JP2006158027A - Domestic power system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To satisfy a rational relationship between power selling and power purchasing, and to rationally control a storage water heater in a domestic power system including the storage water heater and a private power generator and constituted so as to sell power to a commercial power supply. <P>SOLUTION: If power Egen generated by the private power generator exceeds the total Ecsm of the quantity of power used by domestic electrical appliances and the power Egen possibly has excess power, the minimum thermal storage is increased from the first minimum thermal storage value Kmin_L to the second minimum thermal storage value Kmin_H higher than it. If a thermal storage K_real within a hot water storage tank is smaller than the second minimum thermal storage value Kmin_H, a heat pump unit is operated by the private power generator 21, and water is additionally heated within the hot water tank until a second target thermal storage Kaim_2 smaller and better than a first target thermal storage Kaim is attained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hot water storage hot water supply device that operates a heat pump unit with electric power, heats the water supply until it reaches a target heat storage amount commanded by the control device, and stores it in a hot water storage tank, a solar power generation device, and other private power generation devices In-house power systems that are configured to allow so-called “selling power” by reverse power flow from the power generation device to the commercial power source side, The present invention relates to an improvement for rationally controlling and operating a hot water storage type hot water supply apparatus while maintaining a balance.

  2. Description of the Related Art Conventionally, there is a hot water storage type hot water supply device that stores hot water heated by an electric power operated heat pump unit in a hot water storage tank for use by a user. In particular, as this type of hot water supply device, the lowest water in the hot water storage tank is heated by a heat pump unit and sent as hot hot water to the uppermost part in the hot water storage tank. Hot water is stored in the upper part of the tank and is not mixed with the water in the lower part of the hot water tank. When the hot water in the hot water storage tank is output (for example, the tap is opened to consume hot water outside the hot water storage tank), hot water is supplied from the hot water outlet pipe connected to the uppermost part of the hot water storage tank, and the lowermost part of the hot water storage tank. Water is supplied into the hot water storage tank through a water supply pipe connected to the hot water tank.

  Such a hot water storage type hot water supply device also generally has a function as a heating heat source. For example, hot water in a hot water storage tank is circulated outside the hot water storage tank and used as a heat source for floor heating or the like, and then returned to the hot water storage tank. It comes to return. Naturally, when such heating is performed, the heat stored by the heating is used, that is, the amount of heat stored in the tank is reduced accordingly.

  However, since commercial power is supplied to the heat pump unit, heat is stored using the so-called “midnight power” during the midnight power hours (currently, from 23:00 to 7:00 the next day) when the electricity rate is low, Many are devised not to store heat as much as possible during the daytime when the fee is high. To that end, of course, it is necessary to predict the amount of heat used the next day after the midnight power hours, and conventionally, the amount of stored heat is averaged by the amount of heat used by hot water every day for a certain period of time, Add the extra amount (margin) to the amount of heat used for hot water supply, and the amount of heat used for heating (this is also averaged by the amount of heat used for daily hot water supply for a certain period, adding a slight increase if necessary) The target heat storage amount for one day was added, and this amount of heat storage was planned during the midnight power hours.

Furthermore, from other viewpoints, various devices based on past data have been conventionally used so as not to cause unnecessary heat storage or to prevent a shortage of heat storage. For example, in the following Patent Document 1, in view of the amount of hot water stored in the tank, from the viewpoint of avoiding excess or deficiency in this, the amount of heat when the most amount of heat is required in the past week is set as the target amount of stored heat. If there was.
JP 2002-168524 A

  On the other hand, in recent years, solar power generators are also installed in ordinary households, and if there is a sufficient margin in the power generation of the power generators depending on the power usage situation in the household, surplus generated power is Increasingly, so-called “power sale” is also possible by output to the side (reverse power flow). In the future, not only a solar power generation device but also a fuel cell device and the like will be provided in each home as a form of a private power generation device.

Therefore, conventionally, the surplus power is not simply sold, but as recognized in Patent Document 2 below, the generated power is larger than a predetermined difference as compared with the power consumption in the home. At times, there was a proposal to operate the heat pump unit with the surplus power for the time being even in the daytime. However, the main purpose is to prevent voltage fluctuations in the home power system.
JP 2004-194485 JP

  However, in the technique recognized in the above-mentioned Patent Document 2, it is not necessary to boil, that is, even when the amount of heat stored in the hot water storage tank is still sufficient until the end of the day, the heat pump is unconditionally powered. There is a drawback that it works. Certainly, even if it is not necessary to boil, if the amount of stored heat is further increased, the amount of additional heat for the next day of midnight power after that can be reduced, so the power consumption in the midnight power hours is low. It may be enough. However, conversely, even if you sell power, you might have gained a larger profit than the power saving effect of purchasing electricity, but in a sense, you might be wasted.

  Having said that, it may be disadvantageous for a hot water storage hot water supply system to send all surplus power to selling electricity. For example, even if it is devised to take a sufficient amount of heat storage as disclosed in Patent Document 1, depending on the weather environment of the day, the target heat storage amount was stored in the midnight time zone of the previous day. If hot water is lost greatly due to large natural heat dissipation, or if there is a sudden increase in the amount of use during the day, etc. only on that day, the amount of stored heat is insufficient during the evening when hot water is used in large quantities. Therefore, it will fall below the set minimum heat storage amount, and eventually it will be overheated with a large amount of electricity in the daytime time zone.

  In view of this point, the present invention reduces the amount of stored heat by the surplus of generated power so that the amount of stored heat does not become insufficient in accordance with the situation of the day even during the time when hot water will be used in large quantities after the evening. On the other hand, it is reasonable not to run the heat pump unit in vain even though it is judged that it is no longer necessary because there is already enough margin. It is intended to provide reasonable control of hot water storage type hot water supply equipment, satisfying general power selling and buying relations.

In order to achieve the above object, the present invention
The heat pump unit is operated by electric power, the hot water supplied to the user is stored in the hot water storage tank by heating the water supply until the target heat storage amount commanded by the control device is reached, and the heat storage amount of the stored hot water is When the temperature falls below the minimum amount of heat storage, it is equipped with a hot water storage hot water supply device that operates and heats the heat pump unit again, and a private power generation device. In a domestic power system that is configured to drive the product and to sell power by reverse power flow to the commercial power supply side;
If the power generated by the in-house power generator exceeds the total amount of power used by household appliances and surplus power is expected, the minimum heat storage will be higher than the previous first value. Increase to the second minimum heat storage value;
At this time, if the heat storage amount in the hot water storage tank is lower than the second minimum heat storage amount value, the heat pump unit is operated by the private power generator, and may be lower than the target heat storage amount value. Boil the hot water in the hot water tank until it reaches the target heat storage amount;
Rather, if the amount of heat stored in the hot water storage tank exceeds the second minimum heat storage amount, sell the surplus generated power to the commercial power source by reverse power flow;
We propose an in-home power system characterized by

  Here, the minimum heat storage amount is raised from the first value to the second minimum heat storage amount value when the power generated by the in-house power generator exceeds the total amount of power used by household appliances. We propose a subordinate structure that is after a predetermined time has passed. This reacts instantaneously or over and under the generation output in a very short time, the minimum heat storage amount fluctuates between the first and second values, and the heat pump unit of the hot water storage hot water supply system is frequently turned on and off This is in order to prevent the user from making a mistake.

  In addition, in the above, the in-house power generation device may be a solar power generation device that is already widely used, a fuel cell device that is expected to be widely used in the future, or a power generation device that can be installed at home. Anything is applicable.

  According to the present invention, a very rational operation of the domestic power system can be achieved by appropriately selecting the second minimum heat storage amount value and the second target heat storage amount by design. As before, if the power generated by the private power generator exceeds the total amount of power used by household appliances and surplus power is expected, the heat pump unit can be operated unconditionally. In other words, the above-described drawbacks associated with unconditionally selling power are reduced.

  That is, when surplus power is generated in the generated power, the minimum heat storage amount is higher than the first value that is set as a minimum for the amount of stored hot water in the hot water storage tank in the day use. Since the second minimum heat storage amount is reset, the heat pump unit is activated when the heat storage amount of hot water actually stored in the hot water storage tank falls below the second minimum heat storage amount value at this time. By increasing the heat storage amount to the second target heat storage amount with electric power, it is possible to create a situation that can respond to unexpected large-scale use of hot water after the evening with a margin.

  In addition, it is natural that the second target heat storage amount may be smaller than the first target heat storage amount, and the former is set on the assumption of daily consumption, but the latter is used for hot water after the evening. This is because it is set only on the premise that there is a margin.

  On the other hand, if the heat storage amount of hot water actually stored in the hot water storage tank is larger than that even if the minimum heat storage amount is raised to the second minimum heat storage amount value, a large amount of hot water will be used after the evening. Therefore, the generated power can be sold as it is without driving the heat pump unit. Thus, the idea of balancing power selling and power purchase based on judgment according to the situation has not been accepted so far, and in fact, waste can be greatly reduced.

  Hereinafter, preferred embodiments of the present invention will be described. First, FIG. 1 (A) schematically shows the configuration of a domestic power system having a hot water storage hot water supply device 11 and a private power generation device 21. I started explaining.

  As already described, the hot water storage type hot water supply device 11 may be of a known and appropriate configuration, and the heat pump unit (not shown) is operated by electric power and heats the water supply until the target heat storage amount commanded by the control device (not shown) is reached. Thus, the hot water is stored in a hot water storage tank (not shown), and the stored hot water is provided for the user. Since the present invention is not specifically limited to the internal configuration, further detailed description is omitted.

  The commercial power AC is connected to the hot water storage hot water supply device 11 and each household appliance from the power distribution unit 23 via the power measurement unit 24 so that the electric power can be supplied to the hot water storage hot water supply device 11 (heat pump unit). The power consumption is known by the power measurement unit 26, and the power consumption of each home appliance (abbreviated as “home appliance” in the figure) 12 is also known by the power measurement unit 27.

  On the other hand, for example, there is a solar power generation device 21 as the private power generation device 21, for example, the power generation power is measured after the power conditioner 22 is converted into a stable voltage power output by converting direct current to alternating current. While being monitored by the unit 25, the power is supplied to the power receiving / distributing device 23, and the hot water storage type hot water supply device 11 and the domestic appliance 12 can be driven by this generated power.

  Furthermore, the private power generation device 21 is configured to output the generated power to the commercial power source according to conditions by so-called reverse power flow through the power distribution device 23, so that so-called power sale is also possible. Yes. The total electric power used in the home and the electric power sold by the reverse power flow can be measured by the power measuring unit 24 of the main system.

  The switching control device 31 is provided for system control according to the present invention described below. As will be described later, the heat pump unit of the hot water storage hot water supply device 11 is driven by the generated power of the private power generation device 21 under certain conditions. However, under other conditions, the generated power is output to the commercial power side by reverse flow and sold.

  In the following, each case will be described with reference to FIG. 1 (B). As already mentioned, the hot water storage type hot water supply device 11 is basically basically a midnight power time zone where the electricity rate is low (current During the day of the next day, heat is stored using so-called “late-night power” between 23:00 and 7:00 the next day) and is not stored as much as possible during the high daytime hours. The heat storage amount that can sufficiently cover the heat storage amount that will be used is set as the target heat storage amount Kaim.

  Therefore, in the time zone around the morning in FIG. 1 (B) where the horizontal axis is the time of day, the hot water actually boiled in a hot water storage tank (not shown) of the hot water storage type hot water supply device 11 is the target. It has a heat quantity close to the heat storage quantity Kaim. The actual heat storage amount of hot water in the hot water storage tank is shown by the curve K_real, but the actual heat storage amount K_real that reached the target heat storage amount Kaim in the morning is usually as shown in FIG. A monotonous event in which a person eats from the start of breakfast and has a lunchtime meal, and if that is the case, it will eventually pass through the hours when the hot water is used most after the evening and reach the midnight power hours again. A simple reduction curve.

  If the degree of decrease in the heat storage amount K_real falls below the predetermined minimum heat storage amount Kmin_L, even if it is not yet in the midnight power time zone, the heat pump unit is operated by commercial power AC. Is driven to increase boiling. In other words, the target heat storage amount Kaim has a margin in its value due to the contrivances already described with respect to Patent Document 1 and the like so that it is not necessary to increase the amount of heat in the time zone where such a high power charge is required. It is normally set.

  Fig. 1 (B) also shows an example of the elapsed time of the generated power of the private power generator 21 with a curve Egen. For example, in the case of a solar power generator, the generated power Egen increases from the beginning of the rising sun. Reduce towards the sunset. Therefore, as shown at time T1, particularly during the daytime, the generated power Egen of the private power generator 21 exceeds the total amount Ecsm of the amount of power used by the household appliances 12, and surplus power is expected in the generated power A situation can occur.

  In such a case, in the present invention, when the switching control device 31 recognizes that such a situation has occurred based on the power value information obtained from each of the power measurement units 25 to 27 via, for example, power superimposed communication, the switching control device 31, as indicated by an arrow Kset, raises the minimum heat storage amount from the previous first value Kmin_L to a second minimum heat storage amount value Kmin_H higher than this. In addition, if the actual heat storage amount K_real in the hot water storage tank is lower than the second minimum heat storage amount value Kmin_H at this time, a command is given to operate the heat pump unit with the generated power of the private power generator 21, The hot water in the hot water storage tank is boiled and increased until the second target heat storage amount Kaim_2, which may be lower than the target heat storage amount Kaim, is reached. The actual heat storage amount K_real and the like can be known through various sensors normally provided in the hot water storage type hot water supply apparatus 11.

  In the case shown in the figure, the actual heat storage amount K_real decreases and reaches the second minimum heat storage amount value Kmin_H at time T2, where boiling starts, the actual heat storage amount K_real starts increasing, and the time after time ta has elapsed. The case where the second target heat storage amount Kaim_2 is satisfied at T3 is shown. That is, in the period ta from time T2 to T3, the heat pump unit is driven so that a surplus amount of heat is given to the hot water in the hot water storage tank by the surplus power of the private power generator 21. As a result, the weather conditions of the day (mainly temperature environment conditions) were poor, and the hot water stored up to the target heat storage amount Kaim during the midnight time of the previous day was greatly lost due to large natural heat dissipation, or suddenly only on that day Even if there is a large increase in usage during the day, a sufficient margin can be expected. After the evening, the amount of heat storage becomes insufficient during the time when a large amount of hot water is used, which is less than the set minimum heat storage amount, and eventually it is still necessary to increase the amount of heat during the daytime hours. Will be released.

  It should be noted that the second target heat storage amount Kaim_2 may be smaller than the original first target heat storage amount Kaim, and the former is set on the assumption that it will be used for the entire day as described above. However, the latter only needs to be based on the premise that there is room for the use of hot water after the evening.

  After the time T3, the switching control device 31 releases the drive of the heat pump unit in the private power generation device 21, so that the generated power Egen of the private power generation device 21 is used by household appliances as shown at time T4. Over the time tb until the total amount of power Ecsm falls, the power generated by the private power generator 21 flows backward to the commercial power source and can be sold rationally. Of course, as will be recognized after the time T4, if the power generated by the private power generator 21 falls below the total energy Ecsm used by household appliances, the minimum heat storage value will again be the first value. Returned to Kmin_L.

  Naturally, unlike the case shown in FIG. 1 (B), the heat storage amount K_real in the hot water tank exceeds the value Kmin_H even though the value of the minimum heat storage amount has been raised to the second value Kmin_H. As long as the switching control device 31 does not drive the heat pump unit in the private power generation device 21, the surplus generated power is sold to the commercial power source by reverse power flow. Even though there is sufficient room in the hot water storage tank, the waste of additional boiling can be omitted, and the economic effect of selling electricity can be received.

  In the above, when the generated power Egen of the private power generator exceeds the total energy Ecsm used by household appliances, the minimum heat storage amount was immediately increased to the second minimum heat storage amount value Kmin_H, but it will be increased. It is assumed that after a predetermined time has elapsed, the state where the total electric energy used by the home appliances Ecsm exceeds the total power generation Egen of the in-house power generator exceeds the predetermined time. Practically desirable. It reacts instantaneously or over and under power generation output for an extremely short time, the minimum heat storage amount fluctuates between the first and second values, and the heat pump unit of the hot water storage hot water supply system is frequently turned on and off. This is to prevent electrical and mechanical stress from being applied.

  In the above, the private power generation device 21 is a widely used solar power generation device, but is not limited thereto. In addition to a fuel cell device that is expected to be widely used in future systems, any power generator that can be installed at home is applicable in the present invention.

It is explanatory drawing regarding the general | schematic structure and the aspect of control of the household electric power system in one Embodiment of this invention.

Explanation of symbols

11 Hot water storage water heater
12 Domestic appliances
21 In-house power generator (solar power generator)
22 Power conditioner
23 Power distribution equipment
24-27 Power measurement unit
31 Switching control device

Claims (4)

The heat pump unit is operated by electric power, the hot water supplied to the user is stored in the hot water storage tank by heating the water supply until the target heat storage amount commanded by the control device is reached, and the heat storage amount of the stored hot water is A hot water storage hot water supply device that operates the heat pump unit again when the heat storage amount falls below the minimum heat storage amount, and a private power generation device, and the power generation output of the private power generation device is a household including the hot water storage type hot water supply device. In a domestic power system that can drive internal appliances and can also sell power by reverse power flow to the commercial power supply side;
When the power generated by the private power generator exceeds the total amount of power used by the household appliances and surplus power is expected in the generated power, the minimum heat storage amount is determined from the first value so far. Increase to a second minimum heat storage value higher than this;
At this time, if the heat storage amount in the hot water storage tank is lower than the second minimum heat storage amount value, the heat pump unit is operated by the private power generator, and is lower than the target heat storage amount value. Boil the hot water in the hot water tank until it reaches a good second target heat storage;
On the other hand, when the heat storage amount in the hot water storage tank exceeds the second minimum heat storage amount value, selling power to the commercial power source by the reverse power flow;
A domestic power system characterized by A home power system according to claim 1;
The minimum heat storage amount is raised from the first value to the second minimum heat storage amount value because the generated power of the private power generator exceeds the total amount of power used by the household appliances. After a predetermined period of time;
A domestic power system characterized by A home power system according to claim 1;
The private power generator is a solar power generator;
A domestic power system characterized by A home power system according to claim 1;
The private power generator is a fuel cell device;
A domestic power system characterized by

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