JP5664852B2 - Solar water heating system - Google Patents

Description

  According to the present invention, solar heat collection is performed by forcibly circulating a heat medium between a heat exchanger for heat exchange heating of hot water in a hot water storage tank and a solar heat collection panel by operating a circulation pump. As for the solar hot water system used to store heat in a hot water storage tank and to use this hot water for hot water supply, etc., in particular, it delays the start of boiling in the heat collection panel, even if boiling occurs due to boiling steam The present invention relates to a technique for enabling to suppress / prevent water collapse and heat medium shortage in a heat collecting circuit.

  Conventionally, in solar water heaters that do not use a circulation pump, which is a forced circulation means, it has been proposed to install a mechanically operated flow control valve in the hot water outlet pipe for connecting the collector that absorbs solar heat and the hot water tank (For example, refer to Patent Document 1). In this device, a hole is formed through a partition wall that partitions the hot water discharge pipe as a flow control valve, and the hole is closed by a valve body biased by a bimetal. In this way, if the water temperature rises due to heat collection by the collector, the bimetal is bent and the valve body is opened, so that the flow rate of the hot water is increased by increasing the water temperature so as to increase.

Moreover, in a solar system in which a single heat collector group is configured for each of the plurality of heat collector panels, and the plurality of heat collector groups are arranged in series, the flow rate near the heat medium outlet for each of the plurality of heat collector groups. It has also been proposed to provide a control device and increase the flow rate as the temperature of the heat medium increases (see, for example, Patent Document 2). In this device, as an example of the flow rate control device, a shape memory alloy is proposed that opens and closes so as to reduce the flow rate when the temperature is low and increase the flow rate when the temperature is high.
Furthermore, in a solar water heater, as an on-off valve provided at the heat medium outlet of the heat collecting panel, it is opened and closed by a shape memory alloy wire, opened when the heat medium becomes high temperature, restored when it becomes low temperature What has been closed has been proposed (see, for example, Patent Document 3).

Japanese Patent Publication No.56-2259 JP 59-1003007 A JP 59-119140 A

  By the way, in the heat collection panel installed on the roof of a house, etc., an internal heat medium (for example, antifreeze liquid) may boil by being illuminated with strong sunlight. When boiling occurs, as a result, boiling steam (bubbles) is generated and filled in the heat collecting panel, and as a result, the heat medium falls from the heat collecting panel into the semi-enclosed heat collecting circuit. There is a risk of inconveniences such as causing water collapse or overflowing from the gas-liquid separator and causing a shortage of heat medium during the subsequent heat collecting operation.

  With the spread of solar heat use in recent years, it is becoming possible to install a heat collecting panel at a higher place than before (for example, a height difference of 10 m or more on the roof of a three-story house). There is a tendency that the height difference between the heat collecting panel and the hot water storage tank becomes larger. In connection with this, it is thought that the possibility of the occurrence of the inconvenience is further increased.

  In addition, as a conventional technique, when the temperature of the heat medium increases due to heat collection, a technique for obtaining a larger amount of heat collection by circulating more heat medium and using it for hot water storage has been adopted. However, this method is for normal heat collecting operation, and there is a risk of further inconvenience due to the occurrence of boiling as described above.

  The present invention has been made in view of such circumstances, and its purpose is to delay the start of boiling to make it difficult for boiling to occur, and to prevent inconvenience caused by boiling even if boiling occurs. The object is to provide a solar water heating system that is less likely to occur.

In order to achieve the above object, in the present invention, a heat collecting panel for collecting solar heat and heating a heat medium, a hot water storage tank, a heat exchanger for heat exchange heating of hot water in the hot water storage tank, and a circulation A solar hot water system comprising a heat collection circuit that heats and heats hot water in the hot water storage tank to store heat as hot water by circulating a heat medium between the heat collecting panel and the heat exchanger by operating a pump. The following specific items are to be provided. That is, a flow rate adjusting means for changing the flow rate of the heat medium flowing in the heat collecting circuit according to the heat medium temperature is provided, and the flow rate adjusting means is in inverse proportion to the heat medium temperature of the heat medium. reducing the circulation amount, or, a configuration for reducing change the circulation amount of heat medium if more than a predetermined heating medium temperature.

When this specific matter is provided, when the heating medium is heated to the high temperature side, the circulation amount of the heating medium is gradually reduced in inverse proportion to the heating medium temperature, or the circulation amount of the heating medium is reduced and changed. Become. For this reason, the amount of heat collected by the heat collection panel is also limited to a smaller value, and even during the heat collection operation, the amount of heat collected in the heat collection panel and the collection is higher than when the circulation flow rate is large. The staying time of the heat medium in the flow path of the heat collecting circuit after leaving the heat panel becomes longer, and the heat radiation further proceeds. As a result, the boiling of the heat collecting panel is difficult to occur and the start of boiling is delayed. Even reached if ultimately boils, with Tei because water collapse circulation amount of heat medium is reduced is suppressed, is suppressed lowering of the boiling steam to be lowered from the side of the heat collection panel (bubbles) Will be. As a result, the residence time of the heat medium and boiling steam in the flow path of the heat collecting circuit from the heat collecting panel to the hot water storage tank, etc. is lengthened and the heat dissipation is increased. ) Is hindered, the boiling steam is prevented from descending, and the occurrence of a shortage of heat medium can be avoided.

In addition, in the solar hot water system of the present invention, by interposing a gas-liquid separator to the heat collecting circulation circuit between a downstream position before Symbol heat exchanger and the heat exchanger and the circulation pump, the flow it was decided to interposed heat collection circulation circuit between the heat exchanger and the gas-liquid separator adjusting means a position downstream of the heat exchanger (claim 1). In this way, the heat medium that has passed through the heat exchanger, that is, the heat medium that has become low temperature by heat exchange heating in the heat exchanger is introduced into the flow rate adjusting means. Will be. For this reason, the amount of heat collection can be increased by increasing the flow rate of the heat medium in the flow rate adjusting means, and there is no hindrance to the heat storage in the hot water storage tank by the heat collection operation. On the other hand, the heat medium before boiling or at the stage of occurrence of boiling becomes high temperature, and heat storage in the hot water storage tank does not take heat away from the heat exchanger. By reducing the amount, actions such as delaying the start of boiling according to claim 1 and avoiding the occurrence of inconvenience associated with the occurrence of boiling can be obtained effectively.

Further, in the solar hot water system of the present invention, as the flow rate adjusting means, a valve body disposed so as to be movable in the opening and closing direction with respect to the flow path of the heat collection circuit portion, and the valve body according to the heat medium temperature. And a spring made of a shape memory alloy to be operated, and the valve made of the shape memory alloy spring receives heat from a heat medium having a temperature equal to or higher than its operating temperature to flow through the heat collecting circuit. It can be set as the structure moved to the side to close (Claim 2 ). In this way, the operation of the flow rate adjusting means according to the present invention, which reduces the circulation amount of the heat medium as the heat medium temperature rises, can be performed without requiring driving energy or turning on the power for control. This can be realized by a configuration that operates mechanically according to the medium temperature. As a result, the boiling of the heat medium in the heat collection panel may occur from the time it is first installed, or it is highly likely that the heat collection operation will not occur when the heat collection operation is stopped. Even in this case, the effect of the present invention can be obtained regardless of the presence or absence of energization.

As described above, according to the solar hot water system of the present invention, when the heating medium is heated to the high temperature side, the flow rate of the heating medium can be gradually reduced in inverse proportion to the heating medium temperature, or Since the flow rate of the heat medium can be reduced and changed, the amount of heat collected by the heat collection panel can be limited to a smaller amount, even when the circulation flow rate is large even during the heat collection operation. In comparison, the residence time of the heat medium in the heat collection circuit and in the flow path of the heat collection circuit after exiting the heat collection panel can be made longer, and heat dissipation can be further advanced. As a result, it becomes difficult to cause boiling in the heat collecting panel, and the start of boiling can be delayed. Then, even if reached eventually boils, it is possible to flow the amount of the heating medium is suppressed reduced Tei because water collapses, boiling vapor (bubbles) to be lowered from the side of the heat collection panel Lowering can also be suppressed. As a result, the residence time of the heat medium and the boiling steam in the flow path of the heat collection circuit extending from the heat collection panel to the hot water storage tank or the like can be increased, and the heat radiation can be increased. It is possible to prevent the occurrence of a shortage of the heat medium by preventing the collapse (falling water) and the boiling steam from descending.

In particular, since the pre-Symbol flow regulating means have to be interposed heat collection circulation circuit between said heat exchanger, a gas-liquid separation unit installed downstream of the heat exchanger, the flow rate adjustment delaying or boiling starting with the reduction of the circulation amount of heat medium by means, on the Ru give effect of avoiding such disadvantages occur due to boiling occurs, it is possible to further optimize.

Further, according to claim 2 , the flow rate adjusting means includes a valve body and a spring made of a shape memory alloy, and the shape memory alloy spring has a heat from a heat medium at or above its operating temperature. In response to this, the valve body is moved to the side where the flow path of the heat collecting circuit is closed, so that the flow rate of the heat medium is reduced as the heat medium temperature rises. Can be realized by a configuration that operates mechanically in accordance with the temperature of the heating medium without requiring driving energy or power-on for control. As a result, the boiling of the heat medium in the heat collection panel may occur from the time it is first installed, or it is highly likely that the heat collection operation will not occur when the heat collection operation is stopped. Even in this case, the effect of the present invention can be obtained regardless of the presence or absence of energization.

It is a mimetic diagram showing an embodiment of a solar hot water system concerning the present invention. FIG. 2 is a cross-sectional explanatory view according to the first embodiment of the flow rate adjusting means of FIG. 1, FIG. 2 (a) shows a normal heat collecting operation state, and FIG. 2 (b) is when the internal heat medium becomes high temperature The operating state of is shown. FIG. 3 is a cross-sectional explanatory view according to a second embodiment of the flow rate adjusting means of FIG. 1, FIG. 3 (a) shows a normal heat collecting operation state, and FIG. 3 (b) is when the internal heat medium becomes high temperature The operating state of is shown. 4A and 4B are cross-sectional explanatory views according to a third embodiment of the flow rate adjusting means of FIG. 1, FIG. 4A shows a normal heat collecting operation state, and FIG. 4B is a time when the internal heat medium becomes high temperature. The operating state of is shown. It is a perspective view of the valve body used in 3rd Embodiment of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a solar water heating system according to an embodiment of the present invention. In the figure, reference numeral 1 is, for example, a system main body installed on the ground, 2 is a heat collection panel for collecting solar heat by a heat medium (for example, antifreeze) passing through the inside, 3 is a hot water storage tank, 4 is a heat collection panel 2 And a heat collecting circuit that stores heat from the heat medium as hot water in the hot water storage tank 3 by circulating a heat medium between the heat exchanger 43 in the hot water storage tank 3 and a hot water storage tank for tap water and the like from the outside A water supply passage for supplying water into 3, 6 is a hot water supply passage for supplying hot water to the hot water tap (not shown) using hot water stored in the hot water storage tank 3, and 7 is a controller for controlling the operation of this solar hot water system. .

  The heat collecting panel 2 is installed on the roof of a house, for example, and is provided with a heat medium temperature sensor 21 for detecting the heat medium temperature Ts of the heat medium that has been most heated by heat collection.

  The hot water storage tank 3 is an airtight container configured in a hermetic manner by, for example, stainless steel. The hot water storage tank 3 is provided with a hot water storage tank temperature sensor 31 that detects the temperature Tt of hot water or water (hereinafter referred to as “hot water”) near the bottom of the hot water storage tank 3. The upstream end of the water supply channel 5 is connected to an external water pipe or the like, and the downstream end is connected to the bottom of the hot water storage tank 3 via a check valve (not shown). Further, the hot water outlet 6 has an upstream end connected to the top of the hot water storage tank 3 and a downstream end connected to an auxiliary heat source machine, a hot water tap, etc. (not shown).

  The heat collection and circulation circuit 4 is a heat storage heat exchanger (for example, a coil-type heat exchanger) 43 in the heat collection panel 2 and the hot water storage tank 3 through a circulation path 42 by operating a circulation pump (for example, a variable flow pump) 41. It is comprised so that it may circulate between. The circulation path 42 returns the high-temperature heat medium heated in the heat collection panel 2 from the vicinity of the top thereof, led to the heat storage heat exchanger 43 in the hot water storage tank 3, and then led to the suction side of the circulation pump 41. A path 42a, and a forward path 42b for discharging heat from the discharge side of the circulation pump 41 to supply heat to the bottom of the heat collecting panel 2 for heat collection by heat exchange in the heat storage heat exchanger 43. It is composed of The circulation pump 41 is started by the controller 7 when the temperature difference between the hot water temperature Tt in the hot water storage tank 3 and the heat medium temperature Ts of the heat collecting panel 2 becomes a set value or more, and the heat collecting operation is performed. Is supposed to start.

  A semi-sealed accumulation tank 44 is interposed in the return path 42 a formed in the system main body 1, and the top portion of the accumulation tank 44 communicates with the bottom portion of the reserve tank 45 through a communication pipe 451. The heat medium and / or air overflowing from the accumulation tank 44 is allowed to escape into the reserve tank 45 through the communication pipe 451. A gas-liquid separation unit is configured by a combination of the accumulation tank 44 and the reserve tank 45. The accumulation tank 44 is provided with a low liquid level sensor 441 for detecting the presence of a heat medium above a predetermined liquid level on the bottom side. Based on detection information from the low liquid level sensor 441, the controller 7. Thus, the operation of the circulation pump 41 is allowed to avoid the idling operation of the circulation pump 41.

  The controller 7 includes an MPU, a memory, and the like, and is installed in advance based on the output of input setting signals / operation signals from the remote controller 71 and the output of detection signals from the temperature sensors 21, 31 and the low liquid level electrode 441. Various controls such as heat collection operation control are performed by program execution and a control circuit. Briefly describing the heat collection operation control, for example, it is confirmed based on the hot water temperature Tt detected by the hot water tank temperature sensor 31 that the amount of heat stored in the hot water tank 3 is insufficient, and the heat collection panel temperature sensor 21. It is confirmed that the heat medium temperature Ts detected by the above is higher than a predetermined temperature difference α ° C. (for example, 6 ° C.) than the hot water temperature Tt, and after confirming that these start conditions are satisfied, the circulation pump 41 is operated to start the heat collecting operation.

  As a result, a high-temperature heat medium is supplied from the heat collection panel 2 to the heat storage heat exchanger 43 through the return path 42a, and the hot water in the hot water storage tank 3 is heat-exchanged and heated in the heat storage heat exchanger 43. The heated heat medium is supplied to the heat collecting panel 2 through the flow rate adjusting means 8, the accumulation tank 44, the circulation pump 41, and the outgoing path 42b. The heat medium supplied to the heat collection panel 2 is reheated while proceeding to the top in the heat collection panel 2, and the heat medium that has become high temperature is supplied to the heat storage heat exchanger 43 through the return path 42a. So that it is circulated. Then, the hot water in the hot water storage tank 3 is heat-exchanged and heated, so that the amount of heat collected by the heat transfer medium moves to the hot water in the hot water storage tank 3 and is stored in the hot water storage tank 3 as hot water storage. .

  On the premise of the solar hot water system having the above-described configuration, the flow rate adjusting means 8 which is a characteristic component of the present embodiment is an accumulator tank 44 which is an outlet side of the heat storage heat exchanger 43 and a gas-liquid separation unit. Is interposed in a return path 42a. The flow rate adjusting means 8 sets the flow opening of the return path 42a to the maximum opening amount when the temperature of the heat medium in the return path 42a is within the range of the normal heat collecting operation, while the heat medium temperature is the normal heat collecting operation. If the temperature rises beyond the time range and rises to the high temperature side, the flow opening is gradually reduced to the minimum opening amount side (closed side). That is, the flow rate (flow rate) of the heat medium is reduced in inverse proportion to the increase in the heat medium temperature. The heat medium temperature range at the time of the heat collecting operation means that the heat medium heated by collecting heat by the heat collecting panel 2 heats and heats hot water in the hot water storage tank 3 by the heat storage heat exchanger 43. Is a low temperature heat medium temperature range derived from the heat storage heat exchanger 43. In the situation where the temperature of the heat medium is remarkably increased due to heat collection in summer, etc., and the hot water temperature (including the feed water temperature) in the hot water storage tank 3 subject to heat exchange heating is originally high, Even after the heat exchange heating in the heat collecting operation, when the temperature rises beyond the heat medium temperature range in the normal heat collecting operation to the high temperature side, the flow opening amount is gradually reduced. When the temperature rises to the high temperature side to the boiling temperature of the heat medium (for example, 50 ° C.), the flow rate adjusting means 8 restricts the flow opening to the minimum opening amount so as to be in a communication state with a very small minimum opening amount. It has become. That is, when the temperature of the heat medium becomes higher, the flow path resistance is changed more greatly by narrowing the flow opening of the heat medium.

  Hereinafter, the flow rate adjusting units 8a, 8b, and 8c according to the first to third embodiments configured to operate mechanically according to the heat medium temperature will be described as the flow rate adjusting unit 8. The flow rate adjusting means 8 uses a normal flow rate control valve and a control unit that controls the operation according to the detected value of the heat medium temperature, and if the heat medium temperature exceeds a predetermined set temperature, the valve It is also possible to adopt a configuration in which the operation is controlled so that the opening is gradually reduced, and the operation is controlled so that the opening is maintained at the minimum opening amount when reaching the boiling temperature of the heat medium (for example, 50 ° C.) or a slightly lower temperature. . On the other hand, by adopting a configuration that mechanically operates according to the heat medium temperature, such as the flow rate adjusting means 8a, 8b, and 8c, the drive energy and the power supply for control are not required, which will be described later. It becomes possible to obtain the operational effects. The boiling of the heat medium in the heat collecting panel 2 may occur from the time when it is first installed, and is likely to occur when the power is not turned on such as when the heat collecting operation is stopped. The flow rate adjusting means 8a, 8b, 8c are useful in that flow rate adjustment (increase / decrease adjustment of passage resistance) is possible regardless of the presence or absence.

<First Embodiment>
As shown in FIG. 2, the flow rate adjusting means 8 a according to the first embodiment is guided to move so that the communication hole 82 penetrates the partition wall 81 that partitions the return path 42 a, and approaches and separates from the communication hole 82. Thus, a valve body 83 for increasing or decreasing the amount of opening through which the heat medium flows is provided. In order to operate the valve body 83, a normal spring (for example, a coil spring) 84 is disposed on one side of the valve body 83, and a spring (for example, a coil spring) 85 made of a shape memory alloy is disposed on the other side. doing.

  Specifically, the valve chamber 86 is interposed in the return path 42 a, the partition wall 81 and the communication hole 82 are formed in the valve chamber 86, and the valve body 83 is provided on one side of the upstream and downstream sides of the communication hole 82. It is arranged. Then, a normal spring 84 is interposed between one side of the valve body 83 and the inner wall surface 861 of the valve chamber 86 opposite to the valve body 83, and the shape memory alloy spring 85 is disposed on the other side of the valve body 83. And an inner wall surface 862 of the valve chamber 86 facing each other.

  The spring 85 made of a shape memory alloy substantially maintains a contracted state if the heat medium in the return path 42a is in the heat medium temperature range during the normal heat collecting operation, while the normal spring 84 has an elastic force released. Thus, the distance between the valve body 83 and the communication hole 82 is increased, and the flow path opening is maintained at the maximum opening amount (see the state shown in FIG. 2A). When the heat medium in the return path 42a exceeds the heat medium temperature range during normal heat collecting operation and becomes higher, that is, when the heat medium temperature becomes equal to or higher than the operating temperature of the spring 85 made of shape memory alloy, While the shape memory alloy-made spring 85 expands in proportion to the temperature rise, the normal spring 84 is pushed and contracted, so that the valve body 83 gradually approaches the communication hole 82. Along with this, the passage opening is gradually narrowed. That is, the flow rate of the heat medium is reduced in inverse proportion to the increase in the heat medium temperature. When the temperature of the heating medium reaches the boiling temperature of the heating medium, or when the temperature of the heating medium approaches the boiling temperature, the valve body 83 pressed by the shape memory alloy spring 85 comes into contact with the stopper 87 and stops. And the communication opening 82 are maintained at the minimum opening amount (see the state shown in FIG. 2B).

  By interposing such a flow rate adjusting means 8a in the return path 42a, the following operational effects can be obtained. That is, if the heat medium is in the heat medium temperature range during normal heat collection operation, the flow opening is maintained at the maximum opening amount, so that the flow resistance is minimized and the heat medium is smoothly circulated and collected. Thermal operation can be performed satisfactorily. On the other hand, when the temperature of the heating medium exceeds the above-mentioned temperature range of the heating medium, and the temperature of the heating medium is increased, the flow opening is gradually narrowed, the flow resistance is increased, and the circulation flow rate is restricted to be smaller. Accordingly, the amount of heat transported by the heat collecting panel 2 is also limited to be smaller. Thereby, even during the heat collection operation, the residence time of the heat medium in the return path 42a after exiting the heat collection panel 2 and the heat collection panel 2 is longer than when the circulation flow rate is large. It will become more heat dissipation. As a result, the boiling of the heat collecting panel 2 hardly occurs and the start of boiling can be delayed.

  And even if it finally reaches boiling, the flow opening is restricted to the minimum opening amount and the flow path resistance is maximized, so that the flow of the internal heating medium is also restricted and water collapse is suppressed, Resisting the boiling steam (bubbles) about to descend from the heat collecting panel 2 side, it is possible to suppress the descending. As a result, the heat medium and boiling steam stay in the return path 42a from the heat collecting panel 2 to the hot water storage tank 3 and the like can be made longer to increase the heat dissipation. The steam can be returned to the liquid, and the descending pressure from the heat collecting panel 2 toward the system main body 1 such as the hot water storage tank 3 can be reduced. As a result, it is possible to prevent water from collapsing (falling water) due to boiling, to prevent boiling steam from continuously descending toward the system body 1, and insufficient heat medium due to overflow from the accumulator tank 44. Can be prevented.

<Second Embodiment>
FIG. 3A shows that when the heat medium is in the heat medium temperature range during normal heat collection operation, the flow opening of the return path 42a is maintained at the maximum opening amount by the flow rate adjusting means 8b according to the second embodiment. Indicates the state. This flow rate adjusting means 8b ensures the minimum opening amount by the stopper 87 in the flow rate adjusting means 8a of the first embodiment when the heating medium temperature is raised to a high temperature (for example, the boiling temperature). Instead, the valve body 83 is secured by a bypass 85 that is always in communication, and the communication hole 82 can be pressed to a fully closed state by a spring 85 made of a shape memory alloy (FIG. 3B). reference).

  Since the configuration other than this point is almost the same as that of the flow rate adjusting means 8a of the first embodiment, the same reference numerals as those of the first embodiment are used and detailed description thereof is omitted.

  The same effect as that of the flow rate adjusting unit 8a of the first embodiment can be obtained also by the flow rate adjusting unit 8b of the second embodiment.

<Third Embodiment>
FIG. 4 shows the flow rate adjusting means 8c according to the third embodiment. The flow rate adjusting means 8c is more specific than the first or second embodiment, and includes a main body housing 91 interposed in the return path 42a, a valve guide 92 fitted in the main body housing 91, and A valve seat 93, a valve body 94 held by the valve guide 92 so as to be movable forward and backward, and a spring (for example, a coil spring) 95 made of a shape memory alloy interposed between the valve guide 92 and the valve body 94. It is prepared.

  The valve guide 92 includes an outer cylindrical portion 921 fitted into the inner peripheral surface of the main body housing 91, and an inner cylindrical portion 923 integrated by a plurality of ribs 922, 922,... Extending radially from the outer cylindrical portion 921. The valve shaft portion 941 of the valve body 94 is slidably held in the inner cylinder portion 923 in the front-rear direction (vertical direction in FIG. 4).

  The valve seat 93 is fitted into the inner peripheral surface of the main body housing 91 and fixed together with the valve guide 92. The valve seat 93 bulges to the inner peripheral side on one side and the peripheral edge of a later-described valve portion 942 of the valve body 94. And a valve seat portion 932 that contacts the portion.

  As shown in detail in FIG. 5, the valve body 94 includes a valve portion 942 and a valve shaft portion 941 extending from the center position of the valve portion 942 to the one side along the central axis X. The valve portion 942 is formed with a plurality of (four in the illustrated example) slit openings 943, 943,... Extending radially from the outer edge portion and penetrating in the central axis X direction. The slit openings 943, 943,... Are for securing a minimum opening amount as will be described later.

  The one end of the spring 95 made of shape memory alloy is supported on the inner peripheral side of the ribs 922, 922,... Of the valve guide 92, and the other end is supported on the inner peripheral side of one side surface of the valve portion 942 of the valve body 94. Has been. This shape memory alloy spring 95 maintains a contracted state if the heat medium in the return path 42a is within the temperature range of the heat medium during the normal heat collecting operation. As shown in a), the valve portion 942 is maintained at the position farthest from the valve seat portion 932 of the valve seat 93, and the flow opening in the main body housing 91 is also maintained at the maximum opening amount. On the other hand, when the heat medium in the return path 42a becomes higher than the temperature range of the heat medium, the shape memory alloy spring 95 extends in proportion to the temperature rise, and the valve portion 942 is moved to the valve seat portion 932. When the heating medium is heated to a predetermined temperature near the boiling temperature, the spring 95 made of a shape memory alloy is in the maximum extension state as shown in FIG. 4B, and the valve portion 942 is moved to the valve seat. It will be in the state pressed against the part 932. Accordingly, the flow opening is limited to the minimum opening amount constituted by the slit openings 943, 943,..., And the flow path resistance is maximized.

  Also by the flow rate adjusting means 8c of the third embodiment described above, it is possible to obtain the same effects as the flow rate adjusting means 8a of the first embodiment. That is, even during the heat collection operation, the residence time of the heat medium in the heat collection panel 2 and the return path 42a after exiting the heat collection panel 2 is longer than when the circulation flow rate is large. As a result, the heat radiation is further advanced. As a result, the boiling of the heat collecting panel 2 hardly occurs and the start of the boiling can be delayed. And even if it eventually reaches the boiling point, the flow opening is restricted to the minimum opening amount and the flow path resistance is maximized, which prevents the progress of water collapse (falling water) accompanying boiling, and the boiling steam is generated in the system. It is possible to prevent continuous lowering to the main body 1 side, and it is possible to prevent a shortage of the heat medium due to overflow from the accumulation tank 44.

<Other embodiments>
Note that the present invention is not limited to the above embodiments, and includes other various embodiments. That is, in each of the above embodiments, as a change characteristic of the flow opening amount using the springs 85 and 95 made of the shape memory alloy, the flow opening is limited in inverse proportion to the increase in the heat medium temperature, and the flow amount of the heat medium (flow rate). However, the present invention is not limited to this, and the flow opening amount may be smaller than before and the flow rate of the heat medium may be reduced step by step when the temperature exceeds a certain set temperature. .

  Furthermore, although the heat exchanger 43 was installed in the hot water storage tank 3 in the above embodiment, the present invention is not limited to this, and the heat exchanger is installed outside the hot water storage tank 3 and collects the heat exchanger. While the heat medium of the heat circulation circuit is circulated and supplied to the heat source side, the hot water in the hot water storage tank 3 is circulated and supplied to the heated side by another circulation pump, so that the hot water in the hot water storage tank is heat-exchanged and heated by the heat medium. A solar water heating system configured as described above is also included in the present invention.

2 Heat collection panel 3 Hot water storage tank 4 Heat collection circulation circuit 8, 8a, 8b, 8c Flow rate adjusting means 41 Circulation pump 42 Return path 44 Accumulation tank (gas-liquid separation part)
85,95 Shape memory alloy spring

Claims (2)

A heat collecting panel for collecting solar heat to heat the heat medium, a hot water storage tank, a heat exchanger for heat exchange heating of the hot water in the hot water storage tank, and the heat collecting panel and the heat exchange by operating a circulation pump A solar water heating system comprising a heat collection and circulation circuit that heat-exchanges and heats hot water in the hot water storage tank to store heat as hot water storage by circulating a heat medium between the tank and
A flow rate adjusting means for changing the flow rate of the heat medium flowing in the heat collection circuit according to the heat medium temperature;
The flow rate adjusting means is configured to reduce the flow rate of the heat medium in inverse proportion to the heat medium temperature of the heat medium, or to reduce and change the flow rate of the heat medium when the temperature exceeds a predetermined heat medium temperature. ,
A gas-liquid separation unit is interposed in the heat collection and circulation circuit unit between the heat exchanger and the circulation pump at a downstream position of the heat exchanger,
The flow rate adjusting means that is interposed in the heat collecting circulation circuit between the heat exchanger and the gas-liquid separator a position downstream of the heat exchanger,
Solar heat hot water system characterized in that. The solar hot water system according to claim 1 ,
The flow rate adjusting means includes a valve body disposed so as to be movable in the open / close direction with respect to the flow path of the heat collection circuit portion, and a spring made of a shape memory alloy that operates the valve body in accordance with the heat medium temperature. With
The shape memory alloy spring is configured to receive heat from a heat medium at or above its operating temperature and move the valve body to the side that closes the flow path of the heat collection circuit,
Solar water heating system.