JP5652745B2 - 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 the hot water storage tank and use this hot water for hot water supply etc., especially when the height difference between the heat collecting panel and the hot water storage tank or heat exchanger is larger than before It relates to a technique for enabling installation without inconvenience.

  Conventionally, measures against inconvenience that may occur when a rubber hose is used as a circulation path constituting a circulation circuit between a heat collecting panel and a hot water storage tank, for example, a possibility that air enters the circulation path from the outside through a tube wall. Therefore, a separate circulation pump is installed in the circulation path separately from the circulation pump for heat collection operation, and the circulation pump for heat collection operation is automatically operated when heat collection is possible, while a separate circulation pump is installed. It has been proposed to remove intruded air from the open expansion tank by intermittently operating in a time zone in which heat can be collected and simultaneously operating two units at regular intervals (see, for example, Patent Document 1). ).

  In addition, proposals have been made to increase the heat collection efficiency in response to changes in the weather in a short time by making the circulation flow rate of the heat medium variable using a DC pump as a circulation pump (for example, patents). Reference 2).

Japanese Utility Model Publication No. 63-37635 JP 2009-275971 A

  By the way, in recent years, with the spread of solar heat utilization, it is becoming more and more conventional to install a heat collection panel (e.g., on the roof of a three-story house). There is a tendency for the difference in height to be larger. Along with this, there is a possibility that a phenomenon that has not been a problem in the past may become inconvenient. In other words, as a result of boiling of the heat collection panel due to the strong sunlight, bubbles are generated in the heat collection panel, and the heat medium (for example, antifreeze liquid) is collected from the heat collection panel in a semi-enclosed manner as the bubbles are generated. Even if it falls in the heat circulation circuit, if it is about the conventional height difference (for example, less than 9 m), it will naturally recover and return to a predetermined state. That is, when the heat collecting panel cools after a certain period of time, the heat medium is pushed back into the heat collecting panel by the atmospheric pressure and naturally returns to a state where the heat collecting panel is filled with the heat medium. However, when the heat collection panel is installed at a higher location (for example, a height difference of 10 m or more), even if the heat collection panel cools, the heat medium cannot be returned into the heat collection panel only at atmospheric pressure. It will be difficult and will cause inconvenient conditions.

  As a countermeasure against this, it is conceivable to control the operation so that the head of the circulation pump is raised by the above-described height difference at the start of the heat collecting operation. However, if such operation control is uniformly executed at the start of the heat collecting operation, there is a risk of causing inconveniences such as unnecessary consumption of the operation energy and deterioration of the durability of the circulation pump. On the other hand, it may be possible to configure a solar hot water system with different control contents for each installation environment, but doing so increases the cost and the work associated with providing the system, and promotes the use of solar heat. It also leads to obstructing.

  The present invention has been made in view of such circumstances, and the object of the present invention is to make it possible to provide the same control specifications for various installation environments having different height differences. Another object of the present invention is to provide a solar water heating system that can surely avoid the occurrence of inconveniences even when installed in an installation environment where the height difference is larger than that of a normal one.

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 Solar hot water provided with 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 collection panel and the heat exchanger by operating a pump The following specific items were prepared for the system. That is, it is provided with bubble generation determination means for determining whether or not bubbles are generated in the heat collection circuit, and when it is determined that bubbles are generated by the bubble generation determination means, except when it is determined that bubbles are generated It is assumed that the circulation pump is configured to control the operation with a capacity larger than the normal capacity of

When this specific matter is provided, even if the heat collection panel is installed in a place with a level difference higher than usual, as a result of the boiling of the heat medium in the heat collection panel, bubbles are generated inside, Even if there is a descending phenomenon that the heat medium descends from the heat collection panel due to the generation of bubbles, the circulation pump is operated with a large capacity, so the heat medium in the heat collection circuit is transferred to the heat collection panel. It can be pushed up to fill the heat collecting panel. Therefore, it is possible to provide a solar hot water system with the same control specifications even in various installation environments with different height differences, and it is inconvenient even if installed in an installation environment with a height difference larger than a normal one. ing so that the generation can be reliably avoided. In addition, the present invention includes a pump stop timer that counts an elapsed time that has elapsed in a state where the circulation pump has stopped operating, and the elapsed time that is counted by the pump stop timer as the bubble generation determination unit is a set time. If the value is exceeded, it is determined that bubbles are generated (claim 1). By doing in this way, even if it is a case where a bubble generate | occur | produces based on reasons other than boiling generation | occurrence | production in a heat collection panel, the bubble generation | occurrence | production can be detected reliably. That is, if the operation stop state of the circulation pump continues, the air that permeates through the tube wall of the circulation path increases and bubbles are generated. This can be accurately detected by the pump stop timer.

  In the solar hot water system of the present invention, a heating medium temperature detecting means for detecting the temperature of the heating medium in the heat collecting panel or a temperature equivalent to the heating medium temperature is provided, and as the bubble generation determining means, the heating medium temperature detecting means If the detected heat medium temperature is equal to or higher than the set temperature, it can be determined that bubbles are generated (claim 2). In this way, it can be specifically determined whether or not bubbles are generated, and the operation of the circulation pump can be performed more accurately.

  And an expansion tank interposed in the heat collection circuit, and a liquid level detection means for detecting the liquid level of the heat medium in the expansion tank. If the liquid level of the medium exceeds the set liquid level, it can be determined that bubbles are generated. By doing so, if boiling occurs in the heat collecting panel and the heat medium falls due to the boiling, the liquid level detected by the liquid level detecting means rises and exceeds the set liquid level. This makes it possible to reliably determine whether or not bubbles are generated.

As described above, according to the solar hot water system of the present invention, even if the heat collection panel is installed in a place with a level difference higher than usual, boiling occurs in the heat medium in the heat collection panel. As a result, even if bubbles are generated inside and the phenomenon that the heating medium descends from the heat collection panel is generated, the circulation pump can be operated with high capacity, The heat medium in the circulation circuit can be pushed up to the heat collection panel to fill the heat collection panel. Therefore, it is possible to provide a solar hot water system with the same control specifications even in various installation environments with different height differences, and it is assumed that the installation is performed in an installation environment where the height difference is larger than a normal one. ing so that it can be also surely avoid the occurrence of inconvenience. In addition, if the elapsed time measured by the pump stop timer exceeds the set time value, it is determined that bubbles are generated, so when bubbles are generated based on a reason other than the occurrence of boiling in the heat collecting panel, If the operation stop state of the circulation pump continues, even if air that permeates through the pipe wall of the circulation path increases and bubbles are generated, this can be accurately detected by the pump stop timer. become able to.

  In particular, according to claim 2, if the heat medium temperature detected by the heat medium temperature detecting means is equal to or higher than the set temperature, it is specifically determined whether or not bubbles are generated by adopting a configuration in which it is determined that bubbles are generated. The circulation pump can be operated more accurately.

  According to a third aspect of the present invention, the liquid level detection means for detecting the liquid level of the heat medium in the expansion tank is provided, and if the liquid level of the heat medium exceeds the set liquid level by the liquid level detection means, it is determined that bubbles are generated. By adopting the configuration, boiling occurs in the heat collecting panel, and if the heat medium falls due to it, the liquid level detected by the liquid level detection means rises and exceeds the set liquid level, It is possible to reliably determine whether or not bubbles are generated.

It is a mimetic diagram showing an embodiment of a solar hot water system concerning the present invention. It is a block diagram which shows the structure which concerns on the operation control of the solar hot water system of FIG. It is a flowchart concerning heat collection operation control. It is a flowchart which concerns on the pump capability switching setting process based on bubble generation | occurrence | production determination.

  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 A heat collection circuit for storing heat as heat storage in the hot water storage tank 3 by circulating a heat medium between the hot water storage tank 3 and the hot water storage tank 3, water supply for supplying tap water or the like into the hot water storage tank 3 from the outside Reference numeral 6 denotes a hot water outlet for supplying hot water to a 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 the solar hot water system.

  The heat collection panel 2 is installed, for example, on the roof of a house, and a heat collection panel temperature sensor 21 as heat medium temperature detection means for detecting the temperature of the fins constituting the heat collection panel 2 is installed in the vicinity of the top position. . The fin temperature detected by the heat collection panel temperature sensor 21 is equivalent to the heat medium temperature Ts of the heat medium that has been most heated by heat collection, and the heat medium temperature Ts is detected by detecting the fin temperature. It is like that.

  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). A water supply temperature sensor 51 for detecting a water supply temperature and a water supply flow rate sensor 52 for detecting a water supply flow rate are interposed in the water supply channel 5. Further, the upstream end of the hot water supply passage 6 is connected to the top of the hot water storage tank 3, and a hot water temperature sensor 61 for detecting the temperature of the hot water discharged from the hot water storage tank 3 is interposed near the top of the hot water storage tank 3. .

  The heat collection circuit 4 circulates the heat medium between the heat collection panel 2 and the heat storage heat exchanger (for example, a coil heat exchanger) 43 in the hot water storage tank 3 through the circulation path 42 by the operation of the circulation pump 41. It is comprised as follows. The circulation path 42 is provided with a forward path 42 a that leads from the vicinity of the top of the high-temperature heat medium that has been passed through the heat collection panel 2 and led to the inlet side of the heat storage heat exchanger 43 in the hot water storage tank 3. In addition, the heat storage heat exchanger 43 is configured to include a return path 42b for deriving the heat medium having a low temperature by heat exchange from the outlet side of the heat storage heat exchanger 43 and returning it to the bottom of the heat collecting panel 2. In the circulation path 42 including the forward path 42a and the return path 42b, a portion extending between the system main body 1 and the heat collecting panel 2 is piped using, for example, a PE (polyethylene) pipe.

  A semi-sealed tank 44 is interposed in the return path 42 b formed in the system main body 1, and the top of the tank 44 communicates with the bottom of the reserve tank 45 via a communication pipe 451. The heat medium overflowing from the tank 44 is released into the reserve tank 45 through the communication pipe 451. An expansion tank is configured by a combination of the tank 44 and the reserve tank 45. The tank 44 is provided with a liquid level electrode 441 for detecting a lower limit liquid level at a predetermined liquid level position on the bottom side, and the liquid level in the tank 44 is lowered to the lower limit liquid level by the liquid level electrode 441. When detected, the operation of the circulation pump 41 is forcibly stopped by the controller 7 so that the idling operation of the circulation pump 41 is avoided.

  The circulation pump 41 is constituted by a variable flow pump (for example, a DC pump), and its discharge capacity can be adjusted up or down. In the case of a DC pump, if the current value is increased, the rotational speed increases and the discharge amount increases, and if the current value is decreased, the rotational speed decreases and the discharge amount is reduced. In particular, the controller 7 controls the circulation pump 41 to operate / stop or switch between normal capacity and large capacity.

  The solar hot water system described above is controlled by the controller 7 in response to the output of the input setting signal / operation signal from the remote controller 71 and the output of the detection signal from the temperature sensors 21, 31, etc. The controller 7 includes an MPU, a memory, and the like, and various controls are performed by executing a program installed in advance and a control circuit. Then, the controller 7 determines whether or not bubbles are generated in the heat collection circuit 4 including the heat collection operation control means 72 for performing the heat collection operation and the heat collection panel 2 as shown in FIG. Alternatively, the determination by the bubble generation determination means 73 and the bubble generation determination means 73 for determining whether or not the external air enters through the pipe wall of the piping of the circulation path 42 and air bubbles are present. In addition to the pump capacity switching setting means 74 for increasing / decreasing the pump capacity of the circulation pump 41 based on the result, a hot water supply control means (not shown) is provided.

  First, the pump capacity switching setting process by the pump capacity switching setting means 74 will be described with reference to FIG. 3. First, if it is not determined that bubbles are generated by the bubble generation determining means 73, "0" is set in the pump capacity flag. (NO in step S11, step S12). If it is determined that bubbles are generated by the bubble generation determination means 73, “1” is set in the pump capacity flag (YES in step S11, step S13). The processing by the pump capacity switching setting means 74 is continuously executed regardless of whether or not the heat collection operation is being executed by the heat collection operation control means 72, and after the pump capacity flag is set to “1”. When the operation of the circulation pump 41 with a large capacity is executed, the initial setting is reset to “0”.

  The bubble generation determination process by the bubble generation determination unit 73 in step S11 is performed as follows. As a first determination item, it is determined whether or not the heat medium temperature Ts detected by the heat collecting panel temperature sensor 21 exceeds a boiling temperature Tf set in advance as the temperature at which the heat medium boils. The boiling temperature Tf is, for example, 80 ° C. when the heat medium is an antifreeze liquid. If the heat medium temperature Ts exceeds the boiling temperature Tf even once, the pump capacity flag is set to “1” as described above, and the circulation pump 41 is operated with a large capacity in the next heat collecting operation. . The reason for this is that even if it boils, it may cool after that, and the bubbles may disappear, but it will be grasped other than conducting various tests to see what state it is at the next heat collection operation start timing Can not do it. Therefore, if boiling occurs even once, the circulation pump 41 is operated with a large capacity just in case at the start of the next heat collecting operation.

  As a second determination item, it is determined whether or not the elapsed time during which the circulation pump 41 continues in the operation stop state is equal to or longer than a set time ts (for example, 24 hours). If the operation stop state continues for the set time ts or longer, it is determined that air has entered from the tube wall of the circulation path 42 and bubbles of a predetermined amount or more are generated, and the pump capacity flag is set to “ 1 ”is set.

  By the bubble generation determination process described above, in addition to the generation of bubbles accompanying the occurrence of boiling in the heat collecting panel 2, both the generation of bubbles due to the penetration of air through the tube wall of the circulation path 42 are reliably determined. Will be able to.

  Based on the above bubble generation determination process and pump capacity switching setting process, the heat collection operation control by the heat collection operation control means 72 is performed as follows. That is, as shown in FIG. 4, first, whether or not the amount of heat stored in the hot water storage tank 3 is insufficient is confirmed based on, for example, the hot water temperature Tt detected by the hot water tank temperature sensor 31 (step S1). If it is full (a state in which the hot water temperature Tt that is the bottom temperature of the hot water storage tank 3 has reached the upper limit temperature), the heat collecting operation is not performed and the process proceeds to the next control (NO in step S1). If the amount of stored heat is insufficient (YES in step S1), the heat medium temperature Ts detected by the heat collecting panel temperature sensor 21 is higher than the hot water temperature Tt by α ° C. (for example, 6 ° C.) or more. Is confirmed, and if the heat medium temperature Ts is low, the heat collection operation is not performed and the system waits (NO in step S2). If the heat medium temperature Ts is higher than the hot water temperature Tt + α ° C., the heat collecting operation is started (YES in step S2). That is, heat collection is performed by operating the circulation pump 41 on condition that the heat medium temperature Ts is higher than a hot water temperature Tt at the bottom of the hot water storage tank 3 by a predetermined set temperature difference (for example, a temperature difference of 6 ° C.). Start driving. At the start of the heat collecting operation, the pump capacity switching setting means 74 confirms whether the operating capacity of the circulation pump 41 is set to the normal capacity or a large capacity larger than the normal capacity. That is, it is confirmed whether "0" or "1" is set in the pump capacity flag by the above-described pump capacity switching setting process (step S3). If the pump capacity flag is “0”, the circulation pump 41 is operated with the normal capacity (NO in step S3, step S4). If the pump capacity flag is “1”, the circulation pump 41 has a larger capacity than the normal capacity. Is operated for a set operation time (for example, 2 minutes), and thereafter it is operated with normal capacity (YES in step S3, step S5). The set operation time for operating at high capacity may be set in consideration of a time value corresponding to the time required for the heat medium in the heat collecting circuit 4 to make one revolution. That is, even if the heat medium is lowered from the heat collecting panel 2 side to the system main body 1 side, the heat medium is pushed up to the heat collecting panel 2 and filled in the heat collecting panel 2. What is necessary is just to set the time value required to circulate to the 1 side.

  Thereby, when the circulation pump 41 is operated with the normal capacity, a high-temperature heat medium is supplied from the heat collection panel 2 to the heat storage heat exchanger 43 through the outgoing path 42a, and the hot water storage tank in the heat storage heat exchanger 43 is supplied. The heat medium that has become low temperature by heat exchange heating of the hot water in 3 is returned to the heat collecting panel 2 through the return path 42b. The heat medium returned 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 forward 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 other hand, when the circulation pump 41 is operated with a larger capacity than the normal capacity, for example, the solar heat is strong and the heat medium in the heat collecting panel 2 is boiled. Even if there is a descending phenomenon (so-called waterfall phenomenon or water collapse phenomenon) in which the heat medium descends from the heat collecting panel 2 with the occurrence, the heat collecting panel 2 is higher or lower than usual than the system main body 1. Even if it is installed in a place with a difference (for example, a height difference of 10 m or more), the heat medium in the heat collection circuit 4 is pushed up to the heat collection panel 2 by the pump operation with a large capacity, and the heat collection panel 2 Can be charged to. Thereafter, the circulation pump 41 is operated with the normal capacity, and the amount of heat collected on the heat medium is reduced without consuming wasteful operating energy and without impairing the durability of the circulation pump 41. It 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.

  In the case of the above embodiment, it is possible to provide a solar hot water system having the same control specifications even in various installation environments having different height differences, and it is installed in an installation environment in which the height difference is larger than a normal one. Even if it happens, the occurrence of inconvenience can be surely avoided.

<Other embodiments>
In addition, this invention is not limited to the said embodiment, Other various embodiment is included. That is, in the embodiment, as the bubble generation determination process by the bubble generation determination unit 73, it is determined whether or not the heat medium temperature Ts detected by the heat collection panel temperature sensor 21 has exceeded the boiling temperature Tf. However, the present invention is not limited to this. For example, determination is made using a reserve tank liquid level sensor (for example, a liquid level electrode) 452 as a liquid level detecting means for detecting a liquid level at the time of boiling provided in the reserve tank 45. Also good. That is, if boiling occurs in the heat collecting panel 2, the heat medium descends and the tank 44 overflows, and the overflowing heat medium flows into the reserve tank 45 through the communication pipe 451 and the liquid level rises. If the rise in the liquid level is detected by the reserve tank liquid level sensor 452, it may be determined that bubbles are generated. Of course, the detection of the liquid level at the time of boiling by the reserve tank liquid level sensor 452 may be adopted instead of determining whether or not the heating medium temperature Ts exceeds the boiling temperature Tf, or may be used in combination. It may be configured.

  Further, instead of detecting the liquid level at the time of boiling by the liquid level sensor 452, the generation of bubbles is determined by detecting the generation of the overflowing heat medium flow by the water flow sensor 454 disposed in the overflow pipe 453 of the reserve tank 45. May be performed. In other words, when the liquid level at the boiling point is exceeded, the excess heat medium is discharged through the overflow pipe 453. Therefore, by detecting the occurrence of the flow, bubbles equivalent to detecting the liquid level at the boiling point are detected. A determination can be made. Therefore, the overflow pipe water flow sensor 454 can also constitute the liquid level detecting means.

  Moreover, 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 is collected with respect to 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 circuit 21 Heat collection panel temperature sensor (heat medium temperature detection means)
41 Circulation pump 44 Tank (expansion tank)
45 Reserve tank (expansion tank)
73 Bubble generation determination means 75 Pump stop timer 452 Reserve tank liquid level sensor (liquid level detection means)
454 Overflow pipe water flow sensor (liquid level detection means)

Claims (3)

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 by circulating a heat medium between the tanks,
When a bubble generation determining means for determining whether or not bubbles are generated in the heat collecting circuit, when the bubble generation determination means determines that bubbles are generated, it is a normal time other than when it is determined that bubbles are generated. While being configured to operate and control the circulating pump with greater capacity than
A pump stop timer that counts the elapsed time that the circulating pump stops operating;
It said bubble generating judging means, if it exceeds the set time value has elapsed time measured by said pump stop timer, that is configured to determine the bubble generation,
Solar heat hot water system characterized in that. The solar hot water system according to claim 1,
A heating medium temperature detecting means for detecting the temperature of the heating medium in the heat collecting panel or a temperature equivalent to this heating medium temperature;
The said bubble generation | occurrence | production determination means is a solar hot water system comprised so that a bubble generation | occurrence | production may be determined if the heat-medium temperature detected by the said heat-medium temperature detection means is more than preset temperature. The solar hot water system according to claim 1 or 2,
An expansion tank interposed in the heat collection circuit, and a liquid level detection means for detecting the liquid level of the heat medium in the expansion tank,
The said bubble generation | occurrence | production determination means is a solar hot water system comprised so that a bubble generation | occurrence | production may be determined if the liquid level of a heat medium exceeds a setting liquid level by the said liquid level detection means.

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