JP2013036712A - Device for calculating reduction heat amount and method for calculating flow rate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for calculating a flow rate for calculating an amount of heat to be reduced with high precision and high responsiveness according to output from a flow rate sensor.SOLUTION: A flow rate calculating section 54f in a reduction heat amount calculating device starts measurement of time using a rising edge of a pulse as a trigger on the basis of a detection signal from the flow rate sensor and counts the number of edges Ce corresponding to the number of pulses according to rising edges appearing within predetermined measurement time Tn. Then, the flow rate calculating section 54f measures a time T2 relating to fraction pulses remaining after the measurement time Tn is over in a final pulse cycle, for a final pulse which is counted last in the measurement time Tn. The flow rate calculating section 54f calculates the number of pulses per unit time on the basis of the counted number of edges Ce and add time (Tn+T2) obtained by adding the measurement time Tn and the time T2 relating to the fraction pulses, thereby calculating a flow rate Q.

Description

  The present invention relates to a reduced heat amount calculation device and a flow rate calculation method.

  In recent years, the use of natural energy, particularly solar energy, has been promoted against the background of the manifestation of the effects of global warming. For example, a solar hot water supply system is known (see, for example, Patent Document 1). In addition, in order to expect the expansion of the use of solar thermal energy, a mechanism for declaring the environmental value of the amount of heat reduced by the solar hot water supply system has been established, such as a green heat certificate. It is required to measure the amount of heat when making a certificate of the amount of heat, but the requirement of the meter is that it is a cumulative calorimeter that is a legal meter.

  By the way, this legal measuring instrument is expensive and is required to have an expiry date due to verification, which is different from the service life of the solar hot water supply system, which has been an adverse effect of promoting the spread. In view of this, a method has been proposed in which the flow rate is calculated using an inexpensive flow rate sensor that has not obtained a measurement test, and the amount of heat is measured based on this to reduce the cost of the entire system.

JP 2003-279144 A

  However, according to the conventional method, although the flow rate is calculated according to the output of the flow rate sensor, the accuracy of the calculated flow rate may be lowered particularly in a low flow rate region. For this reason, it has been desired to calculate the flow rate with the same accuracy as that obtained from the measurement test. In this regard, although it is possible to improve the calculation accuracy by sufficiently securing the time required for one flow rate calculation, the calculation cycle for obtaining the flow rate tends to be prolonged, and the responsiveness is inferior. May cause problems.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for calculating a flow rate for calculating a reduced heat amount with high accuracy and high responsiveness according to an output from a flow rate sensor. is there.

  In order to solve such a problem, the first invention heats at least one of a solar water heater that heats supplied water to make preheated hot water, and supplied water and preheated hot water supplied from the solar water heater. And at least one of preheated hot water supplied from the solar water heater and mixed water in which the preheated hot water and cold water are mixed is used as detection target water, and the detection target water is used. A flow rate sensor that outputs in accordance with the flow rate, a first temperature sensor that detects a water temperature before being heated by the solar water heater, a second temperature sensor that detects a temperature of water to be detected, a first temperature sensor, and a first temperature sensor (2) Based on the signal value from the temperature sensor and the flow rate calculated according to the output of the flow rate sensor, the amount of heat that can be reduced during heating in the water heater by heating of the solar water heater is calculated. Providing heat calculation device. Here, the reduced heat quantity calculation device starts time measurement with a predetermined output change corresponding to one pulse period as a trigger, and counts the number of pulses according to the output change that appears within a predetermined measurement time. And a fraction pulse measuring means for measuring a fractional pulse remaining after the end of the measurement time in one cycle of the last pulse for the last pulse counted at the end of the measurement time, and the number of counted pulses. Calculation means for calculating the flow rate of the liquid by calculating the number of pulses per unit time based on the fractional pulse.

  Here, in the first invention, the fractional pulse measuring means measures the fractional pulse as the time related to the fractional pulse, and the computing means calculates the number of counted pulses and the time related to the fractional pulse in the measurement time. It is preferable to calculate the number of pulses per unit time based on the added addition time. Alternatively, the fraction pulse measuring means measures the fraction pulse as a fraction pulse ratio in the final pulse, and the computing means is based on the number of counted pulses, the fraction pulse ratio, and the measurement time. The number of pulses per unit time may be calculated.

  In the first invention, the pulse number measuring means preferably determines the rising edge of the pulse as a predetermined output change corresponding to one pulse period.

  Further, the second invention comprises a solar water heater that heats supplied water to make preheated hot water, and a water heater that heats at least one of the supplied water and the preheated hot water supplied from the solar water heater. At least one of preheated hot water supplied from a solar water heater and mixed water in which the preheated hot water and cold water are mixed is used as a detection target water, and an output corresponding to the flow rate of the detection target water is used. A flow rate sensor to be performed, a first temperature sensor for detecting the water temperature before being heated by the solar water heater, a second temperature sensor for detecting the temperature of the detection target water, and signals from the first temperature sensor and the second temperature sensor In a reduced heat quantity calculation device that calculates a reduced heat quantity that can be reduced during heating in a water heater by heating of a solar water heater based on the value and the flow rate calculated according to the output of the flow sensor It provides a flow rate calculating method for calculating the flow rate in response to an output of the flow sensor. In this case, the flow rate calculation method includes a first step of starting time measurement using a predetermined output change corresponding to one pulse period as a trigger based on the output of a flow rate sensor that outputs a pulse corresponding to the flow rate of the liquid; The second step of counting the number of pulses according to the output change that appears within a predetermined measurement time, and the end of the measurement time of the last pulse for one cycle, with respect to the last pulse counted at the end of the measurement time A third step of measuring the remaining fractional pulses, a fourth step of calculating the number of pulses per unit time based on the counted number of pulses and the fractional pulses, and the number of pulses per unit time And a fifth step of calculating the flow rate of the liquid.

  According to the present invention, by considering fractional pulses, the number of pulses per unit time can be obtained with high resolution. As a result, the flow rate of the liquid can be accurately calculated without being affected by the weight of the unit pulse. In addition, since the measurement time only needs to include one or more pulses corresponding to one cycle, the time required for detection may be short, and even in this case, the weight of the unit pulse There is no such a situation as to affect. Thereby, the flow rate for calculating the reduced heat quantity can be calculated with high accuracy and high responsiveness.

Explanatory drawing which shows typically the structure of the solar hot water supply system 1 including the reduction calorie | heat amount calculation apparatus 5 concerning this embodiment. The block diagram which shows the structure of the reduction calorie | heat amount calculation apparatus 5 Explanatory drawing functionally showing the configuration of the MPU 51 of the reduced heat amount calculation device 5 The flowchart which shows a series of procedures regarding flow volume calculation concerning this embodiment. Explanatory drawing which shows typically the flow volume calculation process concerning this embodiment Explanatory drawing schematically showing the flow rate calculation process by the conventional method Configuration diagram of a solar water heating system including a reduced heat amount calculation device according to a modification

  FIG. 1 is an explanatory view schematically showing a configuration of a solar hot water supply system 1 including a reduced heat quantity calculation device 5 according to the present embodiment. The solar hot water supply system 1 includes a water pipe 11, a cold water pipe 12, a hot water pipe 13, a mixed water pipe 14, and a heated water pipe 15. Further, the solar hot water supply system 1 includes a solar water heater 2, a mixing valve 3, and a water heater 4.

  The water pipe 11 supplies water to each of household water appliances such as a kitchen, a washroom, a bath, and a toilet. Moreover, the water pipe 11 is branched and the cold water pipe 12 is connected to the branch location. The cold water pipe 12 guides cold water flowing through the water pipe 11 to the solar water heater 2.

  The solar water heater 2 has a heat collector 21, a heat medium pipe 22, and a hot water tank 23. The heat collector 21 is installed on the roof of a sunny house or the like, and takes in solar heat to warm the heat medium. The heat medium pipe 22 connects the heat collector 21 and the hot water storage tank 23 and has a structure in which the heat medium flows inside. The heat medium circulates through the heat collector 21 and the hot water tank 23 via the heat medium pipe 22. The hot water storage tank 23 introduces the cold water from the cold water pipe 12 and heats the cold water with the warmed heat medium flowing through the heat medium pipe 22 to obtain preheated hot water to store hot water.

  The hot water pipe 13 is a pipe for supplying preheated hot water from the hot water tank 23 to the hot water heater 4 side. A mixing valve 3 is installed at the end of the hot water pipe 13, and preheated hot water from the hot water pipe 13 is supplied to the mixing valve 3 from a hot water inlet 31 of the mixing valve 3. Further, the cold water pipe 12 is branched at the connection point A, and the cold water from the cold water pipe 12 can be supplied to the mixing valve 3 through the cold water inlet 32 of the mixing valve 3. The mixing valve 3 mixes preheated hot water and cold water that flow in as described later to obtain mixed water.

  The mixed water pipe 14 is a pipe that connects the mixed water outlet 33 of the mixing valve 3 and the water heater 4, and the mixed water is supplied from the mixing valve 3 to the water heater 4 through the pipe 14. In this embodiment, the mixing valve 3 is a hot water mixing valve with an automatic temperature adjustment function that automatically adjusts the mixing ratio of hot water and cold water so that the temperature of the mixed water becomes a predetermined temperature. The configuration of the valve 3 is not limited to this.

  The water heater 4 includes, for example, a gas burner and a heat exchanger, and generates heated water (that is, hot water) having a temperature determined by a user or the like. This water heater 4 is connected to a hot water remote controller or the like provided in a house, and based on a control signal received from the hot water remote controller or the like, for example, the power on, the power off, and the temperature of the generated hot water are Is set.

  The heated water pipe 15 is a pipe that connects the water heater 4 and a shower port on the hot water supply side. The heated water warmed by the water heater 4 is supplied to the user or the like through the heated water pipe 15.

  With the above configuration, the solar hot water supply system 1 converts the cold water from the water pipe 11 into the preheated hot water by the solar water heater 2 using solar heat and supplies it to the hot water heater 4. And the amount of carbon dioxide emitted can be reduced.

  Next, the reduced heat amount calculation apparatus 5 according to the present embodiment will be described. The reduced heat amount calculation device 5 calculates and integrates and displays the amount of heat reduced by using the solar water heater 2, and includes a first temperature sensor 51, a second temperature sensor 52, a flow rate sensor 53, and a calculation. A display 54 and a home display 55 are provided. Note that the reduced heat amount calculation device 5 may have a function of calculating and integrating and displaying a gas charge and carbon dioxide emission amount in addition to the heat amount.

  The first temperature sensor 51 is disposed in the cold water pipe 12 and detects the water temperature before being heated by the solar water heater 2, that is, the temperature of the cold water. The second temperature sensor 52 is disposed in the hot water pipe 13 and detects the temperature of the preheated hot water in the pipe (that is, in the hot water pipe 13) from when heated by the solar water heater 2 until it is supplied to the water heater 4. It is.

  The flow rate sensor 53 is disposed in the hot water pipe 13 and detects the flow rate of preheated hot water supplied from the solar water heater 2 to the water heater 4. The flow sensor 53 is of an impeller type, for example, and is configured to output a number of pulses corresponding to the number of rotations of the impeller when preheated hot water flows. In the following description, the flow sensor 53 is described as an impeller type, but the present invention is not limited to this, and the flow sensor 53 may have another configuration.

  The calculation display 54 has a function of calculating and integrating and displaying the amount of heat and the amount of carbon dioxide reduced by using the solar water heater 2. Note that the display function is also installed in the home display 55, and the reduced amount of heat and carbon dioxide are displayed on the calculation display 54 and the home display 55.

  FIG. 2 is a configuration diagram showing the calculation display 54 according to the present embodiment. As shown in FIG. 2, the calculation display 54 includes a microprocessor (MPU) 54a. The MPU 54a operates according to a predetermined program, and includes a CPU 54a1, a ROM 54a2, and a RAM 54a3.

  The CPU 54a1 executes various processes and controls according to a predetermined program. The ROM 54a2 is a read-only memory that stores programs executed by the CPU 54a1. The RAM 54a3 is a readable / writable memory that stores various data and has an area necessary for the processing operation of the CPU 54a1.

  In the present embodiment, the ROM 54a2 stores a program for calculating the amount of heat, the fuel cost, and the amount of carbon dioxide reduced by using the solar water heater 2. Therefore, the CPU 54a1 that executes this program calculates the reduced fuel cost and the amount of carbon dioxide.

  Further, the reduced heat amount calculation device 5 includes a memory unit 54b, a display unit 54c, and an interface unit 54d.

  The memory unit 54b is a recording medium capable of holding various stored data even when the power supply is interrupted, and an electrically erasable / rewritable memory having various storage areas necessary for processing operations of the CPU 54a1 ( EEPROM) or the like is used.

  As the display unit 54c, an LCD, an LED, or the like is used. The display unit 54c performs various displays such as a reduced heat amount, a reduced carbon dioxide amount, and a reduced fuel cost calculated by the CPU 54a1. In addition, in this embodiment, although the display part 54c is provided in the main-body part of the reduction calorie | heat amount calculation apparatus 5 installed in the outdoors, it is not restricted to this, You may provide in a house like the house indicator 55. .

  The interface unit 54d is electrically connected to the first and second temperature sensors 51 and 52 and the flow rate sensor 53, and enables communication between the various sensors 51 to 53 and the MPU 54a.

  FIG. 3 is a functional block diagram of the calculation display 54 shown in FIGS. 1 and 2. As shown in FIG. 3, the calculation display 54 includes a correlation data storage unit 54e, a flow rate calculation unit 54f, and a reduced heat amount calculation unit 54g.

  The correlation data storage unit 54e stores correlation data between the output (number of pulses in the present embodiment) obtained from the flow sensor 53 and the flow rate. Specifically, the correlation data storage unit 54e stores a calculation formula for calculating the flow rate from the number of pulses obtained from the flow rate sensor 53 as correlation data.

  When the output is obtained from the flow sensor 53, the flow rate calculation unit 54f calculates the flow rate Q of the preheated hot water based on the correlation data stored in the correlation data storage unit 54e.

  The reduced heat amount calculating unit 54g calculates various reduced heat amounts such as a heat amount, a carbon dioxide amount, and a fuel cost that are reduced by using the solar water heater 2. Specifically, the reduced heat amount calculation unit 54g includes the flow rate Q calculated by the flow rate calculation unit 54f, the temperature of cold water detected by the first temperature sensor 51, and the temperature of preheated hot water detected by the second temperature sensor 52. From this, the amount of heat reduced is calculated. The reduced heat amount calculation unit 54g calculates a reduced fuel cost from the reduced heat amount, the hot water supply efficiency, and the fuel unit price. Similarly, the reduced heat amount calculation unit 54g calculates the reduced carbon dioxide amount from the reduced heat amount, the hot water supply efficiency, and the carbon dioxide generation amount per unit fuel.

  One of the features of this embodiment is the flow rate calculation method related to the flow rate Q by the flow rate calculation unit 54f, and the details of the operation will be described below. The flow rate calculation unit 54f has a pulse number measurement unit 54f1, a fractional pulse measurement unit 54f2, and a calculation unit 54f3 when this is functionally grasped. The pulse number measuring means 54f1 starts time measurement with a predetermined output change corresponding to one pulse period as a trigger, and counts the number of pulses according to the output change appearing within a predetermined measurement time. The fractional pulse measuring means 54f2 measures the fractional pulse remaining after the end of the measurement time in one cycle of the final pulse for the last pulse counted at the end of the above-mentioned measurement time. The calculating means 54f3 calculates the flow rate Q of preheated hot water by calculating the number of pulses per unit time based on the counted number of pulses and fractional pulses.

  FIG. 4 is a flowchart showing a series of procedures relating to the flow rate calculation according to the present embodiment. The process shown in this flowchart is called at a predetermined cycle and executed by the MPU 51 (flow rate calculation unit 54f).

  First, in step 1 (S1), the flow rate calculation unit 54f starts monitoring the detection signal from the flow rate sensor 53, and determines whether or not there is a rising edge of a pulse. In the present embodiment, since the flow rate calculation unit 54f uses the rising edge of the pulse as a predetermined output change corresponding to one pulse period, the presence or absence of the rising edge is determined in Step 1. If an affirmative determination is made in step 1, that is, if there is a rising edge of the pulse, the process proceeds to step 2 (S2). On the other hand, if a negative determination is made in step 1, that is, if there is no rising edge of the pulse, the determination in step 1 is performed again.

  In step 2 (S2), the flow rate calculation unit 54f starts the first timer T1 and starts time measurement. That is, by this step 2, the time measurement by the first timer T1 is started with the rising edge of the first appearing pulse as a trigger.

  In step 3 (S3), when the rising edge of the pulse appears in the detection signal being monitored, the flow rate calculation unit 54f counts it as the number of edges. The rising edge determined in step 1 is included in the number of edges, and the initial value of the counter that counts the number of edges is “1”. If the rising edge is determined in step 3, the counter is incremented by “1”.

  In step 4 (S4), the flow rate calculation unit 54f determines whether or not the measurement time by the first timer T1 has reached a predetermined measurement time Tn. If an affirmative determination is made in step 4, that is, if the first timer T1 reaches the measurement time Tn, the process proceeds to step 5 (S5). On the other hand, if a negative determination is made in step 4, that is, if the first timer T1 has not reached the measurement time Tn, the process returns to step 3.

  In step 5, the flow rate calculation unit 54f starts the second timer T2 and starts time measurement. That is, in step 5, the time measurement by the second timer T2 is started with the first timer T1 reaching the measurement time Tn as a trigger.

  In step 6 (S6), the flow rate calculation unit 54f monitors the detection signal from the flow rate sensor 53, and determines whether or not there is a rising edge of the pulse. If an affirmative determination is made in step 6, that is, if there is a rising edge of the pulse, the process proceeds to step 7 (S7). On the other hand, if a negative determination is made in step 6, that is, if there is no rising edge of the pulse, the determination in step 6 is performed again.

  In step 7, the flow rate calculation unit 54f stops the timer T2 and ends the time measurement by the timer T2. In step 7, the time measurement by the second timer T2 is terminated with the rising edge of the pulse appearing next to the last pulse counted at the end of the measurement time, that is, the end point of one cycle related to the last pulse as a trigger. That is, the time measured by the timer T2 indicates the time related to the fractional pulse remaining after the end of the measurement time Tn in one cycle of the last pulse.

  In step 8 (S8), the flow rate calculation unit 54f calculates the number of pulses per unit time based on the counted number of edges (number of pulses), measurement time Tn, and time T2 related to the fractional pulse. Specifically, the number of pulses per unit time is calculated by dividing the counted number of edges by an addition time (Tn + T2) obtained by adding the time T2 related to the fractional pulse to the measurement time Tn.

  In step 9 (S9), the flow rate calculation unit 54f calculates the flow rate Q of the preheated hot water based on the number of pulses per unit time. The flow rate calculation unit 54f refers to the correlation data stored in the correlation data storage unit 54e (for example, a map or arithmetic expression that defines the correspondence between the number of pulses per unit time and the flow rate), and the pulses per unit time. The flow rate Q is uniquely calculated from the number.

  As described above, in the present embodiment, the flow rate calculation unit 54f starts time measurement using the rising edge of the pulse as a trigger based on the detection signal from the flow rate sensor 53 as shown in FIG. 5 (pulse number measurement unit 54f1). ). The flow rate calculation unit 54f counts the number of edges Ce corresponding to the number of pulses in accordance with the rising edge that appears within the predetermined measurement time Tn (pulse number measuring means 54f1). Next, the flow rate calculation unit 54f, for the last pulse counted at the end of the measurement time Tn (for example, the fifth pulse shown in FIG. 5), remains after the end of the measurement time Tn in one cycle of the last pulse. The time T2 related to the fractional pulse to be measured is measured (fractional pulse measuring means 54f2). Then, the flow rate calculation unit 54f calculates the number of pulses per unit time based on the counted number of edges Ce and the addition time (Tn + T2) obtained by adding the time T2 related to the fractional pulse to the measurement time Tn (calculation means) 54f3). Thereby, the flow rate calculation unit 54f calculates the flow rate Q based on the number of pulses per unit time (calculation unit 54f3).

  FIG. 6 is an explanatory diagram showing the concept of flow rate calculation by a conventional method. According to the conventional method, when time measurement is started using a rising edge of a pulse as a trigger, the number Cp of rising edges of the pulse that appear within a predetermined time Ts is counted. Then, the number of pulses per unit time is calculated based on the fixed time Ts and the counted number of edges (number of pulses) Cp, thereby calculating the flow rate.

  In the detection signal (time-series pulse train) output from the flow rate sensor, the number of pulses included per unit time is smaller in the low flow rate region than in the high flow rate region. For this reason, unless the above-mentioned fixed time Ts is ensured, the weight per unit pulse may increase and the calculation accuracy of the flow rate may decrease. For example, when 10 unit pulses are output per second, when the fixed time Ts is 10 seconds, the unit pulse corresponding to one pulse period corresponds to 1% of the entire pulse. Therefore, for example, even when the fixed time Ts ends immediately after counting the rising edge, the rising edge is counted as equivalent to the unit pulse, so in the low flow rate region where the influence of the weight of the unit pulse is large, It will be reflected as an error in the flow rate. In this case, it may be possible to suppress the weight of the unit pulse by setting the constant time Ts to be long, but there is a problem that the flow rate calculation period per time becomes long and the responsiveness decreases.

  In this regard, according to the present embodiment, the flow rate calculation unit 54f can obtain the number of pulses per unit time with high resolution by considering the time T2 related to the fractional pulses. Thereby, the hot water flow rate Q can be accurately calculated without being affected by the weight of the unit pulse. In addition, according to the present embodiment, the measurement time Tn only needs to include one or more unit pulses, so that the time required for detection may be short, and even in such a case. There is no situation where the weight of the unit pulse is affected. As a result, the flow rate Q for calculating the reduced heat quantity can be calculated with high accuracy and responsiveness based on the output from the flow rate sensor 53.

  In the present embodiment, the flow rate calculation unit 54f uses the rising edge of the pulse as an output change corresponding to one cycle of the pulse. According to this method, since one pulse period can be properly grasped as an electrical detection signal, the number of pulses per unit time can be obtained with high accuracy.

  However, the output change corresponding to one pulse period may be the falling edge of the pulse without using the rising edge of the pulse, or may be any definable point in one pulse period.

  Further, in the present embodiment, in calculating the number of pulses per unit time, this is used as the fractional pulse time T2 in order to consider the fractional pulse. However, the calculation of the number of pulses per unit time only needs to be performed based on the number of counted edges and fractional pulses. For example, first, the first time from the rising edge of the final pulse to the end timing of the measurement time Tn is measured, and the fractional pulse included in the final pulse is based on the first time and the fractional pulse time T2. (Fractional pulse time T2 / (first time + fractional pulse time T2)) is calculated. Then, the ratio of the fractional pulse included in the final pulse is subtracted from the counted number of edges Ce, and the number of pulses per unit time is calculated by dividing the subtracted value by the measurement time Tn.

  Note that the flow rate calculation method shown in the present embodiment can be used not only in a scene where a flow rate is actually calculated using a flow rate sensor but also in calibration for calibrating individual differences of flow rate sensors, for example. When calibrating the flow sensor, install the flow sensor in the test flow path, flow the specified flow rate through the flow path, calculate the flow rate according to the output from the corresponding flow sensor, and use this as the specified flow rate. By comparing, calibration data is obtained. In such a calibration scene, by applying the above-described flow rate calculation method, the flow rate can be calculated with high responsiveness, and this can be detected with high accuracy. As a result, appropriate calibration data relating to one flow sensor can be obtained at an early stage, so that productivity at the time of calibration can be improved.

  Furthermore, in this embodiment, the 2nd temperature sensor 52 and the flow sensor 53 may be arrange | positioned as follows. FIG. 7 is a configuration diagram of the solar hot water supply system 1 including the reduced heat amount calculation device 5 according to the modification.

  As shown in FIG. 7, the second temperature sensor 52 and the flow rate sensor 53 may be provided on the downstream side of the mixing valve 3 (more specifically, on the downstream side of the mixing valve 3 and the upstream side of the water heater 4). Good. In this case, the flow rate sensor 53 uses the mixed water in which the preheated hot water and the cold water are mixed as the detection target water, and performs output according to the flow rate of the detection target water. Further, the second temperature sensor 52 also detects the temperature of the detection target water. As described above, in the embodiment shown in FIG. 1, the preheated hot water supplied from the solar water heater 2 is the detection target water, and the second temperature sensor 52 and the flow rate sensor 53 are the temperature and flow rate of the preheated hot water that is the detection target water. However, the present invention is not limited to this, and the temperature and flow rate may be detected using a mixed water in which preheated hot water and cold water are mixed as detection target water.

  In addition, even if it is configured as in the modified example, the calculation of the reduced heat quantity can be performed without any problem. This will be specifically described below. First, when the preheated hot water is the detection target water, assuming that the flow rate of the preheated hot water is R1 and the temperature is T1, and the temperature of the cold water is T2, the reduced amount of heat is (T1-T2) · R1. Calculated based on

  On the other hand, when the mixed water is the detection target water and the temperature of the mixed water is T3 and the flow rate is R3, the reduced heat quantity is calculated based on (T3-T2) · R3. . Here, T3 = {(T1 · R1) + (T2 · R2)} / (R1 + R2). R2 is the flow rate of cold water mixed with preheated hot water. Therefore, R3 = R1 + R2.

  From these relational expressions, (T3-T2) · R3 is as follows. That is, (T3-T2) * R3 = T3 * R3-T2 * R3 = {(T1 * R1) + (T2 * R2)}-T2 * R3 = {(T1 * R1) + (T2 * R2)}- T2 · (R1 + R2) = T1 · R1−T2 · R1 = (T1−T2) · R1. Therefore, even if configured as in the modification, the calculation of the reduced heat quantity can be performed without any problem.

  Furthermore, the heat quantity reduced by both may be calculated by combining this embodiment and the modification shown in FIG.

  As described above, in the present embodiment, on the premise of the solar hot water supply system, the MPU configuring the reduced heat amount calculation device has been described as a method for calculating the flow rate as one function thereof, but the present invention is limited to this embodiment. Needless to say, various modifications are possible within the scope of the invention. For example, the present invention is not only applied to a solar hot water supply system but also widely applicable as a method for detecting the flow rate of a liquid flowing through a flow path, and the reduced heat amount calculation device and the flow rate calculation method itself that realize the flow rate calculation method described above are the present invention. Act as part of

DESCRIPTION OF SYMBOLS 1 Solar water heating system 13 Hot water pipe 2 Solar water heater 3 Mixing valve 4 Water heater 5 Reduction | restoration calorie | heat amount calculation apparatus 51 1st temperature sensor 52 2nd temperature sensor 53 Flow sensor 54 Calculation display 54e Correlation data storage part 54f Flow volume calculation part 54f1 Pulse Number measuring means 54f2 Fractional pulse measuring means 54f3 Calculation means 54g Reduction heat quantity calculation section 55 Household display

Claims (5)

Used in a solar water heating system having a solar water heater that heats supplied water to make preheated hot water, and a water heater that heats at least one of the supplied water and the preheated hot water supplied from the solar water heater A flow rate sensor that performs at least one of preheated hot water supplied from the solar water heater and mixed water in which the preheated hot water and cold water are mixed as detection target water, and performs output according to the flow rate of the detection target water; A first temperature sensor for detecting a water temperature before being heated by a solar water heater, a second temperature sensor for detecting a temperature of the detection target water, signal values from the first temperature sensor and the second temperature sensor, and Based on the flow rate calculated according to the output of the flow rate sensor, the reduced heat amount for calculating the reduced heat amount that can be reduced during heating in the water heater by heating the solar water heater In the detection device,
Based on the output of the flow sensor that outputs a pulse corresponding to the flow rate of the liquid, time measurement is started with a predetermined output change corresponding to one pulse period as a trigger, and the output change that appears within a predetermined measurement time In response, a pulse number measuring means for counting the number of pulses,
For the last pulse counted at the end of the measurement time, the fraction pulse measuring means for measuring the fractional pulse remaining after the end of the measurement time in the last pulse one cycle,
An apparatus for calculating a reduced heat quantity, comprising calculating means for calculating a flow rate of the liquid by calculating the number of pulses per unit time based on the counted number of pulses and the fractional pulse. The fraction pulse measuring means measures the fraction pulse as time related to the fraction pulse,
The calculation means calculates the number of pulses per unit time based on the counted number of pulses and an addition time obtained by adding a time related to the fractional pulse to the measurement time. 1. The reduced heat amount calculation device described in 1. The fractional pulse measuring means measures the fractional pulse as a fractional pulse ratio in the final pulse,
The said calculating means calculates the pulse number per said unit time based on the number of the counted pulses, the ratio of the said fractional pulse, and the said measurement time. Reduced calorie calculation device.   4. The reduced heat amount calculation apparatus according to claim 1, wherein the pulse number measurement unit determines a rising edge of a pulse as a predetermined output change corresponding to the one pulse period. 5. Used in a solar water heating system having a solar water heater that heats supplied water to make preheated hot water, and a water heater that heats at least one of the supplied water and the preheated hot water supplied from the solar water heater A flow rate sensor that performs at least one of preheated hot water supplied from the solar water heater and mixed water in which the preheated hot water and cold water are mixed as detection target water, and performs output according to the flow rate of the detection target water; A first temperature sensor for detecting a water temperature before being heated by a solar water heater, a second temperature sensor for detecting a temperature of the detection target water, signal values from the first temperature sensor and the second temperature sensor, and Based on the flow rate calculated according to the output of the flow rate sensor, the reduced heat amount for calculating the reduced heat amount that can be reduced during heating in the water heater by heating the solar water heater In sensing device, a flow rate calculation method for calculating the flow rate in response to an output of the flow sensor,
A first step of starting time measurement using a predetermined output change corresponding to one pulse period as a trigger based on the output of the flow sensor that outputs a pulse corresponding to the flow rate of the liquid;
A second step of counting the number of pulses in response to the output change appearing within a predetermined measurement time;
A third step of measuring, for the last pulse counted at the end of the measurement time, a fractional pulse remaining after the end of the measurement time in one cycle of the last pulse;
A fourth step of calculating the number of pulses per unit time based on the counted number of pulses and the fractional pulse;
And a fifth step of calculating a liquid flow rate based on the number of pulses per unit time.

Images