JP2003307351A - Water heating appliance utilizing solar heat - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water heating appliance utilizing solar heat capable of allowing the hot water of a normal temperature for hot-water supply to store heat in a short time, and efficiently storing the heat in accordance with weather condition. <P>SOLUTION: The heat collecting operation is started with temperature difference ON/OFF control for switching ON and OFF a circulation pump on the basis of a temperature difference between a bottom temperature of a heat storage tank and a return temperature from a collector (P1), and the amount of solar radiation is estimated and detected (P2). The proportional heat collection control is performed for changing and adjusting an operational flow rate of the circulation pump to adjust the return temperature to be 40°C, when the present amount of solar radiation is enough for heating to a first target temperature of 40°C or more (P3-YES, P5). When the bottom temperature of the heat storage tank becomes 40°C, and the heat storage of 40°C in the entire heat storage tank is completed, the amount of solar radiation is estimated and detected again (P6-YES, P7). Here, the proportional heat collection control is performed to adjust the return temperature to be 60°C, when the amount of solar radiation is enough for heating to a second target temperature of 60°C or more (P3-YES, P5). After that, the temperature is changed step-by-step to the final target temperature of 75°C to perform the heat storage to the heat storage tank step-by-step. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention stores solar heat as hot water by forcibly circulating water in a heat storage tank with a solar heat collector (collector) by operating a circulation pump to heat the water, and the hot water is stored. The present invention relates to a solar water heating system used to send water to a hot water tap through an auxiliary heat source device such as a water heater and use it for hot water supply.

[0002]

2. Description of the Related Art Hitherto, as a heat collecting operation control by a solar water heating system of this kind, the following proportional operation control is generally performed. That is, the circulation pump 70 shown in FIG. 8 is continuously operated so that the temperature of the collector 3 (surface temperature) or the hot water temperature at the outlet of the collector 3 reaches a certain set temperature (for example, 60 to 75 ° C.). This is to change and control the circulation flow rate. In this case, a variable flow rate pump is used as the circulation pump 70, and the discharge flow rate, that is, the circulation flow rate is changed and controlled by, for example, changing and controlling the number of revolutions thereof. It should be noted that the surface temperature of the collector 3 is heated by the solar radiation of the sun, while heat is removed by heat exchange with the circulating water inside, so that the temperature of the hot water raised by the solar heat and returned to the heat storage tank is almost the same. Will be represented.

Further, the heat storage tank 2 is provided by a solar water heating system.
The hot water having the heat stored therein is usually taken out from the heat storage tank 2 and used for hot water supply. At that time, the heat storage tank 2 is used.
The hot water inside may be lower than the temperature required for hot water supply. Therefore, generally, as shown in FIG. 8, an auxiliary heat source device (for example, a water heater) 100 is provided between the heat storage tank 2 and the hot water tap.
The hot water extracted from the heat storage tank 2 is heated by the auxiliary heat source device 100 and then is supplied to the hot water tap at the downstream end.

However, since the amount of solar radiation of the sun changes variously depending on the weather conditions, according to the heat collection operation control described above, when the amount of solar radiation is small, hot water of the set temperature is stored in the heat storage tank. It takes a long time to store heat in 2 and
The heat collection efficiency, that is, the utilization efficiency of solar heat will also be reduced. In addition, if hot water is used up to that point, it is necessary to add heating by the auxiliary heat source device 100, and more energy (fossil fuel energy or electric energy) is consumed for heating, which is a disadvantage. .

That is, even if the sun rises, if the temperature of the collector 3 rises only to the set temperature, or if the amount of solar radiation is such that the temperature rises only around the set temperature, the temperature rises to the set temperature. Therefore, the circulation flow rate is controlled to be extremely small, the heat collection efficiency is significantly reduced, and it takes a long time to store heat. In particular, such inconvenience is likely to occur during the period from sunrise to morning.

The present invention has been made in view of the above circumstances, and an object thereof is to allow hot water having a temperature required for hot water supply to store heat in a shorter time.
An object of the present invention is to provide a solar water heating system that can efficiently store the heat according to the weather conditions.

[0006]

In order to achieve the above object, the water at the bottom of the heat storage tank is supplied to a solar heat collector by the operation of a circulation pump, and the hot water heated by the solar heat collector is used for the heat storage. Performing a heat collection operation of forced circulation so as to return to the top of the tank, and for the solar water utilizing hot water device configured to store solar heat as hot water in the heat storage tank, the following various specific items are provided: did.

That is, in the invention according to claim 1, the solar radiation amount detecting means for detecting the solar radiation amount of the sun, and the first temperature detecting means for detecting the temperature of the hot water to be returned from the solar heat collector to the top of the heat storage tank. The temperature detecting means and the heat collecting operation control means for controlling the heat collecting operation by operating the circulation pump so that the temperature detected by the first temperature detecting means becomes the target temperature. And, as the heat collection operation control means, it is assumed to have a target temperature setting unit that sets a target temperature based on the detected solar radiation amount from the solar radiation amount detection unit, and as the target temperature setting unit, with the detected solar radiation amount. The temperature lower than the heat storage temperature determined by the relationship is set as the target temperature.

The above "heat collection operation control" is as follows.
Even if the circulation pump is operated continuously and the circulation flow rate by the circulation pump is changed and adjusted so that the detected temperature becomes the target temperature, the circulation pump is intermittently turned on and off at a constant flow rate. ON / OFF to make the detected temperature reach the target temperature.
Either operation control may be performed. This point is the same as in claim 2 or claim 3 below.

According to the above-mentioned claim 1, the temperature lower than the heat storage temperature corresponding to the detected solar radiation amount by the target temperature setting unit,
That is, if the current solar radiation amount, the temperature lower than the hot water temperature after heating that can be heated at the circulation flow rate at the normal heat collection efficiency is first set as the target temperature in the heat collection operation control,
When the heat collection operation control (operation control of the circulation pump) is performed with such a target temperature, it becomes possible to store heat in a shorter time than when the above-mentioned heat storage temperature is set as the target temperature from the beginning, and the solar heat is stored. It can also be used with high efficiency. For example, when the above proportional operation control is executed, the circulation flow rate becomes larger when the target temperature is initially set to 40 ° C. than when the target temperature is set to 75 ° C., or the ON / OFF operation control described above is performed. In the case of executing the above, since the ON operation time of the circulation pump becomes longer, the hot water of the target temperature can be stored in the heat storage tank in a short time, and the utilization efficiency of solar heat is increased. In addition, since the hot water of the target temperature on the low temperature side is stored in the heat storage tank at an early stage, even if it is heated by the auxiliary heat source device for supplying hot water, energy consumption for the heating can be reduced.

According to the second aspect of the invention, the solar radiation amount detecting means for detecting the amount of solar radiation received by the solar heat collector, and the temperature of the hot water to be returned from the solar heat collector to the top of the heat storage tank are detected. And a heat collection operation control means for performing heat collection operation control by operating the circulation pump so that the temperature detected by the first temperature detection means becomes the target temperature. And, as the heat collection operation control means, it is assumed to have a target temperature setting unit that sets a target temperature based on the detected solar radiation amount from the solar radiation amount detection unit, and as the target temperature setting unit, with the detected solar radiation amount. A temperature lower than the heat storage temperature determined by the relationship is first set as the target temperature, and thereafter, the target temperature is set to the heat storage temperature or to the high temperature side temperature in the range up to the heat storage temperature in a stepwise manner.

According to the second aspect, the heat collection operation control is performed based on the target temperature set to a temperature lower than the heat storage temperature determined according to the detected solar radiation amount, and hot water of the target temperature is stored in the heat storage tank. Then, next, the heat collection operation control based on the target temperature changed and set to the temperature on the higher temperature side is performed, and hot water of the temperature on the higher temperature side is stored in the heat storage tank. The heat is stored in stages. For this reason,
In addition to obtaining the effect according to the first aspect, it becomes possible to further continue the heat storage of the hot water on the higher temperature side. As a result, from the viewpoint of utilization efficiency of solar heat, heat storage up to a higher temperature side can be efficiently performed according to weather conditions.

Here, in the setting of changing the target temperature by the target temperature setting unit, even if the temperature lower than the heat storage temperature is set as the first target temperature, the heat storage temperature is changed and set as the second target temperature. Alternatively, the intermediate temperature between the first target temperature and the heat storage temperature may be changed and set as the second target temperature. In the latter case, the heat storage temperature may be further changed and set as the third target temperature, or the intermediate temperature on the higher temperature side may be stepwise changed and set as the third or fourth target temperature and set at the final stage. The heat storage temperature may be changed and set as the target temperature, or any of them may be set. Note that such a stepwise change setting can be similarly adopted in the next claim 3. The first target temperature may be determined by the relationship between the temperature of the bottom of the heat storage tank supplied from the heat storage tank to the solar heat collector and the detected amount of solar radiation, but the normal temperature required for hot water supply. It is preferable to set (for example, 40 ° C.). With this configuration, when the auxiliary heat source device is installed on the hot water supply side, it is possible to supply the hot water stored in the heat storage tank as it is without heating the auxiliary heat source device. It is possible to omit energy consumption for heating at.

In the invention according to claim 3, the solar radiation amount detecting means for detecting the amount of solar radiation received by the solar thermal combustor and the temperature of the hot water to be returned from the solar heat collector to the top of the heat storage tank are detected. The first temperature detecting means and the heat collecting operation control means for controlling the heat collecting operation by operating the circulation pump so that the temperature detected by the first temperature detecting means becomes the target temperature. As the heat collecting operation control means in this case, the target is based on the seasonal information output section that outputs information on the current season by timing, and the detected solar radiation amount from the solar radiation amount detection means or the seasonal information from the seasonal information output section. And a target temperature setting unit for setting the temperature. Then, as the target temperature setting unit, a temperature lower than the heat storage temperature determined in relation to the detected solar radiation amount is first set as a target temperature, and thereafter, the target temperature is set according to the seasonal information from the seasonal information output unit. It is configured to change and set to a predetermined high temperature side temperature.

According to the third aspect, all the effects according to the second aspect can be obtained, and it is possible to change the change setting of the target temperature by the target temperature setting section in consideration of the current season information. Become. Therefore, first, it is possible to store the hot water of the target temperature on the low temperature side early, and then efficiently continue the storage of the hot water of the higher temperature side according to the seasonal variation characteristic of the amount of solar radiation. The above "season information" means January / February /
March ... Even for monthly information such as spring, summer, autumn,
It may be information about the four seasons such as winter. Then, for each month, the second target temperature is changed and set to, for example, 55 ° C from December to February, 65 ° C from June to August, and 60 ° C in other months. For each season, the second target temperature may be changed to 55 ° C. in winter, 65 ° C. in summer, and 60 ° C. in spring or autumn. By doing so, for example, even in the winter season, compared to the case where 60 ° C. is uniformly set as the second target temperature, heat storage that corresponds to actual weather conditions or solar radiation conditions becomes possible.

In the solar water heating system according to any one of claims 1 to 3, when performing the operation control for continuously operating while changing and adjusting the circulation flow rate of the circulation pump, the following operation may be performed. That is, the circulation pump is constituted by a variable flow rate pump, and the operation control flow rate by the circulation pump is used as the heat collection operation control means in two or more layers having a temperature difference between the bottom and the top in the heat storage tank. It may be configured such that the detected temperature is changed and adjusted by proportional control so as to reach the target temperature while being limited to a preset stratification flow range as a low flow range in which is formed (claim 4). By limiting the operation control flow rate of the circulation pump within the above-mentioned stratification flow rate range, two or more layers having a temperature difference from the bottom to the top are formed in the heat storage tank. That is, even if the hot water heated by the solar heat collector is returned to the heat storage tank, the heated water is accumulated in order from the top without being stirred around because of the low flow rate. For this reason, after the heat collection operation is started, even if the bottom of the heat storage tank is still low in temperature, hot water of the target temperature is secured at the top of the heat storage tank early, and it is possible to use hot water of the target temperature early.

In the solar water heating system according to any one of claims 1 to 4, there is further provided second temperature detecting means for detecting the temperature of water or hot water at the bottom of the heat storage tank, and the heat collecting operation is performed. As a control means, a temperature difference for intermittently turning on and off the circulation pump at a predetermined flow rate according to the difference between the temperatures detected by the first temperature detecting means and the second temperature detecting means when the heat collecting operation is started. ON / OFF
A configuration may be added in which the operation control is first executed and then the operation control of the circulation pump based on the target temperature is started (claim 5). In this case, even if the amount of solar radiation is insufficient, first the temperature difference is turned ON / OFF.
By starting the operation control, it becomes possible to store even a small amount of solar heat even if the temperature is lower than the target temperature.

As the solar radiation amount detecting means used in the solar water heating system according to any one of claims 1 to 5, various types can be adopted. For example, as the solar radiation amount detecting means, a solar cell disposed on the surface of the solar heat collector may be provided, and the solar radiation amount may be estimated and detected based on the power generation amount of the solar cell (claim 6). ). In this case, the amount of solar radiation can be directly detected and grasped as compared with the configuration described later, and the heat collection control can be executed more appropriately.

Alternatively, a flow rate detecting means for detecting a circulating flow rate by the operation of the circulation pump and a second temperature detecting means for detecting a temperature of water or hot water at the bottom of the heat storage tank are further provided, and the solar radiation amount detecting means is provided. The amount of solar radiation at that time is estimated and detected based on the amount of collected heat obtained by multiplying the detected flow rate by the flow rate detection means and the temperature difference between the both detected temperatures by the first and second temperature detection means. The configuration may be adopted (claim 7). In this case, the solar radiation amount is detected by calculation using the detection means usually provided for other uses for the solar water heater without installing a special sensor for detecting the solar radiation amount. You will be able to do it.

The first temperature detecting means in the solar water heating system according to any one of claims 1 to 7 is the surface temperature of the solar heat collector during forced circulation, or the temperature of the circulating water inside. Alternatively, the temperature of hot water returned from the solar heat collector to the top of the heat storage tank may be detected (claim 8). The surface temperature of the solar heat collector, which receives solar radiation and exchanges heat with the water inside, is almost the same as the temperature of the hot water heated by the solar heat collector and returned to the heat storage tank. Further, the position where the temperature of the circulating water inside the solar heat collector is detected may be an internal position of the solar heat collector or an outlet position. In these cases, the heat radiation amount in the pipe between the solar heat collector and the heat storage tank may be taken into consideration. Further, the detection position of the temperature returned to the top of the heat storage tank may be in the middle of the piping or at the top position of the heat storage tank.

[0020]

As described above, according to the solar water heating system of claim 1, the temperature lower than the heat storage temperature corresponding to the detected solar radiation amount by the target temperature setting unit is the target temperature in the heat collection operation control. Therefore, the heat storage temperature can be stored in a shorter time than the case where the heat storage temperature is set as the target temperature from the beginning, and the solar heat can be used with high efficiency. In addition, even though it is on the low temperature side, the hot water of the above target temperature is stored in the heat storage tank at an early stage, so even if it is heated by the auxiliary heat source device to supply hot water, energy consumption for that heating is reduced. be able to.

According to the solar water heating system of claim 2,
It is possible to obtain all of the effects according to claim 1, and further,
First of all, after storing the hot water of the target temperature on the low temperature side early,
The heat of the hot water on the higher temperature side can be continued to be stored, and the heat can be stored in the heat storage tank in stages.
Thereby, from the viewpoint of utilization efficiency of solar heat, it becomes possible to efficiently store heat up to a higher temperature side according to the weather condition. By setting the normal temperature required for hot water supply as the first target temperature, if an auxiliary heat source device is installed on the hot water supply side, the heat is not stored in the heat storage tank without heating the auxiliary heat source device. The hot water thus generated can be supplied as it is, and energy consumption for heating in the auxiliary heat source device can be eliminated.

According to the solar water heating system of claim 3,
In addition to being able to obtain all the effects of claim 2, the target temperature setting unit changes the target temperature to store the heat of hot water on the higher temperature side according to the seasonal variation characteristic of the amount of solar radiation in consideration of the current season information. Can be efficiently continued. Therefore, compared with the case where the target temperature is uniformly changed and set to 60 ° C. even in the winter, for example, it is possible to perform heat storage corresponding to the actual weather or solar radiation.

According to claim 4, in the solar water heating system according to any one of claims 1 to 3, after the heat collecting operation is started, even if the bottom of the heat storage tank is still low in temperature, It is possible to secure hot water of the target temperature at the top early.
It is possible to achieve early use of hot water at the target temperature and reduce energy consumption for heating in the auxiliary heat source machine as much as possible.

According to a fifth aspect, in the solar water heating system according to any one of the first to fourth aspects, even when the amount of solar radiation is insufficient, the ON / OF is first set.
By starting the F operation control, even if the temperature is lower than the target temperature, the solar heat can be stored as much as possible, and then the heat storage based on the target temperature thereafter can be executed to further improve the utilization efficiency of the solar heat. be able to.

According to claim 6, in the solar water heating system according to any one of claims 1 to 5, it is possible to directly detect and grasp the amount of solar radiation detected by the amount of solar radiation detecting means. The heat collection control can be executed more appropriately. Further, when the solar cell is used as a power source for the solar water heating system, it can be used together without installing a special sensor as a solar radiation amount detecting means.

According to a seventh aspect, in the solar water heating system according to any one of the first to fifth aspects, the solar water heating system is installed in the solar water heating system without installing a special sensor for detecting the amount of solar radiation. On the other hand, it becomes possible to detect the amount of solar radiation by calculation using the detection means usually provided for other purposes.

According to the eighth aspect, a specific mode can be specified as the first temperature detecting means used in the solar water heating system according to any one of the first to seventh aspects.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> FIG. 1 shows a solar water heating system according to a first embodiment of the present invention, in which 2 is a heat storage tank.
3 is a solar heat collector.

The heat storage tank 2 is a closed container made of, for example, a stainless steel plate. At the bottom of the heat storage tank 2, the downstream end of the water supply circuit 4 and the upstream end of the outflow path 5a of the heat collection circuit 5 are connected in communication with each other, and the water heater 100 as an auxiliary heat source device (not shown) is provided at the top. The upstream end of the hot water supply circuit 6 for supplying hot water via (see FIG. 8) and the downstream end of the return path 5b of the heat collection circuit 5 are connected in communication with each other. The heat storage tank 2 is filled with tap water supplied from the water supply circuit 4, and is supplemented from the water supply circuit 4 by the amount of hot water used through the hot water supply circuit 6.

A circulation pump 7 composed of a variable flow rate pump (for example, a DC pump) is interposed in the outflow path 5a of the heat collecting circuit 5. Also, the collector 3 has
A surface temperature sensor 9 which detects the surface temperature thereof and is used as a first temperature detecting means, and a solar cell 12 which is used as a part of the solar radiation amount detecting means are arranged, and a bottom position is provided at the bottom of the heat storage tank 2. A bottom temperature sensor 10 is provided as a second temperature detecting means for detecting the temperature of the water or hot water (hereinafter referred to as "bottom temperature").

The circulation pump 7 is operated and controlled by the controller 13 including the heat collection operation control means based on the outputs of the sensors 9 and 10 and the solar cell 12 to perform the heat collection operation. There is. The controller 13 is provided with an MPU, a memory, etc., and is configured to execute a program installed in advance and various controls by a control circuit. That is, the controller 13 serves as heat collection operation control means as shown in FIG.
1, the ON / OFF operation control unit 132, and the target temperature setting unit 133 that sets the target temperature in the proportional heat collection control unit 131.
And the proportional heat collection control by the proportional heat collection control unit 131 and the temperature difference ON by the ON / OFF operation control unit 132.
A switching control unit 134 that switches the OFF control and a solar radiation amount estimation unit 135 that constitutes a part of the solar radiation amount detecting means that estimates and detects the solar radiation amount based on the output from the solar cell 12 are provided.

The proportional heat collection control unit 131 sets the operation control flow rate of the circulation pump 7 as a low flow rate range in which two or more layers having a temperature difference are formed between the bottom and the top of the heat storage tank 2. The rotation speed of the circulation pump 7 is controlled so that the detected temperature (surface temperature) of the surface temperature sensor 9 becomes the target temperature set by the target temperature setting unit 133 while limiting within a preset stratification flow rate range. The feedback heat control (FB control) is used to change and adjust to perform proportional heat collection control. Since the circulation pump 7 is a variable flow pump of a type in which the discharge flow rate changes according to the change in the rotation speed, the rotation speed is controlled in order to control the operation of the circulation pump 7 at the operation control flow rate. . As a specific example of the FB control of the rotation speed, the control rotation speed N = K × (surface temperature-target temperature) is set (K: proportional constant). As a result, the surface temperature is kept constant at the target temperature because the heat collected by solar radiation is heat-exchanged with the water sequentially supplied by circulation, and the hot water in the heat storage tank 2 is substantially constant at the target temperature. Is returned.

Here, the above-mentioned stratified flow rate range means that the inside of the heat storage tank 2 is not agitated by the return hot water from the return path 5b, and the hot water of higher temperature is stored in layers on the upper side and the temperature from the bottom to the top is increased. The low flow rate range is such that a layer having a difference is formed, but on the other hand, it is set to a predetermined flow rate range in order to suppress a decrease in heat collection efficiency and maintain the heat collection efficiency to some extent. That is, as shown in FIG. 3 which shows the relationship between the heat collection efficiency and the circulation flow rate for one collector 3, the heat collection efficiency of about 50 to 90% is achieved with respect to the MAX value (heat collection efficiency of about 50%). The lower limit value of the circulation flow rate range corresponding to the obtained low efficiency range is set to β (L / min). Then, the upper limit value of the circulation flow rate range, that is, the maximum flow rate at which stratification with a temperature difference can be formed without decreasing the heat collection efficiency in the collector 3 is set to α (L / min). That is, β to α are set as the stratified flow rate range. Since this is for one collector 3, if there are two or more collectors 3, it is sufficient to multiply the above β and α by that number.

The target temperature setting unit 133 is adapted to change the target temperature in stages such that the first target temperature and the second target temperature are gradually increased to higher temperatures. That is, first, the temperature on the low temperature side is set as the first target temperature, and in the next step, the temperature on the higher temperature side is changed and set as the second target temperature. Specifically, a temperature lower than the hot water temperature (heat storage temperature) that can be heated by the current solar radiation amount obtained by the solar radiation amount estimation unit 135 is set as the first target temperature, and the heat storage at this first target temperature is When completed, the intermediate temperature between the first target temperature and the heat storage temperature is set as the second target temperature in the next stage, and when the heat storage at the second target temperature is completed, the third target temperature that is the final target temperature is set. As above, the heat storage temperature is set. At this time, if the heat storage temperature that is the final target temperature is, for example, 75 ° C., the auxiliary heat source device 100 (FIG. 8) is set as the first target temperature.
The normal temperature for hot water supply without heating at 40 ℃
Is set and, for example, 60 ° C. is set as the second target temperature.

The ON / OFF operation control unit 132 fixes the circulation pump 7 at the above α according to the difference between the detected temperatures of the collector surface temperature sensor 9 and the bottom temperature sensor 10, and turns it on / off. It is designed to operate intermittently. That is, if the temperature difference of "surface temperature-bottom temperature" is 7 ° C or more, the circulation pump 7 is turned on,
When the temperature difference is 4 ° C. or less, the circulation pump 7 is turned off to perform the intermittent operation by the temperature difference ON-OFF control.

When the heat collecting operation is started, the switching control section 134 first starts the temperature difference ON-OFF control by the ON / OFF operation control section 132, and during the execution of this control, the solar radiation estimation section 135 If it is determined that the obtained current amount of solar radiation is the amount of solar radiation sufficient for performing heat collection based on the first target temperature in the proportional heat collection control unit 131, the proportional heat collection control unit 131 performs proportional heat collection control. It is designed to switch to. Then, when the heat storage is completed by the proportional heat collection control based on the first target temperature, if it is determined that the current amount of solar radiation is sufficient to collect heat based on the next second target temperature, the second amount of solar radiation is determined. While the proportional heat collection control based on the target temperature is continued, if the amount of solar radiation is not sufficient, the temperature difference ON / OFF control by the ON / OFF operation control unit 132 is switched.

The solar radiation amount estimating unit 135 uses the solar cell 12
From the output of the information on the amount of power generation from, the current amount of solar radiation is estimated and detected from the predetermined relationship between the amount of power generation and the amount of solar radiation.

The heat collecting operation control by the controller 13 will be described below with reference to FIG. When the heat collecting operation switch is turned on by the operation of the switch by the user or the output of the operation command by the built-in clock or the detection of solar radiation, the heat collecting operation is started. When the heat collecting operation is started, first, the above-mentioned O
Temperature difference ON-OFF by N / OFF operation control unit 132
Control is started and even if the amount of solar radiation is low, even a little heat is collected and stored (P1). Then, the current solar radiation amount is estimated by the solar radiation amount estimation unit 135 during execution of this control (P2).
Until it is determined that the current amount of solar radiation is sufficient to heat to a temperature equal to or higher than the temperature (normal temperature 40 ° C.) set as the first target temperature by the target temperature setting unit 133, that is, while it is insufficient. The temperature difference ON / OFF control is continued (NO in P2 and P3, P4).

When it is determined that the current amount of solar radiation is sufficient to heat the temperature to the first target temperature or higher,
The proportional heat collection control by the proportional heat collection control unit 131 is started so that the surface temperature of the collector surface temperature sensor 9 becomes the first target temperature (YES in P2 and P3, P5). That is,
Even if the current amount of solar radiation can heat up to 75 ° C,
As the first target temperature, the temperature on the low temperature side of 40 ° C. is intentionally set, and the proportional heat collection control is performed so as to reach the first target temperature. In this proportional heat collection control, the operation control flow rate (circulation flow rate) is changed and adjusted by FB controlling the rotation speed of the circulation pump 7 so that the detected surface temperature becomes the first target temperature. At this time, the FB control value is equal to the above-mentioned α (L / mi
When it exceeds n), the FB control value is forcibly set to α (L / min) to maintain the stratified heat storage, while the FB control value is extremely low such as less than β (L / min) due to sudden clouding. If it becomes the flow rate, that is, the circulation flow rate is β
When the amount of solar radiation suddenly changes so that heat cannot be collected unless FB control is performed below (L / min), the circulation pump 7 is temporarily turned off (the proportional heat collection control is stopped) to wait for the recovery of the amount of solar radiation. . As described above, while the change adjustment of the circulation flow rate is maintained within the stratification flow rate range of β to α, it is continued until the bottom temperature of the heat storage tank 2 reaches the normal temperature (40 ° C.) which is the first target temperature (P6). NO, P5).

If all of the heat storage tank 2 is filled with the hot water of the first target temperature by the execution of this proportional heat collection control, that is, since it is gradually accumulated from the top side, it is detected by the bottom temperature sensor 10. When the bottom temperature reaches the first target temperature, the solar radiation amount at that time is estimated again (YES in P6, P7). This solar radiation amount is the second target temperature (for example, 60) which is set next by the target temperature setting unit 133.
If there isn't enough to heat to a temperature above
That is, if the amount of solar radiation is insufficient, the temperature difference ON / OFF control is switched to the temperature difference ON / OFF control by the ON / OFF operation control unit 132, and the temperature difference ON / OFF control is maintained until the amount of solar radiation reaches the above-described sufficient level (NO in P8). , P9). On the other hand, if the amount of solar radiation is sufficient to the extent that the heat storage of the hot water at the first target temperature is completed, the target temperature of the proportional heat collection control up to then is changed to the second target temperature, The proportional heat collection control is continued (YES in P8, P10).

Although not shown, the heat storage tank 2
When the bottom temperature of the heat storage tank reaches the second target temperature and the heat storage of the second target temperature is completed in all of the heat storage tanks 2, the above P7-
Similar to the process of P10, the target temperature is changed to the third target temperature (75 ° C.) which is the final heat storage temperature to perform the proportional heat collection control,
The heat of the third target temperature is stored.

According to the above, the amount of solar radiation is the final heat storage temperature (7
Even if it can be heated up to 5 ℃, first of all
Perform stepwise heat storage by storing heat at 40 ° C as the target temperature, then at 60 ° C as the second target temperature, and finally at 75 ° C as the third target temperature. As a result, heat can be stored in a significantly shorter time than in the case where proportional control is performed in which the final heat storage temperature of 75 ° C. is changed to the target temperature from the beginning to change and adjust the circulation amount of the circulation pump 7. At that time, in the proportional heat collection control of the present embodiment in which the first to third target temperatures are set to the target temperatures, the operation control flow rate of the circulation pump 7 is limited to the stratification flow rate range, so that the heat storage tank 2 is stratified. Heat storage (heat storage in a stratified state) is performed, and hot water of the target temperature at that time can be secured very early to the top of the heat storage tank 2. Further, even when the proportional heat collection control is not performed due to insufficient solar radiation, the temperature difference ON / OFF control is performed, so that the utilization efficiency of solar heat can be sufficiently increased depending on the weather conditions. .

<Second Embodiment> FIG. 5 shows a solar water heating system according to a second embodiment of the present invention. In the second embodiment, the solar cell 12 of the first embodiment is omitted and a solar radiation amount detecting means different from that of the first embodiment is adopted, while the first embodiment is used.
The controller 14 includes a heat collecting operation control means having a configuration different from that of the embodiment. Along with this, a flow rate sensor 8 as a flow rate detecting means for detecting the circulation flow rate, which is not provided in the first embodiment, and a collector 3 arranged in the return path 5b of the heat collecting circuit 5 near the heat storage tank 2. A return temperature sensor 11 as a first temperature detecting means for detecting the heated hot water temperature (hereinafter referred to as "return temperature") returned from the heat storage tank 2 to the heat storage tank 2 is added. Since the other constituent elements of the second embodiment are the same as those of the first embodiment, the same constituent elements are designated by the same reference numerals and detailed description thereof will be omitted.

As in the first embodiment, the controller 14 is provided with an MPU, a memory and the like, and various controls are executed by executing a program installed in advance and a control circuit. That is, the controller 14 serves as a heat collecting operation control means as shown in FIG.
1, a target temperature setting unit 141 that sets target temperatures in the ON / OFF operation control unit 132 and the proportional heat collection control unit 131.
And a calendar unit 142 as a seasonal information output unit that measures the current seasonal information and outputs a second target temperature predetermined according to the seasonal information to the target temperature setting unit 141.
And the proportional heat collection control by the proportional heat collection control unit 131 and the temperature difference ON by the ON / OFF operation control unit 132.
A switching control unit 134 for switching the OFF control, and a solar radiation amount calculation unit 143 forming a part of the solar radiation amount detecting means for estimating and detecting the solar radiation amount based on the outputs from the various sensors 8, 10, 11 are calculated. I have it.

The target temperature setting unit 141 sets the first target temperature as the first target temperature setting unit 133 as in the first embodiment.
The target temperature and the second target temperature are sequentially changed and set to higher temperatures, and the temperature value acquired from the calendar unit 142 is set as the second target temperature. Is different from the target temperature setting unit 133 of the first embodiment. Specifically, a temperature lower than the hot water temperature (heat storage temperature) that can be heated by the current solar radiation amount obtained by the solar radiation amount estimation unit 135 is set as the first target temperature, and the heat storage at this first target temperature is When completed, the second target temperature of the next stage is an intermediate temperature between the first target temperature and the heat storage temperature, and the calendar unit 142 is used.
When the temperature output from is set and the heat storage at the second target temperature is completed, the heat storage temperature is set as the third target temperature which is the final target temperature. On this occasion,
If the heat storage temperature, which is the final target temperature, is 75 ° C., for example, the first target temperature is a normal temperature at which hot water can be supplied without heating in the auxiliary heat source device 100 (FIG. 8), as in the first embodiment, for example. The temperature is set to 40 ° C., and the second target temperature is set to a temperature value in consideration of a seasonal variation characteristic described later.

The calendar section 142 grasps at least the month of the present as seasonal information by timekeeping, and outputs a temperature value previously associated with this seasonal information to the target temperature setting section 141. . For example, the present is 12
55 ° C is output during the winter months from March to February, 65 ° C is output during the summer months from June to August, and 60 ° C is output during the spring season from March to May and the autumn season from September to November. It is supposed to do.

The solar radiation amount calculation unit 143 has a flow rate sensor 8
On the basis of the circulation flow rate value detected by, and the temperature difference obtained by subtracting the bottom temperature detected by the bottom temperature sensor 10 from the return temperature detected by the return temperature sensor 11,
The amount of heat collected per unit time is calculated, and the current amount of solar radiation is estimated from the correlation between the amount of collected heat and the amount of solar radiation.

Most of the heat collecting operation control by the controller 14 has the same contents as the controller 13 of the first embodiment except that the setting of the second target temperature is different. That is, as shown in FIG. 4, when the heat collecting operation is started, first, the ON / OFF operation control unit 13 is started.
The temperature difference ON-OFF control by 2 is started (P1), and the current solar radiation amount is estimated by the solar radiation amount calculation unit 143 during the execution of the control (P2). The temperature difference ON / OFF control is performed until it is determined that the current amount of solar radiation is sufficient to heat to a temperature equal to or higher than the temperature set as the first target temperature by the target temperature setting unit 141 (normal temperature 40 ° C.). (P2, P3: NO, P4) while the current solar radiation amount is determined to be sufficient to heat the temperature to the first target temperature or higher, the collector surface temperature sensor 9 surface The proportional heat collection control by the proportional heat collection control unit 131 is started so that the temperature becomes the first target temperature (YES in P2 and P3, P5). By this proportional heat collection control, the bottom temperature of the heat storage tank 2 is the normal temperature (first temperature), which is the first target temperature, in a state where the change adjustment of the circulation flow rate is maintained within the stratified flow rate range of β to α described in the first embodiment. Continue until the temperature reaches 40 ° C. (NO in P6, P5).

If all of the heat storage tank 2 is filled with the hot water of the first target temperature by the execution of this proportional heat collection control, that is, since it is gradually accumulated from the top side, it is detected by the bottom temperature sensor 10. When the bottom temperature reaches the first target temperature, the solar radiation amount at that time is estimated again (YES in P6, P7), and the second target temperature in consideration of the current seasonal variation characteristic is acquired from the calendar unit 142. Yes (P11). This solar radiation amount is the second target temperature (for example, 4
If it is not enough to heat up to a temperature of 60 ° C or more in the case of a month, that is, if the amount of solar radiation is insufficient, it turns on.
The temperature difference ON / OFF control by the FF operation control unit 132 is switched to the temperature difference O until the amount of solar radiation reaches the above-mentioned sufficient level.
Continue N / OFF control (NO in P8, P9). On the contrary, if the amount of solar radiation is sufficient, the target temperature of the proportional heat collection control until then is changed to the second target temperature and the proportional heat collection control is continued (YES in P8, P1).
0).

When the bottom temperature of the heat storage tank 2 reaches the second target temperature and the heat storage at the second target temperature is completed in all of the heat storage tank 2, the target is processed in the same manner as the processing of P7 to P10. The temperature is changed to the third target temperature (75 ° C.) which is the final heat storage temperature, the proportional heat collection control is performed, and the heat is stored at the third target temperature.

According to the above, the same operation and effect as those of the first embodiment can be obtained, and in addition, the second target temperature considering the fluctuation characteristics of the solar heat etc. based on the season can be obtained especially in the intermediate stage of the stepwise heat storage. It can be used to store heat. Therefore, first, the hot water of the first target temperature on the low temperature side can be stored early, and then the heat water of the second target temperature on the higher temperature side according to the seasonal variation characteristic of the solar heat can be efficiently stored. This makes it possible to perform the stepwise heat storage more efficiently than in the case where the second target temperature is uniformly set regardless of the season.

<Other Embodiments> The present invention is based on the first embodiment.
The present invention is not limited to the second embodiment and includes various other embodiments. That is, the solar radiation amount detecting means using the solar cell 12 in the first embodiment may be applied to the second embodiment, or conversely, the solar radiation amount calculating unit 143 in the second embodiment may be used. The quantity detecting means may be applied to the first embodiment.

Further, the solar radiation amount detecting means 15 using a thermocouple as shown in FIG. 7 may be applied to the first or second embodiment. The solar radiation amount detection means 15 of FIG.
Divides the heat receiving area 151, which receives solar radiation, into four equal parts,
The two regions are colored black with good heat absorption, and the other two regions are colored with white, which easily reflects heat.
2 have thermocouples 153 and white areas 154 and 154, respectively.
Also, a thermocouple 155 is installed in each of them. Then, the potential difference between one set of thermocouples 153 and 153 and the other set of thermocouples 155 and 155 is detected, and the current amount of solar radiation is estimated from the correlation between the potential difference and the amount of solar radiation. It was done. The upper side of the heat receiving area 151 is covered with a transparent windshield to protect it from wind.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a solar water heating system according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing contents of a controller according to the first embodiment.

FIG. 3 is a graph showing the relationship between heat collection efficiency and circulation flow rate.

FIG. 4 is a flowchart showing heat collection control according to the first embodiment and the second embodiment.

FIG. 5 is a schematic view showing a solar water heating system according to a second embodiment.

FIG. 6 is a block diagram showing the contents of a controller of the second embodiment.

FIG. 7 is a plan view showing another form of the solar radiation amount detecting means.

FIG. 8 is a schematic diagram showing a relationship between a solar water heating system and an auxiliary heat source device.

[Explanation of symbols]

2 heat storage tank 3 collector (solar heat collector) 7 circulation pump 8 flow rate sensor (flow rate detection means) 9 collector surface temperature sensor (first temperature detection means) 10 bottom temperature sensor (second temperature detection means) 11 return temperature sensor ( 1st temperature detection means) 12 Solar cell (solar radiation amount detection means) 13, 14 Controller (heat collection operation control means) 15 Solar radiation amount detection means 131 Proportional heat collection control part 132 ON / OFF operation control parts 133, 141 Target temperature setting Part 135 Solar radiation amount estimation unit (solar radiation amount detection means) 142 Calendar portion (seasonal information output portion) 143 Solar radiation amount calculation portion (solar radiation amount detection means)

Claims (8)

[Claims] 1. A heat collector for supplying water at the bottom of a heat storage tank to a solar heat collector by operating a circulation pump and forcibly circulating hot water heated by the solar heat collector to the top of the heat storage tank. In a solar-powered hot water device configured to operate and store solar heat as hot water in the heat storage tank, solar radiation amount detection means for detecting the amount of solar radiation of the sun, and the solar heat collector to the top of the heat storage tank. First temperature detecting means for detecting the temperature of hot water to be returned, and heat collecting for controlling heat collecting operation by operating the circulation pump so that the temperature detected by the first temperature detecting means becomes a target temperature. Operation control means, the heat collection operation control means has a target temperature setting unit for setting a target temperature based on the detected solar radiation amount from the solar radiation amount detection unit, the target temperature setting unit is the detection solar radiation. amount Solar water heater, characterized in that it is configured to set the temperature lower than the heat storage temperature determined by the relationship as the target temperature. 2. A heat collector for supplying water at the bottom of a heat storage tank to a solar heat collector by operating a circulation pump and forcibly circulating hot water heated by the solar heat collector to the top of the heat storage tank. In operation, in the solar water utilizing hot water device configured to store solar heat as hot water in the heat storage tank, solar radiation amount detecting means for detecting the amount of solar radiation received by the solar heat collector, and from the solar heat collector First temperature detecting means for detecting the temperature of hot water to be returned to the top of the heat storage tank,
Heat collection operation control means for performing heat collection operation control by operating the circulation pump so that the temperature detected by the first temperature detection means becomes a target temperature, and the heat collection operation control means comprises the solar radiation amount. It has a target temperature setting unit that sets a target temperature based on the detected solar radiation amount from the detection means, and this target temperature setting unit first sets a temperature lower than the heat storage temperature determined by the relationship with the detected solar radiation amount as the target temperature. Then, thereafter, the target temperature is set to the heat storage temperature or to the high temperature side temperature in the range up to the heat storage temperature in a stepwise manner, and is configured to be set gradually. 3. A heat collector for supplying water at the bottom of the heat storage tank to a solar heat collector by operating a circulation pump and forcibly circulating hot water heated by the solar heat collector to the top of the heat storage tank. In a solar-powered hot water device configured to perform operation and store solar heat as hot water in the heat storage tank, a solar radiation amount detecting means for detecting the amount of solar radiation received by the solar thermal combustor, and heat storage from the solar heat collector. First temperature detecting means for detecting the temperature of the hot water to be returned to the top of the tank,
And a heat collection operation control means for performing heat collection operation control by operating the circulation pump so that the temperature detected by the first temperature detection means reaches a target temperature. And a target temperature setting unit for setting a target temperature based on the detected solar radiation amount from the solar radiation amount detection unit or the seasonal information from the seasonal information output unit, The target temperature setting unit first sets a temperature lower than the heat storage temperature determined in relation to the detected solar radiation amount as a target temperature, and thereafter, the target temperature is predetermined according to the seasonal information from the seasonal information output unit. A solar water heating system characterized in that it is configured to be changed and set to a high temperature side temperature. 4. The solar water heating system according to claim 1, wherein the circulation pump is a variable flow rate pump, and the heat collection operation control means is operated by the circulation pump. While the control flow rate is limited to a stratified flow rate range preset as a low flow rate range in which two or more layers having a temperature difference are formed between the bottom and the top in the heat storage tank, the detected temperature is set to the target temperature. A solar water heating device configured to change and adjust by proportional control so that 5. The solar water heating system according to claim 1, further comprising second temperature detecting means for detecting a temperature of water or hot water at the bottom of the heat storage tank. The heat collecting operation control means starts the first heat collecting operation and then
The circulation pump is turned on at a predetermined flow rate according to the difference between the temperatures detected by the temperature detecting means and the second temperature detecting means.
A solar-heated hot water device configured to first execute temperature difference ON / OFF operation control for intermittent operation of OFF and then start operation control of a circulation pump based on a target temperature. 6. The solar water heating system according to any one of claims 1 to 5, wherein the solar radiation amount detecting means includes a solar cell arranged on the surface of the solar heat collector. A solar-heated hot water device configured to estimate and detect the amount of solar radiation based on the amount of power generated by a solar cell. 7. The solar water heating system according to any one of claims 1 to 5, wherein flow rate detecting means for detecting a circulation flow rate by the operation of the circulation pump, water at the bottom of the heat storage tank, or A second temperature detecting unit for detecting the temperature of the hot water is further provided, and the solar radiation amount detecting unit detects a flow rate detected by the flow rate detecting unit and a temperature difference between the both detected temperatures detected by the first and second temperature detecting units. A solar water heating system configured to estimate and detect the amount of solar radiation at that time based on the amount of collected heat obtained by multiplying by. 8. The solar-heated water heating device according to claim 1, wherein the first temperature detecting means is the surface temperature of the solar heat collector during forced circulation or circulating water inside. Or the temperature of hot water returned from the solar heat collector to the top of the heat storage tank.