JP2008281309A - Heat storage control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine a heat generation quantity of the day so that electricity cost is minimized. <P>SOLUTION: This heat storage control device has an actual database 31 storing a heat consumption actual quantity of a user of a plurality of days in the past, an assumption generating part 34 generating a candidate of a heat generation quantity generated at midnight by one or more as an assumption N, and a frequency distribution arithmetic operation part 32 determining the frequency distribution of the heat consumption actual quantity stored in the actual database 31 and calculating a probability X of causing a heat shortage in the daytime with every assumption N based on its frequency distribution, and also has an electricity cost arithmetic operation part 35 determining the sum total of an electricity cost expected value Cn (Yen) at midnight and an electricity cost expected value Cd (Yen) by additional generation in the daytime for every assumption N, an assumption evaluating part 36 determining as the heat generation quantity Na to be generated at midnight by selecting the assumption N of minimizing this sum total, and a heat generation control means 37 controlling starting or stopping of a heat generator 1 based on the heat generation quantity Na determined by the assumption evaluating part 36. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat storage control device, and more particularly, to a heat storage control device that determines the amount of heat generation in a heat storage system that temporarily stores and uses heat (heat / cold heat) generated using inexpensive late-night power. is there.

  In general, heat storage systems such as heater water heaters (electric water heaters) and heat pump water heaters (EcoCute) and ice storage air conditioning systems (Eco Ice) are used for the heat of the past few days (heat / cold heat). ) The amount of heat generation for the day is determined from the actual consumption.

  As this type of conventional electric hot water supply system, for example, the average value of hot water consumption for several days is calculated, and by boiling only the amount of hot water with the correction amount ± α added to it, unnecessary hot water boiling is prevented. Things have been proposed. Here, α (correction value) is calculated from the outside air temperature and the consumption results of the previous day (see, for example, Patent Document 1).

JP 2005-257213 A

  However, in the method of correcting the generated heat amount on the day to the past actual consumption average value by α calculated from the outside air temperature, the electricity bill is not always the minimum. It is based on the premise that heat is generated in the late-night charge period, and it is necessary to generate heat more frequently than the average in order to prevent heat shortage such as running out of hot water, but how much more heat is used. As a result, there is a possibility that it may not lead to cost reduction of electricity bills.

  The present invention has been made to solve such problems, and an object of the present invention is to obtain a heat storage control device capable of determining the heat generation amount on the day so that the electricity cost is minimized.

  The present invention is a heat storage control device for controlling a heat generation device that accumulates heat generated by using midnight power in a heat storage tank, and stores a heat consumption performance amount of a user for a plurality of past days. And assuming generation means for generating one or more assuming heat generation amount candidates to be generated at midnight, obtaining the frequency distribution of the actual heat consumption amount stored in the actual result database, and based on the frequency distribution, For each assumption, a frequency distribution calculating means for calculating the probability of daytime heat shortage, and for each assumption, obtain the sum of the late-night electricity cost expectation value and the daytime additional electricity cost expectation value based on the probability An electricity bill calculating means, an assumption evaluating means for selecting the assumption that the sum obtained by the electricity bill calculating means is minimum, and determining the heat generation amount to be generated at midnight, and the assumption evaluating means Based on the heat generation amount determined by a heat storage controller having a heat generation control means for controlling the start and stop of the heat generating device.

  The present invention is a heat storage control device for controlling a heat generation device that accumulates heat generated by using midnight power in a heat storage tank, and stores a heat consumption performance amount of a user for a plurality of past days. And assuming generation means for generating one or more assuming heat generation amount candidates to be generated at midnight, obtaining the frequency distribution of the actual heat consumption amount stored in the actual result database, and based on the frequency distribution, For each assumption, a frequency distribution calculating means for calculating the probability of daytime heat shortage, and for each assumption, obtain the sum of the late-night electricity cost expectation value and the daytime additional electricity cost expectation value based on the probability An electricity bill calculating means, an assumption evaluating means for selecting the assumption that the sum obtained by the electricity bill calculating means is minimum, and determining the heat generation amount to be generated at midnight, and the assumption evaluating means The heat generation control device is provided with a heat generation control means for controlling the start / stop of the heat generation device based on the heat generation amount determined by the above, so that the heat generation of the day so that the electricity bill is minimized The amount can be determined.

Embodiment 1 FIG.
1 is a diagram showing a configuration of a heat storage system according to Embodiment 1 of the present invention. As shown in FIG. 1, the heat storage system according to Embodiment 1 includes a heat generation device 1, a heat storage tank 2, and a heat storage control device 3. Using the electric power, the heat generation device 1 heats or cools the water supply until water (including hot water and ice) of the amount and temperature determined by the heat storage control device 3 is stored in the heat storage tank 2.

  The heat generating device 1 is a device that generates heat or cold by electricity. For example, a heat pump type hot water heater (EcoCute) corresponds to a heat pump, and a heater type water heater (electric water heater) corresponds to an electric heater. . The hot water (or cold heat) generated by the heat generating device 1 heats (or cools) the tap water to generate hot water (or ice).

  The heat storage tank 2 stores hot water (or ice) generated by the heat generating device 1 until the user uses it.

  The heat storage control device 3 determines the heat generation amount of the day from the past heat consumption results, and starts and stops the heat generation device 1 so that the heat generation amount is satisfied.

  Generally, a heat storage system generates heat in the midnight zone where an inexpensive midnight charge can be applied, and the user consumes the heat in the daytime. If the same-day consumption more than the heat generated at midnight is predicted, the heat storage control device 3 performs additional heat generation (called “boiling increase” in the water heater).

  2 and 3 are diagrams illustrating an internal configuration of the heat storage control device 3 illustrated in FIG. 1. However, for convenience of illustration, FIG. 2 shows only the configuration that operates when generating heat at midnight, and FIG. 3 only shows the configuration that operates when generating additional heat during the daytime. Therefore, in practice, all of the configurations shown in FIGS. 2 and 3 are provided in the heat storage control device 3 according to the first embodiment (however, some overlap is included).

  As shown in FIG. 2, the heat storage control device according to the first embodiment generates a frequency distribution from the record database 31 that records the user's heat consumption record and the record data of the record database 31, and the daytime heat burnout occurs. A frequency distribution calculation unit 32 for obtaining a probability of performing from the frequency distribution, a clock (internal clock) 33 for outputting the current season data and day-of-week data to the frequency distribution calculation unit 32, and the amount of heat generated at midnight according to the heat capacity of the heat storage tank 2 An assumption generation unit 34 that generates candidates, an electric charge calculation unit 35 that calculates an electric charge expected value for each candidate generated by the assumption generation unit 34, and an electric charge expected value that is the smallest among the candidates. A hypothetical evaluation unit 36 to be selected and a heat generation control unit 37 that controls the heat generation device 1 by determining the start / stop time of the heat generation device 1 so as to obtain the heat amount of the selected candidate are provided. It has been. Moreover, as shown in FIG. 3, the heat storage tank temperature input part 38 into which the measurement temperature of the heat storage tank 2 is input, and the heat-out determination part 39 which determines whether it is out of heat based on the said measurement temperature are further provided. It has been.

The heat storage control device 3 according to the first embodiment is configured as described above and operates as follows.
First, the operation at the time of heat generation at midnight in the heat storage control device 3 according to the first embodiment will be described based on FIG.

  The actual result database 31 records the past daily heat consumption actual amount of the heat storage system for a predetermined number of days (for example, every 30 days) by season (spring, summer, autumn, winter) and by day of the week (weekday / holiday).

  The frequency distribution calculation unit 32 acquires seasonal data and day data indicating the current season and day of the week from the clock 33, and based on the acquired current season data and day of the week data, from the results database 31, the current season / day of the week. The past heat consumption performance amount data corresponding to the above is extracted, and the frequency distribution shown in FIG. 4 is calculated and obtained, and based on the frequency distribution, a late-night heat generation amount candidate generated by the assumption generation unit 34 to be described later For each hypothesis N that is, the probability X that a daytime heat burnout occurs is obtained.

  The assumption generation unit 34 generates one or more candidates for the amount of heat generated at midnight. For example, when the maximum heat capacity of the heat storage tank 2 is Nmax, 100 assumptions N are generated from 0 to Nmax in increments of Nmax × 0.01.

  For each assumption N (amount of late-night heat production) generated by the assumption generation unit 34, the electricity bill calculator 35 expects an electricity bill expectation value Ca (N) that takes that day (by the electricity bill expectation value at midnight and additional generation during the daytime). Calculate the sum of the expected electricity bills). The following formula shows the expected electricity bill Ca (N) on the day as a function of assumption N.

  First, as in the conventional heat storage system, the electricity cost Cn (N) when generating and storing heat by the amount of heat N in the midnight time zone is expressed by the following equation (1).

Cn (N) = N × 0.278 × Pn ÷ En (1)
here,
Cn: Expected electricity bill at midnight (yen)
N: Late night heat production (MJ)
0.278: kWh and MJ calorie conversion coefficient (kWh / MJ)
Pn: Unit price of late-night electricity (yen / kWh)
En: Average efficiency (%) of the heat generator at midnight

  Furthermore, in the daytime, heat shortage occurs only with the amount of heat N. As a result, when additional heat is generated until the sum of the heat generation amount on the day reaches M, the daytime electricity bill Cd (N) is expressed by the following formula ( 2).

Cd (N) = X * (MN) * 0.278 * Pd / Ed (2)
here,
Cd: Expected electricity bill for daytime (yen)
X: Probability that heat consumption is N or more (%)
M: Past maximum heat consumption (MJ)
Pd: Unit price for daytime electricity (yen / kWh)
Ed: Average efficiency (%) of the heat generator in the daytime

  Therefore, the expected electricity bill Ca (N) on the day is expressed by the following equation (3).

Ca (N) = Cn (N) + Cd (N) (3)
here,
Ca: Expected electricity bill for the day (yen)

  The assumption evaluation unit 36, based on the electric charge expectation value Ca (N) required for the current day for each assumption N obtained by the electric charge calculation unit 35, from among a plurality of assumptions N, the electric charge expected value Ca (N ) Is selected as the heat generation target value, and is output as the heat generation amount Na at midnight on that day.

  The heat generation control unit 37 determines and controls the start / stop time of the heat generation device 1 so that the amount of heat generated at midnight becomes the heat generation amount Na determined as the heat generation target value by the assumption evaluation unit 36. .

  The above is the operation of determining and controlling the start / stop time of the heat generation device 1 for minimizing the electricity cost of the heat storage system in the heat storage control device 3 according to the first embodiment. Conventionally, all the heat generated more than necessary has been lost due to heat dissipation, but in the first embodiment, this can prevent generation of heat more than necessary and save electricity costs. It also contributes to reducing CO2 emissions by reducing electricity consumption from an environmental point of view.

  Next, based on FIG. 3, the operation | movement at the time of the additional heat production | generation in the daytime in the heat storage control apparatus 3 which concerns on this Embodiment 1 is demonstrated.

  The late-night heat generation amount Na determined by the operation at the time of late-night heat generation described with reference to FIG. 2 described above is determined from the viewpoint of minimizing the expected electricity bill, and thus more than usual in the daytime. The day when the heat is used, heat burns out. In that case, additional heat generation is performed by the following operation.

  The heat storage tank temperature input unit 38 acquires the temperature of the heat storage tank 2 measured by the heat storage tank thermometer 20 installed in the heat storage tank 2. The acquisition may be performed constantly, but is performed at predetermined time intervals. The heat storage tank thermometer 20 is composed of a plurality of thermometers, and the plurality of thermometers are equally installed from the upper part to the lower part of the heat storage tank 2 at a predetermined interval.

  The heat-out determination unit 39 predicts and determines whether heat is out of the acquired temperature of the heat storage tank 2. That is, if the temperature of all locations in the heat storage tank 2 measured by the plurality of thermometers provided in the heat storage tank 2 is close to the tap water temperature (or a preset reference value) (that is, the tap water temperature) Or, if the temperature falls within a predetermined range from the reference value), it is determined that the heat has run out. This is based on the fact that the hot water and cold water in the heat storage tank 2 are slow to mix, and the hot water layer and the cold water layer are normally separated cleanly. For example, in the case of the hot water heat storage tank 2, if the temperature at the top is extremely close to the tap water temperature, the heat is burned out.

  The heat generation control unit 37 obtains the maximum heat consumption record M for the current season / day of the week from the record database 31 (or frequency distribution) when the heat burn determination unit 39 determines that the heat burn occurs in the daytime. The additional heat generation amount to be generated is determined as the difference between the maximum heat consumption record M and the generated heat amount Na generated at midnight the previous day, and the heat generation apparatus 1 is activated and activated so as to generate additional heat by M-Na. Determine and control stop time.

  The performance database 31 further stores the frequency distribution of the actual heat consumption amount and the average efficiency of the heat generating device 1 for each season, and the assumption evaluation unit 36 calculates the expected electricity bill for each season. Also good.

  Conventionally, additional heat was generated so as to fill half or all of the heat storage tank 2 when heat shortage is likely to occur. However, according to the first embodiment, it is added after grasping the amount of heat that can be actually consumed. Since heat generation is performed, it is possible to prevent heat generation more than necessary.

  As mentioned above, according to this Embodiment 1, it is a heat storage control apparatus for controlling the heat generation apparatus which accumulate | stores the heat | fever produced | generated using late-night electric power in a thermal storage tank, Comprising: The user for the past several days The actual result database 31 for storing the actual heat consumption amount, a hypothetical generation unit 34 for generating one or more heat generation amount candidates generated at midnight as the assumption N, and the frequency distribution of the actual heat consumption amount stored in the actual result database 31 And a frequency distribution calculation unit 22 for calculating the probability X that a daytime heat burnout occurs for each assumption N based on the frequency distribution, and the midnight electricity bill expected value Cn (yen) for each assumption N An assumption evaluation unit 36 that obtains the sum of the electricity bill expected value Cd (yen) due to additional generation in the daytime, selects an assumption N that minimizes the sum, and determines the heat generation amount Na to be generated at midnight; Determined by the assumption evaluation unit 36 Since the heat generation control unit 37 that controls the start / stop of the heat generation device 1 is provided based on the generated heat generation amount Na, the heat generation amount that probabilistically minimizes the electricity cost is determined. Can do. As a result, excessive heat generation can be prevented and power consumption can be minimized, thereby contributing to CO2 reduction.

  In addition, in order to prevent heat loss, the possibility of heat loss on the day is determined from the current heat remaining amount of the heat storage tank 2, and further includes a heat loss determination 39 for determining whether or not heat loss occurs, When the heat-out determining unit 39 determines that a heat-out occurs, the heat generation control unit 37 generates additional generated heat generated in the daytime at the midnight of the previous day and the maximum consumed heat amount in the frequency distribution of FIG. Since it is determined as a difference from the amount of heat and the heat generation device 1 is instructed to generate additional heat, even in the additional heat generation, it is possible to prevent generation of more heat than necessary. Excessive heat generation can be prevented and power consumption is minimized, which can contribute to CO2 reduction.

It is the figure which showed the structure of the thermal storage system which concerns on Embodiment 1 of this invention. It is the figure which showed the structure of the thermal storage control apparatus which concerns on Embodiment 1 of this invention (at the time of late-night heat generation). It is the figure which showed the structure of the thermal storage control apparatus which concerns on Embodiment 1 of this invention (at the time of additional heat generation in the daytime). It is explanatory drawing which showed an example of the frequency distribution of the heat demand calculated | required in the thermal storage control apparatus which concerns on Embodiment 1 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Heat generation apparatus, 2 Thermal storage tank, 3 Thermal storage control apparatus, 20 Thermal storage tank thermometer, 31 Performance database, 32 Frequency distribution calculation part, 33 Clock, 34 Assumption generation part, 35 Electricity cost calculation part, 36 Assumption evaluation part, 37 Heat generation control unit, 38 heat storage tank temperature input unit, 39 heat burnout determination unit.

Claims (4)

A heat storage control device for controlling a heat generation device that accumulates heat generated using midnight power in a heat storage tank,
A performance database that stores the amount of heat consumed by users in the past multiple days,
Hypothetical generation means for generating one or more candidates on the assumption of heat generation candidates generated at midnight;
A frequency distribution calculation means for calculating a frequency distribution of the actual amount of heat consumption stored in the performance database and calculating a probability that a daytime heat burn will occur for each of the assumptions based on the frequency distribution;
For each of the assumptions, an electricity bill calculation means for obtaining a sum of an expected electricity bill at midnight and an expected electricity bill by additional daytime generation based on the probability;
Assumption evaluation means for selecting the assumption that the sum obtained by the electricity bill calculation means is minimum and determining it as a heat generation amount to be generated at midnight;
A heat storage control device comprising: heat generation control means for controlling start / stop of the heat generation device based on the heat generation amount determined by the assumption evaluation means. The assumption evaluation means includes:
When the amount of heat generation at midnight is assumed to be the above assumed N (MJ), the expected midnight electricity bill Cn (yen) is the midnight power unit price Pn (yen / kWh) and the average efficiency En (%) of the heat generating device at midnight. ) And
From the probability X (%) of daytime heat burnout in the assumption N, the daytime power unit price Pd (yen / kWh), and the average efficiency Ed (%) in the daytime zone of the heat generation device 1 Calculate the expected electricity bill Cd (yen)
Among the plurality of assumptions N, a hypothesis N that minimizes the sum of the expected electricity bills Cn (yen) and Cd (yen) between midnight and daytime is determined and determined as the heat generation amount Na to be generated at midnight. The heat storage control device according to claim 1, wherein: The actual database further stores the frequency distribution of the actual heat consumption amount and the average efficiency of the heat generating device for each season,
The heat storage control device according to claim 1, wherein the assumption evaluation unit calculates the expected electricity bill for each season. In order to prevent heat shortage, it is possible to determine the possibility of heat burn of the day from the current heat remaining amount of the heat storage tank, further comprising a heat burn determination means for determining whether a heat burn occurs,
When the heat burn determination means determines that heat burn occurs, the heat generation control means adds the additional heat generated in the daytime to the maximum heat consumption in the frequency distribution and the heat generated generated at midnight the previous day. The heat storage control device according to any one of claims 1 to 3, wherein the heat generation device is commanded to generate additional heat.

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