JP2011149673A - Solar heat hot water supply system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar heat hot water supply system capable of properly performing an antifreezing operation without separately disposing an outside air temperature sensor. <P>SOLUTION: This solar heat hot water supply system includes a heat medium circulation pipe conduit 7 for circulating a heat medium between a solar heat collector 1 and a hot water storage tank 2, a heat medium circulation pump P of the heat medium circulation pipe conduit 7, a circulation pipe conduit 15 for reheating, branched from a warm water circulation pipe conduit 17 of an auxiliary heat source machine 3, and connected with a liquid-liquid heat exchange section 141 disposed in the heat medium circulation pipe conduit 7, an opening/closing valve 151 for the circulation pipe conduit 15 for reheating, and a control section C. The auxiliary heat source machine 3 has a function of the antifreezing operation for circulating the warm water in the warm water circulation pipe conduit 17. The control section C executes control to perform the antifreezing operation of the heat medium circulation pipe conduit 7 by driving the heat medium circulation pump P and circulating the heat medium in the heat medium circulation pipe conduit 7 in conjunction with the antifreezing operation of the auxiliary heat source machine 3, and to perform the antifreezing operation of the circulation pipe conduit 15 for reheating by opening the opening/closing valve 151 of the circulation pipe conduit 15 for reheating and circulating the warm water in the circulation pipe conduit 15 for reheating. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention uses the solar heat collected by a solar heat collector to heat and store hot water supplied to a hot water storage tank, and supplies the hot water in the hot water storage tank to an auxiliary heat source device such as a water heater. The present invention relates to a solar water heating system to be used, and more particularly to a system for preventing freezing of a heat medium circulation pipe disposed between a solar heat collector and a hot water storage tank.

  In this type of solar hot water supply system, in the case of solar heat collection operation for heating the water supplied to the hot water storage tank, the solar heat supply system is connected to the heat medium circulation line connecting the solar heat collector and the heat dissipating part provided in the hot water storage tank. The heat medium is circulated by a heat medium circulation pump to warm the water in the hot water storage tank through the heat radiating section (paragraph 0007 of Patent Document 2). During hot water supply operation, usually, when the hot water in the hot water storage tank is at a temperature higher than the hot water set temperature, the hot water set temperature is obtained by mixing the hot water from the hot water tank with the water from the tap water. The auxiliary heat source unit supplies hot water without heating, and if the hot water in the hot water storage tank is lower than the set hot water temperature, additional heat is set by burner combustion etc. with the auxiliary heat source unit. The temperature is adjusted to the hot water supply.

  By the way, conventionally, in a solar system in which a solar heat collector is provided to supply hot water or the like, an outside air temperature sensor is attached in the vicinity of the solar heat collector, and the solar circulation pump is operated when the outside air temperature falls below a certain temperature (1 ° C.). Thus, there is a technique for preventing freezing of a water supply pipe and a hot water supply pipe that are connected to the solar heat collector by utilizing the amount of heat in the solar heat collector (Claim 2 of Patent Document 1).

JP 2002-130699 A JP 2003-148804 A

  However, in the conventional solar system, since it is necessary to attach an outside air temperature sensor in the vicinity of the solar heat collector in order to perform the antifreezing operation, the antifreezing operation is performed without providing such an outside air temperature sensor. I can't. In addition, the outside air temperature sensor may not be able to accurately perform the freeze prevention operation due to the influence of solar radiation depending on the installation location near the solar heat collector and the accurate outside air temperature is not detected.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the solar hot water supply system which can perform a freeze prevention operation appropriately, without providing an external temperature sensor separately.

The solar hot water supply system according to the present invention is:
A solar collector that collects solar heat,
A hot water storage tank for storing hot water from a tank heated by solar heat,
A heat medium circulation path is formed between the solar heat collector and the hot water storage tank, and a part of the circulation path is arranged in the hot water storage tank to heat the water supplied to the hot water storage tank by the circulating heat medium. A heat-medium circulation pipe having a heat radiating section;
A heat medium circulation pump for circulating the heat medium in the heat medium circulation pipe,
Auxiliary heat source comprising a hot water supply heating section connected to a pipe downstream of the hot water storage tank for supplying hot water, and a hot water heating section for heating hot water having a hot water circulation pipe and circulating in the hot water circulation pipe Machine,
A reheating circulation line branched from the hot water circulation line and connected to a liquid-to-liquid heat exchange section provided in the heat medium circulation line;
An on-off valve provided in the reheating circulation line to stop or enable hot water circulation in the reheating circulation line;
A control unit,
The auxiliary heat source machine has an anti-freezing operation function for circulating hot water in the hot water circulation pipe when there is a risk of freezing of the hot water circulation pipe,
In conjunction with the antifreezing operation of the auxiliary heat source unit, the control unit opens the reheating circulation line opening / closing valve and circulates hot water in the reheating circulation line to recirculate the reheating circulation line. A control structure for performing the freeze prevention operation.

  From the above configuration, when the anti-freezing operation is started in the auxiliary heat source machine, it is predicted that the reheating circulation pipe may also be frozen. Therefore, even if an outside air temperature sensor is not separately provided in the vicinity of the solar heat collector, the reheating circulation pipe is properly linked by linking the antifreezing operation of the reheating circulation line with the antifreezing operation of the auxiliary heat source unit. Road freezing prevention operation can be performed.

  In conjunction with the freeze prevention operation of the auxiliary heat source unit, the control unit further drives the heat medium circulation pump to circulate the heat medium in the heat medium circulation pipe to perform the freeze prevention operation of the heat medium circulation pipe. It is desirable to have a control configuration.

  From the above configuration, when the freeze prevention operation is started in the auxiliary heat source machine, it is predicted that the heat medium circulation pipe may also freeze. Therefore, even if an outside air temperature sensor is not separately provided in the vicinity of the solar heat collector, the freezing prevention operation of the heating medium circulation pipe is linked with the freezing prevention operation of the auxiliary heat source machine, thereby accurately Freezing prevention operation can be performed.

When performing the freeze prevention operation of the heat medium circulation pipe in conjunction with the freeze prevention operation of the auxiliary heat source unit, the control unit drives the heat medium circulation pump when the solar heat collection operation is stopped. It is desirable to have a control configuration in which the heat medium is circulated in the circulation line to perform the freeze prevention operation of the heat medium circulation line.
Even in a situation where the possibility of freezing of the heat medium circulation pipe is expected, the heat medium circulation pump is driven and the heat medium is circulated in the heat medium circulation pipe during the solar heat collection operation. Freezing of the circulation line can be prevented. On the other hand, when the solar heat collecting operation is stopped, the heat medium circulation pump is stopped, so that the heat medium circulation pipe may be frozen. Therefore, from the above configuration, the antifreezing operation of the heat medium circulation pipe is performed in conjunction with the antifreezing operation of the auxiliary heat source unit only when the solar heat collecting operation is stopped. Freezing prevention operation can be performed accurately.

  As described above, according to the solar hot water supply system according to the present invention, the reheating circulation line can be operated by interlocking with the antifreezing operation of the auxiliary heat source unit without separately providing an outside air temperature sensor in the vicinity of the solar heat collector. In addition, the freeze prevention operation of the heat medium circulation pipe can be performed accurately.

It is a mimetic diagram showing a schematic structure of a solar hot water supply system by an embodiment. It is a flowchart which shows operation | movement of the freeze prevention driving | operation in the solar hot water supply system of embodiment. It is a flowchart which shows the operation | movement of the solar-heat collection determination in a solar-heating hot-water supply system. It is a flowchart which shows the operation | movement of the freeze prevention driving | operation as other embodiment.

First, the basic configuration of the solar hot water supply system will be described.
As shown in FIG. 1, the present solar water heating system includes a solar heat collector 1 that collects solar heat, a hot water storage tank 2 that stores hot water using solar heat in the solar heat collector 1, and a hot water storage tank 2. It consists of a mixing valve 64 that enables mixing of hot water from the tank and water (tap water, etc.) sent from the water, a gas water heater that is connected to the downstream side of the hot water storage tank 2 and supplies hot water. An auxiliary heat source unit 3, a control unit C for controlling the operation of the system, a remote controller 4 for setting a hot water supply set temperature, and the like.

  The solar heat collector 1 is formed in a panel shape. For example, the solar heat collector 1 is placed vertically on a veranda of an apartment house or installed on a roof of a building. The solar heat collector 1 includes a heat collecting section (not shown) that forms a flow path of a heat medium that is heated by solar radiation, and a solar power generating section 1a in which a solar cell for performing solar power generation is installed. . The solar power generation unit 1a supplies driving power to a heat medium circulation pump P described later.

  In the hot water storage tank 2, a water supply pipe 5 for supplying water is connected to a lower water supply port, a hot water discharge pipe 6 for discharging hot water from a tank is connected to an upper hot water outlet, and tank temperature sensors 20a, 20a, 20b, 20c, 20d are installed, and the temperature of the tank hot water in the hot water storage tank 2 is detected by these tank temperature sensors 20a, 20b, 20c, 20d. The detected temperature signals of the tank temperature sensors 20a, 20b, 20c, and 20d are output to the control unit C and used for temperature control during hot water supply operation. The temperature detected by the uppermost tank temperature sensor 20a can be treated as the temperature of the tank hot water in the hot water storage tank 2.

  In the water supply pipe 5, a water supply source valve 51, a water filter 52, a pressure reducing valve 53, an incoming water temperature sensor 54, a check valve 55 and a drain valve 56 are arranged in order from the upstream side. The pressure reducing valve 53 is a valve that adjusts the water supply pressure to the hot water storage tank 2. When the tank hot water in the hot water storage tank 2 decreases, the pressure on the downstream side of the pressure reducing valve 53 decreases and water is supplied to the hot water storage tank 2 accordingly. Is supplied with water. The incoming water temperature sensor 54 detects the temperature of the water flowing through the water supply pipe 5.

  The hot water storage tank 2 and the auxiliary heat source unit 3 are connected via a hot water discharge pipe 6. The hot water discharge pipe 6 includes a hot water temperature sensor 61 that detects the temperature of hot water discharged from the hot water storage tank 2 and a pressure relief valve 62 between the hot water storage tank 2 and the auxiliary heat source unit 3 in order from the upstream side, a pressure relief valve 62, and a normally closed state. A solar solenoid valve 63, a mixing valve 64, a water amount sensor 65, a mixing sensor 66, a high cut sensor 67, and the like are disposed. The water amount sensor 65 detects the flow rate flowing through the tap water pipe 6 and outputs a detection signal to the control unit C. Further, the mixing sensor 66 and the high cut sensor 67 detect the temperature of the mixed hot water in the hot water discharge pipe 6.

  A water supply pipe 50 for mixing branched from the water supply pipe 5 is connected to the mixing valve 64. The mixing valve 64 is a valve that controls the temperature of the mixed hot water supplied to the auxiliary heat source unit 3 by mixing and controlling the tank hot water discharged from the hot water storage tank 2 and the water supplied from the mixing water supply pipe 50. The opening degree is controlled according to the command signal from the part C. The mixing water supply pipe 50 is provided with a check valve 58 for preventing a reverse flow upstream.

  The solar heat collector 1 and the hot water storage tank 2 are connected by a heat medium circulation line 7 through which the heat medium circulates. The heat medium circulation pipe 7 is a heat medium circulation forward path 7a that sends the heat medium heated by the solar heat collector 1 to the hot water storage tank 2, and heat radiation that heats and heats the water supplied to the hot water storage tank 2 with the heat medium. The part 7b and a heat medium circulation return path 7c for returning the heat medium cooled by heat exchange to the solar heat collector 1 are connected to each other. Further, the heat medium circulation pipe 7 is provided with a bypass path 14 that bypasses the heat medium circulation forward path 7a and the heat medium circulation return path 7c. The heat radiating portion 7 b is configured by a pipe bent in a U shape or the like below the hot water storage tank 2. Note that warm water (including warm water mixed with antifreeze liquid) is used as the heat medium.

  In the heating medium circulation return path 7c of the heating medium circulation pipe 7, in order from the upstream side, an open-type cistern 8 for temporarily storing the heating medium, the heating medium circulation pump P, and a heating medium sensor 71 for detecting the heating medium temperature. A normally open heat valve 72 and the like are provided. A heat medium sensor may also be provided in the heat medium circulation forward path 7a.

  In the systern 8, a high water level switch 81 for detecting an abnormally high water level of the heat medium, a low water level switch 82 for detecting an abnormally low water level of the heat medium, and a water level switch for preventing the heat medium circulation pump P from idling. 83 is disposed. Further, an overflow pipe 84 for discharging the heat medium out of the cistern 8 when the heat medium overflows is disposed above the cistern 8.

  The heat medium circulation pump P is driven by the power generated by the solar power generation unit 1 a in the solar heat collector 1. In addition, since the heat medium circulation pump P includes an uncertain element that the power generation in the solar power generation unit 1a depends on the amount of solar radiation, the power of the commercial power source is supplied from the control unit C through the control board 33 as necessary. It can also be driven. And if solar radiation hits the solar heat collector 1 and heat collection and solar power generation are performed, solar heat collection operation is performed. In this solar heat collection operation, the heat medium circulation pump P is driven by power supply from the solar power generation unit 1 a, whereby the heat medium heated by the solar heat collector 1 is circulated to the heat radiating unit 7 b in the hot water storage tank 2. The water supplied to the hot water storage tank 2 is heated to store the hot water in the tank. During the solar heat collecting operation, the solar solenoid valve 63 provided in the hot water discharge pipe 6 is kept closed so that the hot water from the hot water storage tank 2 is not discharged.

  The auxiliary heat source unit 3 includes a hot water supply heating unit (hot water supply heating unit) 31 including a hot water supply heat exchanger 311 and a hot water supply gas burner 312, and a heating heater including a heating heat exchanger 321 and a heating gas burner 322. A unit (heating unit for warm water) 32 and a control board 33 for controlling the operation of the heating units 31 and 32 are provided. These heating units 31 and 32 constitute a can body of the auxiliary heat source unit 3.

  The hot water supply heat exchanger 311 is connected to the hot water discharge pipe 6 led out from the hot water storage tank 2 by piping. During the hot water supply operation, if the hot water in the hot water storage tank 2 is higher than the hot water supply set temperature, the hot water from the hot water storage tank 2 is not heated by the hot water heat exchanger 311 of the auxiliary heat source unit 3 without additional heating. Water from the mixing water supply pipe 50 is mixed by the mixing valve 64 to adjust the temperature to the hot water supply set temperature. On the other hand, if the tank hot water in the hot water storage tank 2 is lower than the hot water supply set temperature, The hot water mixed with water is supplied to the auxiliary heat source unit 3 side, the hot water supply gas burner 312 is combusted, and additionally heated by the hot water supply heat exchanger 311 to adjust the temperature to the hot water supply set temperature. The hot water adjusted to a predetermined hot water supply set temperature in this manner is supplied from a hot water supply pipe L from a hot water outlet terminal such as a currant provided in a wash basin, a kitchen, a bathroom, or the like.

  The heating heat exchanger 321 is connected to the hot water circulation conduit 17 for circulating hot water (including hot water mixed with antifreeze liquid). The hot water in the hot water circulation pipe 17 is circulated by driving a hot water circulation pump P2 provided in the auxiliary heat source unit 2. The hot water circulation pump P2 is driven by a commercial power source. The hot water circulation line 17 is branched into a heating circulation line 16 and a reheating circulation line 15. The heating circulation line 16 is connected to a heater W installed outside the auxiliary heat source unit 3. The reheating circulation line 15 is connected to a liquid-to-liquid heat exchanging unit 141 provided in the bypass line 14 in the heat medium circulation line 7, and the heat in the heat medium circulation line 7 is separated from the solar heat collector 1. The medium can be heated. In addition, as the structure of the liquid heat exchanger 141, for example, a double pipe structure in which a pipe constituting the reheating circulation pipe 15 is provided so as to cover the circumference of the pipe constituting the bypass path 14, or through a partition wall. For example, the bypass passage 14 may be connected to one chamber and the reheating circulation conduit 15 may be connected to the other chamber.

  The heating circulation line 16 is provided with a normally closed thermal valve (open / close valve) 161, and the reheating circulation line 15 has a normally closed thermal valve (on the upstream side of the liquid heat exchanger 141 ( On-off valve) 151 is provided. The heat medium circulation return path 7 c is provided with a normally open heat valve 72 that stops or enables the flow of the heat medium to the solar heat collector 1 on the downstream side of the connection with the bypass path 14. A normally closed heat valve 142 is provided to stop or enable the flow of the heat medium from the heat medium circulation return path 7a to the heat medium circulation forward path 7c.

  The heating unit 32 for heating is normally used as a heating unit for supplying heat to the heater W or the like, but there is a possibility that bacteria such as Legionella bacteria may propagate without the tank hot water in the hot water storage tank 2 being replaced. When the amount of heat collected by the solar heat collector 1 is small due to insufficient solar radiation or when the tank hot water is not stored in the hot water storage tank 2, the heat valve 151 of the reheating circulation line 15 is opened to exchange the heat. It is also activated during a reheating operation in which hot water is circulated through the section 141 to forcibly heat the heat medium in the heat medium circulation pipe 7 and raise the temperature of the tank hot water in the hot water storage tank 2. During this reheating operation, in order to prevent the heat medium from being circulated to the solar heat collector 1 side, the normally open heat valve 72 of the heat medium circulation return path 7c is closed and the normally closed heat valve 142 of the bypass path 14 is closed. Open the valve.

  The auxiliary heat source unit 3 is provided with an outside air temperature sensor 34. The temperature detected by the outside air temperature sensor 34 is monitored, and when there is a risk of freezing of the hot water circulation line 17, the hot water circulation line 17 is heated. Freezing prevention operation is performed to circulate the. The freeze prevention operation of the auxiliary heat source device 3 is executed by a control command from the control board 33. Specifically, when the temperature detected by the outside air temperature sensor 34 becomes a certain temperature (for example, 4 ° C.) or less, the hot water circulation pump P2 of the hot water circulation pipe 17 is driven and the heating gas burner 322 is burned to heat the heating. The exchanger 321 is heated, and hot water is circulated in the hot water circulation pipe 17 so that the operation for preventing freezing of the hot water circulation pipe 17 is performed. When the temperature detected by the outside air temperature sensor 34 reaches a predetermined temperature (for example, 7 ° C.), the heating gas burner 322 is stopped from burning, and the hot water circulation pump P2 is stopped to prevent freezing of the hot water circulation line 17. Driving is terminated. The heating gas burner 322 may not be burned during the freeze prevention operation of the hot water circulation pipe 17 in the auxiliary heat source unit 3.

  The control unit C is composed mainly of a microcomputer, and a predetermined control program is stored in a built-in ROM (not shown) or the like. This control unit C is connected to the remote controller 4 disposed in the kitchen or the like via the control board 33 in the auxiliary heat source unit 3 and is electrically connected to various devices such as the sensors and valves described above. Control is performed by exchanging signals with these devices. Although not shown in the figure, the remote controller 4 is a display unit that displays operation switches, switches such as a temperature setting switch for inputting a hot water supply set temperature, a heating set temperature, and the like, a hot water set temperature, a tank hot water amount in the hot water storage tank 2, and the like. Etc.

  In addition, the control unit C controls the operation of the antifreezing operation of the heat medium circulation pipe 7 and the reheating circulation pipe 15 in conjunction with the antifreezing operation of the auxiliary heat source unit 3 described above. The operation of the freeze prevention operation of the heat medium circulation line 7 and the reheating circulation line 15 will be described below.

  Referring to the flowchart of FIG. 2, when the freeze prevention operation of the auxiliary heat source unit 3 is started (S1), the thermal valve 151 of the reheating circulation line 15 is opened (S2). The hot water circulation pump P2 of the hot water circulation line 17 is driven by the start of the freeze prevention operation of the auxiliary heat source unit 3, and the heat exchanger 321 is heated by the combustion of the gas burner 322, so that the inside of the hot water circulation line 17 of the auxiliary heat source unit 3 Hot water is circulated. Therefore, in conjunction with the start of the freeze prevention operation of the auxiliary heat source unit 3, the hot water is circulated in the reheating circulation line 15 by opening the thermal valve 151 of the reheating circulation line 15. Thus, the anti-freezing operation of the reheating circulation conduit 15 is performed.

  Next, it is determined whether or not the solar heat collecting operation is stopped (S3). If the solar heat collecting operation is stopped (“YES” in S3), the heat medium circulation pump P is driven by a commercial power source (S4). Then, the normally closed thermal valve 142 of the bypass passage 14 is opened (S5). In conjunction with the start of the freeze prevention operation of the auxiliary heat source unit 3, the heat medium in the heat medium circulation pipe 7 is circulated by driving the heat medium circulation pump P, and the solar heat collector 1 and the hot water storage tank 2 are circulated. An antifreezing operation is performed in which the heat medium circulation pipe 7 is warmed through a heat medium that is circulated by the amount of heat, and further by the amount of heat from the liquid-to-liquid heat exchanger 141. On the other hand, when the solar heat collecting operation is being performed (“NO” in S3), the heat medium circulation pump P is driven by the power supplied from the solar power generation unit 1a, and the heat medium is circulated in the heat medium circulation line 7. Therefore, the antifreezing operation of the heat medium circulation pipe 7 is not performed. In this case, it is monitored whether or not the solar heat collecting operation is stopped (S3). When the solar heat collecting operation is stopped, the antifreezing operation of the heat medium circulation pipe 7 is performed (S4 and S5). Further, when the freeze prevention operation of the auxiliary heat source unit 3 is completed during the monitoring of the solar heat collecting operation (“YES” in S6), the thermal valve 151 of the reheating circulation line 15 is closed (S7). Then, the freeze prevention operation of the reheating circulation line 15 is completed.

  Then, while the anti-freezing operation of the reheating circulation line 15 and the heating medium circulation line 7 is being performed, it is monitored whether or not the anti-freezing operation of the auxiliary heat source unit 3 has been completed (S8). When the freeze prevention operation of the auxiliary heat source unit 3 is completed (“YES” in S8), the heat valve 151 of the reheating circulation line 15 is closed (S9) and the normally closed heat valve of the bypass line 14 is closed. 142 is closed (S10), and the drive of the heat medium circulation pump P is stopped (S11). The combustion of the gas burner 322 is stopped due to the end of the freeze prevention operation of the auxiliary heat source unit 3, the heating of the heat exchanger 321 is stopped, and the hot water circulation pump P2 in the hot water circulation line 17 is stopped and the inside of the auxiliary heat source unit 3 is stopped. The hot water circulation in the hot water circulation pipe 17 is stopped. Accordingly, the hot water circulation into the reheating circulation line 15 is also stopped, and the thermal valve 151 of the reheating circulation line 15 is closed in conjunction with the end of the freeze prevention operation of the auxiliary heat source unit 3. Then, the freeze prevention operation of the reheating circulation line 15 is completed. Further, in conjunction with the end of the freeze prevention operation of the auxiliary heat source unit 3, the heat medium circulation pump P of the heat medium circulation line 7 is stopped to stop the circulation of the heat medium in the heat medium circulation line 7. The freeze prevention operation of the heat transfer medium circulation line 7 is completed.

  When the solar heat collection operation is started during the monitoring of whether or not the freeze prevention operation of the auxiliary heat source unit 3 is finished in step S8 (S12), the electric power from the commercial power supply to the heat medium circulation pump P Although the supply is stopped and the freeze prevention operation of the heat medium circulation pipe 7 is finished, the electric power supply to the heat medium circulation pump P is immediately switched to the electric power from the solar power generation unit 1a (S13) and the solar heat collection operation is performed. Done.

  As described above, according to the present embodiment, it is predicted that the reheating circulation line 15 and the heat medium circulation line 7 may be frozen when the freeze prevention operation is started in the auxiliary heat source unit 3. Is done. Therefore, even if the outside air temperature sensor is not separately provided in the vicinity of the solar heat collector 1, the anti-freezing operation of the reheating circulation line 15 and the heating medium circulation line 7 is interlocked with the anti-freezing operation of the auxiliary heat source unit 3. As a result, the freeze prevention operation of the reheating circulation line 15 and the heat medium circulation line 7 can be performed appropriately. Further, the cost can be reduced because the outside air temperature sensor is not provided near the solar heat collector 1.

Next, a heat collection determination method for determining whether or not the solar heat collection operation in step S3 or step S12 will be described. As described above, during the solar heat collecting operation, the heat medium circulation pump P is driven by the solar power generation voltage in the solar power generation unit 1a regardless of the commercial power source.
Referring to the flowchart of FIG. 3, as a heat collection determination while the solar heat collection operation is stopped, a state where the power generation voltage of the solar power generation unit 1 a is equal to or higher than the pump drive voltage value (for example, 5 V) of the heat medium circulation pump P is predetermined. When the time (for example, 1 minute) is continued ("YES" in S21), it is determined that the solar heat collecting operation is started and the solar heat collecting operation is being performed (S22). On the other hand, even if the power generation voltage of the solar power generation unit 1a is still less than the pump drive voltage value of the heat medium circulation pump P, or the power generation voltage of the solar power generation unit 1a exceeds the pump drive voltage value of the heat medium circulation pump P When the state is not continued for a predetermined time (“NO” in S21), it is determined that the solar heat collecting operation is stopped (S24). The above operation is a monitoring operation as to whether or not the solar heat collection operation is started while the solar heat collection operation is stopped.

  As a heat collection determination during the solar heat collection operation, a state where the power generation voltage of the solar power generation unit 1a is lower than the pump drive voltage value (for example, 5V) of the heat medium circulation pump P continues for a predetermined time (for example, 1 minute). If it is determined (“YES” in S23), it is determined that the solar heat collecting operation is stopped and the solar heat collecting operation is stopped (S24). On the other hand, even if the power generation voltage of the solar power generation unit 1a is still higher than the pump drive voltage value of the heat medium circulation pump P or the power generation voltage of the solar power generation unit 1a is less than the pump drive voltage value of the heat medium circulation pump P When the state is not continued for a predetermined time (“NO” in S23), it is determined that the solar heat collecting operation is being performed (S22). The above operation is a monitoring operation as to whether or not the solar heat collection operation is stopped during the solar heat collection operation.

  By the way, conventionally, as a method of determining solar heat collection, a solar radiation sensor that detects the amount of solar radiation is provided, and when the output of this solar radiation sensor exceeds a predetermined value, the heat medium circulation pump is forcibly driven and near the hot water tank inlet The heat collection was determined by monitoring the temperature rise of the heat medium (Japanese Utility Model Publication No. 63-11560). In this way, when monitoring the temperature rise of the heat medium, if the heat collection capacity of the solar heat collector is small and the temperature rise of the heat medium is small, there is a risk of erroneous detection of the heat collection, and time is also required for the heat collection determination. In addition, it was necessary to provide a solar radiation sensor.

  On the other hand, according to the solar heat collection determination in this embodiment, as described above with reference to FIG. 3, the determination is based on the solar power generation voltage in the solar power generation unit 1 a installed in the solar heat collector 1. By doing so, it is not necessary to provide a solar radiation sensor that causes high costs, and the solar heat collector 1 can accurately and quickly determine the state in which solar heat can be collected. In addition, during the solar heat collecting operation, the heat medium circulation pump P is driven by the solar power generation voltage in the solar power generation unit 1a regardless of the commercial power source, so that energy saving can be achieved.

(Other embodiments)
As another embodiment, only the freeze prevention operation of the reheating circulation line 15 may be executed in conjunction with the freeze prevention operation of the auxiliary heat source device 3. For example, as shown in the flowchart of FIG. 4, in conjunction with the start of the freeze prevention operation of the auxiliary heat source unit 3 (“YES” in S31), the thermal valve 151 of the reheating circulation line 15 is opened (S32). Then, the freeze prevention operation of the reheating circulation line 15 is started. When the anti-freezing operation of the reheating circulation line 15 is executed, in conjunction with the end of the anti-freezing operation of the auxiliary heat source unit 3 (“YES” in S33), the thermal operation of the reheating circulation line 15 is performed. The valve 151 is closed (S34), and the freeze prevention operation of the reheating circulation line 15 is also completed.

  In addition, this invention is not limited only to the said embodiment, It can change suitably in the range of this invention, For example, it links with the freezing prevention driving | operation of the auxiliary heat source machine 3, for example, the heat-medium circulation pipe line 7 Only the anti-freezing operation may be executed. In this case, for example, steps S2, S7 and S9 in the flowchart of FIG. 2 may not be executed.

DESCRIPTION OF SYMBOLS 1 Solar collector 2 Hot water storage tank 3 Auxiliary heat source machine 7 Heat-medium circulation line 7b Heat radiation part 15 Reheating circulation line 17 Hot water circulation line 31 Hot water supply heating unit (heating part for hot water supply)
32 Heating unit for heating (heating unit for hot water)
141 Liquid-to-liquid heat exchanger 151 Thermally operated valve (open / close valve)
C Control part P Heat medium circulation pump P2 Hot water circulation pump

Claims (3)

A solar collector that collects solar heat,
A hot water storage tank for storing hot water from a tank heated by solar heat,
A heat medium circulation path is formed between the solar heat collector and the hot water storage tank, and a part of the circulation path is arranged in the hot water storage tank to heat the water supplied to the hot water storage tank by the circulating heat medium. A heat-medium circulation pipe having a heat radiating section;
A heat medium circulation pump for circulating the heat medium in the heat medium circulation pipe,
Auxiliary heat source comprising a hot water supply heating section connected to a pipe downstream of the hot water storage tank for supplying hot water, and a hot water heating section for heating hot water having a hot water circulation pipe and circulating in the hot water circulation pipe Machine,
A reheating circulation line branched from the hot water circulation line and connected to a liquid-to-liquid heat exchange section provided in the heat medium circulation line;
An on-off valve provided in the reheating circulation line to stop or enable hot water circulation in the reheating circulation line;
A control unit,
The auxiliary heat source machine has an anti-freezing operation function for circulating hot water in the hot water circulation pipe when there is a risk of freezing of the hot water circulation pipe,
In conjunction with the antifreezing operation of the auxiliary heat source unit, the control unit opens the reheating circulation line opening / closing valve and circulates hot water in the reheating circulation line to recirculate the reheating circulation line. Solar water heating system with a control configuration that performs anti-freezing operation. In the solar hot water supply system according to claim 1,
In conjunction with the freeze prevention operation of the auxiliary heat source unit, the control unit further drives the heat medium circulation pump to circulate the heat medium in the heat medium circulation pipe to perform the freeze prevention operation of the heat medium circulation pipe. A solar water heating system with a control configuration. In the solar hot water supply system according to claim 2,
When performing the freeze prevention operation of the heat medium circulation pipe in conjunction with the freeze prevention operation of the auxiliary heat source unit, the control unit drives the heat medium circulation pump when the solar heat collection operation is stopped. A solar water heating system having a control configuration in which a heat medium is circulated in the circulation pipe to prevent the heat medium circulation pipe from being frozen.

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