at the next time point is the same as the ratio of the room temperature, water temperature, and temperature coefficient at adjacent time points with the same standard load. Given the temperature coefficient A1 at time 1 of normal load A, and the temperature coefficients B1, B2, and B3 at time 1, 2, and 3 of standard load B, estimate the temperature coefficients A2 and A3 at time 2 and 3 of normal load A. Using the difference algorithm A1-B1=A2-B2=A3-B3, the formula for A2 is A2=A1-B1+B2, and the formula for A3 is A3=A2-B2+B3. A3 can then be calculated accordingly. n Based on the year-on-year calculation methods A1 / A2=B1 / B2 and A2 / A3=B2 / B3, the formula for calculating A2 is: A2=A1 ×B2 ÷B1, and the formula for calculating A3 is A3=A2 ×B3 ÷B2. A can then be calculated accordingly. n .

5. The heating room temperature control method based on temperature estimation according to claim 1, characterized in that... Temperature estimation can be categorized by temperature into room temperature estimation and water temperature estimation, and by method into two types: direct reference method and temperature coefficient method. The direct reference method involves directly using a reference method to estimate the room temperature or water temperature under normal load. The temperature coefficient method first uses the reference method or the fixed value method to estimate the temperature coefficient at the current time, and then estimates the water temperature or room temperature at the current time based on the measured or estimated room temperature or water temperature at the current time. The so-called constant value algorithm is used when the inherent heating characteristics and variable heating characteristics of ordinary load and standard load differ too much or there is no reference standard load. It utilizes the stability characteristics of the temperature coefficient curve to directly or empirically correct the temperature coefficient of the ordinary load measured on-site once as the temperature coefficient of subsequent time points. In the control of room temperature in heating, temperature estimation mainly involves the following two situations: (1) Estimating the current room temperature of normal load, the direct reference method or the temperature coefficient method can be used. The main purpose is to understand the actual room temperature of normal load and determine whether adjustment is needed; (2) Estimating the target water temperature of normal load, only the temperature coefficient method can be used. The main purpose is to determine the target water temperature at each time point based on the target room temperature set by the normal load at each time point.

6. The heating room temperature control method based on temperature estimation according to claim 1, characterized in that... When the inherent or variable heating characteristics of a heating load change, the average values ​​of room temperature, water temperature, and temperature coefficient will also change, and the curves will shift upward or downward. To maintain the consistency of the estimation accuracy before and after the change, it is necessary to correct the estimated room temperature, water temperature, and temperature coefficient after the change. There are three ways to correct these values: Correction method (6.1) After the inherent heating characteristics or variable heating characteristics of normal load and standard load change respectively or simultaneously, the correction can be carried out by re-measuring the normal load and establishing a new reference relationship based on the measured value. Correction method (6.2): ​​If the inherent heating characteristics or variable heating characteristics of the standard load change, the changes in the average values ​​of room temperature, water temperature and temperature coefficient at the same time interval before and after the change can be statistically analyzed. An increase is positive and a decrease is negative. The room temperature, water temperature and temperature coefficient at each time point after the change of the standard load are subtracted from the above changes before being included in the estimation. This is equivalent to "eliminating" the impact of the change in the inherent heating characteristics or variable heating characteristics of the standard load on the room temperature, water temperature and temperature coefficient. Correction method (6.3) If the inherent heating characteristics or variable heating characteristics of the normal load change, the change in the average values ​​of room temperature, water temperature and temperature coefficient of the standard load after the change of the normal load can be simulated by statistical standard load. An increase is positive and a decrease is negative. Estimate the change in the average values ​​of room temperature, water temperature and temperature coefficient after the change of the normal load, and add the change value to the estimated room temperature, water temperature and temperature coefficient at each time point after the change of the normal load. This is equivalent to "reflecting" the impact of the change in the inherent heating characteristics or variable heating characteristics of the normal load on the room temperature, water temperature and temperature coefficient. If the same difference algorithm is used for normal load, the estimated room temperature, water temperature and temperature coefficient at each time point after the normal load changes need to be corrected by adding the change value. If the normal load uses a year-on-year calculation method, then after the normal load changes, you need to select an estimated room temperature, water temperature, and temperature coefficient at a certain point in time, and add the change value.

7. The heating room temperature control method based on temperature estimation according to claim 1, characterized in that... In a quality-regulating heating system, the standard load has a room temperature acquisition and water temperature monitoring device, while the ordinary load requires at least a handheld pipe wall thermometer as a temporary water temperature measurement device, as well as a manual flow regulation device. The ordinary load can then quickly adjust the room temperature to the target room temperature. The specific steps are as follows: Step (7.1) Measure the room temperature and water temperature at the current time on site and calculate the temperature coefficient at the current time; or, if the on-site measurement has been completed, the temperature coefficient at the current time can be estimated by using the reference method. Step (7.2) Estimate the target water temperature at the current time based on the current temperature coefficient and the target room temperature at the current time; Step (7.3): If the deviation between the measured or estimated actual water temperature at the current time and the target water temperature is greater than or equal to the action value, the system will adjust the actual water temperature at the current time to the target water temperature. On the basis of keeping the circulating water volume of the heating system constant, the system will calculate the target opening degree of the manual flow regulating device according to the working flow characteristic curve of the manual flow regulating device and execute it. That is, the average temperature of the supply and return water at the user end will be finely adjusted by adjusting the opening degree of the flow regulating device. Otherwise, the manual flow regulating device does not need to be adjusted. After step (7.4) N, repeat steps (7.1) to (7.3), where N is an integer greater than or equal to 1, which is set by the user.

8. A heating room temperature control method based on temperature estimation according to claim 1, characterized in that... In a quality-regulating heating system, the standard load has a room temperature acquisition and water temperature monitoring device, while the ordinary load has an electric flow regulating device, and supply and return water temperature monitoring devices. When the heating system has a data transmission system and a centralized or distributed control system, the ordinary load can autonomously control the room temperature according to a self-set room temperature control strategy. The specific operation steps are as follows: Step (8.1) A certain normal load autonomously sets the room temperature control strategy, that is, determines the target room temperature at each time point within a control cycle; considering that there is a heat dissipation and heating link between water temperature and room temperature, when setting the target room temperature, it should be set in advance according to the actual situation of the heating load. The room temperature control strategies for the following normal loads can all be set in advance according to the actual situation of the heating load, and will not be repeated. Step (8.2) Estimate the temperature coefficient of the normal load at the current time point through on-site measurement or reference method; Step (8.3) Calculate the target water temperature at the current time based on the estimated normal load temperature coefficient and the target room temperature at the current time, and record it as the calculated target water temperature at the current time; Step (8.4) Under normal load, at each time point, the difference between the calculated target water temperature at the previous time point and the actual water temperature at the current time point needs to be calculated. The difference can be positive or negative and is recorded as the "water temperature difference" at each time point. Step (8.5) adds the cumulative value of the "water temperature difference" of the previous M time points to the target water temperature calculated in step (8.3) at the current time point to obtain the execution target water temperature at the current time point, so as to ensure that when the adjustment is not in place at some time points, the average water temperature is as close as possible to the average target water temperature, so as to achieve the balance of the overall heat supply. M is an integer starting from 1, which can be set by the user. Step (8.6) uses an electric flow regulating device to adjust the actual water temperature to the target water temperature and maintain it while keeping the circulating water volume of the quality regulation heating system constant; From step (8.7) to the next time point, repeat steps (8.2) to (8.6) to control the actual water temperature at each subsequent time point to the target water temperature, thereby achieving the purpose of controlling the actual room temperature at each subsequent time point to the target room temperature.

9. A heating room temperature control method based on temperature estimation according to claim 1, characterized in that... In a temperature-regulating heating system, the standard load includes room temperature acquisition and water temperature monitoring devices, as well as an electric flow regulating device. All ordinary loads include an electric flow regulating device, and supply and return water temperature monitoring devices. When the heating system has a data transmission system and a centralized or decentralized control system, all ordinary loads can achieve autonomous room temperature control based on the room temperature control strategy of the referenced standard load or a self-set room temperature control strategy. The specific operation steps are as follows: Step (9.1) Standard load autonomously controls room temperature: Each standard load follows the autonomously set room temperature control strategy, directly using the collected room temperature as the control object, and ensuring that the room temperature meets the autonomously set room temperature control strategy through water temperature control. Step (9.2) forms multiple quality regulation subsystems: When the room temperature control strategy of the normal load is the same as that of the standard load, the normal load calculates the target water temperature at each time point according to the actual water temperature of the reference standard load and then adjusts the water temperature to the target water temperature and maintains it through the electric flow regulating device. Multiple quality regulation subsystems are formed with the standard load as the unit. Step (9.3) Quality regulation subsystem autonomously controls room temperature under normal load: When the room temperature control strategy of the normal load is different from the reference standard load, refer to steps (8.2) to (8.6) and repeat to control the actual water temperature at each subsequent time point to the target water temperature, so as to achieve the purpose of controlling the actual room temperature at each subsequent time point to the target room temperature.

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