JP3574611B2 - Exhaust heat recovery system - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an exhaust heat recovery system that performs hot water supply and air conditioning management by using exhaust heat generated from a drive source when a generator is driven by a drive source using natural gas, oil, or the like as a fuel.
[0002]
[Prior art]
2. Description of the Related Art In a relatively small area such as an office building or a commercial facility, a system in which a generator is driven by a driving source using gas, oil, or the like as a fuel and self-supplied by itself is sometimes used. In particular, in recent years, small gas turbines that are driven with low fuel consumption and low noise using city gas or petroleum as the fuel as the driving source of the generator have been adopted, and the above system has attracted attention due to its increased versatility. It is supposed to be.
[0003]
By the way, the above-mentioned electric power self-sufficiency system may be provided with an exhaust heat recovery system that performs hot water supply and air conditioning in the same area using exhaust heat generated from a driving source when driving the generator. Many. An example is shown in FIG. In the figure, reference numeral 101 denotes a gas turbine, 102 denotes a heat exchanger for exhaust heat recovery, 103 denotes a hot water storage tank, 104 denotes a hot water tap, 105 denotes a water supply tank, 106 denotes a heat exchanger for adjusting hot water supply temperature, and 107 denotes a cooling tower. is there. The gas turbine 101 and the exhaust heat recovery heat exchanger 102 are connected by an exhaust gas introduction pipe 108, and the exhaust heat recovery heat exchanger 102 is further provided with an exhaust tower 109 for discharging exhaust gas heated from water. I have.
[0004]
The exhaust heat recovery heat exchanger 102 and the hot water storage tank 103 are connected by a primary pipe 110 constituting a closed system for circulating water (hot water). Further, the hot water storage tank 103, the hot water tap 104, and the hot water temperature adjusting heat exchanger 106 are connected by a secondary pipe 111 constituting a closed system for circulating hot water. The water supply tank 105 is connected to the secondary pipe 111 by a water supply pipe 112. Further, the heat exchanger 106 for adjusting hot water supply temperature and the cooling tower 107 are connected by a refrigerant pipe 113 constituting a closed system for circulating water as a refrigerant.
[0005]
In the above exhaust heat recovery system, the exhaust heat of the gas turbine 101 is introduced into the exhaust heat recovery heat exchanger 102 and exhausted through the hot water storage tank 103, but the water circulating through the primary piping in the exhaust heat recovery heat exchanger 102 This is heat-exchanged and heated. The water (hot water) heated in the exhaust heat recovery heat exchanger 102 flows into the hot water storage tank 103. The water (hot water) in the hot water storage tank 103 circulates through the secondary pipe 111 and flows out of the system when the hot water tap 104 is opened, and is used. When the remaining amount of water (hot water) in the hot water storage tank 103 decreases, water is supplied from the water supply tank 105 as appropriate.
[0006]
By the way, in the above-mentioned exhaust heat recovery system, if the use of water (hot water) circulating in the secondary pipe 111 is small, the temperature in the system will rise excessively. Therefore, including such a case, the excess heat energy is recovered in the hot-water supply temperature adjusting heat exchanger 106 and released into the atmosphere in the cooling tower 107.
[0007]
[Problems to be solved by the invention]
In the exhaust heat recovery system, the cooling system including the hot water supply temperature adjusting heat exchanger 106 and the cooling tower 107 is required, so that the entire system becomes complicated and large-scale, and the cost for installation increases. That is the problem.
[0008]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an exhaust heat recovery system that has a simple structure, is compact, and can stably supply hot water.
[0009]
[Means for Solving the Problems]
As means for solving the above problems, an exhaust heat recovery system having the following configuration is employed. In other words, the exhaust heat recovery system according to claim 1 of the present inventionAn exhaust heat recovery heat exchanger that heats the heat medium by performing heat exchange between exhaust gas and a heat medium generated from a drive source when driving the generator, and the heated heat medium and water A heat exchanger for water heating that heats the water by performing heat exchange between the water and a waste heat recovery system that uses the heated water for hot water supply and air conditioning management,
A buffer tank for temporarily storing the heat medium heated in the exhaust heat recovery heat exchanger is provided, and the exhaust heat recovery heat exchanger is installed at a position higher than the buffer tank, and the buffer tank is Open to the atmosphereIt is characterized by the following.
[0014]
In this exhaust heat recovery system, since the buffer tank is open to the atmosphere, there is no need to employ a pressure-resistant structure for the heat exchanger for exhaust heat recovery and the buffer tank, so that the structure of each part can be simplified. .In addition, since the heat exchanger for exhaust heat recovery is located higher than the buffer tank, even if the pump that supplies the heat medium to the heat exchanger for exhaust heat recovery stops due to loss of power or failure, the heat Since the heat medium in the recovery heat exchanger naturally flows down to the buffer tank by the action of gravity, the heat medium does not abnormally heat, and high safety is ensured.
[0015]
Claim2The exhaust heat recovery system according to the present disclosure is configured to perform heat exchange between exhaust gas generated from a driving source and a heat medium when driving a generator, thereby heating the heat medium, and an exhaust heat recovery heat exchanger that heats the heat medium. A heat exchanger for heating the water by causing heat exchange between the heat medium and the water, and an exhaust heat recovery system that uses the heated water for hot water supply and air conditioning management. So,
A buffer tank for temporarily storing the heat medium heated in the heat exchanger for exhaust heat recovery, the buffer tank being opened to the atmosphere through a pipe, and condensing vapor of the heat medium in the pipe. It is characterized in that a condenser is provided.
[0016]
In this exhaust heat recovery system,By providing a condenser in the pipe that opens the buffer tank to the atmosphere, even if the vaporized heat medium attempts to escape into the atmosphere through the pipe, it is condensed in the condenser and returned to the buffer tank. This prevents the occurrence of a situation such as a reduction in the exhaust heat recovery capability due to a shortage of the heat medium.
[0017]
Claim3The exhaust heat recovery system describedThe exhaust heat recovery system according to claim 1 or 2,A lid made of a heat insulating material is floated on the heat medium in the buffer tank.
[0018]
In this exhaust heat recovery system,By floating the lid made of a heat insulating material on the heat medium in the buffer tank, even if the buffer tank is open to the atmosphere, the amount of heat energy escaping into the atmosphere is suppressed, and the heat energy recovered from the exhaust heat is wasted. It will be available without.
[0019]
Claim4The exhaust heat recovery system describedIn the exhaust heat recovery system according to any one of claims 1 to 3,An inverter control pump for introducing the heat medium from the buffer tank to the heat exchanger for water heating, a third temperature detecting means for detecting the temperature of the water, and a detection result of the third temperature detecting means. And third control means for controlling the driving of the inverter control pump.
[0020]
In this waste heat recovery system, the temperature of the water heated in the heat exchanger for water heating is constantly detected, a large amount of heat energy is recovered from the waste heat, and the heat energy per unit volume of the heat medium becomes excessive. If it is deemed to be large, the amount of heat medium supplied to the hot water supply (air conditioning) side is reduced by reducing the flow rate of the heat medium by reducing the transport amount of the pump, reducing the amount of heat medium introduced into the heat exchanger for water heating. Reduce. Conversely, if the required heat energy cannot be recovered from the exhaust heat and the heat energy per unit volume of the heat medium is deemed to be insufficient, the drive of the inverter control pump is controlled to increase the transport amount and reduce the flow rate of the heat medium. The heat energy supplied to the hot water supply (air conditioning) side is increased by increasing the amount of heat medium introduced into the water heating heat exchanger. Accordingly, even when the exhaust heat recovery is not stable, hot water supply and air conditioning management can be stably performed.
[0021]
Claim5The exhaust heat recovery system according to the present disclosure is configured to perform heat exchange between exhaust gas generated from a driving source and a heat medium when driving a generator, thereby heating the heat medium, and an exhaust heat recovery heat exchanger that heats the heat medium. A heat exchanger for heating the water by causing heat exchange between the heat medium and the water, and an exhaust heat recovery system that uses the heated water for hot water supply and air conditioning management. Exhaust means for exhausting the exhaust gas to be introduced into the heat exchanger for exhaust heat recovery before introduction into the heat exchanger for exhaust heat recovery, and first temperature detection for detecting the temperature of the heat medium Means, first control means for operating the exhaust means based on the detection result of the first temperature detection means, second temperature detection means for detecting the temperature of the water, and heat exchange for water heating Heating means for additionally heating the water heated in the vessel, and detection means for the second temperature detection means. Second control means for operating the heating means on the basis of the above, a buffer tank for temporarily storing the heat medium heated in the exhaust heat recovery heat exchanger, and a heat source for water heating from the buffer tank. An inverter control pump for introducing the heat medium into the exchanger, a third temperature detecting means for detecting the temperature of the water, and controlling the drive of the inverter control pump based on a detection result of the third temperature detecting means And a third control unit.
[0022]
In this exhaust heat recovery system, the first, second, and third control means redundantly control the main components (exhaust means, heating means, inverter control pump, etc.) involved in each control. The control is independent of each other, so if one of the control systems fails, the other control systems will not be affected by this and stable hot water supply and air conditioning management will be possible. I can do it.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
A first embodiment of an exhaust heat recovery system according to the present invention will be described with reference to FIGS.
FIG. 1 shows a configuration of an exhaust heat recovery system provided in parallel with the electric power self-sufficiency system, and FIG. The electric power self-sufficiency system itself obtains electric power by driving a generator using a small gas turbine as a drive source, and an exhaust heat recovery system attached to this system removes exhaust gas generated from the gas turbine when driving the generator. Hot water is supplied using heat.
[0024]
In each figure, reference numeral 1 denotes a gas turbine, and 2 denotes heat exchange between an exhaust gas and a heat medium (actually water is used, but here, it is referred to as a "heat medium" for convenience) to heat the heat medium. The heat exchanger for exhaust heat recovery 3 is a buffer tank for temporarily storing the heat medium heated in the heat exchanger for exhaust heat recovery 2, and the heat exchanger 4 is for heat exchange between the heated heat medium and water. In addition, a water heating heat exchanger for heating water (water actually used for hot water supply), 5 is a gas water heater (heating means) for additionally heating water heated in the water heating heat exchanger 4, Reference numeral 6 denotes a hot water tap for taking out heated water as needed, reference numeral 7 denotes a water supply tank that compensates for a shortage of used water, and P1, P2, and P3 denote pumps that transport a heat medium or water.
[0025]
The gas turbine 1 and the exhaust heat recovery heat exchanger 2 are connected by an exhaust gas introduction pipe 8. A temperature sensor TS1 that detects the temperature of the exhaust gas is provided in the exhaust gas introduction pipe 8 immediately before the introduction of the exhaust gas into the heat exchanger 2 for exhaust heat recovery. Further, the exhaust heat recovery heat exchanger 2 is provided with an exhaust tower 9 for discharging the exhaust gas heating the heat medium.
[0026]
The exhaust heat recovery heat exchanger 2, the buffer tank 3, and the pump P1 are connected by a primary heat medium pipe 10 constituting a primary heat medium circulation system for circulating a heat medium. Further, the buffer tank 3, the water heat exchanger 4, and the pump P2 are connected by a secondary heat medium pipe 11 constituting a secondary heat medium circulation system for circulating the heat medium. Further, the water heating heat exchanger 4, hot water tap 6, and pump P3 are connected by a water pipe 12 constituting a water circulation system for circulating water. Note that the heat exchanger for exhaust heat recovery 2 is installed at a position higher than the buffer tank 3.
[0027]
FIG. 3 shows the structure of the heat exchanger 2 for exhaust heat recovery. The heat exchanger for heat recovery 2 has a housing 20 in which a stainless steel heat transfer tube 22 to which a number of aluminum cooling fins 21 are attached is stored in a meandering state. In the upper part of the housing 20, an exhaust gas inlet 20a and an outlet 20b are provided separately on both sides. An exhaust gas inlet pipe 8 is connected to the inlet 20a, and an exhaust tower 9 is connected to the outlet 20b. ing. The heat transfer tube 22 is connected to the primary heat medium pipe 10 and forms a part of a primary heat medium circulation system.
[0028]
The exhaust heat recovery heat exchanger 2 has a three-way switching valve (exhaust) that guides the exhaust gas introduced through the exhaust gas introduction pipe 8 to the exhaust tower 9 and discharges the exhaust gas to the atmosphere before introduction into the exhaust heat recovery heat exchanger 2. Means) V1 is provided, and a bypass flow passage 14 is provided between the three-way switching valve V1 and the exhaust tower 9. As the three-way switching valve V1, a butterfly valve that swings between the adjacent introduction port 20a and the inlet of the bypass flow path 14 and blocks a part or the entirety of the bypass flow path 14 is employed.
[0029]
Returning to FIG. 1, a three-way switching valve V2 for bypassing the heat medium introduced into the heat exchanger for exhaust heat recovery 2 before and after the heat exchanger for heat recovery 2 and a bypass pipe 15 are provided in the primary heat medium pipe 10. Is provided.
[0030]
A temperature sensor (first temperature detecting means) TS2 for detecting the temperature of the heat medium is provided in the primary heat medium pipe 10 after the heat medium is led out from the heat exchanger for exhaust heat recovery 2. The three-way switching valve V1 is controlled to switch between opening and closing based on the detection result of the temperature sensor TS2 (exhaust heat recovery system control process; details will be described later). The introduction into the exchanger 2 is prevented. Further, the three-way switching valve V2 is also controlled based on the detection result of the temperature sensor TS2, so that the heat medium is bypassed in synchronism with the three-way switching valve V1 to prevent introduction into the exhaust heat recovery heat exchanger 2. I have.
[0031]
A communication pipe 16 that connects the inside of the buffer tank 3 and the exhaust tower 9 is provided above the buffer tank 3. The communication pipe 16 that communicates with the buffer tank 3 is inclined, and a condenser 17 that condenses the vapor of the heat medium flowing through the communication pipe 16 is provided in the middle. In the buffer tank 3, a lid 3a made of a heat insulating material is floated so as to cover the liquid surface of the heat medium.
[0032]
A temperature sensor (third temperature detecting means) TS3 for detecting the temperature of the heated water is provided in the water pipe 12 immediately after the water is led out from the water heating heat exchanger 4. The pump P2 employs an inverter control pump, and its driving is controlled based on the detection result of the temperature sensor TS3 (hot water supply temperature control process; details will be described later). The amount of introduction has been changed.
[0033]
The water pipe 12 is provided with a bypass pipe 17 for bypassing the water introduced into the water heating heat exchanger 4 before and after the water heating heat exchanger 4. Is provided. Further, a gas pipe 18 is connected to the gas water heater 5 so as to receive a gas supply from a gas supply system separately constructed, and the gas pipe 18 is used to introduce gas into the gas water heater 5. An intermittent gas introduction valve V3 is provided.
[0034]
In the bypass pipe 17 immediately before the introduction of the water into the gas water heater 5, a water introduction valve V4 for interrupting the introduction of the water into the gas water heater 5 is provided. The gas water heater 5 operates by detecting the introduction of water when the water introduction valve V4 is opened, heats the introduced water and discharges it to the water circulation system.
[0035]
Further, a temperature sensor (second temperature detecting means) TS4 for detecting the temperature of the water before heating is provided in the water pipe 12 immediately before introducing the water into the heat exchanger 4 for heating water. Switching of opening and closing of the water introduction valve V4 is controlled based on the detection result of the temperature sensor TS4 (hot water supply compensation control process; details will be described later), and the water heater 5 is operated.
[0036]
The water supply tank 7 is connected to the water pipe 12 by a water supply pipe 19, and when the remaining amount of water in the water pipe 12 constituting the water circulation system becomes low, water is appropriately supplied through the water supply pipe 19.
[0037]
The structure of the exhaust heat recovery by the exhaust heat recovery system configured as described above will be described. First, the exhaust gas discharged from the gas turbine 1 is introduced into the exhaust heat recovery heat exchanger 2 through an exhaust gas introduction pipe 8, and performs heat exchange with the heat medium flowing through the primary heat medium circulation system to heat the heat medium. The gas is discharged from the exhaust tower 9 into the atmosphere.
[0038]
The heat medium heated in the exhaust heat recovery heat exchanger 2 is introduced into the buffer tank 3 by the operation of the pump P1, and is temporarily stored. The heat medium stored in the buffer tank 3 is introduced into the secondary heat medium circulation system by the action of the pump P2, and is introduced into the water heating heat exchanger 4 to exchange heat with water flowing through the water circulation system to remove water. It is heated and again introduced into the buffer tank 3.
[0039]
The water heated in the water heat exchanger 4 circulates through the water circulation system by the action of the pump P3, and flows out of the system when the hot water tap 6 is opened, and is used.
[0040]
Next, the flow of processing when operating the exhaust heat recovery system will be described. The initial state of each part of the exhaust heat recovery system before operation is as follows: (three-way switching valve V1: bypasses exhaust gas, three-way switching valve V2: introduces heat medium into exhaust heat recovery heat exchanger 2, gas introduction valve V3: closed, water introduction Valve V4: closed, pumps P1, P2: stopped, pump P3: activated).
[0041]
When the exhaust heat recovery system is operated from this state, as shown in the flowchart of FIG. 4, it is determined in step S1 whether or not the exhaust gas temperature t1 is higher than 200 ° C. based on the detection result of the temperature sensor TS1. If the exhaust gas temperature t1 is equal to or lower than 200 ° C., the gas turbine 1 is considered to be stopped, and the state of each part of the exhaust heat recovery system is changed to the position A (the three-way switching valve V1: exhaust gas bypass, three-way Switching valve V2: heat medium is introduced into exhaust heat recovery heat exchanger 2, gas introduction valve V3 is opened, water introduction valve V4 is closed, and pumps P1, P2, and P3 are operated. Thereafter, the exhaust heat recovery system includes an exhaust heat recovery system control process (first control means) PS1, a hot water supply temperature control process (second control means) PS2, and a hot water supply compensation control process (third control means) PS3. It will be controlled by three independent processes.
[0042]
If the exhaust gas temperature t1 is higher than 200 ° C., it is considered that the gas turbine 1 is operating, and the state of each part of the exhaust heat recovery system is changed to the position B (the three-way switching valve V1: the exhaust heat recovery heat exchanger in step S3). 2, the exhaust gas is introduced into the heat exchanger 2, and the three-way switching valve V2: heat medium is introduced into the exhaust heat recovery heat exchanger 2, the gas introduction valve V3 is opened, the water introduction valve V4 is closed, and the pumps P1, P2, and P3 are operated. Thereafter, the exhaust heat recovery system is controlled by three independent processes of the exhaust heat recovery system control process PS1, the hot water supply temperature control process PS2, and the hot water supply compensation control process PS3, as in the above case.
[0043]
The exhaust heat recovery system control process PS1 is shown in the flowchart of FIG. In the control process, first, in step S4, the opening and closing of the three-way switching valve V1 is continuously controlled based on the detection result of the temperature sensor TS2 so that the heat medium temperature t2 immediately after exhaust heat recovery is maintained at 80 ° C. When the heat medium temperature t2 becomes higher than 80 ° C., the three-way switching valve V1 is switched to (exhaust gas bypass) to discharge the exhaust gas to the atmosphere before introducing the exhaust heat recovery heat exchanger 2 to interrupt the exhaust heat recovery. When the heat medium temperature t2 becomes lower than 80 ° C., the three-way switching valve V1 is switched to (introduce exhaust gas into the heat exchanger for exhaust heat recovery 2) to introduce the exhaust gas into the heat exchanger for exhaust heat recovery 2, and exhaust heat And so on.
[0044]
While the three-way switching valve V1 is controlled, the value of the heating medium temperature t2 is observed, and if it is confirmed that the temperature is 90 ° C. or more in step S5, the three-way switching valve V2 is set to (bypass the heating medium) in step S6. Then, in step S7, an alarm is issued to prompt confirmation of the operation of the exhaust heat recovery heat exchanger 2 or the three-way switching valve V1. Further, if it is not confirmed in step S8 that the state where the heating medium temperature t2 is 100 ° C. or higher is maintained for 60 seconds or longer, the process returns to step S4 and the processing is repeated, and the state where the temperature is 100 ° C. or higher is maintained for 60 seconds or longer. If confirmed, the system is shut down in step S9.
[0045]
The hot water supply temperature control process PS2 is shown in the flowchart of FIG. In the control process, first, in step S10, the drive of the pump P2 is continuously controlled based on the detection result of the temperature sensor TS3 so that the water temperature t3 immediately after heating is maintained at 65 ° C. When the water temperature t3 is higher than 65 ° C., the rotation speed of the pump P2 is reduced to reduce the amount of heat medium introduced into the water heating heat exchanger 4 to reduce the heat energy supplied to the water. If the temperature becomes lower, the number of revolutions of the pump P2 is increased to increase the amount of heat medium introduced into the heat exchanger 4 for heating water, so that the heat energy supplied to the water is increased.
[0046]
While the drive of the pump P2 is controlled, the value of the water temperature t3 is observed. If it is confirmed in step S11 that the temperature has reached 75 ° C. or higher, an alarm is issued in step S12 prompting confirmation of the operation of the pump P2. If it is not confirmed that the water temperature t3 has reached 75 ° C. or higher, the process returns to step S10 and the process is repeated.
[0047]
The hot water supply compensation control process PS3 is shown in the flowchart of FIG. In the control process, first, in step S13, it is determined from the detection result of the temperature sensor TS4 whether the water temperature t4 immediately before heating is lower than 45 ° C.
[0048]
If the water temperature t4 is lower than 45 ° C., in step S14, the water introduction valve V4 is opened, the gas water heater 5 is operated, and the introduced water is heated to further heat the water in the water circulation system. If the water temperature t4 is equal to or higher than 45 ° C., the process of step S13 is repeated.
[0049]
Even after the gas water heater 5 is operated, the value of the water temperature t4 is observed in step S15, and if it is confirmed that the temperature has reached 50 ° C. or higher, the water inlet valve V4 is closed in step S16, and the gas water heater 5 is closed. Stops, and the process of step S13 is repeated. On the other hand, if it is confirmed in step S17 that the water temperature t4 has fallen below 35 ° C., it is considered that the gas water heater 5 has malfunctioned, and an alarm is issued in step S18.
[0050]
All of the above processes are independently executed, but if the operation stop of the exhaust heat recovery system is selected in step S19, all the processes stop processing at the same time (see FIG. 4). At this time, the state of each part of the exhaust heat recovery system is maintained as it was when the operation stop was selected, and if it was confirmed in step S20 that 30 minutes had elapsed since the stop of operation, the parts of the exhaust heat recovery system were determined in step S21. The position is returned to the initial position, and all the processing ends.
[0051]
In the exhaust heat recovery system configured as described above, the heat medium temperature t2 immediately after the exhaust heat recovery is constantly detected, and when the temperature exceeds 80 ° C., the exhaust gas to be introduced into the exhaust heat recovery heat exchanger 2 is discharged. By discharging to the atmosphere before introduction, only the heat energy required for hot water supply is recovered in the heat exchanger for waste heat recovery 2, and excess heat energy is introduced to the heat exchanger for waste heat recovery 2. Since it is discharged into the atmosphere before cooling, conventional cooling equipment is not required.
[0052]
In the above exhaust heat recovery system, the water temperature t3 after being heated in the water heating heat exchanger 4 is always detected, and if the water temperature t3 greatly exceeds 65 ° C., the heat energy per unit volume of the heat medium becomes excessive. Therefore, the flow rate of the heat medium is reduced by reducing the transport amount of the pump P2, the heat medium introduction amount to the water heating heat exchanger 4 is reduced, and the heat energy supplied to the hot water supply side is reduced. Conversely, if the water temperature t3 is lower than 65 ° C., it is considered that the heat energy per unit volume of the heat medium is not sufficient, and the drive of the pump P2 is controlled to increase the transport amount to increase the flow rate of the heat medium, thereby increasing the heat exchange for water heating. The amount of heat medium introduced into the vessel 4 is increased to increase the heat energy supplied to the hot water supply side. Thereby, even if the exhaust heat recovery is not stable, hot water supply and air conditioning management can be performed stably.
[0053]
In the above exhaust heat recovery system, the water temperature t4 introduced into the water heating heat exchanger 4 is always detected, and when the water temperature t4 falls below 45 ° C., the gas water heater 5 is operated, and the water heating heat exchange is performed. The heated water in the vessel 4 or the water to be heated is additionally heated. This makes it possible to stably perform hot water supply and air conditioning management even when necessary heat energy cannot be recovered from exhaust heat, such as immediately after the system is started.
[0054]
In the exhaust heat recovery system, since the buffer tank 3 is of the open-to-atmosphere type, it is not necessary to employ a pressure-resistant structure in the heat exchanger 2 for exhaust heat recovery and the buffer tank 3 itself. Thereby, the structure of each part of the system can be simplified.
[0055]
Further, by floating the lid 3a made of a heat insulating material on the heat medium in the buffer tank 3, even if the buffer tank 3 is open to the atmosphere, the amount of heat energy escaping into the atmosphere can be suppressed and recovered from the exhaust heat. The waste heat energy can be used without waste.
[0056]
Further, even if the vapor of the heat medium attempts to escape to the atmosphere through the communication pipe 16, the vapor is condensed in the condenser 17 and returned to the buffer tank 3. This prevents the occurrence of a situation such as a reduction in the exhaust heat recovery capability due to a shortage of the heat medium.
[0057]
In addition, when the pump P1 for supplying the heat medium to the heat exchanger for heat recovery 2 is stopped due to loss of power or a failure thereof, the heat exchanger 2 for heat recovery is positioned higher than the buffer tank 3. In addition, since the buffer tank 3 is open to the atmosphere, the heat medium in the exhaust heat recovery heat exchanger 2 naturally flows down to the buffer tank 3 by the action of gravity, so that the heat medium is abnormally heated. And high security is ensured.
[0058]
In addition, in the exhaust heat recovery system, the three processes of the exhaust heat recovery system control process, the hot water supply temperature control process, and the hot water supply compensation control process redundantly control the components of the system involved in each control. And are executed independently and individually. For example, even if a malfunction occurs in the heat exchanger for exhaust heat recovery 2 or the three-way switching valve V1 and the exhaust heat recovery system control process issues an alarm, the hot water supply temperature control process and the hot water supply compensation control process affect this. It is performed independently without being performed, so that a stable hot water supply can be obtained.
[0059]
Next, a second embodiment of the exhaust heat recovery system according to the present invention will be described with reference to FIGS. Note that the same reference numerals are given to the components already described in the first embodiment, and description thereof will be omitted.
In the exhaust heat recovery system of the present embodiment, as shown in FIG. 8, the secondary heat medium circulation system and the pump P2 are not provided, and the heat exchanger 4 for water heating uses heat flowing through the primary heat medium circulation system. Heat exchange is performed between the medium and water flowing through the water circulation system.
[0060]
Further, in the present embodiment, the water pipe 12 is provided with a bypass pipe 30 for bypassing the water introduced into the water heating heat exchanger 4 immediately before and immediately after the water heating heat exchanger 4. 30 is provided with a three-way switching valve V5. Further, an on-off valve V6 is provided between the three-way switching valve V5 and the heat exchanger 4 for water heating. The three-way switching valve V5 is controlled to switch between opening and closing based on the detection result of the temperature sensor TS3 (hot water supply temperature control process), and changes the amount of water introduced into the water heating heat exchanger 4.
[0061]
The structure of the exhaust heat recovery by the exhaust heat recovery system configured as described above will be described. First, the exhaust gas discharged from the gas turbine 1 is introduced into the exhaust heat recovery heat exchanger 2 through an exhaust gas introduction pipe 8, and performs heat exchange with the heat medium flowing through the primary heat medium circulation system to heat the heat medium. The gas is discharged from the exhaust tower 9 into the atmosphere.
[0062]
The heat medium heated in the exhaust heat recovery heat exchanger 2 flows through the primary heat medium circulation system by the action of the pump P1, and a part of the heat medium is introduced into the buffer tank 3 and temporarily stored. The heat medium flowing through the primary heat medium circulation system is introduced into the water heating heat exchanger 4, heat-exchanges with the water flowing through the water circulation system to heat the water, and is again introduced into the buffer tank 3.
[0063]
The water heated in the water heat exchanger 4 circulates through the water circulation system by the action of the pump P3, and flows out of the system when the hot water tap 6 is opened, and is used.
[0064]
Next, the flow of processing when operating the exhaust heat recovery system will be described. The initial state of each part of the exhaust heat recovery system before operation is as follows: (three-way switching valve V1: bypasses exhaust gas, three-way switching valve V2: introduces heat medium into exhaust heat recovery heat exchanger 2, gas introduction valve V3: closed, water introduction The valve V4 is closed, the three-way switching valve V5 is bypassing the heat exchanger 4 for heating water, the pump P1 is stopped, and the pump P3 is operated.
[0065]
When the exhaust heat recovery system is operated from this state, as shown in the flowchart of FIG. 9, it is determined in step S22 whether or not the exhaust gas temperature t1 is higher than 200 ° C. based on the detection result of the temperature sensor TS1. If the exhaust gas temperature t1 is equal to or lower than 200 ° C., the gas turbine 1 is considered to be stopped, and the state of each part of the exhaust heat recovery system is switched to the position C (the three-way switching valve V1: exhaust gas bypass, three-way Switching valve V2: Heat medium introduction into exhaust heat recovery heat exchanger 2, gas introduction valve V3: open, water introduction valve V4: closed, three-way switching valve V5: bypass water heating heat exchanger 4, pumps P1, P3 : Operation). Thereafter, the exhaust heat recovery system is controlled by three independent processes: an exhaust heat recovery system control process PS1, a hot water supply temperature control process PS2, and a hot water supply compensation control process PS3.
[0066]
If the exhaust gas temperature t1 is higher than 200 ° C., it is considered that the gas turbine 1 is operating, and the state of each part of the exhaust heat recovery system is changed to the position D (the three-way switching valve V1: exhaust heat recovery heat exchanger) in step S24. 2, exhaust gas is introduced into the heat exchanger 2, a three-way switching valve V2: a heat medium is introduced into the heat exchanger 2 for exhaust heat recovery, a gas introducing valve V3 is opened, a water introducing valve V4 is closed, and a three-way switching valve V5 is supplied to the water heating heat exchanger 4. Water is introduced, and the pumps P1 and P3 are switched to operation. Thereafter, the exhaust heat recovery system is controlled by three independent processes of the exhaust heat recovery system control process PS1, the hot water supply temperature control process PS2, and the hot water supply compensation control process PS3, as in the above case.
[0067]
However, the exhaust heat recovery system control process PS1 and the hot water supply compensation control process PS3 are the same as those in the first embodiment, and thus are omitted here, and only the hot water supply temperature control process PS2 that is different in processing is shown in FIG. 10 and described. Note that the flow of processing after the operation stop of the exhaust heat recovery system is selected is the same as that of the first embodiment, and thus is omitted here.
[0068]
In the hot water supply temperature control process PS2 of the present embodiment, first, in step S25, the three-way switching valve V5 is continuously controlled so that the water temperature t3 immediately after heating is maintained at 65 ° C. When the water temperature t3 becomes higher than 65 ° C., the three-way switching valve V5 is opened to reduce the amount of heat medium introduced into the water heating heat exchanger 4 to reduce the heat energy supplied to the water, and the water temperature t3 becomes lower than 65 ° C. If so, the three-way switching valve V5 is closed, the amount of heat medium introduced into the water heating heat exchanger 4 is increased, and the heat energy supplied to the water is increased.
[0069]
Even after the operation of the three-way switching valve V5 is controlled, the value of the water temperature t3 is observed in step S26, and if it is confirmed that the temperature has reached 75 ° C. or higher, an alarm prompting confirmation of the operation of the three-way switching valve V5 in step S27. Then, in step S28, the three-way switching valve V5 bypasses the exhaust gas and the on-off valve V6 is closed. If it is not confirmed that the water temperature t3 has reached 75 ° C. or higher, the process returns to step S25 and the process is repeated.
[0070]
In the above exhaust heat recovery system, the water temperature t3 after being heated in the water heating heat exchanger 4 is always detected, and when the water temperature t3 exceeds 65 ° C., the heat energy per unit volume of the heat medium becomes excessive. Considering that the amount is large, the amount of water introduced into the water heating heat exchanger 4 is reduced to reduce the heat energy supplied to the hot water supply side. Thereby, even if the exhaust heat recovery is not stable, hot water supply and air conditioning management can be performed stably.
[0071]
Also in the exhaust heat recovery system, the three processes of the exhaust heat recovery system control process, the hot water supply temperature control process, and the hot water supply compensation control process control the components of the system involved in the respective controls redundantly. Are not configured and are executed independently of each other, so that a stable hot water supply can be obtained.
[0072]
By the way, in each of the first and second embodiments, the case where the recovered heat energy is used for hot water supply has been described. However, the exhaust heat recovery system according to the present invention is not limited to this. It can also be used for air conditioning management. Further, in each of the embodiments, the gas water heater 5 is employed as the heating means. However, a heating means which performs heating using fuel or electric power other than gas may be employed.
It goes without saying that each of the set values adopted in the first and second embodiments can be appropriately changed.
[0073]
【The invention's effect】
As described above, according to the exhaust heat recovery system according to claim 1 of the present invention,Since the buffer tank is open to the atmosphere, there is no need to adopt a pressure-resistant structure for the heat exchanger for exhaust heat recovery and the buffer tank, so the structure of each part can be simplified, and the system can be made more compact and installation costs can be reduced. Can be reduced.
In addition, since the heat exchanger for exhaust heat recovery is located higher than the buffer tank, even if the pump that supplies the heat medium to the heat exchanger for exhaust heat recovery stops due to loss of power or failure, the heat Since the heat medium in the recovery heat exchanger naturally flows down to the buffer tank by the action of gravity, the heat medium does not abnormally heat. Therefore, high security can be ensured.
[0076]
Claim2According to the exhaust heat recovery system described above, by providing a condenser in the pipe that opens the buffer tank to the atmosphere, even if the vaporized heat medium attempts to escape to the atmosphere through the pipe, the heat medium is condensed in the condenser and stored in the buffer tank. Therefore, occurrence of a situation such as reduction of exhaust heat recovery capability due to shortage of the heat medium is prevented, and stable hot water supply and air conditioning management can also be realized.
[0077]
Claim3According to the exhaust heat recovery system described above, even if the buffer tank is open to the atmosphere, the amount of heat energy escaping into the atmosphere is suppressed by floating the lid made of a heat insulating material on the heat medium in the buffer tank. Since the heat energy recovered from the exhaust heat can be used without waste, the efficiency of the system can be improved.
[0078]
Claim4Exhaust heat recovery system describedToAccording to the present invention, it is possible to increase or decrease the flow rate of the heat medium by increasing the transfer amount of the inverter control pump and adjust the heat energy supplied to the hot water supply or the air conditioning side by increasing or decreasing the amount of the heat medium introduced into the heat exchanger for water heating. Thereby, even when the exhaust heat recovery is not stable, stable hot water supply and air conditioning management can be realized.
[0079]
Claim5According to the described exhaust heat recovery system, each control means is not configured to redundantly control the main components involved in each control, but performs control independently of each other, Even if a failure occurs in any of the control systems, the other control systems are not affected by this. Therefore, even in such a case, stable hot water supply and air conditioning management can be realized.
[Brief description of the drawings]
FIG. 1 is a first embodiment of an exhaust heat recovery system according to the present invention, and is a block diagram illustrating a configuration of an exhaust heat recovery system provided alongside a power self-sufficiency system.
FIG. 2 is a perspective view showing a specific internal structure of the exhaust heat recovery system.
FIG. 3 is a side view showing the internal structure of the heat exchanger for exhaust heat recovery.
FIG. 4 is a flowchart showing a processing procedure when operating the exhaust heat recovery system.
FIG. 5 is a flowchart showing a processing procedure of an exhaust heat recovery system control process.
FIG. 6 is a flowchart showing a processing procedure of a hot water supply temperature control process.
FIG. 7 is a flowchart showing a processing procedure of a hot water supply compensation control process.
FIG. 8 is a block diagram showing a configuration of an exhaust heat recovery system according to a second embodiment of the present invention, which is provided in conjunction with a power self-sufficiency system.
FIG. 9 is a flowchart showing a processing procedure when operating the exhaust heat recovery system.
FIG. 10 is a flowchart showing a processing procedure of a hot water supply temperature control process.
FIG. 11 is a block diagram showing a configuration of a conventional exhaust heat recovery system.
[Explanation of symbols]
1 Gas turbine
2 Exhaust heat recovery heat exchanger
3 buffer tank
3a Lid
4 Heat exchanger for water heating
5 Gas water heater (heating means)
6 hot water taps
17 Condenser
V1 Three-way switching valve (exhaust means)
P2 pump (Inverter control pump)
TS2 Temperature sensor (first temperature detecting means)
TS3 temperature sensor (third temperature detecting means)
TS4 Temperature sensor (second temperature detecting means)
PS1 Exhaust heat recovery system control process (first control means)
PS2 Hot water supply temperature control process (second control means)
PS3 Hot water supply compensation control process (third control means)

Claims (5)

An exhaust heat recovery heat exchanger that heats the heat medium by performing heat exchange between exhaust gas and a heat medium generated from a drive source when driving the generator, and the heated heat medium and water A heat exchanger for water heating that heats the water by performing heat exchange between the water and a waste heat recovery system that uses the heated water for hot water supply and air conditioning management,
A buffer tank for temporarily storing the heat medium heated in the exhaust heat recovery heat exchanger is provided, and the exhaust heat recovery heat exchanger is installed at a position higher than the buffer tank, and the buffer tank is An exhaust heat recovery system that is open to the atmosphere. An exhaust heat recovery heat exchanger that heats the heat medium by performing heat exchange between exhaust gas and a heat medium generated from a drive source when driving the generator, and the heated heat medium and water A heat exchanger for water heating that heats the water by performing heat exchange between the water and a waste heat recovery system that uses the heated water for hot water supply and air conditioning management,
A buffer tank for temporarily storing the heat medium heated in the heat exchanger for exhaust heat recovery, the buffer tank being opened to the atmosphere through a pipe, and condensing vapor of the heat medium in the pipe. An exhaust heat recovery system comprising a condenser. The exhaust heat recovery system according to claim 1 , wherein a lid made of a heat insulating material floats on the heat medium in the buffer tank . An inverter control pump for introducing the heat medium from the buffer tank to the heat exchanger for water heating, a third temperature detecting means for detecting the temperature of the water, and a detection result of the third temperature detecting means. The exhaust heat recovery system according to any one of claims 1 to 3, further comprising third control means for controlling the driving of the inverter control pump . An exhaust heat recovery heat exchanger that heats the heat medium by performing heat exchange between exhaust gas and a heat medium generated from a drive source when driving the generator, and the heated heat medium and water A heat exchanger for water heating that heats the water by performing heat exchange between the water and a waste heat recovery system that uses the heated water for hot water supply and air conditioning management,
Exhaust means for exhausting the exhaust gas to be introduced into the heat exchanger for exhaust heat recovery before introduction to the heat exchanger for exhaust heat recovery, first temperature detecting means for detecting the temperature of the heat medium, First control means for operating the exhaust means based on the detection result of the first temperature detection means, second temperature detection means for detecting the temperature of the water, and heating in the heat exchanger for water heating. Heating means for additionally heating the water, a second control means for operating the heating means based on a detection result of the second temperature detecting means, and a heating means for heating the waste heat recovery heat exchanger. A buffer tank for temporarily storing the heat medium, an inverter control pump for introducing the heat medium from the buffer tank to the heat exchanger for water heating, and third temperature detection means for detecting the temperature of the water. , Detection result of the third temperature detecting means The third exhaust heat recovery system, characterized in that it comprises a control means for controlling the drive of the inverter control pump based.

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