JP2015190696A - Cogeneration system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cogeneration system capable of improving energy efficiency.SOLUTION: A cogeneration system includes a heat collection panel 11 for receiving solar light and collecting solar heat, a solar heat hot water storage tank 12 for storing the heat collected by the heat collection panel 11, a power generation unit 41 for generating power with the usage of fuel, a waste heat hot water storage tank 42 for storing waste heat of the power generation unit 41, a waste heat transfer mechanism 80 for supplying the waste heat of the power generation unit 41 to the heat collection panel 11 and raising a temperature of the heat collection panel 11, and a control device 120 for supplying the waste heat of the power generation unit 41 to the heat collection panel 11 by the waste heat transfer mechanism 80 when it is estimated that the surplus waste heat of the power generation unit 41 which cannot be stored in the waste heat hot water storage tank 42 is generated.

Description

  The present invention relates to a technology of a cogeneration system that stores and uses solar heat and exhaust heat from a fuel cell.

  Conventionally, a technology of a cogeneration system that stores and uses solar heat and exhaust heat from a fuel cell is known. For example, as described in Patent Document 1.

  In Patent Document 1, hot water (heat) can be accommodated from a consumer (house) provided with a fuel cell system (cogeneration system) to a customer (house) provided with a solar hot water system. Technology is disclosed.

  In such a technology, surplus energy of a consumer provided with a fuel cell system can be accommodated to a consumer provided with the other solar hot water system, and overall high-efficiency operation can be realized. Can do.

  However, the technique as described in Patent Document 1 has room for improvement from the viewpoint of improving energy efficiency.

  Specifically, the solar water heating system described in Patent Document 1 includes a heat collector (solar water heater) that collects solar heat, and a solar heat storage tank (hot water storage tank) that stores heat from the heat collector. To do. In such a solar water heating system, a heat medium is circulated between a heat collector that has become hot due to solar heat and a solar heat storage tank having a temperature lower than that of the heat collector. And can supply heat.

  However, if the heat medium is circulated when the temperature of the heat collector is lower than the temperature of the solar heat storage tank, for example, immediately after sunrise, the heat of the solar heat storage tank is taken away by the heat collector. Therefore, even if the heat collector receives sunlight immediately after sunrise, the heat medium cannot be circulated until the temperature of the heat collector becomes higher than the temperature of the solar heat storage tank.

  Thus, when the temperature of the heat collector is lower than the temperature of the solar heat storage tank, solar heat cannot be immediately stored in the solar heat storage tank, and there is room for improvement from the viewpoint of improving energy efficiency.

JP 2012-159243 A

  The present invention has been made in view of the above situation, and a problem to be solved is to provide a cogeneration system capable of improving energy efficiency.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, in claim 1, a heat collector that receives sunlight to collect solar heat, a solar heat storage tank that stores heat collected by the heat collector, a power generation device that generates power using fuel, An exhaust heat storage tank that stores exhaust heat of the power generation device, an exhaust heat transfer mechanism that supplies the exhaust heat of the power generation device to the heat collector and raises the temperature of the heat collector, and an exhaust of the power generation device Control that causes the exhaust heat transfer mechanism to supply exhaust heat of the power generation device to the heat collector when it is predicted that surplus heat that cannot be stored in the exhaust heat storage tank will occur. A device.

  According to a second aspect of the present invention, the exhaust heat transfer mechanism includes a heat exchanger capable of exchanging heat with the exhaust heat storage tank, and an exhaust for circulating a heat medium between the heat collector and the heat exchanger. And a heat transfer conduit.

  According to a third aspect of the present invention, the exhaust heat transfer mechanism includes a heat exchanger capable of exchanging heat with a hot water supply pipe that supplies the heat medium in the exhaust heat storage tank to a hot water supply demand, and the heat collector. An exhaust heat transfer pipe for circulating a heat medium between the heat exchanger and the heat exchanger.

  According to a fourth aspect of the present invention, the exhaust heat transfer pipe is connected to a solar heat transfer pipe that circulates a heat medium between the heat collector and the solar heat storage tank. And the exhaust heat transfer mechanism is provided at a connection portion between the solar heat transfer pipe and the exhaust heat transfer pipe, and communicates the heat collector with the solar heat storage tank. A first state in which communication between the heat collector and the heat exchanger is interrupted; a first state in which communication between the heat collector and the heat exchanger is established and communication between the heat collector and the solar heat storage tank is interrupted. A switching mechanism for switching between the two states is further provided.

  In Claim 5, The collector temperature detection means which detects the temperature of the said heat collector, The tank temperature detection means which detects the temperature in the said solar thermal storage tank is further comprised, The said control apparatus is the said Only when the temperature of the heat collector is lower than the temperature in the solar heat storage tank, the exhaust heat of the power generator is supplied to the heat collector.

  In claim 6, the control device calculates a supply heat amount of exhaust heat supplied to the heat collector, calculates a time required to supply the supply heat amount to the heat collector, Only when the time from the time until the time when the collector is expected to be able to collect solar heat becomes less than the required time, the exhaust heat of the power generator is supplied to the collector. To do.

  In Claim 7, the said control apparatus makes the solar heat storage the surplus heat amount of the surplus estimated that it cannot be stored in the said waste heat storage tank among the waste heat of the said power generation apparatus, and the temperature of the said heat collector. The necessary heat amount required to raise the temperature in the tank is calculated, and the smaller one of the surplus heat amount and the necessary heat amount is set as the supplied heat amount.

  In Claim 8, the said control apparatus raises the minimum calorie | heat amount which is the minimum value of the waste heat estimated to be stored in the said waste heat storage tank, and the temperature of the said heat collector to the temperature in the said solar thermal storage tank The required amount of heat required for the calculation is calculated, and the smaller one of the minimum heat amount and the required heat amount is set as the supplied heat amount.

  In Claim 9, the said control apparatus is the waste heat which is predicted to be stored in the said waste heat heat storage tank and the surplus heat amount of the surplus heat which cannot be stored in the said waste heat heat storage tank among the waste heat of the said power generation device And calculating the minimum amount of heat that is the minimum value of the above and the amount of heat necessary to raise the temperature of the collector to the temperature in the solar heat storage tank, and the excess heat amount, the minimum amount of heat, and the necessary amount of heat Of these, the smallest value is set as the supply heat amount.

  As effects of the present invention, the following effects can be obtained.

  In claim 1, when it is predicted that surplus heat that cannot be stored in the waste heat storage tank will be generated in the exhaust heat of the power generation device, the temperature of the heat collector is increased using the surplus. be able to. As a result, when the temperature of the heat collector is lower than the temperature in the solar heat storage tank, the temperature of the heat collector can be increased, so that the solar heat can be quickly stored, and thus energy efficiency. Can be improved.

  In Claim 2, energy efficiency can be improved with a simple configuration.

  In claim 3, energy efficiency can be improved with a simple configuration.

  In claim 4, by using a solar heat transfer pipe provided in advance, it is possible to improve energy efficiency with a simple configuration.

  In claim 5, the temperature of the heat collector can be raised only when necessary (when solar heat cannot be stored).

  According to the sixth aspect of the present invention, the amount of supplied heat can be supplied to the heat collector in accordance with the timing at which the heat collector can collect solar heat.

  In claim 7, when the required heat quantity is smaller than the surplus heat quantity, it is possible to cover all the necessary heat quantity from the surplus heat quantity, so by supplying the necessary heat quantity (necessary heat quantity) to the heat collector, The temperature of the collector can be raised sufficiently. On the other hand, when the surplus heat amount is smaller than the required heat amount, only the surplus heat amount is supplied to the heat collector so that the heat stored in the exhaust heat storage tank exceeds the surplus and is supplied to the heat collector. Can be prevented.

  In claim 8, when the required heat quantity is smaller than the minimum heat quantity, there is no possibility that all the heat stored in the exhaust heat storage tank is lost, so the required heat quantity (necessary heat quantity) is supplied to the collector. By doing, the temperature of the said heat collector can fully be raised. On the other hand, when the minimum heat amount is smaller than the required heat amount, only the minimum heat amount is supplied to the heat collector, so that all the heat stored in the exhaust heat storage tank is lost, and further to the heat collector. It is possible to prevent the heat supply from being continued.

  According to the ninth aspect of the present invention, it is possible to prevent the heat stored in the exhaust heat storage tank from being supplied to the heat collector beyond the surplus. Further, it is possible to prevent the supply of heat to the heat collector from being continued in a state in which all the heat stored in the exhaust heat storage tank has been lost.

The schematic diagram which showed the whole structure of the hot water supply system which concerns on one Embodiment of this invention. The schematic diagram which showed the basic operation | movement of the hot water supply system. The figure which showed the time change of the solar radiation amount irradiated to a heat collecting panel, and the temperature of a heat collecting panel. The figure which showed the time change of the heat storage rate of an exhaust heat hot water storage tank. The figure which showed the flow of the process of preheat control (excess heat amount prediction control). The figure which showed the flow of the process of preheat control (start time determination control). The figure which showed the flow of the process of preheat control (preheat execution control). The schematic diagram which showed a mode that the waste heat of an electric power generation unit was supplied to a heat collecting panel. The schematic diagram which showed the whole structure of the hot water supply system which concerns on a modification.

First, the hot water supply system 1 which concerns on one Embodiment of the cogeneration system which concerns on this invention is demonstrated using FIG.
In the following description, water having a relatively low temperature is described as “water”, and water having a relatively high temperature is described as “hot water”. However, there is no substantial difference between water and hot water other than the difference in temperature.

  The hot water supply system 1 is provided at the customer's site to boil hot water using exhaust heat or the like and supply hot water according to hot water supply demand. Here, the “customer” means all things having a demand for hot water supply such as a house and various facilities. “Hot water supply demand” means various facilities where hot water is used, such as a bathroom. The hot water supply system 1 mainly includes a solar water heating system 10, a first water supply pipe 20, a connection pipe 30, a fuel cell system 40, a hot water supply pipe 60, a discharge pipe 70, a waste heat transfer mechanism 80, a panel temperature sensor 90, a first One tank temperature sensor 100, a second tank temperature sensor 110, and a control device 120 are provided.

  The solar hot water system 10 collects and stores solar heat and supplies the heat as necessary. The solar hot water system 10 mainly includes a heat collection panel 11, a solar hot water storage tank 12, a first heat exchanger 13, and a first pipeline 14.

  The heat collection panel 11 is an embodiment of the heat collector according to the present invention. The heat collection panel 11 receives sunlight and collects solar heat. The heat collection panel 11 is formed in a flat plate shape so that it can receive sunlight on a wide surface. The heat collecting panel 11 is installed in a sunny place (for example, on the roof of a house).

  The solar heat storage tank 12 is an embodiment of the solar heat storage tank according to the present invention. The solar hot water storage tank 12 stores the heat collected by the heat collection panel 11. The solar hot water storage tank 12 is formed in a box shape having a space in which water (hot water) can be stored. The solar hot water storage tank 12 can store solar heat by storing a heat medium (in this embodiment, water (hot water)) warmed by heat from the heat collecting panel 11.

  The first heat exchanger 13 transfers heat from a high-temperature fluid (liquid) to a low-temperature fluid (liquid). The first heat exchanger 13 is provided in the solar hot water storage tank 12. The first heat exchanger 13 moves heat (heat exchange) between the water stored in the solar hot water storage tank 12 and the antifreeze liquid flowing through the first heat exchanger 13.

  The first conduit 14 is an embodiment of the solar heat transfer conduit according to the present invention. The first conduit 14 circulates a heat medium (in the present embodiment, an antifreeze liquid) between the heat collection panel 11 and the first heat exchanger 13. The first conduit 14 mainly includes an outward conduit 14a and a return conduit 14b.

  The outgoing line 14 a communicates the heat collection panel 11 and the first heat exchanger 13. One end of the outgoing line 14a is connected to the heat collecting panel 11 (more specifically, one end of a pipe arranged so as to cover the entire surface of the heat collecting panel 11 (circulate in the heat collecting panel 11)). The The other end of the outgoing line 14 a is connected to one end of the first heat exchanger 13.

  The return pipe 14 b communicates the heat collection panel 11 and the first heat exchanger 13. One end of the return pipe 14b is connected to the heat collection panel 11 (more specifically, the other end of the pipe arranged over the entire surface of the heat collection panel 11). The other end of the return pipe 14 b is connected to the other end of the first heat exchanger 13.

  The insides of the first pipeline 14, the heat collecting panel 11, and the first heat exchanger 13 are filled with antifreeze. A pump (not shown) is provided in the middle of the first pipeline 14. By driving the pump, the antifreeze liquid can be circulated in the order of the forward line 14 a, the heat collection panel 11, the return line 14 b, and the first heat exchanger 13.

  The first water supply pipe 20 supplies clean water to the solar hot water storage tank 12. One end of the first water pipe 20 is connected to the solar hot water storage tank 12. When the amount of water (hot water) in the solar hot water storage tank 12 decreases, clean water is supplied from the first water supply pipe 20 into the solar hot water storage tank 12 by the reduced amount.

  The connection line 30 supplies hot water in the solar hot water storage tank 12 to an exhaust heat hot water storage tank 42 of the fuel cell system 40 described later. One end of the connection line 30 is connected to the solar hot water storage tank 12. The other end of the connection line 30 is connected to the exhaust heat hot water storage tank 42.

  The fuel cell system 40 generates power using fuel, stores heat (exhaust heat) generated during the power generation, and supplies the heat as necessary. The fuel cell system 40 mainly includes a power generation unit 41, an exhaust heat hot water storage tank 42, and a radiator 43.

  The power generation unit 41 is an embodiment of the power generation device according to the present invention. The power generation unit 41 extracts (generates power) electric power using a fuel such as hydrogen. As a system of the power generation unit 41, for example, SOFC (solid oxide fuel cell) is used. The SOFC power generation unit 41 is normally operated continuously for 24 hours except when maintenance is performed. The electric power generated by the power generation unit 41 is supplied to various electric loads (electric appliances and the like) provided at the consumer. When the power generation unit 41 generates power, exhaust heat is generated at the same time.

  The exhaust heat storage tank 42 is an embodiment of the exhaust heat storage tank according to the present invention. The exhaust heat hot water storage tank 42 stores the exhaust heat of the power generation unit 41. The exhaust heat hot water storage tank 42 is formed in a box shape having a space in which water (hot water) can be stored. The exhaust heat hot water storage tank 42 is connected to the power generation unit 41. The exhaust heat hot water storage tank 42 can store the exhaust heat by storing a heat medium (water (hot water) in the present embodiment) heated by the exhaust heat of the power generation unit 41. The exhaust heat hot water storage tank 42 is provided with an auxiliary heat source (not shown). The auxiliary heat source can boil the water in the exhaust heat hot water storage tank 42 using fuel.

  The radiator 43 is for radiating the excess heat that cannot be stored in the exhaust heat storage tank 42 out of the exhaust heat of the power generation unit 41 to the outside. The radiator 43 is attached to the power generation unit 41. The radiator 43 can dissipate the exhaust heat by moving the exhaust heat of the power generation unit 41 to the outside air.

  The waste heat hot water storage tank 42 temporarily supplies the water stored therein to the power generation unit 41. The power generation unit 41 boiles the water received from the exhaust heat hot water storage tank 42 by its own exhaust heat and returns it to the exhaust heat hot water storage tank 42 again. The exhaust heat hot water storage tank 42 can store the exhaust heat of the power generation unit 41 by storing the hot water (boiled water) received from the power generation unit 41. In addition, when a sufficient amount of hot water cannot be obtained only by the exhaust heat of the power generation unit 41, the auxiliary heat source can be driven to boil the deficient hot water using fuel.

  Further, there is a limit to the amount of heat that can be stored in the exhaust heat hot water storage tank 42. Therefore, when the amount of heat stored in the exhaust heat hot water storage tank 42 reaches the upper limit value, the radiator 43 is activated. As a result, surplus heat that cannot be stored in the exhaust heat hot water storage tank 42 can be radiated from the radiator 43 to the outside. The amount of heat stored in the exhaust heat hot water storage tank 42 can be measured by using a second tank temperature sensor 110 described later.

  The hot water supply pipe 60 supplies hot water in the exhaust heat hot water storage tank 42 to hot water supply demand (for example, a bathroom etc.). One end of the hot water supply pipe 60 is connected to the exhaust heat hot water storage tank 42. The other end of the hot water supply pipe 60 is connected to the hot water supply demand.

  The exhaust heat transfer mechanism 80 supplies the exhaust heat of the power generation unit 41 to the heat collection panel 11 and raises the temperature of the heat collection panel 11. The exhaust heat transfer mechanism 80 mainly includes a second heat exchanger 81, a second pipe 82, a first three-way valve 83, and a second three-way valve 84.

  The second heat exchanger 81 is an embodiment of the heat exchanger according to the present invention. The second heat exchanger 81 transfers heat from a high temperature fluid (liquid) to a low temperature fluid (liquid). The second heat exchanger 81 is provided in the exhaust heat hot water storage tank 42. The second heat exchanger 81 moves (heat exchanges) heat between the hot water stored in the exhaust heat hot water storage tank 42 and the antifreeze liquid flowing through the second heat exchanger 81.

  The second pipeline 82 is an embodiment of the exhaust heat transfer pipeline according to the present invention. The second pipe line 82 circulates a heat medium (in the present embodiment, an antifreeze liquid) between the second heat exchanger 81 and the first pipe line 14. The second conduit 82 mainly includes an outward conduit 82a and a return conduit 82b.

  The outgoing line 82 a communicates the second heat exchanger 81 and the outgoing line 14 a of the first line 14. One end of the outgoing line 82 a is connected to one end of the second heat exchanger 81. The other end of the outgoing line 82 a is connected to a midway portion of the outgoing line 14 a of the first line 14 via a first three-way valve 83.

  The return pipe line 82 b communicates the second heat exchanger 81 and the return pipe line 14 b of the first pipe line 14. One end of the return pipe 82 b is connected to the other end of the second heat exchanger 81. The other end of the return pipe 82 b is connected to a midway portion of the return pipe 14 b of the first pipe 14 via the second three-way valve 84.

  The first three-way valve 83 is an embodiment of the switching mechanism according to the present invention. The first three-way valve 83 connects the outward conduit 14a of the first conduit 14 and the outward conduit 82a of the second conduit 82 to each other. The first three-way valve 83 can switch the flow path of the antifreeze liquid flowing in the forward conduit 14a and the forward conduit 82a by switching the state to the first state or the second state.

  Here, the “first state” of the first three-way valve 83 means that the upstream side (solar hot water storage tank 12 side) and the downstream side (heat collection panel 11 side) of the outgoing line 14a communicate with each other and the outgoing line 14a. This is a state where the communication between the pipe and the outgoing line 82a is blocked. That is, in the first state, the heat collection panel 11 and the solar hot water storage tank 12 are communicated, and the communication between the heat collection panel 11 and the second heat exchanger 81 is blocked.

  In addition, the “second state” of the first three-way valve 83 communicates the downstream side of the outgoing line 14a and the outgoing line 82a, and the upstream side of the outgoing line 14a and the downstream side of the outgoing line 14a. This is a state in which the communication with the outgoing line 82a is blocked. That is, in the second state, the heat collection panel 11 and the second heat exchanger 81 are communicated, and the communication between the heat collection panel 11 and the solar hot water storage tank 12 is blocked.

  The second three-way valve 84 is an embodiment of the switching mechanism according to the present invention. The second three-way valve 84 connects the return pipeline 14b of the first pipeline 14 and the return pipeline 82b of the second pipeline 82 to each other. The second three-way valve 84 can switch the flow path of the antifreeze liquid flowing through the return conduit 14b and the return conduit 82b by switching the state to the first state or the second state.

  Here, the “first state” of the second three-way valve 84 means that the upstream side (the heat collecting panel 11 side) and the downstream side (the solar heat storage tank 12 side) of the return pipe 14b communicate with each other and the return pipe 14b. This is a state in which the communication with the return pipe 82b is blocked. That is, in the first state, the heat collection panel 11 and the solar hot water storage tank 12 are communicated, and the communication between the heat collection panel 11 and the second heat exchanger 81 is blocked.

  The “second state” of the second three-way valve 84 communicates the upstream side of the return line 14b and the return line 82b, and the downstream side of the return line 14b and the upstream side of the return line 14b. In this state, communication with the return pipe 82b is blocked. That is, in the second state, the heat collection panel 11 and the second heat exchanger 81 are communicated, and the communication between the heat collection panel 11 and the solar hot water storage tank 12 is blocked.

  The interiors of the second heat exchanger 81 and the second pipeline 82 are filled with the antifreeze liquid as in the first pipeline 14. A pump (not shown) is provided in the middle of the second pipe line 82. By driving the pump in a state where the first three-way valve 83 and the second three-way valve 84 are respectively switched to the second state, the antifreeze liquid is sent to the outgoing line 82a, the outgoing line 14a, the heat collecting panel 11, and the return pipe. The passage 14b, the return pipe 82b, and the second heat exchanger 81 can be circulated in this order.

  The panel temperature sensor 90 is an embodiment of the collector temperature detecting means according to the present invention. The panel temperature sensor 90 detects the temperature of the heat collection panel 11. The panel temperature sensor 90 is provided in the heat collection panel 11, and can detect the temperature of the surface (surface which receives sunlight) of the heat collection panel 11.

  The first tank temperature sensor 100 is an embodiment of the tank temperature detecting means according to the present invention. The first tank temperature sensor 100 detects the temperature in the solar hot water storage tank 12. The first tank temperature sensor 100 is provided in the solar hot water storage tank 12 and can detect the temperature of water (hot water) stored in the solar hot water storage tank 12.

  The second tank temperature sensor 110 detects the temperature in the exhaust heat hot water storage tank 42. The second tank temperature sensor 110 is provided in the exhaust heat hot water storage tank 42 and can detect the temperature of water (hot water) stored in the exhaust heat hot water storage tank 42.

  The control device 120 controls the operation of the hot water supply system 1. The control device 120 is mainly configured by an arithmetic processing device such as a CPU, a storage device such as a RAM and a ROM, an input / output device such as an I / O, and a display device such as a monitor. The control device 120 stores in advance various information, programs, and the like for controlling the operation of the hot water supply system 1.

The control device 120 is connected to the panel temperature sensor 90 and can receive a signal related to the temperature of the heat collection panel 11.
The control device 120 is connected to the first tank temperature sensor 100 and can receive a signal related to the temperature in the solar hot water storage tank 12.
The control device 120 is connected to the second tank temperature sensor 110 and can receive a signal related to the temperature in the exhaust heat hot water storage tank 42.
The control device 120 is connected to the first three-way valve 83 and can control the operation of the first three-way valve 83 (switching between the first state and the second state).
The control device 120 is connected to the second three-way valve 84 and can control the operation of the second three-way valve 84 (switching between the first state and the second state).

  Below, basic operation | movement of the hot water supply system 1 comprised as mentioned above is demonstrated using FIG.

  In the solar hot water system 10, when sunlight is irradiated to the heat collection panel 11, the heat collection panel 11 collects solar heat and raises the temperature of the internal antifreeze. The antifreeze liquid is supplied to the first heat exchanger 13 through the return pipe 14b. The first heat exchanger 13 moves the heat of the high-temperature antifreeze supplied from the heat collection panel 11 to the water stored in the solar hot water storage tank 12. Thereby, the water in the solar hot water storage tank 12 is boiled. The antifreeze liquid deprived of heat in the first heat exchanger 13 is supplied again to the heat collection panel 11 via the forward line 14a. In this way, by circulating the antifreeze liquid between the heat collection panel 11 and the first heat exchanger 13, heat from the heat collection panel 11 is stored in the solar hot water storage tank 12 using water (hot water) as a heat medium. Can do.

  In the fuel cell system 40, the water in the exhaust heat hot water storage tank 42 is boiled by exhaust heat generated simultaneously with the operation (power generation) of the power generation unit 41. In this way, the exhaust heat from the power generation unit 41 can be stored in the exhaust heat hot water storage tank 42 using water (hot water) as a heat medium. When hot water is used for hot water supply such as in a bathroom, hot water in the exhaust heat hot water storage tank 42 is supplied to the hot water supply via the hot water supply pipe 60. At this time, the same amount of water (or hot water) as the hot water supplied to the hot water supply demand is supplied from the solar hot water storage tank 12 to the exhaust heat hot water storage tank 42 via the connection pipe 30. In this way, the exhaust heat hot water storage tank 42 is always filled with water (or hot water). Moreover, the temperature of the water (or hot water) in the exhaust heat hot water storage tank 42 is maintained as high as possible by supplying the water (or hot water) in the solar heat hot water storage tank 12 to the exhaust heat hot water storage tank 42. Can do.

  When hot water is supplied from the solar hot water storage tank 12 to the exhaust heat hot water storage tank 42 via the connection pipe 30, the same amount of hot water as that hot water is supplied via the first water supply pipe 20 to the solar hot water storage tank 12. Supplied to. In this way, the solar hot water storage tank 12 is always filled with water (or hot water).

  As described above, in the hot water supply system 1, hot water is boiled using the solar heat collected in the heat collection panel 11 and the exhaust heat of the power generation unit 41, and the hot water can be supplied to the hot water supply demand.

  Here, when the water in the solar hot water storage tank 12 is boiled using the solar heat collected in the heat collecting panel 11 as described above, the temperature of the heat collecting panel 11 becomes higher than the temperature in the solar hot water storage tank 12. Need to be. This will be specifically described below.

  In FIG. 3, the solar radiation amount irradiated to the heat collection panel 11 in one day and the time change of the temperature of the heat collection panel 11 are shown. FIG. 3 shows the sunrise time (heat collection start time) H1 in the day and the temperature (solar heat storage tank temperature) Tt in the solar hot water storage tank 12 when solar heat is not supplied from the heat collection panel 11. Show. The temperature Tt in the solar hot water storage tank 12 changes with time, but is shown as constant in FIG. 3 for convenience of explanation.

  In the time zone (before the sunrise time H1 or after 18:00) when sunlight is not irradiated on the heat collection panel 11 (the amount of solar radiation is 0), the temperature of the heat collection panel 11 is greatly reduced. To do. When the temperature of the heat collecting panel 11 is lowered to a temperature lower than the temperature Tt in the solar hot water storage tank 12, the antifreeze is circulated between the heat collecting panel 11 and the first heat exchanger 13 (see FIG. 2). The heat in the solar hot water storage tank 12 is taken and the heat is supplied to the heat collecting panel 11. That is, the water in the solar hot water storage tank 12 cannot be heated and boiled, and on the contrary, heat is taken away from the water, which is not preferable.

  Therefore, normally, even after sunrise time H1 (in a state where sunlight is applied to the heat collection panel 11), until the temperature of the heat collection panel 11 becomes equal to or higher than the temperature Tt in the solar hot water storage tank 12 (time H2) does not circulate the antifreeze liquid between the heat collecting panel 11 and the first heat exchanger 13.

  Thus, even if the solar panel is irradiated with sunlight, if the temperature of the thermal collector panel 11 is lower than the temperature Tt in the solar hot water storage tank 12, the solar heat is supplied to the solar hot water storage tank. Can't save to 12.

  On the other hand, FIG. 4 shows the ratio of the amount of heat actually stored in the exhaust heat hot water storage tank 42 (heat storage ratio) to the upper limit of the amount of heat that can be stored in the exhaust heat hot water storage tank 42 in the same day as FIG. The change is shown by a solid line. When the heat storage ratio is 100 (%), it means that the heat quantity is stored in the exhaust heat hot water storage tank 42 up to the upper limit. Moreover, when heat (hot water) is used for hot water supply demand, the heat storage rate decreases.

  As described above, the power generation unit 41 is normally operated continuously for 24 hours. Moreover, the time zone (in the example of FIG. 4 around 7 o'clock and around 19 o'clock) in which heat (hot water) is used in hot water supply demand (for example, bathroom) is generally determined. For this reason, a heat storage rate increases with progress of time by the exhaust heat from the power generation unit 41 until the time zone when heat is used for hot water supply demand.

  However, there is a limit to the amount of heat that can be stored in the exhaust heat hot water storage tank 42. For this reason, when the heat storage ratio reaches 100 (%) (full storage), the exhaust heat storage hot water out of the exhaust heat of the power generation unit 41 until the amount of heat is used according to the hot water supply demand (time zone Wt in FIG. 4). The surplus that cannot be stored in the tank 42 is radiated from the radiator 43 to the outside.

  Thus, even if exhaust heat is generated in the power generation unit 41, exhaust heat exceeding the capacity of the exhaust heat hot water storage tank 42 can be stored and is exhausted wastefully.

  From the above, in the hot water supply system 1 according to the present embodiment, when it is predicted in advance that the surplus heat that cannot be stored in the exhaust heat hot water storage tank 42 out of the exhaust heat of the power generation unit 41 will be generated. Using the exhaust heat of 41, the temperature of the heat collection panel 11 is rapidly raised to the temperature Tt in the solar hot water storage tank 12 or higher. Thereby, the solar heat collected by the heat collecting panel 11 is stored in the solar hot water storage tank 12 without waste, and energy efficiency is improved. Hereinafter, control of the hot water supply system 1 (hereinafter, this control is referred to as “preheat control”) will be described.

It should be noted that various predicted values used in the following description (power generation exhaust heat amount D _t , predicted heat demand S _t , hot water loss L _t, etc., which will be described later) are HEMS (Home Energy Management System) provided to consumers. Can be determined based on past data stored in the database.

  The preheat control is a surplus heat amount prediction control that predicts surplus of the exhaust heat of the power generation unit 41, a start time determination control that determines a time to start supplying heat to the heat collection panel 11, and an actual heat collection panel 11. It can be divided into preheating execution control for supplying heat to the heat. Therefore, below, each control is demonstrated in order.

First, the surplus heat amount prediction control process will be described in detail with reference to FIG.
In the present embodiment, it is assumed that the control device 120 executes the surplus heat amount prediction control once a day at a predetermined time.

In step S101 of FIG. 5, the control device 120 substitutes an initial value for the value of the time step number t.
Here, the number of time steps is a numerical value determined in advance corresponding to the time. In this embodiment, the time step number t corresponding to 0 o'clock is set to 0, the time step number t corresponding to 1 o'clock is set to 2, the time step number t corresponding to 1 o'clock is set to 2. It shall be defined as 24. That is, the number of time steps t is a value that increases by 1 every hour, with 0:00 being 0.

The initial value of the time step number t is a value corresponding to the current time. For example, if the current time is 3:00 in step S101, the control device 120 substitutes 3 for the value of the number of time steps t.
In the following, for the sake of convenience, the time is represented using the time step number t. For example, the description “time t” means “time corresponding to the number of time steps t”.
After performing the process of step S101, the control device 120 proceeds to step S102.

In step S <b> 102, the control device 120 calculates a heat quantity (predicted heat quantity) Q _t of exhaust heat that is predicted to be stored in the exhaust heat hot water storage tank 42 at time t.
The predicted heat quantity Q _t can be calculated using a mathematical formula: “predicted heat quantity Q _t = predicted heat quantity Q _t−1 + generated heat quantity D _t −predicted heat demand S _t −hot water storage loss L _t ”.

Here, it is predicted that the predicted heat quantity Q _t-1 is stored in the exhaust heat hot water storage tank 42 at time t-1 (time step one time before time t (one hour before in this embodiment)). It is the amount of heat of exhausted heat.
Further, the waste heat amount D _t during power generation is predicted to be supplied to the waste heat hot water storage tank 42 from the power generation unit 41 that is predicted to be generated from the power generation unit 41 between time t-1 and time t. The amount of exhaust heat generated).
The predicted heat demand _St is the amount of heat that is predicted to be used in hot water supply demand between time t-1 and time t.
The hot water storage loss L _t is the amount of heat (loss) that is unintentionally lost from the exhaust heat hot water storage tank 42 between time t-1 and time t. In the present embodiment, the hot water storage loss L _t is subtracted. However, in actual calculation, a predetermined ratio (for example, 90 (%)) may be multiplied.

  After performing the process of step S102, the control device 120 proceeds to step S103.

In step S103, the control device 120 determines whether or not the predicted heat quantity _Qt is greater than zero.
When the controller 120 determines that the predicted heat quantity _Qt is greater than 0, the controller 120 proceeds to step S201.
When the controller 120 determines that the predicted heat quantity Q _t is 0 or less, the controller 120 proceeds to step S104 (see FIG. 6).

In step S104, the control unit 120, the predicted amount of heat _{Q t} is whether it is not more than the upper limit _{Q max} amount of heat can be stored in the heat storage tank 42 (i.e., thermal storage proportion of waste heat hot water storage tank 42 is 100 (%) Or less) is determined.
Controller 120, if the predicted quantity of heat _{Q t} is determined to be larger than the upper limit value _{Q max,} the process proceeds to step S105.
When determining that the predicted heat quantity Q _t is equal to or lower than the upper limit value Q _max , the control device 120 proceeds to step S107.

In step S105, the controller 120, the value of the surplus heat QS, adds the difference between the predicted amount of heat _{Q t} and the upper limit value _{Q max (Q t -Q max)} .
Here, the surplus heat quantity QS is a variable into which a value obtained by summing the surplus heat quantity at each time is substituted. That is, by repeatedly performing the process for each time, a total value of the surplus heat at each time can be obtained as the surplus heat QS.
After performing the process of step S105, the control device 120 proceeds to step S106.

In step S106, the control unit 120, the value of the predicted heat _{Q t,} substitutes the value of the upper limit value _{Q max.}
This makes the value of the predicted heat _{Q t,} when used as a predicted amount of heat _{Q t-1} in the process of step S102 after the loop (proceeds to step again from step S110 S102), the predicted amount of heat _{Q t-1} This is to prevent the value from exceeding the upper limit value Q _max of the exhaust heat hot water storage tank 42.
After performing the process of step S106, the control device 120 proceeds to step S109.

In step S107, the control unit 120 determines whether the predicted heat _{Q t} is larger than the minimum amount of heat _{Q min.}
Here, the minimum heat quantity Q _min is a variable (see step S108) into which the minimum value is substituted among the predicted heat quantities Q _t at each time. That is, the control device 120 determines whether or not the predicted heat quantity Q _{t at} time t is larger than the minimum value among the predicted heat quantities at each previous time.
Controller 120, when it is determined that the predicted amount of heat _{Q t} is less than or equal to the minimum amount of heat _{Q min,} the process proceeds to step S108.
When the control device 120 determines that the predicted heat amount Q _t is larger than the minimum heat amount Q _min , the control device 120 proceeds to step S109.

In step S108, the control unit 120, the value of the minimum amount of heat _{Q min,} substitutes the value of the predicted heat _{Q t.}
After performing the process of step S108, the control device 120 proceeds to step S109.

In step S109, the control device 120 adds 1 to the value of the number of time steps t.
After performing the process of step S109, the control device 120 proceeds to step S110.

In step S110, the control device 120 determines whether or not the time step number t is a predetermined value tf.
Here, the predetermined value tf is a value set to end the processing loop from step S102 to step S110. In the present embodiment, it is assumed that the processing loop from step S102 to step S110 is repeated until 24:00 (time t = 24), and 24 is set as the predetermined value tf.
When determining that the time step number t is the predetermined value tf, the control device 120 proceeds to step S201 (see FIG. 6).
When determining that the number of time steps t is not the predetermined value tf, the control device 120 proceeds to step S102 again (loops).

Thus, the control device 120 calculates the predicted heat quantity Q _t at each time t until 24 o'clock (step S102), and when there is a time when the predicted heat quantity Q _t exceeds the upper limit value _Qmax (step S104). , and calculates the surplus heat QS by summing the amount exceeding the upper limit value _{Q max} (step S105).
In addition, the control device 120 sets the smallest value among the predicted heat amounts Q _t at each time t as the minimum heat amount Q _min (steps S107 and S108).
In addition, when the predicted heat quantity _Qt becomes 0 or less, the control device 120 ends the surplus heat quantity prediction control, and proceeds to step S201 (step S103).

  In the present embodiment, the surplus heat amount prediction control as described above is performed once a day, but the present invention is not limited to this. For example, it can be performed a plurality of times a day (for example, each time (every hour)).

  In the present embodiment, 24 is set as the predetermined value tf (the processing loop from step S102 to step S110 is repeated until 24:00), but the present invention is not limited to this. That is, the value of the predetermined value tf can be set arbitrarily.

  Next, the start time determination control process will be described in detail with reference to FIG.

In step S201 in FIG. 6, the control device 120 needs to supply heat to the heat collection panel 11 (necessary heat) in order to raise the temperature of the heat collection panel 11 to the temperature in the solar hot water storage tank 12 or higher. QN is calculated.
The necessary heat quantity QN can be calculated using a mathematical formula of “necessary heat quantity QN = (solar heat storage tank temperature Tt−heat collecting panel temperature Tp) × antifreeze liquid amount V × specific heat C”.

Here, the solar hot water storage tank temperature Tt is the temperature in the solar hot water storage tank 12 as described above.
The heat collection panel temperature Tp is the temperature of the surface of the heat collection panel 11.
The antifreeze amount V is the total amount of antifreeze circulating between the heat collecting panel 11 and the second heat exchanger 81.
Specific heat C is the specific heat of the antifreeze liquid.
The values of the antifreeze amount V and the specific heat C are known in advance from the configuration of the hot water supply system 1 and are stored in the control device 120.

  After performing the process of step S201, the control device 120 proceeds to step S202.

In step S202, the control device 120 determines whether or not the excess heat quantity QS (see step S105 in FIG. 5) is larger than the necessary heat quantity QN.
When it is determined that the surplus heat quantity QS is larger than the necessary heat quantity QN, the control device 120 proceeds to step S203.
When it is determined that the surplus heat quantity QS is equal to or less than the necessary heat quantity QN, the control device 120 proceeds to step S204.

In step S203, the control device 120 substitutes the value of the necessary heat quantity QN into the value of the supplied heat quantity QP.
Here, the supplied heat quantity QP is a variable into which the value of the heat quantity actually supplied to the heat collecting panel 11 is substituted.
After performing the process of step S203, the control device 120 proceeds to step S205.

In step S204, the control device 120 substitutes the value of the surplus heat quantity QS for the value of the supply heat quantity QP.
After performing the process of step S204, the control device 120 proceeds to step S205.

In step S205, the control unit 120 determines whether the amount of supplied heat QP is greater than the minimum heat _{Q min.}
When it is determined that the supplied heat quantity QP is equal to or less than the minimum heat quantity Q _min , the control device 120 proceeds to step S206.
Controller 120, if the supplied heat quantity QP is determined to be greater than the minimum amount of heat _{Q min,} the process proceeds to step S207.

In step S206, the control device 120 maintains the value of the supply heat quantity QP as the original value (the value of the supply heat quantity QP determined in step S203 or step S204).
After performing the process of step S206, the control device 120 proceeds to step S208.

In step S207, the control unit 120 substitutes the value of the minimum amount of heat _{Q min} of the value of the supplied heat quantity QP.
After performing the process of step S207, the control device 120 proceeds to step S208.

In step S208, the control device 120 calculates a time (supply start time) HP at which heat supply to the heat collecting panel 11 is started.
The supply start time HP can be calculated using a formula of “supply start time HP = heat collection start time H1−necessary time WN”.

Here, the heat collection start time H1 is a time at which the heat collection panel 11 is predicted to be in a state in which solar heat can be collected. Here, the state where the heat collection panel 11 can collect solar heat means a state where the heat collection panel 11 is irradiated with sunlight. The heat collection start time H <b> 1 is the sunrise time (scheduled sunshine time) in the present embodiment, and is the time when the heat collection panel 11 starts to be irradiated with sunlight. The estimated sunshine time (for example, a predicted sunrise time) is stored in the control device 120 in advance.
The required time WN is an embodiment of the required time according to the present invention. The required time WN is the time required to supply the required heat quantity QN to the heat collecting panel 11. The required time WN can be calculated by using a mathematical expression of “required time WN = supplied heat quantity QP / flow rate R / specific heat C / (solar heat storage tank temperature Tt−heat collecting panel temperature Tp)”.

  Here, the flow rate R is a flow rate of the antifreeze liquid circulating between the heat collection panel 11 and the second heat exchanger 81.

  After performing the process of step S208, the control device 120 proceeds to step S301 (see FIG. 7).

In this way, the control device 120 calculates the necessary heat quantity QN (step S201), and substitutes the smaller value of the surplus heat quantity QS and the necessary heat quantity QN for the supplied heat quantity QP (step S202 to step S204). Thereby, it is possible to prevent the heat amount exceeding the surplus heat amount QS from being supplied to the heat collecting panel 11.
Further, the control unit 120, if the minimum amount of heat _{Q min} is equal to or less than the supply heat quantity QP (step S205), and substitutes the value of the minimum amount of heat _{Q min} to supply heat QP (step S207). Thereby, it is possible to prevent the amount of heat exceeding the minimum amount of heat Q _min from being supplied to the heat collecting panel 11.
In this way, the control device 120 substitutes the smallest value among the surplus heat quantity QS, the necessary heat quantity QN, and the minimum heat quantity Q _min for the supply heat quantity QP (from step S201 to step S207).

  Further, the control device 120 calculates the supply start time HP from the heat collection start time H1 and the necessary time WN. By starting the supply of heat to the heat collection panel 11 from the supply start time HP calculated in this way, the temperature of the heat collection panel 11 becomes the highest when the heat collection start time H1 is reached. be able to.

  Next, the preheat execution control process will be described in detail with reference to FIG.

In step S301 in FIG. 7, the control device 120 determines whether or not the current time is included in a time zone (supply time zone) in which heat is to be supplied to the heat collection panel 11.
Here, the supply time zone is specifically a time zone from the supply start time HP to the heat collection start time H1. That is, the control device 120 determines whether or not the time from the current time to the heat collection start time H1 is less than the necessary time WN (see step S208).
When it is determined that the current time is included in the supply time zone, the control device 120 proceeds to step S302.
When it is determined that the current time is not included in the supply time zone, the control device 120 proceeds to step S304.

In step S302, control device 120 determines whether or not heat collection panel temperature Tp is lower than solar hot water storage tank temperature Tt.
When determining that the heat collection panel temperature Tp is lower than the solar hot water storage tank temperature Tt, the control device 120 proceeds to step S303.
When it is determined that the heat collection panel temperature Tp is equal to or higher than the solar hot water storage tank temperature Tt, the control device 120 proceeds to step S304.

  In step S <b> 303, the control device 120 supplies the exhaust heat of the power generation unit 41 to the heat collection panel 11 by controlling the operations of the first three-way valve 83 and the second three-way valve 84. This will be specifically described below.

  As shown in FIG. 8, the control device 120 switches the first three-way valve 83 and the second three-way valve 84 to the second state.

  In this state, the second heat exchanger 81 moves the heat in the exhaust heat hot water storage tank 42 to the antifreeze liquid in the second heat exchanger 81. As a result, the antifreeze liquid having a high temperature is supplied to the heat collecting panel 11 via the forward line 82a and the forward line 14a. The temperature of the heat collecting panel 11 rises due to the heat from the supplied high temperature antifreeze. The antifreeze liquid deprived of heat in the heat collecting panel 11 is supplied again to the second heat exchanger 81 via the return pipe 14b and the return pipe 82b. In this way, by circulating the antifreeze liquid between the heat collection panel 11 and the second heat exchanger 81, the exhaust heat of the power generation unit 41 stored in the exhaust heat hot water storage tank 42 is transferred to the heat collection panel 11. Can be supplied.

  After performing the process of step S303, the control device 120 proceeds to step S305.

  In step S <b> 304, the control device 120 controls the operation of the first three-way valve 83 and the second three-way valve 84 to stop the supply of the exhaust heat of the power generation unit 41 to the heat collection panel 11. That is, the control device 120 switches the first three-way valve 83 and the second three-way valve 84 to the first state. Note that the first three-way valve 83 and the second three-way valve 84 have already been switched to the first state when the process proceeds to step S304 (the supply of exhaust heat from the power generation unit 41 to the heat collection panel 11 is stopped). The control device 120 maintains that state.

  After performing the process of step S304, the control device 120 proceeds to step S305.

In step S305, the control device 120 determines whether or not the current time is the final time.
Here, the last time is a time corresponding to the number of time steps t at the time when the above-described surplus heat amount prediction control (see FIG. 5) is completed.
Specifically, when the surplus heat amount prediction control shifts from step S110 (see FIG. 5) to step S201 (see FIG. 6), the time step number t is 24, and the final time is 24:00. Become. Further, when the surplus heat amount prediction control shifts from step S103 (see FIG. 5) to step S201 (see FIG. 6), the time corresponding to the number of time steps t at that time becomes the final time.

When it is determined that the current time is the final time, the control device 120 ends the preheat execution control and starts the excess heat amount prediction control (see FIG. 5) again.
When determining that the current time is not the final time, the control device 120 proceeds to step S301.

  As described above, when the current time is included in the supply time zone (step S301) and the heat collecting panel temperature Tp is lower than the solar hot water storage tank temperature Tt (step S302), the control device 120 discharges the power generation unit 41. Heat is supplied to the heat collecting panel 11 (step S303).

  As a result, the heat collecting panel temperature Tp can be quickly raised to the solar hot water storage tank temperature Tt or more (step S302), and the heat from the heat collecting panel 11 can be stored in the solar hot water storage tank 12, thereby improving energy efficiency. Can be achieved.

  Moreover, since the heat supplied to the heat collecting panel 11 at this time is an excess of the exhaust heat of the power generation unit 41 that is predicted to be generated in advance, energy efficiency is improved without wasting energy. Can be achieved. For example, in FIG. 4, the time change of the heat storage rate of the exhaust heat hot water storage tank 42 when the preheat control is performed is indicated by a broken line. As shown in FIG. 4, when it is predicted in advance that the heat storage ratio becomes 100 (%) and surplus heat is generated (see the solid line in the time zone Wt), the heat in the exhaust heat hot water storage tank 42 is stored. By supplying heat (exhaust heat) to the heat collecting panel 11, the heat storage ratio of the exhaust heat hot water storage tank 42 is temporarily reduced (see the broken line around 6 o'clock). However, this reduces the time during which the heat storage ratio becomes 100 (%) and the excess heat is generated (0 in the example of the broken line in FIG. 4), and energy is not wasted.

  On the other hand, when the current time is not included in the supply time zone (step S301), the control device 120 does not supply the exhaust heat of the power generation unit 41 to the heat collection panel 11 (step S304). Specifically, when the current time is a time before the supply start time HP, exhaust heat is not supplied to the heat collection panel 11. As a result, the temperature of the heat collection panel 11 can be increased so that the temperature of the heat collection panel 11 becomes the highest in accordance with the heat collection start time H1, and the energy efficiency can be improved.

The supply time zone is calculated based on the supply heat quantity QP.
Therefore, when the value of the surplus heat quantity QS is used as the value of the supply heat quantity QP (step S204), a heat quantity equal to or greater than the surplus heat quantity QS is supplied to the heat collecting panel 11 and is discharged from the exhaust heat hot water storage tank 42. It is possible to prevent the heat from being consumed more than necessary.
Further, when the value of the minimum heat quantity Q _min is used as the value of the supplied heat quantity QP (step S207), a heat quantity equal to or greater than the minimum heat quantity Q _min is supplied to the heat collecting panel 11 and in the exhaust heat hot water storage tank 42. It is possible to prevent all of the exhaust heat from being consumed.

  Even if the current time is included in the supply time zone (step S301), if the heat collection panel temperature Tp is equal to or higher than the solar hot water storage tank temperature Tt (step S302), the power generation unit 41 The exhaust heat is not supplied to the heat collection panel 11 (step S304). In this case, it is because the heat collection panel temperature Tp has already risen sufficiently to the extent that solar heat can be supplied from the heat collection panel 11 to the solar hot water storage tank 12.

  When the surplus heat quantity QS is predicted to be 0 (there is no surplus heat exhaust from the power generation unit 41), the supply heat quantity QP is 0 (from step S202 to step S207), and the exhaust heat from the power generation unit 41 is exhausted. Is not supplied to the heat collecting panel 11. As described above, what is supplied to the heat collecting panel 11 is limited to the surplus heat of the power generation unit 41. As a result, it is possible to suppress the exhaust heat of the power generation unit 41 stored in the solar hot water storage tank 12 from being insufficient and driving the auxiliary heat source.

As described above, the hot water supply system 1 (cogeneration system) according to the present embodiment is
A heat collecting panel 11 (heat collector) that receives sunlight and collects solar heat;
A solar hot water storage tank 12 (solar heat storage tank) for storing heat collected by the heat collecting panel 11;
A power generation unit 41 (power generation device) that generates power using fuel;
An exhaust heat storage tank 42 (exhaust heat storage tank) for storing the exhaust heat of the power generation unit 41;
An exhaust heat transfer mechanism 80 that supplies the exhaust heat of the power generation unit 41 to the heat collection panel 11 and raises the temperature of the heat collection panel 11;
In the case where it is predicted that surplus heat that cannot be stored in the exhaust heat hot water storage tank 42 will be generated in the exhaust heat of the power generation unit 41, the exhaust heat of the power generation unit 41 is collected by the exhaust heat transfer mechanism 80. A control device 120 to be supplied to
It comprises.
With this configuration, when it is predicted that surplus heat that cannot be stored in the exhaust heat hot water storage tank 42 among the exhaust heat of the power generation unit 41 is generated, the heat collection panel 11 is used by using the surplus. The temperature can be increased. By this, when the temperature of the heat collection panel 11 is lower than the temperature in the solar hot water storage tank 12, the temperature of the heat collection panel 11 can be raised, so that the solar heat can be quickly stored. As a result, energy efficiency can be improved.
Further, by using the predicted surplus heat exhausted from the power generation unit 41 as the heat for increasing the temperature of the heat collecting panel 11, energy efficiency can be further improved.

In addition, the exhaust heat transfer mechanism 80
A second heat exchanger 81 (heat exchanger) capable of exchanging heat with the exhaust heat hot water storage tank 42;
A second pipe 82 (exhaust heat transfer pipe) for circulating a heat medium between the heat collection panel 11 and the second heat exchanger 81;
It comprises.
With such a configuration, energy efficiency can be improved with a simple configuration.

The second pipe line 82 is
By being connected to the first pipe line 14 (solar heat transfer pipe line) that circulates the heat medium between the heat collection panel 11 and the solar heat storage tank 12, the heat collection panel 11 is connected via the first pipe line 14. Connected,
The exhaust heat transfer mechanism 80
It is provided in the connection part of the 1st pipe line 14 and the 2nd pipe line 82, and while connecting the heat collection panel 11 and the solar-heated hot water storage tank 12, it interrupts | blocks communication with the heat collection panel 11 and the 2nd heat exchanger 81. A first three-way valve 83 and a second switch for switching between the first state and the second state in which the heat collection panel 11 and the second heat exchanger 81 are communicated with each other and the communication between the heat collection panel 11 and the solar hot water storage tank 12 is blocked. A two-way valve 84 (switching mechanism) is further provided.
By configuring in this way, the energy efficiency can be improved with a simple configuration by using the first pipeline 14 provided in advance.
Further, there is no need to separately provide piping or the like for circulating the heat medium from the second pipe 82 in the heat collection panel 11 (in order to circulate the heat medium from the first pipe 14 in the heat collection panel 11). Therefore, the energy efficiency can be improved with a simpler configuration.

The hot water supply system 1
A panel temperature sensor 90 (heat collector temperature detecting means) for detecting the temperature of the heat collecting panel 11;
A first tank temperature sensor 100 (tank temperature detecting means) for detecting the temperature in the solar hot water storage tank 12;
Further comprising
The control device 120
Only when the temperature of the heat collection panel 11 is lower than the temperature in the solar hot water storage tank 12 (step S302), the exhaust heat of the power generation unit 41 is supplied to the heat collection panel 11.
By configuring in this way, the temperature of the heat collection panel 11 is raised only when necessary, that is, when the temperature of the heat collection panel 11 is lower than the temperature in the solar hot water storage tank 12 and solar heat cannot be stored. be able to.

In addition, the control device 120
Calculate the supply heat quantity QP of the exhaust heat supplied to the heat collecting panel 11 (from step S201 to step S207),
A required time WN (required time) required to supply the supplied heat quantity QP to the heat collecting panel 11 is calculated (step S208),
Only when the time from the current time to the heat collection start time H1 (the time when the heat collection panel 11 is expected to be able to collect solar heat) is less than the required time WN, the exhaust heat of the power generation unit 41 is exhausted. Is supplied to the heat collecting panel 11 (step S208 and step S301).
By configuring in this way, the supply heat quantity QP can be supplied to the heat collection panel 11 in accordance with the timing at which the heat collection panel 11 can collect solar heat.

In addition, the control device 120
Surplus heat quantity QS that is predicted to be unable to be stored in the exhaust heat hot water storage tank 42 among the exhaust heat of the power generation unit 41 (step S105),
The necessary heat quantity QN required to raise the heat collecting panel temperature Tp (temperature of the heat collecting panel 11) to the solar hot water storage tank temperature Tt (temperature in the solar hot water storage tank 12) (step S201),
To calculate
Of the surplus heat quantity QS and the necessary heat quantity QN, the smaller value is set as the supply heat quantity QP (from step S202 to step S204).
By configuring in this way, when the necessary heat quantity QN is smaller than the surplus heat quantity QS, the necessary heat quantity QN can be covered from the surplus heat quantity QS, so that the necessary heat quantity (necessary heat quantity QN) is supplied to the heat collecting panel 11. By supplying to, the temperature of the heat collecting panel 11 can be sufficiently increased. On the other hand, when the surplus heat quantity QS is smaller than the necessary heat quantity QN, only the surplus heat quantity QS is supplied to the heat collecting panel 11 so that the heat stored in the exhaust heat hot water storage tank 42 exceeds the surplus heat collection. Supplying to the panel 11 can be prevented.

In addition, the control device 120
A minimum heat quantity Q _min that is a minimum value of exhaust heat that is predicted to be stored in the exhaust heat hot water storage tank 42 (step S108);
The necessary heat quantity QN required to raise the heat collecting panel temperature Tp to the solar hot water storage tank temperature Tt (step S201),
To calculate
The smaller value of the minimum heat quantity Q _min and the required heat quantity QN is set as the supply heat quantity QP (from step S205 to step S207).
With this configuration, when the required heat quantity QN is smaller than the minimum heat quantity Q _min, there is no possibility that all the heat stored in the exhaust heat hot water storage tank 42 is lost, so the necessary heat quantity (necessary heat quantity QN). Is supplied to the heat collection panel 11, the temperature of the heat collection panel 11 can be sufficiently increased. State the other hand, if the minimum amount of heat Q _min must heat QN smaller than, only the minimum amount of heat Q _min by supplying to the heat collection panel 11, the heat stored in the heat storage tank 42 is lost all Thus, it is possible to further prevent the heat supply to the heat collecting panel 11 from being continued.

In addition, the control device 120
Surplus heat quantity QS that is predicted to be unable to be stored in the exhaust heat hot water storage tank 42 among the exhaust heat of the power generation unit 41 (step S105),
A minimum heat quantity Q _min that is a minimum value of exhaust heat that is predicted to be stored in the exhaust heat hot water storage tank 42 (step S108);
The necessary heat quantity QN required to raise the heat collecting panel temperature Tp to the solar hot water storage tank temperature Tt (step S201),
To calculate
Among the surplus heat quantity QS, the minimum heat quantity Q _min, and the necessary heat quantity QN, the smallest value is set as the supply heat quantity QP (from step S202 to step S207).
By configuring in this way, it is possible to prevent the heat stored in the exhaust heat hot water storage tank 42 from being supplied to the heat collecting panel 11 beyond the surplus. Further, it is possible to prevent the supply of heat to the heat collecting panel 11 from being continued in a state where all the heat stored in the exhaust heat hot water storage tank 42 is lost.

  In this embodiment, water (hot water) and antifreeze liquid are used as the heat medium. However, the heat medium according to the present invention is not limited to this, and can be arbitrarily selected and used. .

  Moreover, in this embodiment, although the 2nd pipe line 82 shall be connected to the middle part of the 1st pipe line 14, this invention is not limited to this. For example, the second pipe line 82 may be directly connected to the heat collection panel 11 instead of the first pipe line 14 to directly communicate the second heat exchanger 81 and the heat collection panel 11. In this case, a control valve for switching the flow of the heat medium (open / close) is provided in each of the first pipe line 14 and the second pipe line 82, and when one control valve is opened, the other control valve is closed. It is desirable to have a configuration.

Moreover, in this embodiment, although the structure which provides the 1st tank temperature sensor 100 in the solar hot water storage tank 12 was illustrated, this invention is not limited to this. For example, a plurality of first tank temperature sensors 100 may be provided in the solar hot water storage tank 12, and an average of the temperatures detected by the plurality of first tank temperature sensors 100 may be set as the temperature in the solar hot water storage tank 12. is there. Alternatively, the first tank temperature sensor 100 may be provided in the lower part of the solar hot water storage tank 12 and preheat control may be performed using the temperature in the lower part of the solar hot water storage tank 12 (part of the solar hot water storage tank 12 having a particularly low temperature). Is possible.
The same applies to the second tank temperature sensor 110 provided in the exhaust heat hot water storage tank 42.

  In the present embodiment, the state where the heat collection panel 11 can collect solar heat (see step S208 in FIG. 6) means a state where the heat collection panel 11 is irradiated with sunlight. However, the present invention is not limited to this. For example, even if sunlight is irradiated on the heat collection panel 11, it is considered that sufficient heat collection may not be possible if the amount of solar radiation is small. Therefore, a state in which the amount of solar radiation applied to the heat collection panel 11 is equal to or greater than a predetermined value may be determined as a state in which the heat collection panel 11 can collect solar heat.

  In the present embodiment, the sunrise time predicted in advance is illustrated as an example of the scheduled sunshine time (heat collection start time H1) (see step S102), but the present invention is not limited to this. For example, the time when the weather changes from being cloudy or raining to sunny is also included in the scheduled sunshine time. In this case, the estimated sunshine time can be determined based on a weather forecast or the like.

  In the present embodiment, the estimated sunshine time is stored in the control device 120 in advance, but the present invention is not limited to this. For example, the control device 120 may be configured to always obtain the latest scheduled sunshine time (predicted sunrise time, weather forecast, etc.) via the Internet or the like.

  In the present embodiment, in step S302, the control device 120 determines whether or not the heat collection panel temperature Tp is lower than the solar hot water storage tank temperature Tt. However, the present invention is not limited to this. . In other words, the control device 120 determines whether or not the heat collection panel temperature Tp is equal to or higher than the solar hot water storage tank temperature Tt. However, actually, it is considered that the temperature of the heat collecting panel 11 cannot be sufficiently stored in the solar hot water storage tank 12 unless the heat collecting panel temperature Tp becomes a temperature that is somewhat higher than the solar hot water storage tank temperature Tt. . Therefore, in step S302, it is determined whether or not the heat collection panel temperature Tp is equal to or higher than a temperature (target temperature) obtained by adding a predetermined value (for example, 5 (° C.)) to the solar hot water storage tank temperature Tt. good. Thereby, the exhaust heat of the power generation unit 41 can be supplied to the heat collection panel 11 until the heat collection panel temperature Tp rises to the target temperature (a temperature higher than the solar hot water storage tank temperature Tt by a predetermined value).

Further, in the present embodiment, various predicted values (the amount of exhaust heat during power generation D _t , the predicted heat demand S _t , the hot water storage loss L _{t and the} like which will be described later) are stored in data accumulated in the HEMS provided at the customer's site. However, the present invention is not limited to this, and various prediction values are determined by other methods (for example, prediction by an external control device), and the prediction values are stored in the control device 120. It is also possible to adopt a configuration in which

  Moreover, the heat collector which concerns on this invention is not restricted to the heat collecting panel 11 which concerns on this embodiment. For example, it is also possible to use a solar power generator that collects solar heat and generates power by receiving sunlight at the same time as the heat collector.

  In the preheat control (surplus heat amount prediction control) of the present embodiment, the time step number t is set to a value that increases by 1 every hour, with 0 being 0, but the present invention is not limited to this. Can be set arbitrarily. For example, finer control is possible by setting the value to increase by 1 every 30 minutes.

  Moreover, the 2nd heat exchanger 81 (one Embodiment of the heat exchanger which concerns on this invention) which concerns on this embodiment is provided in the exhaust heat hot water storage tank 42, and the electric power generation unit stored in the said exhaust heat hot water storage tank 42 Although heat exchange is performed with the exhaust heat 41, the present invention is not limited to this. For example, as shown in FIG. 9, the second heat exchanger 81 can be provided in the middle of the hot water supply pipe 60. As a result, the exhaust heat transfer mechanism 80 can exchange heat with the hot water flowing through the hot water supply pipe 60 and supply the heat to the heat collecting panel 11.

Thus, the exhaust heat transfer mechanism 80 according to the modification (see FIG. 9)
A second heat exchanger 81 (heat exchanger) capable of exchanging heat with the hot water supply pipe 60 for supplying the heat medium in the exhaust heat hot water storage tank 42 to the hot water supply demand;
A second pipe 82 (exhaust heat transfer pipe) for circulating a heat medium between the heat collection panel 11 and the second heat exchanger 81;
It comprises.
With such a configuration, energy efficiency can be improved with a simple configuration.

  As shown in FIG. 9, the second heat exchanger 81 can be provided at an arbitrary position as long as the exhaust heat of the power generation unit 41 can be recovered.

1 Hot water supply system (cogeneration system)
10 Solar water heating system 11 Heat collector panel (heat collector)
12 Solar thermal storage tank (solar thermal storage tank)
14 1st pipeline (solar heat transfer pipeline)
40 Fuel cell system 41 Power generation unit (power generation device)
42 Waste heat storage tank (Exhaust heat storage tank)
60 Hot water supply pipe 80 Waste heat transfer mechanism 81 Second heat exchanger (heat exchanger)
82 Second pipe (exhaust heat transfer pipe)
83 First three-way valve (switching mechanism)
84 Second three-way valve (switching mechanism)
90 Panel temperature sensor (collector temperature detection means)
100 First tank temperature sensor (tank temperature detection means)
120 controller

Claims (9)

A collector that collects solar heat by receiving sunlight,
A solar heat storage tank for storing heat collected by the heat collector;
A power generation device that generates power using fuel;
An exhaust heat storage tank for storing the exhaust heat of the power generation device;
An exhaust heat transfer mechanism for supplying exhaust heat of the power generation device to the heat collector and increasing the temperature of the heat collector;
When it is predicted that surplus heat that cannot be stored in the exhaust heat storage tank will occur in the exhaust heat of the power generator, the exhaust heat of the power generator is transferred to the heat collector by the exhaust heat transfer mechanism. A control device for supplying to
Cogeneration system equipped with. The exhaust heat transfer mechanism is
A heat exchanger capable of exchanging heat with the exhaust heat storage tank;
An exhaust heat transfer line for circulating a heat medium between the heat collector and the heat exchanger;
Comprising
The cogeneration system according to claim 1. The exhaust heat transfer mechanism is
A heat exchanger capable of exchanging heat with a hot water supply pipe for supplying the heat medium in the exhaust heat storage tank to the hot water supply demand;
An exhaust heat transfer line for circulating a heat medium between the heat collector and the heat exchanger;
Comprising
The cogeneration system according to claim 1. The exhaust heat transfer pipe is
By being connected to a solar heat transfer pipe that circulates a heat medium between the heat collector and the solar heat storage tank, it is connected to the heat collector via the solar heat transfer pipe,
The exhaust heat transfer mechanism is
Provided at a connecting portion between the solar heat transfer pipe and the exhaust heat transfer pipe, and communicates the heat collector and the solar heat storage tank and blocks communication between the heat collector and the heat exchanger. A switching mechanism that switches between one state and a second state that communicates the collector and the heat exchanger and blocks communication between the collector and the solar heat storage tank;
The cogeneration system according to claim 2 or claim 3. Collector temperature detection means for detecting the temperature of the collector;
Tank temperature detecting means for detecting the temperature in the solar heat storage tank;
Further comprising
The controller is
Only when the temperature of the heat collector is lower than the temperature in the solar heat storage tank, the exhaust heat of the power generator is supplied to the heat collector.
The cogeneration system according to any one of claims 1 to 4. The controller is
Calculate the supply heat amount of the exhaust heat supplied to the heat collector,
Calculate the time required to supply the supplied heat amount to the collector,
Only when the time from the current time to the time when the collector is predicted to be able to collect solar heat is less than the required time, the exhaust heat of the power generator is sent to the collector. Supply,
The cogeneration system according to any one of claims 1 to 5. The controller is
Excess heat quantity that is predicted to be unable to be stored in the exhaust heat storage tank among the exhaust heat of the power generation device,
The amount of heat required to raise the temperature of the collector to the temperature in the solar heat storage tank; and
To calculate
Of the surplus heat amount and the required heat amount, the smaller value is the supply heat amount.
The cogeneration system according to claim 6. The controller is
A minimum amount of heat that is a minimum value of exhaust heat that is predicted to be stored in the exhaust heat storage tank; and
The amount of heat required to raise the temperature of the collector to the temperature in the solar heat storage tank; and
To calculate
Of the minimum heat amount and the necessary heat amount, the smaller value is set as the supply heat amount.
The cogeneration system according to claim 6. The controller is
Excess heat amount that cannot be stored in the exhaust heat storage tank among the exhaust heat of the power generator,
A minimum amount of heat that is a minimum value of exhaust heat that is predicted to be stored in the exhaust heat storage tank; and
The amount of heat required to raise the temperature of the collector to the temperature in the solar heat storage tank; and
To calculate
Among the surplus heat amount, the minimum heat amount and the necessary heat amount, the smallest value is the supply heat amount.
The cogeneration system according to claim 6.

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