JP2008057854A - Cogeneration system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain the operation of a power generator with a high energy-saving effect while appropriately coping with the use situation of hot and cold water by frequently updating an operation plan. <P>SOLUTION: An operation control device 40 of this cogeneration system derives operation plans of the power generator every predetermined time (every 30 minutes) in a day based on a consumption pattern of electric energy consumed in a load device, a consumption pattern of the amount of hot and cold water consumed in a hot and cold water use device, and the predicted value of the residual amount of hot water in a hot water storage tank, and updates and stores them (step 108), and performs operation according to the updated and stored operation plans and controls the power generator to obtain the amount of generated electric power corresponding to an indicated value of the amount of generated electric power. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cogeneration system.

  The cogeneration system includes a power generation device that supplies power to the load device, an operation control device that controls the power generation device so as to achieve a power generation amount according to a power generation amount instruction value, and hot water that recovers exhaust heat from the power generation device. What is equipped with the hot water storage tank which stores hot water is known.

  As an example of this cogeneration system, there is a cogeneration system disclosed in Patent Document 1. In this cogeneration system, the fuel cell operation is based on once / day (hereinafter referred to as “on / off once control”), and the daily hot water consumption according to the hot water consumption model pattern by time zone is continuous for one day. When exceeding the amount of hot water stored by exhaust heat recovery when operating the fuel cell at a constant operating rate or above, or when exceeding the amount of hot water stored by converting the surplus power into heat by means of electric heat conversion means and adding to the exhaust heat recovery, The control is stopped once on and off, and the fuel cell is operated continuously for one day. At this time, the operation plan for the next day is made only once a day at a predetermined time (for example, at 24:00).

  Another example is a cogeneration system disclosed in Patent Document 2. This cogeneration system can cope with the situation where the demand for electric power and / or hot water supply suddenly decreases in the building (general house, etc.) where the cogeneration system is installed due to the resident's going out, etc. It has become. Specifically, this cogeneration system has a fuel cell (FC), a power demand measuring means (2), a heat demand measuring means (hot water supply demand measuring means 3), and a control means (A). The control means (A) includes a prediction means (9) for predicting demand (from past operation data) and a mode selection means (10 for determining an operation mode based on the demand prediction of the prediction means (9). ) And storage means for storing data in a situation where demand is low.

In this case, it is operated by either normal control logic or logic dedicated to going out. In normal control logic, an operation plan for one day (original operation schedule) is determined in advance, and the system is operated according to the operation plan. When you go out and go home, the logic dedicated to going out considers the reduction of the driving time due to going out from the stoppage to the time you go home, and reexamines (re-predicts) the operation plan. Whether or not the primary energy consumption is within an allowable range of, for example, + 10% for each combination in which the start time and the stop time are changed for each set time interval with respect to the primary energy consumption until the end of the operation Judging.
JP 2005-38676 A JP 2005-09846 A

  By the way, in the cogeneration system of patent document 1, since the operation plan for one day is made only once a day, the operation | movement corresponding to consumption of the unexpected hot water (for example, the morning bath which is not usual) cannot be performed. There was a problem. In addition, in the cogeneration system described in Patent Document 2, a driving plan for one day is not made only once a day, but the driving plan is reconsidered when going out and returning home. As with the above-mentioned Patent Document 1, there is a problem that operation corresponding to unexpected consumption of hot water cannot be performed. In either case, the hot water runs out because it cannot be operated appropriately for unexpected hot water consumption. In order to replenish the hot water, gas or electricity is used for additional cooking, so the energy saving effect is worse than when no hot water is caused.

  In addition, in the cogeneration system described in Patent Document 1 and Patent Document 2, when you are at home but do not use hot water compared to normal, because the operation plan for one day is made only once a day, There was also a problem that operation corresponding to the situation was not possible. That is, since hot water is not used, the heat generated at that time is thrown away even if power is generated, and the energy saving effect is deteriorated.

  The present invention has been made to solve the above-described problems, and is a cogeneration system capable of operating a power generator with good energy-saving effect while appropriately responding to the use situation of hot water by frequently updating the operation plan. The purpose is to provide a system.

  In order to solve the above problems, the structural feature of the invention according to claim 1 is that a power generation device that supplies power to a load device, hot water that recovers exhaust heat from the power generation device, Operation plan of the power generator based on the hot water supply tank that supplies hot water and the consumption pattern of the electric energy consumed by the load device, the consumption pattern of the hot water consumed by the hot water use device, and the predicted amount of remaining hot water in the hot water tank An operation control device that derives and updates and stores at predetermined time intervals within a day, operates in accordance with the updated and stored operation plan, and controls the power generation device so that the power generation amount corresponds to the power generation amount instruction value. It is to be prepared.

  According to a second aspect of the present invention, in the first aspect, the operation control device derives and updates a power consumption pattern, a hot water consumption pattern, and a predicted amount of remaining hot water every predetermined time. It is to remember.

  In addition, the structural feature of the invention according to claim 3 is that, in claim 1 or claim 2, the operation control device detects the amount of electric power and the amount of hot water every predetermined time, and also uses each detection result of this time. Deriving a power consumption pattern and a hot water consumption pattern to update and store them.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the predetermined time is a time sufficient for the operation control device to derive an operation plan, and hot water. It is set so that the heat recovery by the hot water tank can cope with unscheduled use of hot water that does not follow the consumption pattern of water.

  Further, the structural feature of the invention according to claim 5 is that in any one of claims 1 to 4, the consumption pattern of electric energy, the consumption pattern of hot water, and the predicted value of remaining hot water are larger than 24 hours. It is to create time as a unit.

  In the invention according to claim 1 configured as described above, the operation control device includes a consumption pattern of the amount of power consumed by the load device, a consumption pattern of the amount of hot water consumed by the hot water usage device, and the remaining amount in the hot water tank. Based on the predicted amount of hot water, the operation plan of the power generator is derived and stored every predetermined time of the day so that the power generation amount is in accordance with the power generation amount instruction value while operating according to the updated operation plan. To control the power generator. Thereby, since an operation plan can be made more frequently than in the past, even if there is unexpected consumption of hot water, operation corresponding to the consumption can be performed. Therefore, since it is possible to prevent the occurrence of hot water due to unexpected consumption of hot water, it is possible to provide a cogeneration system capable of operating the power generator with good energy saving effect while preventing hot water from running out.

  In the invention according to claim 2 configured as described above, in the invention according to claim 1, the operation control device calculates the consumption pattern of the electric energy, the consumption pattern of the hot water, and the predicted value of the remaining hot water every predetermined time. Since it is derived and updated and stored, the operation plan of the power generator can be derived accurately and reliably based on the derived results.

  In the invention according to claim 3 configured as described above, in the invention according to claim 1 or claim 2, the operation control device detects the amount of electric power and the amount of hot water every predetermined time, and each detection result of this time Also, the consumption pattern of power consumption and consumption consumption pattern of hot water are derived and updated and stored, so that the latest consumption information can be accurately and reliably reflected in the consumption pattern.

  In the invention according to claim 4 configured as described above, in the invention according to any one of claims 1 to 3, the predetermined time is necessary and sufficient for the operation control device to derive the operation plan. Since the time is set so that the heat recovery by the hot water tank can cope with unscheduled use of hot water that does not follow the consumption pattern of hot water, update the operation plan at appropriate time intervals Can do.

  In the invention according to Claim 5 configured as described above, in the invention according to any one of Claims 1 to 4, the consumption pattern of electric energy, the consumption pattern of hot water, and the predicted value of remaining hot water are obtained. Created in units of time greater than 24 hours. As a result, it is possible to create an operation plan in a longer unit rather than a unit of one day, so even if you are at home but do not use hot water compared to normal, the power generation time is shortened and the hot water tank is It is possible to provide a cogeneration system that can operate a power generation device that does not become full and has an energy saving effect. Therefore, by frequently updating the operation plan, it is possible to provide a cogeneration system that can operate the power generation device with good energy saving effect while appropriately responding to the use situation of hot water.

  Hereinafter, an embodiment of a cogeneration system according to the present invention will be described. FIG. 1 is a schematic diagram showing an overview of this cogeneration system. In this cogeneration system, the power generation device 10 that supplies power to the load device 21, the hot water storage tank 30 that stores hot water from which the exhaust heat of the power generation device 10 is collected, and the power generation amount according to the power generation amount instruction value are obtained. And an operation control device 40 that controls the power generation device 10.

  The power generation device 10 is a fuel cell power generation device, and includes a power generator 11 that generates DC power, and a converter (for example, an inverter) 12 that converts the DC power supplied from the power generator 11 into AC power and outputs the AC power. ing. In addition to the fuel cell power generation device, the power generation device 10 may be configured by a prime mover such as a diesel engine, a gas engine, a gas turbine, or a micro gas turbine, and a generator driven by the prime mover.

  The generator 11 includes a reformer, a carbon monoxide reduction device (hereinafter referred to as a CO reduction device), and a fuel cell. In the reformer, the fuel supplied from the fuel supply device 13 is steam-reformed with water supplied from the water supply device 14 to generate a hydrogen-rich reformed gas, which is led to the CO reduction device. The CO reduction device reduces carbon monoxide contained in the reformed gas and leads it to the fuel cell. The fuel cell generates power using hydrogen in the reformed gas supplied to the fuel electrode and air that is an oxidant gas supplied to the air electrode.

  Between the fuel supply device 13 and the power generator 11, a flow meter 13a serving as a fuel input amount detecting means for detecting the amount of fuel input to the power generator 11 is provided. The flow meter 13a detects the detected fuel input amount. Is transmitted to the operation control device 40. Note that the amount of fuel input in the case of a fuel cell power generator refers to the amount of fuel supplied to the reformer.

  The converter 12 is connected to a plurality of load devices 21 installed at the power use place 20 via the power transmission line 15, and the AC power output from the converter 12 is supplied to each load device 21 as necessary. Has been supplied to. The converter 12 is provided with a wattmeter 10a that is a power generation output amount detecting means for detecting the power generation output amount output from the power generation device 10, and the wattmeter 10a sends the detected power generation output amount to the operation control device 40. It is supposed to send.

  The load device 21 is an electric appliance such as an electric lamp, iron, television, washing machine, electric kotatsu, electric carpet, air conditioner, and refrigerator. In addition, the power source 15 of the power company is also connected to the power transmission line 15 that connects the converter 12 and the power use place 20 (system connection), and the total power consumption of the load device 21 is determined by the power generation amount of the power generation device 10. When the amount exceeds, the insufficient power is received from the system power supply 16 and compensated. The wattmeter 22 is power consumption detection means for detecting the power consumption consumed by the load device 21, detects the total power consumption of all the load devices 21 used in the power usage place 20, This is transmitted to the operation control device 40.

  The generator 11 is connected to a cooling circuit 31 through which a heat medium for recovering exhaust heat of the generator 11 and cooling the generator 11 circulates. On the cooling circuit 31, a heat exchanger 32 and a radiator 37 are disposed. The radiator 37 is a cooling means for cooling the heat medium circulating in the cooling circuit 31, and is controlled to be turned on / off by a command from the operation control device 40. The heat medium is cooled in the on state and cooled in the off state. It is something that does not.

  On the other hand, a hot water circulation circuit 33 for heating hot water (hot water) in the hot water tank 30 is connected to the hot water tank 30 described later. A heat exchanger 32 is disposed on the hot water circulation circuit 33. The heat exchanger 32 performs heat exchange between the heat medium circulating in the cooling circuit 31 and the hot water circulating in the hot water circulation circuit 33. As a result, a pump (not shown) is driven during power generation by the power generator 11 so that the heat medium circulates in the cooling circuit 31 and hot water circulates in the hot water circulation circuit 33, so that the exhaust heat of the power generator 11 is exchanged with the heat medium and heat. The hot water is recovered as hot water through the vessel 32 and heated. For example, in the case of a fuel cell power generation device, the exhaust heat of the power generator 11 refers to exhaust heat of a fuel cell stack or exhaust heat of a reformer, and in the case of an engine power generation device, examples include exhaust heat of an engine. However, the present invention is not limited to this, and any recoverable exhaust heat such as heat of the generator itself can be used.

  The hot water tank 30 is provided with one columnar container, in which hot water is stored in a layered manner, that is, hot water in the upper part is the hottest and becomes lower as it goes to the lower part, and the hot water in the lower part is stored at the lowest temperature. It has become so. Hot water stored in the hot water tank 30 is derived from the upper part of the columnar container of the hot water tank 30, and water such as tap water from the water supply device 14 (low temperature water) so as to replenish the derived amount. Is introduced from the lower part of the columnar container of the hot water tank 30. Such a hot water tank 30 is installed near the power generation apparatus 10.

  Inside the hot water tank 30, a temperature sensor group 34 that is a remaining hot water amount detection sensor is provided. The temperature sensor group 34 includes a plurality (ten in the present embodiment) of temperature sensors 34-1, 34-2, 34-3,..., 34-10, and is arranged in the vertical direction (vertical direction). It is arranged at equal intervals (distance of 1/9 of the vertical height in the hot water tank 30). The temperature sensor 34-1 is disposed on the inner upper surface of the hot water tank 30. Each of the temperature sensors 34-1, 34-2, 34-3,..., 34-10 detects the temperature of the liquid (hot water or water) in the hot water storage tank 30 at that position. The amount of remaining hot water in the hot water storage tank 30 is derived based on the detection result of the hot water temperature at each position by the temperature sensor group. The remaining hot water amount represents the amount of heat stored in the hot water tank 30.

  Between the hot water storage tank 30 and the water supply device 14, a temperature sensor 38 that detects the temperature of water (for example, tap water) supplied to the hot water storage tank 30 is provided. The detection result (tap water temperature) of the temperature sensor 38 is transmitted to the operation control device 40.

  A hot water supply pipe 35 is connected to the hot water tank 30. The hot water supply pipe 35 is provided with a gas water heater (not shown), a temperature sensor (not shown), and a flow rate sensor 36 which are auxiliary heating devices in order from the upstream side. The gas water heater heats hot water from the hot water storage tank 30 passing through the hot water supply pipe 35 to supply hot water. The temperature sensor detects the temperature of the hot water after passing through the gas water heater, and the detection signal is transmitted to the operation control device 40. That is, the hot water is heated by the gas water heater so that the temperature of the hot water detected by the temperature sensor becomes the set hot water temperature. Although not shown, tap water from the water supply device 14 joins the hot water supply pipe 35 between the outlet of the hot water tank 30 and the temperature sensor. Thereby, the temperature of the hot water from the hot water tank 30 is lowered. The flow rate sensor 36 detects the amount of hot water consumption (hot water supply amount) supplied from the hot water storage tank 30. A detection signal of the flow sensor 36 is transmitted to the operation control device 40.

  Connected to the hot water supply pipe 35 are a plurality of hot water use devices 26a installed in a hot water use place 25 that uses hot water stored in the hot water tank 30 as hot water supply. Examples of the hot water use device 26a include a bathtub, a shower, a kitchen (kitchen faucet), and a washroom (toilet faucet). The hot water supply pipe 35 is connected to a heat utilization device 26b installed in a hot water use place 25 that uses hot water in the hot water tank 30 as a heat source. Examples of the heat utilization device 26b include bathroom heating, floor heating, and a hot water reheating mechanism. The heat utilization device 26b may use the hot water in the hot water tank 30 directly or indirectly use the hot water in the hot water tank 30. The hot water use device 26a and the heat use device 26b are hot water use devices.

  The operation control device 40 has a microcomputer (not shown), and the microcomputer includes an input / output interface, a CPU, a RAM, and a ROM (all not shown) connected via a bus. The CPU executes a program corresponding to the flowcharts of FIGS. 2 to 7, derives and updates the operation plan of the power generation apparatus, operates in accordance with the updated and stored operation plan, and generates power according to the power generation amount instruction value. The power generation device is controlled so that the quantity becomes constant. The RAM temporarily stores variables necessary for executing the program, and the ROM stores the program.

  Next, the operation of the above-described cogeneration system will be described with reference to FIGS. When the main power supply (not shown) is turned on, the operation control device 40 starts the program in step 100 and advances the program to step 102. The operation control device 40 derives and updates the operation plan every first predetermined time T1 in the day by the processing of steps 102 to 110 shown in FIG. Further, the operation control device 40 operates the power generation device by the processing of steps 602 to 608 shown in FIG. 7 according to the updated operation plan. That is, the operation (power generation) of the power generation apparatus 10 is stopped or continuously generated according to the operation plan.

  The first predetermined time T1 is set to a time shorter than 24 hours (one day), and is 30 minutes in the present embodiment. This first predetermined time T1 is a time necessary and sufficient for the operation control device 40 to derive an operation plan, and heat recovery by the hot water tank 30 is performed for unscheduled use of hot water that does not follow the consumption pattern of hot water. The time is set so that it can be handled.

  The time necessary and sufficient for the operation control device 40 to derive the operation plan may be 5 minutes or more, 10 minutes or more, or 20 minutes or more, depending on the calculation capability of the operation control device 40. The time that can be used for heat recovery by the hot water storage tank 30 for unscheduled use of hot water that does not follow the consumption pattern of hot water amount is 40 minutes or less, 50 minutes or less, or 60 minutes or less, depending on unscheduled use conditions. It is preferable that Therefore, the first predetermined time T1 is determined by each combination of a time necessary and sufficient for the operation control device 40 to derive the operation plan and a time that can be used for heat recovery by the hot water tank 30 for unscheduled use of hot water. It can be set as the preferable range.

  In step 102, the operation control device 40 executes a program according to the power consumption pattern creation routine shown in FIG. 3, and creates and updates a power consumption pattern for one day. This power consumption pattern is a prediction of a power consumption pattern from past power consumption data for a certain period (for example, one week).

  The operation control device 40 initializes a matrix Eo_temp for creating a power consumption pattern (step 202). The operation control apparatus 40 substitutes the power consumption of each time zone for 7 days into each element of the matrix Eo_temp. An example of the result of substitution is shown in FIG. At the beginning of installation of this system, a numerical value of an average consumption model pattern created in advance based on conditions such as family composition and region is substituted. Also, after at least one week of operation, the value of the previous power consumption pattern that is created and updated from the power consumption actually measured for each power generation stoppage time period is substituted.

  In the matrix Eo_temp, as shown in FIG. 8, the column indicates how many days ago the data is, and the row indicates the time zone of the day. The element of 1 row and 1 column is the power consumption measured at 0:00 one day ago, that is, the average value of the power consumption measured from 23:30 two days ago to 0:00 one day ago, for example, FIG. Then it is 300W. The element in 2 rows and 1 column is the power consumption measured at 0:30 the day before, that is, the average value of the power consumption measured from 0:00 to 0:30 the day before, for example, 400 W in FIG. is there. The element in the first row and the second column is the power consumption measured at 0:00 two days ago, that is, the average value of the power consumption measured from 23:30 three days ago to 2:00 two days ago. Then it is 250W. Note that the data of the day before and the data for the previous day are mixed in the data of the day before. Similarly, the data of the previous day and the data of the previous day are mixed in the data of two days ago.

  The operation control device 40 measures the power consumption for each control cycle by the wattmeter 22 (step 204), and filters the measured power consumption (step 206). In step 206, the operation control device 40 performs the following equation 1 based on the measured data and the stored data for the past several cases (29 in this embodiment) each time the power consumption is measured. Filtering is being executed. The control cycle is the same as a second predetermined time T2 described later, and is 1 minute in this embodiment.

  Note that u [k] and y [k] are current data, for example, input data and output values (process values) at time k, and z is a delay operator.

  The operation control device 40 continues to determine “NO” in step 208 until 30 minutes have elapsed from the measurement start time of the power consumption, repeatedly execute the measurement of the power consumption and the filtering process, The average value is calculated by filtering the power consumption for 30 minutes.

  Then, the operation control device 40 determines “YES” in step 208 when 30 minutes have elapsed from the measurement start time of the power consumption, and reads the current time (step 210). For example, it is assumed that the current time is 0:00 and the filter processing value for 30 minutes (23: 0 to 0:00) is 500 W.

  In the matrix Eo_temp, the operation control device 40 deletes the data at the same time (the time when the power consumption is measured and the filter process is completed) seven days ago and the remaining data at the same time (the same line) one by one. Move to the right (step 212). For example, since the current time is 0:00, as shown in FIG. 9, 440 W of the element in the first row and the seventh column, which is the data at 0:00 seven days ago, is deleted. Then, 300 W of the element of 1 row and 1 column, which is 0:00 data of 1 day before, is moved to 1 row and 2 columns, and 250 W of the element of 1 row and 2 columns, which is 0:00 data of 2 days ago, is 1 row. The other elements from 1 row 3 columns to 1 row 6 columns are also moved in the same manner.

  Then, as shown in FIG. 9, the operation control device 40 adds the filter processing value (for example, 500 W) derived as described above to an empty 1-row 1-column of the matrix Eo_temp (step 214). The operation control device 40 derives and updates and stores the predicted power consumption value, that is, the power consumption pattern, by averaging the data of each row of the matrix Eo_temp created in this way (step 216). An example of the derived power consumption prediction value is shown in FIG. The power consumption at 0:00 is 340 W, the power consumption at 0:30 is 420 W,..., And the power consumption at 23:30 is 900 W. An example of this power consumption pattern is shown in FIG.

  Next, in step 104, the operation control device 40 executes a program in accordance with the hot water / water consumption pattern creation routine shown in FIG. 4, and creates and updates a hot water consumption pattern for one day. This hot water consumption pattern is a prediction of a hot water consumption pattern from past hot water consumption data for a certain period (for example, one week).

  That is, the operation control device 40 creates a hot water consumption pattern by the processing of Steps 302 to 316, similarly to the processing of Steps 202 to 216 described above. Specifically, the operation control device 40 initializes a matrix Qout_temp for creating a hot water consumption pattern (step 302). As with the matrix Eo_temp, the matrix Qout_temp indicates how many days ago the column is data, and the row indicates the time zone of the day.

  The operation control device 40 measures the hot water consumption by the flow rate sensor 36 for each control cycle (step 304), and filters the measured hot water consumption (step 306). The operation control device 40 continues to determine “NO” in step 308 until 30 minutes have elapsed from the start of measurement of hot water consumption, repeatedly execute the measurement of the hot water consumption and its filter processing, The average value is calculated by filtering hot water consumption for 30 minutes.

  Then, the operation control device 40 determines “YES” in step 308 when 30 minutes have elapsed from the measurement start time of the hot water consumption, and reads the current time (step 310). In the matrix Qout_temp, the operation control device 40 deletes the data at the same time seven days ago and moves the remaining data at the same time (the same line) one by one to the right (step 312). Then, the operation control device 40 adds the filter processing value derived in Step 306 to an empty 1-row 1-column of the matrix Qout_temp (Step 314). The operation control device 40 derives a hot water consumption predicted value, that is, a hot water consumption pattern by averaging the data of each row of the matrix Qout_temp created in this way, and updates and stores it (step 316). An example of this hot water consumption pattern is shown in FIG.

  Next, in step 106, the operation control device 40 executes a program in accordance with the hot water tank remaining hot water amount estimation routine shown in FIG. 5, and derives and stores the remaining hot water amount of the hot water storage tank 30 at the current time. Specifically, the operation control device 40 measures the temperature of water (for example, tap water) supplied to the hot water tank 30 by the temperature sensor 38 (step 402). The operation control device 40 measures the temperature of the hot water at each position in the hot water tank 30 by the temperature sensors 34-1 to 34-10 (step 404). Then, the operation control device 40 substitutes the temperature of the water to be supplied and the temperature at each position in the hot water storage tank 30 into the following equation 2 to derive the remaining hot water amount in the hot water storage tank 30 (step 406).

Here, Q is the amount of heat [J] stored in the hot water tank 30, Cp is the specific heat of water (4.189 × 10 ⁻³ [J / (kg · K)]), and V is the hot water tank. The volume is 30 (150 l = 150 kg in this embodiment), Tw is the temperature of the tap water, and Ti is the i-th temperature in the hot water tank 30.

  Next, in step 108, the operation control device 40 executes a program according to the operation plan derivation / update storage routine shown in FIG. 6, derives an operation plan for the power generator 10, and sets the operation plan. Is updated and stored.

  The operation control device 40 has the power consumption pattern created and stored in step 102 (pattern shown in FIG. 11) and the hot water consumption pattern created and stored in step 104 (pattern shown in FIG. 12). Is read (step 502), and the remaining hot water storage tank amount derived in step 106 is read (step 504). And the driving | operation control apparatus 40 makes an optimal driving | operation plan using the newest information read by the process of steps 506-518.

The operation control device 40 sets the power generation stop time zone by changing the stop time for stopping power generation (starting power generation stop) and the start time for starting power generation (ending power generation stop) (step 506). For example, the stop time and the start time are changed every 30 minutes within one day (0:00 to 24:00). Thereby, all combinations of the power generation stop time zone are 0: 00 to 0: 00 (not stopped), 0: 00 to 0:30, 0: 00 to 1: 00, ..., 0: 00 to 24: 00, 0:30 to 10:00, ..., 0:30 to 24:00, ..., 23: 00 to 23:30, ..., 23: 00 to 24:00, and 23:30 ˜24: 00 and 1177 ways (= ₄₉ C ₂ +1) can be set.

  The operation control device 40 derives an energy saving effect index value for each of all the combinations (steps 508 to 514). First, the operation control device 40 sets each power consumption stop time zone set in step 506, the power consumption pattern read in step 502, and the following equation 3 in units of time set for the power consumption pattern (24 hours in this embodiment). The amount of exhaust heat recovery at the time is derived (step 508). For example, in the first calculation, the exhaust heat recovery amount for the first combination 0:00 to 0:00 is derived. Further, when an operation plan in which the power generation stoppage time period is from 4:00 to 17:00 is derived as an optimal operation plan, the predicted value of the exhaust heat recovery amount is derived as shown in FIG.

Here, Qin [k] is the exhaust heat recovery amount [J] at time k (time), Eo is the power consumption pattern [W], and td is the prediction interval (30 minutes in this embodiment). is there. a ₁ is the exhaust heat recovery characteristic [W / W], a ₂ is the exhaust heat recovery characteristic [W], and both values are calculated from experimental data obtained using an actual machine. Note that the denominator of the unit of the exhaust heat recovery characteristics a ₁ molecular indicates watt electric represents the watts of heat.

  According to the above formula 3, it is possible to derive the exhausted heat recovery amount every hour on the hour and 30 minutes. Further, if the time is not the power generation stoppage time period set, the exhaust heat recovery amount can be derived using the above equation of Equation 3. If the power generation stoppage time period is set, the exhaust heat recovery amount can be derived using the equation below. That is, since no power is generated, the amount of exhaust heat recovery is zero.

  If the power consumption amount of the power consumption pattern does not exceed the maximum power generation amount of the power generator 11, the power consumption pattern Eo can be used as it is in the above equation 3, but if it exceeds, the power consumption pattern Eo in the above equation 3 is used. Is used instead of the maximum power generation amount of the generator 11.

  The operation control device 40 derives (predicts) the transition of the remaining hot water amount in the hot water tank 30 based on the operation plan based on the power generation stop time period set in step 506 (step 510). The operation control device 40 substitutes the hot water consumption pattern Qout read in step 502, the remaining hot water storage hot water amount Qo read in step 504, and the exhaust heat recovery amount Qin derived in step 508 into the following equation 4 to store the hot water storage tank 30. Derive the amount of remaining hot water. For example, in the first calculation, the transition of the remaining hot water amount in the hot water storage tank 30 for the first combination 0:00 to 0:00 is derived. Further, when an operation plan in which the power generation stoppage time period is from 4:00 to 17:00 is derived as an optimal operation plan, the predicted value of the hot water tank remaining hot water amount is derived as shown in FIG.

  Here, Q [k] is a transition predicted value of the remaining hot water amount in the hot water tank 30. This transition prediction value is derived in units of time corresponding to the hot water consumption pattern (24 hours in the present embodiment).

  The operation control device 40 derives an evaluation function J, which is an energy saving effect index value, in the operation plan based on the power generation stop time period set in step 506 (step 512). The operation control device 40 derives the evaluation function J from the transition predicted value Q [k] of the remaining hot water amount in the hot water storage tank 30 derived in step 510, the power consumption pattern Eo read in step 502, and the following equation 5. In this evaluation function, J is a value obtained by adding the energy saving effect at each time for one day. For example, in the first calculation, the total energy saving effect for one day for the first combination 0:00 to 0:00 is derived. The evaluation function (energy saving effect index value) of the present embodiment is a reduction amount of primary energy (fuel supplied to the power generation apparatus 10). For example, when the power generation stop time period is 0:00 to 0:00, the evaluation function value is 19686 (J).

Here, J ₁ [k] is the energy saving effect at time k, Eo is the power consumption pattern, and Qfull is the maximum hot water tank heat quantity. b ₁ is an energy saving effect conversion value [J / W], b ₂ is an energy saving effect conversion value [J], and both values are calculated from experimental data obtained using an actual machine. c ₁ is an energy saving effect conversion value [J / W] when the hot water storage tank 30 is full in temperature, and c ₂ is an energy saving effect conversion value when the hot water storage tank 30 is full in temperature [J / W]. These values are calculated from the experimental data obtained using the actual machine and the characteristics of the radiator 37.

  Qfull is derived by the following equation (6).

Here, Cp is the specific heat of water (4.189 × 10 ⁻³ [J / (kg · K)]), V is the volume of the hot water tank 30 (150 l = 150 kg in this embodiment), and Tmax is The exhaust heat recovery maximum temperature (for example, 70 ° C.), and Tw is the temperature of tap water.

  Then, the operation control device 40 associates the power generation stop time zone set in step 506 with the evaluation function value (energy saving effect index value) derived in step 512 and stores it in the storage device (step 514).

  The operation control device 40 repeatedly performs the above-described processing of Steps 506 to 514 for all combinations of the above-described power generation stop time period (continues to determine “NO” in Step 516). When the association between the power generation stop time zone and the energy saving effect index value is completed for all the combinations, the operation control device 40 determines “YES” in step 516, and advances the program to step 518.

  In step 518, the operation control device 40 selects the one having the maximum energy saving effect index value from the association between the power generation stop time zone stored so far and the energy saving effect index value. FIG. 15 shows a relationship between the stored power generation stoppage time period and the energy saving effect index value in a three-dimensional graph. In FIG. 15, the horizontal axis indicates the power generation stop time, and the vertical axis indicates the power generation start time. Both axes are shown in increments of 30 minutes from 0:00 to 24:00. The energy saving effect index values are indicated by contour lines. The range indicated by the contour line L1 is the range where the energy saving effect index value is the largest. The energy saving effect index value becomes smaller as going outward from the contour line L1.

  As can be seen from FIG. 15, when the stop time is 3:00 to 5:00 and the start time is 16:00 to 18:00, the energy saving effect index value is maximum. The operation control device 40 derives an operation plan having a power generation stoppage time period composed of a combination of the stop time 4:00 and the start time 17:00 that has the largest energy saving effect index value as the optimum operation plan. To do. Then, the operation control device 40 updates and stores the derived operation plan (step 520).

  In step 110, the operation control device 40 derives and updates the operation plan, and then waits for the first predetermined time T1 to elapse to start the next operation plan derivation and update storage processing. .

  In addition to the above-described operation plan derivation and update storage processing, the operation control device 40 performs a power generation stop operation and a continuous power generation operation as shown in FIG. The operation of the power generator 10 is controlled by switching. The operation control device 40 repeatedly executes the processing of steps 602 to 608 every second predetermined time T2 (for example, every 60 seconds). The second predetermined time T2 is set to a relatively short time value, and is sufficiently smaller than the first predetermined time described above.

  Specifically, in step 602, the operation control device 40 determines whether or not the current time is the latest power generation stop time period derived above. If the current time is the power generation stop time zone, operation controller 40 determines “YES” in step 602 and advances the program to step 604. In step 604, the operation control device 40 performs the power generation stop operation of the power generation device 10. That is, the operation control device 40 sets the power generation amount instruction value to 0 and stops the power generation of the power generation device 10.

  On the other hand, if the current time is not the power generation stop time zone, “NO” is determined in step 602, and the program proceeds to step 606. In step 606, the operation control device 40 performs continuous power generation operation of the power generation device 10. In other words, the operation control device 40 measures the power consumption by the wattmeter 22 every second predetermined time T2 (control cycle), and filters the measured power consumption. This filtering process is performed each time the power consumption is measured, and based on the measured data and stored data for the past several cases (four cases in the present embodiment), the following number 7 similar to the above number 1. The filtering process is executed.

  The operation control device 40 sets this filter processing value as the power generation amount instruction value, and instructs the power generator 11 of the power generation amount instruction value. Thereby, since the electric power generating apparatus 10 can suppress the vibration of electric power generation amount, without tracking the electric power consumption which changes rapidly, efficient electric power generation is attained.

  According to the control described above, when the power consumption changes as shown in FIG. 16, power generation is stopped between 4:00 and 17:00, so the power generation amount is zero. Electric power is generated following the power consumption between 0:00 and 4:00 and between 17:00 and 24:00. According to this operation plan, it is possible to obtain the maximum energy saving effect. In FIG. 16, power consumption is indicated by a thick solid line, and power generation is indicated by a thin thin line.

  As is apparent from the above description, in the present embodiment, the operation control device 40 uses the consumption pattern of the amount of power consumed by the load device 21, the consumption pattern of the amount of hot water consumed by the hot water use devices 26 a and 26 b, and Based on the predicted value of the remaining hot water amount in the hot water tank 30, the operation plan of the power generation apparatus 10 is derived and stored every predetermined time (every 30 minutes) in one day (step 108), and the updated operation plan is stored. And the power generation device is controlled so that the power generation amount according to the power generation amount instruction value is obtained (steps 602 to 608). Thereby, since an operation plan can be made more frequently than in the past, even if there is unexpected consumption of hot water, operation corresponding to the consumption can be performed. Therefore, since it is possible to prevent the occurrence of hot water due to unexpected consumption of hot water, it is possible to provide a cogeneration system capable of operating the power generator with good energy saving effect while preventing hot water from running out.

  Further, the operation control device 40 derives and updates the consumption pattern of the electric energy, the consumption pattern of the hot water and the predicted value of the remaining hot water every predetermined time (every 30 minutes) (steps 102 to 106). Based on the derived result, the operation plan of the power generation device 10 can be accurately and reliably derived.

  In addition, the operation control device detects the amount of electric power and the amount of hot water every predetermined time (every 30 minutes), and also uses each detection result this time to derive and update the consumption pattern of the electric energy and the consumption pattern of the hot water. Since it is stored (steps 102 and 104), the latest consumption information can be accurately and reliably reflected in the consumption pattern.

  In addition, the first predetermined time is a time necessary and sufficient for the operation control device 40 to derive an operation plan, and heat recovery by the hot water tank 30 is performed for unscheduled use of hot water that does not follow the consumption pattern of hot water. Since the time is set so as to correspond, the operation plan can be updated at an appropriate time interval.

  In the above-described embodiment, the consumption pattern of the electric energy, the consumption pattern of the hot water amount, and the predicted value of the remaining hot water amount may be created in units of time longer than 24 hours (for example, two days). As a result, it is possible to create an operation plan of a longer unit instead of a unit of one day. Therefore, even when the person is at home but does not use hot water compared to normal, the power generation time is shortened and the hot water storage tank 30 is heated. Therefore, it is possible to provide a cogeneration system that can operate the power generation apparatus 10 that is not fully charged and has a good energy saving effect. Therefore, by frequently updating the operation plan, it is possible to provide a cogeneration system that can operate the power generation device with good energy saving effect while appropriately responding to the use situation of hot water.

In the above-described embodiment, the energy amount is increased as an index of the energy saving effect, but other indexes (for example, CO ₂ reduction amount, household utility cost) may be adopted.

  Further, as the power generation device 10, there is a power generation device 11 in which the power generator 11 generates AC power and directly outputs it without going through the exchanger 12.

It is a schematic diagram showing an outline of one embodiment of a cogeneration system according to the present invention. It is a flowchart of the control program performed with the operation control apparatus shown in FIG. It is a flowchart of the power consumption pattern creation routine performed with the operation control apparatus shown in FIG. It is a flowchart of the hot water consumption pattern creation routine performed with the operation control apparatus shown in FIG. It is a flowchart of the hot water storage tank remaining hot water amount estimation routine performed with the operation control apparatus shown in FIG. 2 is a flowchart of an operation plan derivation / update storage routine executed by the operation control device shown in FIG. It is a flowchart of the control program performed with the operation control apparatus shown in FIG. It is a figure which shows matrix Eo_temp. It is a figure which shows the update condition of matrix Eo_temp. It is the figure which showed the power consumption prediction value with the matrix. It is a graph which shows an example of a power consumption pattern. It is a graph which shows an example of the hot water consumption pattern. It is a graph which shows the predicted value of the waste heat recovery amount when the operation plan whose power generation stoppage time period is from 4:00 to 17:00 is derived as an optimal operation plan. It is a graph which shows the predicted value of the hot water storage tank residual water amount when the operation plan whose power generation stop time is from 4:00 to 17:00 is derived | led-out as an optimal operation plan. It is a graph which shows an example of the relationship between the stop time and start time of a power generation stop time zone, and an energy saving effect index value. It is a graph which shows the electric power consumption and electric power generation which are fluctuate | varied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Power generation device, 10a ... Wattmeter, 11 ... Generator, 12 ... Converter, 13 ... Fuel supply device, 13a ... Flow meter, 14 ... Water supply device, 15 ... Transmission line, 16 ... System power supply, 21 ... Load Apparatus, 26a ... Hot water use device, 26b ... Heat use device, 30 ... Hot water storage tank, 34 ... Temperature sensor group, 36 ... Flow rate sensor, 40 ... Operation control device.

Claims (5)

A power generator for supplying power to the load device;
A hot water storage tank for storing hot water recovered from the exhaust heat of the power generation device and supplying the hot water to the hot water use device;
Based on the consumption pattern of the amount of power consumed by the load device, the consumption pattern of the amount of hot water consumed by the hot water use device, and the predicted value of the amount of remaining hot water in the hot water tank, An operation control device for deriving and storing the update every predetermined time, operating according to the updated and stored operation plan and controlling the power generation device so that the power generation amount corresponds to the power generation amount instruction value;
Cogeneration system characterized by having   The cogeneration system according to claim 1, wherein the operation control device derives and updates the consumption pattern of the electric energy, the consumption pattern of the hot water, and the predicted value of the remaining hot water every predetermined time. system.   3. The operation control device according to claim 1 or 2, wherein the operation control device detects the amount of electric power and the amount of hot water every predetermined time, and also uses each detection result of this time, and the consumption pattern of the electric energy and the amount of hot water. Cogeneration system characterized by deriving and storing the consumption pattern of   4. The predetermined time according to claim 1, wherein the predetermined time is a time sufficient for the operation control device to derive the operation plan and is not in accordance with a consumption pattern of the hot water amount. A cogeneration system, which is set so that it is time for heat recovery by the hot water tank to correspond to the use of hot water.   5. The method according to claim 1, wherein the consumption pattern of the electric energy, the consumption pattern of the hot water amount, and the predicted value of the remaining hot water amount are created in units of time longer than 24 hours. Cogeneration system.

Images