Solar heating system

Abstract

To provide a solar heating system that can operate only during times when heat can be collected.SOLUTION: A solar heating system 1 is configured to heat water in a heat storage tank 3 by circulating a heat medium between a solar collector 2 and a coil-type heat exchanger 4, and has a control unit 13 that controls the circulation of the heat medium. The control unit 13 performs an inquiry operation in which the heat medium is circulated for a predetermined inquiry time at every inquiry time of a fixed period after the power is turned on, and determines possibility of heat collection on the basis of a predetermined condition and records the determination. If it is determined that heat collection is possible during the inquiry operation, the control unit performs a heat collection operation in which the heat medium is circulated until a heat collection end condition is satisfied.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a solar heating system that heats water using a heat collector that collects heat from the sun. [Background technology]

[0002] Conventionally, solar thermal heating systems are known that start / end operation by determining whether heat collection by a solar collector is possible. For example, Patent Document 1 describes a hot water heating method (solar thermal heating system) that, when heat collection operation is stopped during a set heat collection determination time period, determines whether heat collection operation is possible at regular intervals, and performs heat collection operation when it is determined that heat collection operation is possible. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-38468 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the solar heating system of Patent Document 1 is configured so that the time periods for starting and ending the heat collection determination must be determined in advance. Therefore, if the user does not set the time periods due to forgetting or other reasons, there is a problem that the expected operation cannot be performed satisfactorily.

[0005] Therefore, an object of the present invention is to provide a solar heating system that can be operated automatically only during the time periods when heat can be collected, without specifying the operation time. [Means for solving the problem]

[0006] In order to achieve the above object, the invention described in claim 1 is a solar thermal heating system having a solar collector that heats a heat medium with solar heat and a heat storage tank that has a heat exchanger through which the heat medium passes inside, and circulating the heat medium between the solar collector and the heat exchanger to heat the water in the heat storage tank, and having a control unit that controls the circulation of the heat medium between the solar collector and the heat exchanger, and the control unit circulates the heat medium for a predetermined query time at regular intervals for a predetermined period after the power is turned on, and performs an inquiry operation that determines and records whether heat collection is possible based on predetermined conditions, and if it is determined in the inquiry operation that heat collection is possible, performs a heat collection operation that circulates the heat medium until the heat collection end condition is met, and further, based on the results of the inquiry operation, the control unit creates an operation table that includes a first time when heat collection is possible and a second time when heat collection is not possible, and after the predetermined period has elapsed, the control unit performs normal operation that performs an inquiry operation at the first time based on the operation table. Furthermore, the invention described in claim 2 is characterized in that in the invention described in claim 1, the control unit determines and records whether heat collection is possible at each inquiry time in parallel with normal operation, and every 24 hours, creates a new operation table by combining it with previously recorded records of whether heat collection is possible, and performs normal operation based on the new operation table. Furthermore, the invention described in claim 3 is characterized in that, in the invention described in claim 1 or 2, a return temperature sensor that measures the temperature of the heat medium heated by the heat collector and an in-tank temperature sensor that measures the water temperature around the heat exchanger in the heat storage tank are provided, and the specified condition is whether the temperature difference between the measurement result of the return temperature sensor and the measurement result of the in-tank temperature sensor is equal to or greater than a specified heat collection start temperature, and in that, in inquiry operation, the control unit determines that heat collection is possible if the temperature difference is equal to or greater than the heat collection start temperature, and determines that heat collection is not possible if the temperature difference is below the heat collection start temperature. The invention as set forth in claim 4 is characterized in that in the invention as set forth in claim 3, the heat collection end condition is that the temperature difference falls below a predetermined heat collection end temperature. [Effects of the Invention]

[0007] According to the present invention, a heat transfer medium is circulated between a heat collector and a coil-type heat exchanger to heat water in a heat storage tank, and the heat transfer medium circulation control unit controls the heat transfer medium circulation. After power is turned on, the control unit performs an inquiry operation in which the heat transfer medium is circulated for an inquiry time at regular intervals for a predetermined period after power is turned on, and determines whether heat transfer is possible based on predetermined conditions and records the result. If heat transfer is possible during the inquiry operation, the control unit performs a heat transfer operation in which the heat transfer medium is circulated until a heat transfer end condition is met. Furthermore, based on the results of the inquiry operation, the control unit creates an operation table that includes a first time when heat transfer is possible and a second time when heat transfer is impossible. Then, 24 hours after power is turned on, the control unit performs normal operation in which the inquiry operation is performed at the first time by referring to the operation table. Therefore, the solar heating system automatically operates according to the time period when heat collection by the heat collector is possible, eliminating the need to manually determine an operation schedule. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing a solar heating system. [Figure 2] FIG. 10 is a diagram showing a specific example of temporarily stored data in heat collection data. [Figure 3] 10 is a table showing a specific example of an operation table. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the present invention will now be described with reference to the accompanying drawings. Fig. 1 is a schematic diagram showing the configuration of a solar thermal heating system 1 according to the present invention. Fig. 2 is a diagram showing a specific example of temporarily stored data in heat collection data. Fig. 3 is a table showing a specific example of an operation table.

[0010] As shown in Figure 1, the solar thermal heating system 1 includes a solar collector 2 that collects solar heat and heats a heat medium such as antifreeze, a heat storage tank 3, a coil-type heat exchanger 4 installed in the heat storage tank 3 and through which the heat medium from the solar collector 2 passes, a heat medium supply pipe 5 for supplying the heat medium to the solar collector 2, a heat medium return pipe 6 for returning the heat medium heated by the solar collector 2 from the solar collector 2, an expansion tank 7 that absorbs volume changes due to thermal expansion and contraction of the heat medium and supplies the heat medium, a pump 8 that supplies the heat medium from the expansion tank 7 to the solar collector 2, a supply-side temperature sensor 9 that measures the temperature of the heat medium sent from the pump 8, a flow rate sensor 10 that measures the flow rate of the heat medium sent from the pump 8, an in-tank temperature sensor 11 that measures the water temperature around the coil-type heat exchanger 4, and a return-side temperature sensor 12 that measures the temperature of the heat medium heated by the solar collector 2.

[0011] Furthermore, the solar thermal heating system 1 has a control unit 13 that controls the pump 8 based on the measurement results of the various sensors. The control unit 13 has a calculation mechanism such as a CPU that performs control and calculations, a storage mechanism that stores the measurement results of the various sensors, and a communication mechanism that communicates with the various components of the solar thermal heating system 1.

[0012] The solar thermal heating system 1 heats the water in the thermal storage tank 3 as follows. First, a heat medium is supplied to the expansion tank 7 from a heat medium supply pipe (not shown). Next, the heat medium is sent from the expansion tank 7 to the solar collector 2 through the heat medium supply pipe 5 by a pump 8, the operation of which is controlled by a control unit 13. Next, the heat medium is heated by the solar collector 2, and the heated heat medium is sent to the coil-type heat exchanger 4 through the heat medium return pipe 6. The heated heat medium then passes through the coil-type heat exchanger 4, heating the water in the thermal storage tank 3. The heat medium then returns to the expansion tank 7, where its pressure is adjusted, and is then sent again to the solar collector 2 by the pump 8, thereby circulating the heat medium. By repeating this series of operations, the water in the thermal storage tank 3 is heated and becomes hot water. The heated hot water in the thermal storage tank 3 is then sent to an external device, such as a hot water heater, through a hot water outlet pipe (not shown).

[0013] Hereinafter, specific control and operation of the heat collection operation of the solar thermal heating system 1 will be described. After the power is turned on, the solar thermal heating system 1 performs an inquiry operation to determine whether or not heat collection is possible based on predetermined conditions and to operate the system, and also performs a measurement operation for 24 hours to create a record of whether or not heat collection is possible as heat collection data. As shown in Figure 2, the heat collection data consists of temporarily saved data in which the heat collection possibility corresponding to the time of inquiry is temporarily saved, and past data in which temporary saved data is saved every 24 hours for a predetermined number of days (for example, 7 days). Note that if past data has been saved in advance for a predetermined number of days, the oldest past data is overwritten when new heat collection data is saved from the temporarily saved data.

[0014] Query operation is an operation in which the solar heating system 1 operates the pump 8 for a predetermined query time (e.g., 2 minutes) to circulate the heat medium between the collector 2 and the coil-type heat exchanger 4, and measures the temperature difference ΔT (T2-T1) between the water temperature T1 around the coil-type heat exchanger 4 measured by the in-tank temperature sensor 11 and the temperature T2 of the antifreeze heated by the collector 2 measured by the return-side temperature sensor 12.

[0015] Then, during inquiry operation, if ΔT becomes equal to or greater than the heat collection start temperature (for example, 7°C), the inquiry operation is immediately terminated, and heat collection operation is started in which the pump 8 is operated to continue operation of the solar thermal heating system 1 until ΔT becomes less than the heat collection end temperature (for example, 3°C). At this time, the solar thermal heating system 1 records in the temporarily saved data that heat collection is possible, together with the inquiry time.

[0016] On the other hand, if ΔT does not become equal to or higher than the heat collection start temperature during the inquiry operation, the operation of the pump 8 is stopped after the inquiry time has elapsed, and the inquiry operation is terminated. At this time, the solar thermal heating system 1 records in the temporarily saved data that heat collection is not possible together with the inquiry time.

[0017] During measurement operation, if the inquiry time arrives while the solar thermal heating system 1 is still in heat collection operation, the system will continue heat collection operation without starting the inquiry operation. At this time, the solar thermal heating system 1 records the inquiry time and the fact that heat collection is possible in the temporarily saved data.

[0018] If the number of times that heat collection is possible in the recorded temporarily stored data is equal to or greater than a specified number (for example, twice) 24 hours after the start of measurement operation, the solar thermal heating system 1 stores the temporarily stored data as past data, terminates the measurement operation, and transitions to normal operation, which will be described later. Note that if the number of times that heat collection is possible in the recorded temporarily stored data is less than the specified number, the solar thermal heating system 1 resets the recorded temporarily stored data and performs measurement operation again from the beginning.

[0019] After the measurement operation is completed, the solar thermal heating system 1 performs inquiry operation based on the operation table created from the heat collection data, and transitions to normal operation in which it records whether heat collection is possible and updates the heat collection data. The operation table is a timetable that indicates whether inquiry operation will be performed at an inquiry time. As shown in Figure 3, the operation table is created by setting inquiry times that have been recorded as possible to collect heat at least once in the past heat collection data as first times at which inquiry operation will be performed, and the times before and after those times as second times at which inquiry operation will not be performed, and other inquiry times as second times at which inquiry operation will not be performed.

[0020] A specific operation of the solar thermal heating system 1 during normal operation will now be described. The solar thermal heating system 1 refers to the operation table created from the heat collection data and performs an inquiry operation at the inquiry time, which is the first time in the operation table.

[0021] As in the measurement operation, in the inquiry operation, if ΔT becomes equal to or higher than the heat collection start temperature, the solar thermal heating system 1 ends the inquiry operation and starts the heat collection operation. At this time, it records the inquiry time and the fact that heat collection is possible in the temporarily saved data.

[0022] On the other hand, during inquiry operation, if ΔT does not become equal to or higher than the heat collection start temperature, the solar thermal heating system 1 ends inquiry operation and stops the operation of the pump 8. At this time, it records in the temporarily saved data that heat collection is not possible together with the inquiry time.

[0023] Furthermore, if heat collection operation is ongoing when the inquiry time arrives, the operation table will continue heat collection operation without conducting an inquiry operation regardless of the first time or the second time, and will record the operation as heat collection possible in the heat collection data.

[0024] After 24 hours have passed since the start of normal operation, the solar hot water supply system 1 saves the temporarily stored data as past data. Then, a new operation table is created from the updated heat collection data, and the solar hot water supply system 1 performs normal operation again by referring to the new operation table. In this way, the heat collection data and operation table are updated every 24 hours, and normal operation is repeated. Note that, after 24 hours have passed since the start of normal operation, if the number of times that heat collection is recorded as possible in the temporarily stored data does not meet the specified number, the temporarily stored data is discarded without being saved as past data. The specified number may be the same as that during measurement operation, or may be a different number.

[0025] Furthermore, if a high temperature abnormality occurs during measurement operation or normal operation, the solar thermal heating system 1 stops inquiry operation and heat collection operation for a predetermined time (e.g., 12 hours) regardless of the operation table, and records in the temporarily saved data that heat collection is not possible for each inquiry time while inquiry operation and heat collection operation are stopped.The solar thermal heating system 1 determines that a high temperature abnormality has occurred if the water temperature T1 measured by the in-tank temperature sensor 11 is equal to or higher than a predetermined temperature (e.g., 80°C) and / or if the antifreeze temperature T3 measured by the supply-side temperature sensor 9 is equal to or higher than a predetermined temperature (e.g., 82°C).

[0026] Then, in the solar thermal heating system 1, as in the case where no high temperature abnormality occurs, if the number of times recorded as heat collection possible in the temporarily stored data every 24 hours meets a specified number of times, the temporarily stored data is stored as past data, and if the specified number of times is not met, the temporarily stored data is discarded without being stored as past data.

[0027] The solar thermal heating system 1 of the above embodiment is configured to circulate a heat medium between the solar collector 2 and the coil-type heat exchanger 4 to heat water in the thermal storage tank 3, and includes a control unit 13 that controls the circulation of the heat medium. After power is turned on, the control unit 13 performs an inquiry operation in which the heat medium is circulated for a predetermined period of time at regular intervals during the inquiry time, and determines whether heat collection is possible based on predetermined conditions and records the results. If heat collection is determined possible during the inquiry operation, the control unit 13 performs a heat collection operation in which the heat medium is circulated until a heat collection end condition is met. Furthermore, based on the results of the inquiry operation, the control unit 13 creates an operation table that includes a first time when heat collection is possible and a second time when heat collection is impossible. Then, 24 hours after power is turned on, the control unit 13 refers to the operation table and performs normal operation, performing an inquiry operation at the first time.

[0028] Therefore, the solar thermal heating system 1 does not need to be manually scheduled, as it automatically operates according to the time periods when heat can be collected by the solar collector 2. Also, because it operates only during the time periods when heat can be collected, it is possible to reduce power consumption.

[0029] The solar thermal heating system of the present invention is not limited to the above-described embodiment, and the overall configuration of the solar thermal heating system as well as the control method by the control unit can be appropriately modified as needed.

[0030] For example, in this embodiment, the control unit 13 is configured to perform measurement operation for 24 hours and create 24 hours' worth of heat collection data, but it may also be configured to perform measurement operation for a predetermined period (e.g., 3 days), refer to the heat collection data created as a result, including past data for several days, and then transition to normal operation. The inquiry time may be based on the time that has passed since the start of measurement operation and normal operation, or may be based on the current time. In addition, the conditions for operation such as the period of inquiry times during measurement operation and normal operation, under which the control unit 13 creates the operation table and update table, may be determined in advance or may be determined by external operation such as a remote control. In addition, in this embodiment, whether or not heat can be collected by the solar collector 2 is determined based on whether or not the temperature difference ΔT between the water temperature T1 around the coil-type heat exchanger 4 measured by the in-tank temperature sensor 11 (the temperature T1 measured by the in-tank temperature sensor 11) and the temperature T2 measured by the return-side temperature sensor 12 exceeds a predetermined temperature.However, the configuration may also be such that the determination is made based on whether the temperature T2 measured by the return-side temperature sensor 12 exceeds a predetermined temperature. [Explanation of symbols]

[0031] 1··Solar heating system, 2··Heat collector, 3··Heat storage tank, 4··Coil type heat exchanger, 5··Heat medium supply piping, 6··Heat medium return piping, 7··Expansion tank, 8··Pump, 9··Supply side temperature sensor, 10··Flow rate sensor, 11··Temperature sensor inside tank, 12··Return side temperature sensor, 13··Control unit.

Claims

1. A solar heating system comprising a solar collector that heats a heat medium with solar heat and a heat storage tank that has a heat exchanger therein through which the heat medium passes, and in which the heat medium is circulated between the solar collector and the heat exchanger to heat water in the heat storage tank, a control unit that controls the circulation of the heat medium between the heat collector and the heat exchanger, The control unit performs an inquiry operation in which the heat medium is circulated for a predetermined inquiry time at each inquiry time of a fixed cycle for a predetermined period after the power is turned on, and determines whether heat collection is possible based on predetermined conditions and records the determination, and if it is determined that heat collection is possible in the inquiry operation, performs a heat collection operation in which the heat medium is circulated until a heat collection end condition is met, Furthermore, the control unit creates an operation table including a first time when heat collection is possible and a second time when heat collection is not possible based on the result of the inquiry operation, A solar thermal heating system characterized in that, after the predetermined period has elapsed, the control unit performs normal operation, in which the inquiry operation is performed at the first time based on the operation table.

2. The solar thermal heating system described in claim 1, characterized in that the control unit, in parallel with the normal operation, determines and records whether heat collection is possible for each inquiry time, and every 24 hours, creates a new operation table by combining it with previously recorded records of whether heat collection is possible, and performs the normal operation based on the new operation table.

3. a return temperature sensor for measuring the temperature of the heat medium heated by the heat collector and an in-tank temperature sensor for measuring the water temperature around the heat exchanger in the heat storage tank; the predetermined condition is whether or not a temperature difference between the measurement result of the return temperature sensor and the measurement result of the tank temperature sensor is equal to or greater than a predetermined heat collection start temperature; The solar thermal heating system described in claim 1 or 2, characterized in that, during the inquiry operation, the control unit determines that heat collection is possible if the temperature difference is greater than or equal to the heat collection start temperature, and determines that heat collection is not possible if the temperature difference is below the heat collection start temperature.

4. 4. The solar thermal heating system according to claim 3, wherein the heat collection end condition is that the temperature difference falls below a predetermined heat collection end temperature.

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