JP2009287423A - Cogeneration system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cogeneration system capable of surely preventing overheating of a power generation unit by suitably controlling a switching valve (thermal valve) for switching a circulation piping system. <P>SOLUTION: This cogeneration system is provided with a first circulation piping system for circulating a coolant between a heat exchanger of a first exhaust heat using part for supplying thermal energy to a hot-water supply load and a power generation part, and a second circulation piping system for circulating the coolant between a second exhaust heat using part consisting of a prescribed thermal load and the power generation part. When a control part executes switching from the first circulation piping system to the second circulation piping system in start of self-sustaining, switching from the first circulation piping system to the second circulation piping system is completed before electric power can be supplied from the power generation part, and the power generation part is started after start of circulation of the coolant in the power generation part or in start of circulation, and supply of AC power to an electric power supply target in self-sustaining is started after the electric power can be supplied from the power generation part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a combined heat and power system capable of supplying electric power and heat by receiving fuel supply from the outside.

  For example, as shown in FIG. 5, a combined heat and power system that can supply power and heat by receiving fuel supply from the outside includes a power generation unit 10 that generates power by receiving fuel supply from the outside, and a power generation unit by circulating coolant. 10 recovers exhaust heat generated during power generation to cool the power generation unit 10, exhaust heat recovery coolant circulation pipe 22, hot water storage tank 21, hot water circulation pipe 23 for circulating hot water in the hot water storage tank 21, and exhaust heat recovery. The exhaust heat recovery heat exchanger 24 that exchanges heat between the coolant circulation pipe 22 and the hot water circulation pipe 23, the operation of the power generation unit 10, and the circulation of the exhaust heat recovery coolant circulation pipe 22 and the hot water circulation pipe 23 are controlled. There is a combined heat and power system 100 configured with a control device 80. Here, it is assumed that the power generation unit 10 includes a gas engine and a generator, and is configured so that the power output from the generator and the commercial AC power supply can be connected to the grid.

  By the way, in the combined heat and power system 100 shown in FIG. 5, for example, when the power generation unit 10 is forcibly operated, such as when a commercial AC power supply is interrupted, the power generation unit 10 is configured when the amount of hot water stored in the hot water storage tank 21 is equal to or greater than a predetermined amount. In order to operate the gas engine and the generator without overheating, it is necessary to consume the exhaust heat from the power generation unit 10 by a method other than the supply of the exhaust heat to the hot water storage tank 21.

  As a technique for operating a conventional power generation unit without overheating, for example, there is a combined heat and power system including a radiator for radiating exhaust heat from the power generation unit to the atmosphere. However, when the combined heat and power system is provided with a radiator, there is a problem that the manufacturing cost increases and the energy saving effect decreases.

  Further, as another technique for operating the power generation unit without overheating, for example, the exhaust heat recovered by the exhaust heat recovery coolant circulation pipe can be supplied to the heating terminal, and the power generation unit is forced During operation, there is a combined heat and power system that performs control to force the heating terminal to operate when the exhaust heat recovery control device detects that the amount of hot water stored in the hot water storage tank is greater than or equal to a predetermined amount (for example, the following patents) Reference 1).

  Here, FIG. 6 shows a schematic partial configuration example of the combined heat and power system described in Patent Document 1.

  As shown in FIG. 6, the combined heat and power system 200 described in Patent Document 1 generates power generation units 10 that generate power by receiving fuel supplied from the outside, and exhaust heat generated by the power generation units 10 during power generation due to circulation of coolant. An exhaust heat recovery coolant circulation pipe 22 that recovers and cools the power generation unit 10, a hot water storage tank 21 that stores hot water, a hot water circulation pipe 23 that circulates hot water in the hot water storage tank 21, and a heat exchanger 19 of the power generation unit 10. The exhaust heat recovery heat exchanger 24 for exchanging heat between the exhaust heat recovery coolant circulation pipe 22 and the hot water circulation pipe 23 connected to the hot water supply output and the hot water supply output for supplying hot water from the hot water storage tank 21 to the hot water supply load 70 The heat exchanger 27 for exchanging heat between the pipe 25, the exhaust heat recovery coolant circulation pipe 22 and the hot water circulation pipe 23 connected to the heating terminal 71, the operation of the power generation unit 10, and the exhaust heat recovery coolant It is configured to include a controller 80 for controlling the circulation of the ring pipe 22 and the hot water circulation pipe 23. Hereinafter, the hot water storage tank 21, the hot water circulation pipe 23, the hot water supply output pipe 25, the exhaust heat recovery heat exchanger 24, and the heating heat exchanger 27 installed in the exhaust heat utilization hot water supply / heating unit 20 are connected to the first exhaust heat utilization section. The heating terminal 71 such as a bathroom heater / dryer installed outside the exhaust heat utilization hot water supply / heating unit 20 is defined as a second exhaust heat utilization unit.

  Here, similarly to the combined heat and power system 100 shown in FIG. 5, the power generation unit 10 includes a gas engine and a generator, and is configured to be capable of system interconnection with the power output from the generator and the commercial AC power supply. Assume the case. Further, the exhaust heat recovery coolant circulation pipe 22 includes a first circulation pipe system PL1 for circulating the coolant between the heat exchanger 19 of the power generation unit 10 and the hot water circulation pipe 23, and the heat exchanger 19 of the power generation unit 10. It is possible to configure a second circulation piping system PL2 that circulates the coolant between the heating terminal 71 and the heating terminal 71.

JP 2007-240016 A

  As described above, in the combined heat and power system 200 shown in FIG. 6, in order to prevent the power generation unit 10 from overheating, the amount of hot water stored in the hot water storage tank 21 is a predetermined amount or more, and the first exhaust heat utilization unit is used. If the exhaust heat cannot be recovered, control is performed to recover the exhaust heat by forcibly operating the second exhaust heat utilization unit. At this time, in the combined heat and power system 200 shown in FIG. 6, it is necessary to switch the thermal valves 36, 37, and 38 from the first circulation piping system PL1 to the second circulation piping system PL2.

  Incidentally, in the combined heat and power system 200 shown in FIG. 6, the thermal valves 36, 37 and 38 take time to open and close in order to prevent a water hammer phenomenon caused by a water pressure difference when the valves are opened and closed relatively rapidly. It has a configuration. Then, for example, when the self-sustaining operation is started, the hot water valves 36, 37, and 38 are set in the first circulation piping system PL1, and the hot water storage amount of the hot water storage tank 21 is equal to or larger than a predetermined amount. When it is necessary to switch the circulation path from the first circulation piping system PL1 to the second circulation piping system PL2, the operation of the thermal valves 36, 37 and 38 is performed at the start of the operation of the circulation pump 33 for circulating the coolant. When started, the power generation unit 10 could not be cooled well during the opening / closing operation of the thermal valves 36, 37, and 38, and there was a possibility of overheating.

  The present invention has been made in view of the above problems, and an object of the present invention is to appropriately control a switching valve (thermal valve) or the like for switching the circulation piping system, thereby preventing overheating of the power generation unit more reliably. The point is to provide a combined heat and power system.

  In order to achieve the above object, a combined heat and power system according to the present invention includes a power generation unit that generates power by receiving fuel supply from the outside, and a power storage unit that stores power by receiving power supply from an external commercial AC power supply or the power generation unit A power generation starting unit that starts power generation by receiving power supply from the commercial AC power source or the power storage unit, and an AC output that can output AC power by receiving power supply from the power generation unit or the power storage unit An exhaust heat recovery coolant circulation pipe for recovering exhaust heat generated by the power generation part during power generation by circulating the coolant and cooling the power generation part; and the coolant in the exhaust heat recovery coolant circulation pipe An electric coolant pump to be circulated, and an exhaust heat utilization unit that uses the exhaust heat by exchanging heat with the coolant of the exhaust heat recovery coolant circulation pipe, and the power generation unit are independent of the commercial AC power source. Autonomous operation A combined heat and power supply system, wherein the exhaust heat utilization unit excludes the first exhaust heat utilization unit that supplies thermal energy to the hot water supply load, and the hot water supply load. A second exhaust heat utilization unit configured with a predetermined heat load, wherein the exhaust heat recovery coolant circulation pipe is disposed between the power generation unit and the heat exchanger of the first exhaust heat utilization unit. And a second circulation piping system that circulates the cooling liquid between the power generation unit and the second exhaust heat utilization unit. The heat utilization unit includes a switching valve that switches between the first circulation piping system and the second circulation piping system, and the control unit starts from the first circulation piping system to the second circulation piping system at the start of the self-sustaining operation. Power to the AC output unit from the power generation unit when switching to Before being able to supply, the switching valve is switched so that the switching from the first circulation piping system to the second circulation piping system is completed, and the electric cooling from the power storage unit via the AC output unit Power is supplied to the liquid pump and the electric coolant pump is operated to start circulation of the coolant in the exhaust heat recovery coolant circulation pipe of the power generation unit or simultaneously with the start of circulation of the coolant from the power storage unit. After supplying power to the power generation start unit to start the power generation unit and enabling power supply from the power generation unit to the AC output unit, the electric coolant pump is supplied from the power generation unit via the AC output unit. The first feature is to perform control for starting the supply of AC power to the power load during the self-sustaining operation that is the target of power supply including the self-sustaining operation.

  In the combined heat and power system according to the present invention as described above, the control unit starts supplying AC power from the power generation unit to the power load during independent operation via the AC output unit. When it is detected that the engine is in an overload state, control is performed to cut off power supply to at least the electric load other than the electric coolant pump and the switching valve among the electric loads during the independent operation. And

  According to the combined heat and power system having the above characteristics, when the control unit switches from the first circulation piping system PL1 to the second circulation piping system PL2 at the start of the self-sustaining operation, power is supplied from the power generation unit to the AC output unit. Before it becomes possible, switching from the first circulation piping system for recovering exhaust heat by the first exhaust heat utilization unit to the second circulation piping system for recovering exhaust heat by the second exhaust heat utilization unit is possible. Since the switching valve is switched so as to be completed, before the power generation unit 10 needs to be cooled, that is, before the power can be supplied from the power generation unit to the AC output unit, the coolant in the second circulation piping system It becomes possible to start circulation. Thus, in the combined heat and power system having the above characteristics, when the exhaust heat cannot be recovered using the first exhaust heat utilization unit at the start of the self-sustaining operation, the coolant circulation path is routed from the first circulation piping system PL1. During the opening / closing operation of the switching valve that switches to the second circulation piping system PL2, it is possible to effectively prevent the power generation unit from overheating.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a combined heat and power system according to the present invention (hereinafter referred to as “the present invention system” as appropriate) will be described with reference to the drawings.

<First Embodiment>
A first embodiment of the system of the present invention will be described with reference to FIGS.

  First, the configuration of the system of the present invention will be described with reference to FIGS. Here, FIG. 1 shows a schematic partial configuration example of the system 1 of the present invention, and FIG. 2 shows a schematic configuration example of the exhaust heat utilization unit and its peripheral devices of the system 1 of the present invention.

  In the present embodiment, the present system 1 assumes a cogeneration system. As shown in FIGS. 1 and 2, a power generation unit 10 that generates power by receiving fuel supply from the outside, The exhaust heat generating hot water supply / heating unit 20 is configured to collect exhaust heat generated during operation and supply the exhaust heat to a hot water supply load 70 and a heating terminal 71 (corresponding to a predetermined heat load).

  Further, the system 1 of the present invention includes a self-sustained operation for generating at least a part of the power consumed by the power loads 61 and 62 without being linked to the commercial AC power supply 60, and the power load linked to the commercial AC power supply 60. The grid interconnection operation for generating at least a part of the electric power consumed by 61 and 62 can be executed. Hereinafter, in the present embodiment, the main grid operation is performed during normal times when power can be normally received from the commercial AC power supply 60, and the main power operation is performed in accordance with the heat demand during normal grid connection operations. In the self-sustained operation at the time of the power failure of the commercial AC power supply 60, the main operation for performing the power generation control according to the power demand is assumed in the self-sustained operation at the time of the power failure of the commercial AC power supply 60. explain.

  As shown in FIG. 1, the power generation unit 10 of the system 1 of the present invention includes a power generation unit 11 including a gas engine 11 a that operates using city gas as a fuel and a generator 11 b that is driven by the gas engine 11 a. An inverter 13 (corresponding to an AC output unit) that converts the generated power into AC power having the same voltage and frequency as the commercial AC power source 60, and a storage battery 16 that stores power by receiving power from the external commercial AC power source 60 or the power generating unit 11 ( A DC / DC converter 17 that performs bidirectional voltage conversion between the input / output terminal of the storage battery 16 and the internal node N0 of the inverter 13, and a power generation control device 18 that performs operation and output control of the power generation unit 10. (Corresponding to the control unit) and heat exchange with the exhaust heat of the power generation unit 11 to heat the cooling water and supply it to the exhaust heat utilization hot water supply / heating unit 20 side. It is configured to include a heat recovery heat exchanger 24 to.

  In the present embodiment, during the grid connection operation, the inverter 13 functions as a power generation starting unit that receives power supply from the commercial AC power source 60 and starts the power generation unit 11, and during the independent operation (the commercial AC power source 60 During a power failure), the DC / DC converter 17 and the AC / DC converter 14 of the inverter 13 function as a power generation starting unit that receives power supply from the storage battery 16 and starts the power generation unit 11 of the power generation unit 10.

  The exhaust heat utilization hot water supply / heating unit 20 recovers exhaust heat generated by the generator 11b during power generation by circulating the coolant to cool the generator 11b, and exhaust heat recovery coolant circulation pipe 22 and exhaust heat recovery coolant circulation pipe. An electric coolant pump that circulates the coolant in 22, and heat exchange with the coolant in the exhaust heat recovery coolant circulation pipe 22, an exhaust heat utilization unit 20 a that utilizes exhaust heat, and an exhaust heat utilization unit 20 a and An exhaust heat recovery control device 32 (corresponding to a control unit) that controls the operation of the circulation pump is provided.

  In this embodiment, as shown in FIG. 2, the exhaust heat recovery coolant circulation pipe 22 generates power during normal grid connection operation and independent operation (when the amount of hot water stored in the hot water storage tank 21 is less than a predetermined amount). A first circulation piping system PL1 that circulates the coolant by forming a circulation path that connects between the heat exchanger 19 in the unit 10 and the exhaust heat recovery heat exchanger 24 (first exhaust heat utilization unit); and heating heat A circulation path that communicates between the exchanger 27 and the heating terminal 71 is formed to form a piping system that circulates the coolant. Further, the exhaust heat recovery coolant circulation pipe 22 is connected to the heat exchanger 19 and the heating terminal 71 (second exhaust heat utilization unit) in the power generation unit 10 during the self-sustaining operation (when the hot water storage tank 21 is a predetermined amount or more). The second circulation piping system PL2 that forms a circulation path that communicates between them and circulates the coolant is formed.

  In this embodiment, the electric coolant pump is composed of a plurality of circulation pumps, and is provided with circulation pumps 33 and 35 for circulating the coolant in the exhaust heat recovery coolant circulation pipe 22. . In this embodiment, it is further provided with the circulation pump 34 for circulating the hot water in the hot water circulation piping 23 of the exhaust heat utilization part 20a mentioned later.

  More specifically, in this embodiment, the circulation pump 33 is interposed in the exhaust heat recovery coolant circulation pipe 22 between the heat exchanger 19 of the power generation unit 10 and a switching valve 37 of the exhaust heat utilization unit 20a described later. The circulation pump 35 is interposed in the exhaust heat recovery coolant circulation pipe 22 between the heating terminal 71 and the exhaust heat utilization hot water supply / heating unit 20. A circulation pump 34 is interposed in a hot water circulation pipe 23 of the exhaust heat utilization unit 20a described later.

  The exhaust heat utilization unit 20 a includes a first exhaust heat utilization unit that supplies thermal energy to the hot water supply load 70, and a second exhaust heat utilization unit that includes a predetermined heat load excluding the hot water supply load 70. The first exhaust heat utilization unit is configured such that the hot water storage tank 21, the hot water circulation pipe 23, the hot water supply output pipe 25, the exhaust heat recovery heat exchanger 24, and the heating heat installed in the exhaust heat utilization hot water supply and heating unit 20 are provided. The second exhaust heat utilization unit is configured by a heating terminal 71 such as a bathroom heating dryer installed outside the exhaust heat utilization hot water supply / heating unit 20. The hot water circulation pipe 23 and the hot water supply output pipe 25 are provided with an auxiliary heat source 31, a check valve, a pressure adjustment valve, a temperature sensor, a pressure sensor, a flow meter, etc., as required. In FIG.

  The hot water storage tank 21 of the first exhaust heat utilization unit was heated by the exhaust heat recovery of the power generation unit 10 during normal grid interconnection operation and independent operation (when the amount of hot water stored in the hot water storage tank 21 is less than a predetermined amount). By storing hot water, the recovered exhaust heat can be stored, and the amount of stored hot water is detected by a hot water storage amount detection means such as a temperature sensor (not shown) or a water level sensor (not shown) installed inside. Is configured to be detectable. Connected to the bottom of the hot water storage tank 21 is a water supply pipe 28 for supplying water to the hot water storage tank 21 from a water supply source (not shown) such as a water supply when hot water is supplied from the hot water storage tank 21 to the hot water supply load 70. is doing. Further, the hot water storage tank 21 has a hot water circulation pipe 23 connected to an exhaust heat recovery heat exchanger 24 and a heating heat exchanger 27, which will be described later, and a hot water supply load 70 such as a hot water tap installed in a bath, kitchen, washroom or the like. A hot water supply output pipe 25 for supplying hot water is output.

  The exhaust heat recovery heat exchanger 24 is provided between jacket cooling water, which is exhaust heat recovery coolant that circulates in the exhaust heat recovery coolant circulation piping 22 of the first circulation piping system PL1, and hot water that circulates in the hot water circulation piping 23. The heat exchanger for performing the heat exchange is connected to the exhaust heat recovery coolant circulation pipe 22 of the first circulation piping system PL1 on the primary side, and the hot water circulation pipe 23 is connected to the secondary side. The hot water circulation pipe 23 is a circulation circuit in which hot water taken out from the lower part of the hot water storage tank 21 is heated by the exhaust heat recovery heat exchanger 24 and returned to the upper part of the hot water storage tank 21 for circulation.

  The heating heat exchanger 27 is a heat exchanger that performs heat exchange between hot water circulating in the hot water circulation pipe 23 and jacket cooling water circulating in the exhaust heat recovery coolant circulation pipe 22 of the second circulation pipe system PL2. Yes, the hot water circulation pipe 23 is connected to the primary side, and the exhaust heat recovery coolant circulation pipe 22 of the second circulation pipe system PL2 is connected to the secondary side.

  Further, the exhaust heat utilization unit 20a includes a switching valve that switches between the first circulation piping system PL1 and the second circulation piping system PL2. In addition, although the switching valve of this embodiment is configured to switch to the first circulation piping system PL1 during the execution of the normal grid connection operation, the power generation unit 10 can be forcibly operated in the grid connection operation. In some cases, the second circulation piping system PL2 may be configured to be usable even during system interconnection operation. In this embodiment, the switching valve includes a plurality of switching valves including a three-way valve or an on-off valve. Further, the switching valve is a thermal valve that takes about one minute from the start of the switching operation to the completion of the switching operation. The exhaust heat recovery coolant circulation pipe 22 and the exhaust heat recovery heat exchanger 24 connected to the generator 11b. Three-way valves 37, 38 interposed at a connection point (branch point) to which the exhaust heat recovery coolant circulation pipe 22 connected to the heating terminal 71 and the exhaust heat recovery coolant circulation pipe 22 connected to the heating terminal 71 are connected; The on / off valve 36 is provided in the exhaust heat recovery coolant circulation pipe 22 between the exhaust heat utilization hot water supply / heating unit 20 and the heating terminal 71.

  More specifically, the on-off valve 36 is opened during normal system interconnection operation and during self-sustaining operation (when the hot water storage tank 21 is less than a predetermined amount), and during self-sustained operation (when the hot water storage tank 21 exceeds a predetermined amount). Case). The three-way valves 37 and 38 communicate between the heat exchanger 19 of the power generation unit 10 and the exhaust heat recovery heat exchanger 24 at the time of grid connection operation and independent operation (when the hot water storage tank 21 is less than a predetermined amount). It is switched to constitute the first piping system that forms the forward path and the backward path, and communicates between the heat exchanger 19 of the power generation unit 10 and the heating terminal 71 during self-sustaining operation (when the hot water storage tank 21 exceeds a predetermined amount). Are switched so as to constitute a second piping system that forms an outgoing path and a return path.

  Hereinafter, the control operation during the independent operation of the system 1 of the present invention will be described with reference to FIG.

  The exhaust heat recovery control device 32 constituting the control unit of the system 1 of the present invention has a hot water storage amount detection means when the switching valves 36, 37 and 38 are set in the first circulation piping system PL1 at the start of the self-sustaining operation. Is used to detect the amount of hot water stored in the hot water storage tank 21, and when the amount of hot water stored is greater than or equal to a predetermined amount, switching from the first circulation piping system PL1 to the second circulation piping system PL2 is performed.

  The predetermined amount is the amount of hot water stored in the hot water storage tank 21 detected by the hot water storage amount detecting means in consideration of the amount of exhaust heat that can be recovered by the first exhaust heat utilization unit so that the power generation unit of the power generation unit 10 does not overheat. Set accordingly. Here, FIG. 3 shows the processing operation of the system 1 of the present invention when switching from the first circulation piping system PL1 to the second circulation piping system PL2 at the start of the independent operation in the system 1 of the present invention. .

  When the exhaust heat recovery control device 32 switches from the first circulation piping system PL1 to the second circulation piping system PL2 at the start of the self-sustaining operation, the power supply unit 11 supplies power to the inverter 13 as shown in FIG. Before it becomes possible, the switching valves 36, 37 and 38 are switched so that the switching from the first circulation piping system PL1 to the second circulation piping system PL2 is completed (step # 101).

  Here, as described above, the switching valves 36, 37, and 38 of the present embodiment take about 1 minute for the switching operation. Therefore, the exhaust heat recovery control device 32 performs control so that the switching operation of the switching valves 36, 37, and 38 is started at least 1 minute before the scheduled time when power can be supplied from the power generation unit 11 to the inverter 13.

  Furthermore, the exhaust heat recovery control device 32 constituting the control unit of the system 1 of the present invention performs exhaust heat recovery control when switching from the first circulation piping system PL1 to the second circulation piping system PL2 at the start of the self-sustaining operation. In parallel with the control of the switching valves 36, 37 and 38 by the device 32, power is supplied from the storage battery 16 to the circulation pump 33 via the inverter 13 to operate the circulation pump 33, and the exhaust heat recovery coolant circulation of the power generation unit 11 is performed. Circulation of the coolant in the pipe 22 is started (step # 102).

  The power generation control device 18 constituting the control unit of the system 1 of the present invention starts from the storage battery 16 after the coolant circulation of the exhaust heat recovery coolant circulation pipe 22 of the power generation unit 11 is started or simultaneously with the start of the coolant circulation. Electric power is supplied to the DC / DC converter 17 and the AC / DC converter 14 (power generation starter) of the inverter 13 to start the power generator 11 (start-up, step # 103).

  Subsequently, the exhaust heat recovery control device 32 that constitutes the control unit of the system 1 of the present invention enables the power supply from the power generation unit 11 to the inverter 13 (after the start-up is completed), and then the power generation unit 11 through the inverter 13. Then, the control for starting the supply of the AC power to the power load during the self-sustaining operation that is the power supply target during the self-sustaining operation including the circulation pump 33 is performed (step # 105). Here, electric power is supplied to the circulation pump 35 that circulates the coolant in the second circulation piping system PL2 that circulates the coolant between the power generation unit 11 and the heating terminal 71 as the second exhaust heat utilization unit. Operate.

  Subsequently, the exhaust heat recovery control device 32 configuring the control unit of the system 1 of the present invention starts the forced operation of the heating terminal 71 (step # 106). Thereby, even when the amount of hot water stored in the hot water storage tank 21 is equal to or greater than a predetermined amount at the start of the independent operation, the power generation unit 11 is effectively prevented from overheating, and the independent operation is effectively stopped. The system 1 of the present invention can be operated while preventing it.

  Further, in the present embodiment, after the execution of step # 106, that is, after the supply of AC power from the power generation unit 11 to the power load at the time of self-sustaining operation is started via the inverter 13, the power load at the time of self-sustaining operation becomes an overload state When it is detected ("YES" branch in step # 111), power supply to power loads other than at least the electric coolant pumps 33, 35 and the switching valves 36, 37, 38 among the power loads during the independent operation Is controlled to shut off (step # 112).

<Another embodiment>
In the above-described embodiment, the present invention system 1 has been described on the assumption that it is a cogeneration system including a gas engine 11a and a generator 11b that generate electricity by consuming city gas or the like, but is not limited thereto. For example, a cogeneration system that includes a power generation unit 11 that can supply power to a power load and a waste heat utilization unit 20a that recovers and makes available the exhaust heat of the power generation unit 11, such as a cogeneration system that uses a fuel cell If it is good.

Schematic block diagram showing a schematic partial configuration example of a combined heat and power system according to the present invention The schematic block diagram which shows the schematic structural example of the waste heat utilization part of the cogeneration system which concerns on this invention, and its peripheral device Flowchart showing the processing operation of the combined heat and power system according to the present invention. Schematic block diagram showing a schematic partial configuration example in another embodiment of the combined heat and power system according to the present invention Schematic block diagram showing a schematic partial configuration example of a combined heat and power system according to the prior art Schematic block diagram showing a schematic partial configuration example of a combined heat and power system according to the prior art

Explanation of symbols

1 Combined Heat and Power System 10 According to the Present Invention 10 Power Generation Unit (Power Generation Unit)
10a Power terminal (at the time of grid connection operation)
10b Power terminal (during independent operation)
11 Power generation section 11a Gas engine 11b Generator 13 Inverter (AC output section)
14 AC / DC converter 15 Bidirectional DC / AC converter 15a DC / AC converter 15b DC / AC converter 16 Storage battery (power storage unit)
17 DC / DC converter 18 Power generation control device (control unit)
19 Heat Exchanger 20 Waste Heat Utilization Hot Water Supply Heating Unit 20a Waste Heat Utilization Unit 20b Power Input Terminal 21 Hot Water Storage Tank 22 Waste Heat Recovery Coolant Circulation Pipe 23 Hot Water Circulation Pipe 24 Waste Heat Recovery Heat Exchanger (First Waste Heat Utilization Section)
25 Hot Water Supply Output Pipe 27 Heating Heat Exchanger 28 Water Supply Pipe 31 Auxiliary Heat Source 32 Waste Heat Recovery Control Device (Control Unit)
33 Circulation pump (electric coolant pump)
34 Circulation pump 35 Circulation pump (electric coolant pump)
36 On-off valve (switching valve)
37 Three-way valve (switching valve)
38 Three-way valve (switching valve)
39 Remote control 40 First distribution board 41 Second distribution board 42 Master breaker (MCB)
43 Breaker (MCB)
44 branch breaker 45 current transformer 46 branch breaker 49 operation switch 51 on / off switch 52 2-input changeover switch 53 on-off switch 54 2-input changeover switch 60 commercial AC power supply 61 power load 62 power load 70 hot water supply load 71 heating terminal (second waste heat utilization) Part)
80 Control device 100 Combined heat and power system PL1 according to prior art First circulation piping system PL2 Second circulation piping system

Claims (2)

A power generation unit that generates electricity by receiving fuel supply from the outside;
An electric power storage unit for receiving electric power from an external commercial AC power source or the power generation unit and storing electric power;
A power generation starting unit that starts power generation by receiving power supply from the commercial AC power source or the power storage unit;
AC output unit capable of receiving AC power from the power generation unit or the power storage unit and outputting AC power;
An exhaust heat recovery coolant circulation pipe for recovering exhaust heat generated by the power generation unit during power generation by circulating the coolant and cooling the power generation unit;
An electric coolant pump for circulating the coolant in the exhaust heat recovery coolant circulation pipe;
By exchanging heat with the coolant of the exhaust heat recovery coolant circulation pipe, an exhaust heat utilization unit that utilizes the exhaust heat, and
A control unit that performs control when the power generation unit performs independent operation independently from the commercial AC power supply, and a cogeneration system comprising:
The exhaust heat utilization unit includes a first exhaust heat utilization unit that supplies thermal energy to a hot water supply load, and a second exhaust heat utilization unit that includes a predetermined heat load excluding the hot water supply load. ,
The exhaust heat recovery coolant circulation pipe circulates the coolant between the power generation unit and the heat exchanger of the first exhaust heat utilization unit, the power generation unit, and the second exhaust A second circulation piping system that circulates the cooling liquid between the heat utilization unit, and
The exhaust heat utilization unit includes a switching valve that switches between the first circulation piping system and the second circulation piping system,
When the control unit switches from the first circulation piping system to the second circulation piping system at the start of the self-sustaining operation, before the power can be supplied from the power generation unit to the AC output unit, The switching valve is switched so that the switching from the first circulation piping system to the second circulation piping system is completed, and power is supplied from the power storage unit to the electric coolant pump via the AC output unit. Power is supplied from the power storage unit to the power generation starting unit after the electric coolant pump is operated and the cooling liquid circulation pipe of the exhaust heat recovery cooling liquid circulation pipe of the power generation unit is started or simultaneously with the start of circulation of the cooling liquid. And start the power generation unit,
After power can be supplied from the power generation unit to the AC output unit, the power load from the power generation unit via the AC output unit to the power load during self-sustained operation including the electric coolant pump includes the electric coolant pump. A combined heat and power system that performs control to start supply of AC power.   When the control unit detects that the power load during self-sustained operation is in an overload state after starting the supply of AC power from the power generation unit to the power load during self-sustained operation via the AC output unit, 2. The combined heat and power system according to claim 1, wherein control is performed to cut off power supply to power loads other than at least the electric coolant pump and the switching valve among the power loads during the independent operation.

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