JP2014156806A - Power generating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power generating system capable of improving energy efficiency in a system and also capable of improving quietness.SOLUTION: A power generating system includes: a power generator 1; a heat exchanger 2 in which a heating medium for receiving exhaust heat of the power generator 1 circulates; a boiler 3 for adjusting temperature of the heating medium; and a control device 4 for controlling the power generator 1 and the boiler 3 according to a power load condition and a heat load condition. The control device 4 has a heat main operation mode for adjusting the temperature of the heating medium by stopping the combustion of the boiler 3 and by controlling the power generation amount of the power generator 1 according to the heat load condition, as an operation mode.

Description

  The present invention relates to a power generation system that uses power generated by power generation and exhaust heat.

  2. Description of the Related Art Conventionally, a power generation system that uses exhaust heat generated by a power generation device for a heat load such as heating has been developed. Examples of the power generation device include a generator driven by an engine and a device using a fuel cell. That is, as a power generation system using exhaust heat, a cogeneration device (for example, a gas engine cogeneration device or a fuel cell cogeneration device) can be cited. Conventionally, such a power generation system includes a hot water storage tank, and stores a heat medium that has received exhaust heat when it cannot be used up.

  However, in a power generation system having a hot water storage tank, there are factors that reduce energy saving performance, such as heat radiation from the hot water storage tank and inability to use up the heat in the hot water storage tank. Thus, for example, as described in Japanese Patent Application Laid-Open No. 2000-087801, a power generation system (cogeneration apparatus) that does not include a hot water storage tank has been developed. Such a cogeneration apparatus is basically rated operation, and when the supply temperature to the heat load is insufficient, the boiler is driven to adjust the temperature.

Japanese Patent Laid-Open No. 2000-087801

  However, in the conventional system, for example, when temperature adjustment below the minimum output of the boiler is required, the supply temperature to the heat load is adjusted by controlling the boiler on / off (rated operation / stop). . The operation in which the boiler is turned on / off is less efficient than the rated operation of the boiler. Further, when the boiler is repeatedly turned on / off, the user may feel uncomfortable with the ignition sound and the fire extinguishing sound. Especially in cold regions, boilers are installed indoors to prevent freezing, making it easier to hear sounds.

  As described above, in a conventional system, when driving a heat load having a low required temperature for a boiler, such as floor heating or a panel heater, the energy efficiency and quietness of the system are reduced due to boiler on / off control.

  This invention is made | formed in view of such a situation, and it aims at providing the electric power generation system which can improve quietness while improving the energy efficiency in a system.

  A power generation system according to a first aspect of the present invention includes a power generation apparatus, a heat exchanger through which a heat medium that receives exhaust heat of the power generation apparatus flows, a boiler that adjusts the temperature of the heat medium, and an electric power load A power generation system comprising: a control device that controls the power generation device and the boiler according to a situation and a thermal load status, wherein the control device stops combustion of the boiler and enters a thermal load status as an operation mode. Accordingly, a heat main operation mode for adjusting the temperature of the heat medium by controlling the power generation amount of the power generation device is provided.

  For the power load status and thermal load status, for example, the ratio of generated power to the amount of power used or the amount of commercial power supply is a parameter indicating the power load status, for example, the required temperature of the heat load being used, the temperature of the heat medium, etc. Is a parameter indicating the thermal load status.

  A power generation system according to a second aspect is the power generation system according to the first aspect, wherein the control device is configured to generate the power generation device based on a temperature of the heat medium supplied to a heat load and a required temperature of the heat load in the heat main operation mode. Control the amount of power generation.

  A power generation system according to a third aspect includes a heater for heating the heat medium according to the first or second aspect, wherein the heater is controlled by the control device when the control device is in the heat main operation mode. Driven by the increased power generated by the power generator.

  A power generation system according to a fourth aspect of the present invention is the power generation system according to any one of the first to third aspects, wherein the control device is configured to request a temperature and a heat load of the heat medium supplied to the heat load in the heat main operation mode. The power generation amount to be increased or decreased is calculated based on the temperature, and the power generation amount of the power generation device is controlled based on the calculation result.

  According to the power generation system of claim 1, by setting the operation mode to the heat main operation mode, the combustion of the boiler is stopped, and the temperature of the heat medium supplied to the heat load by the increase or decrease of the power generation amount of the power generation device is Adjusted. As a result, energy efficiency in the system can be increased and quietness can be improved without the boiler being turned on / off.

  According to the power generation system of claim 2, since the power generation amount is controlled based on the temperature of the heat medium supplied to the heat load and the required temperature of the heat load, the power generation amount control with high accuracy according to the heat load situation Is possible.

  According to the power generation system of the third aspect, the temperature of the heat medium can be adjusted more efficiently by driving the heater using the increased power generation output and using the heating of the heat medium by the heater.

  According to the power generation system of the fourth aspect, it is possible to perform the proportional control with high accuracy in accordance with the heat load condition with respect to the power generation device. That is, it is possible to supply a heat medium having a more appropriate temperature according to the required temperature of the heat load, and to give the user a more comfortable feeling of use.

It is a conceptual diagram which shows the structure of the electric power generation system of this embodiment. It is a flowchart which shows control of the control apparatus of this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2. Each figure used for explanation is a conceptual diagram, and the shape of each part may not necessarily be exact. The present invention is a power generation system that does not include a hot water storage tank.

  The power generation system of the present embodiment is a gas engine cogeneration apparatus, and mainly includes a power generation apparatus 1, a heat exchanger 2, a boiler 3, a control apparatus 4, and a heater 5, as shown in FIG. It is equipped with.

  The power generation device 1 includes an engine 11, a generator 12, and an inverter 13. The engine 11 is a gas engine that uses gas as fuel. Examples of the gas include natural gas and propane gas. The generator 12 is mechanically coupled to the engine 11 and is driven by driving the engine 11. The generator 12 is driven by the driving force of the engine 11 to generate power. The inverter 13 converts the electric power generated by the generator 12 and supplies it to the commercial power supply line Z (system power supply side). The generated power is grid-connected.

  The heat exchanger 2 includes a pipe 21 and a pipe 22, and is a device that exchanges heat between heat media (water in the present embodiment) flowing through the pipes 21 and 22. The heat exchanger 2 constitutes a heat circuit for using (supplying) the exhaust heat of the power generator 1 for hot water supply, heating, and the like.

  The pipe 21 is arranged so that the heat medium flowing therethrough receives the exhaust heat of the power generator 1. The heat medium of the pipe 21 receives the exhaust heat of the power generation device 1 by exchanging heat with, for example, exhaust gas of the engine 11 or engine cooling water. The pipe 22 is arranged so that a part thereof is close to the pipe 21 and the heat medium flowing through the pipe 22 can exchange heat with the heat medium in the pipe 21. The pipe 22 is connected to a flow path (pipe) 61 for allowing a heat medium to flow from the heat load Y into the boiler 3. That is, the heat exchanger 2 distributes the heat medium that has received the exhaust heat of the engine 11 and supplies the heat medium that has received the heat to the boiler 3. Note that an electric pump (not shown) is appropriately installed in the pipe, and the electric pump circulates the heat medium. The heat load Y is a low-temperature heat load that is driven at a lower temperature (about 60 ° C.) than a heat load that requires a high temperature, such as a bathroom dryer, and is, for example, a floor heater or a panel heater.

  The boiler 3 is a heat source device that heats the heat medium flowing in from the flow path 61 and causes the heat medium to flow out from the flow path 62. The flow path 62 is a pipe through which a heat medium flows from the boiler 3 toward the heat load Y. The boiler 3 is normally operated by rated operation, and is adjusted by turning on / off when there is a temperature requirement equal to or lower than the minimum output. The boiler 3 includes thermometers (here, thermistors) 31 and 32 that measure the temperature near the outlet of the flow path 61 and the temperature near the inlet of the flow path 62.

  The control device 4 is an electronic control unit (ECU), and controls the operation of the power generation device 1 and the boiler 3 according to the power load status and the heat load status. The control device 4 also receives temperature information from the thermometers 31 and 32. The control device 4 includes a normal operation mode and a heat main operation mode as operation modes. The operation mode will be described later.

  The heater 5 is a heater that is disposed close to the pipe 21. The heater 5 is connected to the inverter 13 (or the commercial power supply line Z), and is driven to consume power when the power generation device 1 generates excessive power. The heater 5 functions as a buffer that absorbs generated power in cases such as when most of the power load stops at once, such as when the power generation device 1 cannot keep up with the power load.

  Here, the operation mode of the control device 4 will be described. The normal operation mode is a mode in which the power generation device 1 and the boiler 3 operate together, and the power generation device 1 is caused to generate power following the power load situation, and the heat medium does not reach the required temperature for the heat load. In this mode, the boiler 3 is heated with the heat medium.

  The heat main operation mode is a mode in which the operation of the boiler 3 is stopped and the power generation apparatus 1 is caused to generate power following the heat load condition. Specifically, in the heat main operation mode, when the temperature of the heat medium supplied to the heat load Y (the temperature of the thermometer 31) has not reached the required temperature of the heat load Y, the power generation amount of the power generator 1 is increased. Then, a part of the power generation amount (increase here) is supplied to the heater 5 to drive the heater 5. When the heater 5 is driven, the heat medium in the pipe 21 receives the heat of the heater 5, and the heat medium temperature of the pipes 22 and 61 is increased by heat exchange.

  As described above, the control device 4 increases the power generation amount and drives the heater 5 in the heat main operation mode, thereby changing the temperature of the heat medium supplied to the heat load Y (the temperature of the thermometers 31 and 32) to the required temperature. Raise up to. The operation mode of the control device 4 is switched according to a user operation. Switching of the operation mode by the user can be executed by turning on / off a switch (button), and can be executed by, for example, the power generator 1 or the remote controller (not shown) of the boiler 3.

  The heat main operation mode will be described more specifically with reference to FIG. When the operation mode is switched to the heat main operation mode (S101), the control device 4 stops (prohibits) the combustion of the boiler 3 (S102). And the control apparatus 4 determines whether the temperature of the thermometer 32 is less than the required temperature (here 60 degreeC) of the heat load Y (S103). When the temperature of the thermometer 32 is less than 60 ° C. (S103: Yes), the control device 4 waits for a predetermined time (here, 5 minutes) to elapse (S104), and the temperature of the thermometer 32 is again 60 ° C. It is determined whether it is less than (S105).

  When the temperature of the thermometer 32 is less than 60 ° C. (S105: Yes), it is determined whether the power generation output (power generation amount) of the power generation device 1 is less than a predetermined power (here, 1250 W) (S106). When the power generation output is less than 1250 W (S106: Yes), the control device 4 increases the power generation amount of the power generation device 1 by a predetermined increased power (250 W in this case) (S107). The increased electric power is consumed when the heater 5 is driven, and the heat medium is heated by the heater 5. Then, after 5 minutes have elapsed (S108: Yes), the control device 4 compares the temperature of the thermometer 32 with the required temperature again (S103).

  The predetermined power (1250 W) can be set to a value obtained by subtracting the predetermined increased power (250 W) from the maximum output (here, 1500 W) of the power generator 1. Further, the predetermined increased power can be set to the power consumption of the heater 5.

  On the other hand, when the temperature of the thermometer 32 is 60 ° C. or higher (S103, S105: No), the control device 4 indicates that the temperature of the thermometer 32 is larger than the required temperature by an allowable error (a value less than the maximum allowable error). It is determined whether or not the temperature is equal to or higher than a predetermined temperature (here, 65 ° C.) (S109). When the temperature of the thermometer 32 is 65 ° C. or higher (S109: Yes), after 5 minutes (S110: Yes), the control device 4 determines again whether the temperature of the thermometer 32 is 65 ° C. or higher. (S111).

  When the temperature of the thermometer 32 is 65 ° C. or higher (S111: Yes), the control device 4 reads a memory (not shown) and determines whether or not the power generation amount of the power generation device 1 is increased in step S107. (S112). That is, the control device 4 determines whether or not the power generation amount has been increased following the required temperature of the heat load Y during the heat main operation mode (S112).

  When the power generation amount has been increased (S112: Yes), the control device 4 decreases the power generation amount of the power generation device 1 by a predetermined increased power (250W) (S113). Then, after 5 minutes have elapsed (S114: Yes), the control device 4 compares the temperature of the thermometer 32 with the required temperature again (S103). Moreover, also when the temperature of the thermometer 32 is less than 65 degreeC (S109, S111: No), the control apparatus 4 compares the temperature of the thermometer 32 with required temperature (S103).

  Here, when the power generation device 1 has not increased the power generation amount in step S107 (S112: No), the control device 4 determines whether the temperature of the thermometer 32 is equal to or greater than the maximum allowable error (here, 70 ° C.). Is determined (S115). The allowable error and the maximum allowable error are set values that can be changed by setting. When the temperature of the thermometer 32 is less than 70 ° C. (S115: No), the control device 4 compares the temperature of the thermometer 32 with the required temperature again (S103).

  On the other hand, when the temperature of the thermometer 32 is 70 ° C. or higher (S115: Yes), the control device 4 stops the power generation of the power generation device 1 (S116). Then, the control device 4 determines whether or not the current condition satisfies a preset power generation resumption condition (S117). In this embodiment, the power generation restart condition is set such that the temperature of the thermometer 32 becomes the required temperature (60 ° C.). The power generation resumption condition is set such that, for example, the temperature of the thermometer 32 is lower than the temperature of the thermometer 32 when power generation is stopped by a set temperature (for example, 10 ° C.) or more and the temperature of the thermometer 32 is lower than 70 ° C. You can also The control device 4 monitors the temperature of the thermometer 32 and determines whether or not the power generation resumption condition is satisfied (S117).

  When the power generation restart condition is satisfied (S117: Yes), the control device 4 restarts the power generation of the power generation device 1 (S118). The amount of power generated at this time may be in accordance with the power load situation. Then, after 5 minutes have elapsed (S114: Yes), the control device 4 compares the temperature of the thermometer 32 with the required temperature again (S103). In the heat main operation mode, the above-described flow is executed, and the power generator 1 is controlled so that the temperature of the heat medium supplied to the heat load Y is 60 to 70 ° C, and further 60 to 65 ° C. The power generator 1 is driven not by on / off control but by output increase / decrease control.

  In the heat main operation mode, the heat medium temperature of the pipe 21 also rises due to an increase in exhaust heat amount of the engine 11 accompanying an increase in power generation amount. By increasing the amount of power generation, the heat medium is supplied with increased exhaust heat and heating by the heater 5, and the heat medium temperature of the pipe 21 rises. In the heat main operation mode, the amount of power generation is controlled following the heat load condition, and the temperature is adjusted using the exhaust heat of the power generation device 1 and the heat of the heater 5.

  According to the power generation system of the present embodiment, the heat main operation mode is provided as the operation mode. In the heat main operation mode, combustion of the boiler 3 is prohibited, and power generation is performed according to the temperature of the heat medium supplied to the heat load Y. The power generation amount of the device 1 is controlled. In other words, according to the present embodiment, by executing the heat main operation mode, the temperature adjustment for the thermal load Y is performed only by the power generation device 1, and the efficiency reduction and quietness reduction due to the on / off control of the boiler 3 are eliminated. can do. According to the present embodiment, the on / off control region of the boiler 3 is proportionally controlled by the increase in the heat output of the power generation device 1, and the energy efficiency and quietness of the system can be improved.

  In addition, by executing the heat main operation mode, the temperature of the heat medium supplied to the heat load Y can be kept substantially constant within the output range of the power generation system, and heating is performed comfortably. In the conventional on / off control of the boiler 3, the supply temperature to the heat load is likely to fluctuate easily, and when used for heating, the temperature of the room or floor is greatly changed, which may cause discomfort to the user. there were. As described above, the temperature change is suppressed in the present embodiment.

  Further, the conversion efficiency from the same fuel is approximately 2 for heat of electric power 1, and it is more efficient to take energy as heat. Therefore, it can be said that it is preferable from the viewpoint of energy efficiency to control the heat medium temperature by using the increase in the amount of exhaust heat of the power generator 1. In the present embodiment, when a high-temperature heat load such as a bathroom heater is used in the heat main operation mode, the control device 4 switches to the normal operation mode, and the boiler 3 is used for heating the heat medium. Switching to the normal operation mode may be performed by a user operation (switch operation or the like).

  The present invention is not limited to the above embodiment. For example, in the heat main operation mode, the control device 4 may obtain the increase / decrease amount of the power generation by calculation instead of the fixed value (predetermined increase power) as described above. For example, the control device 4 may obtain a difference between the temperature of the thermometer 32 and the required temperature, and calculate a necessary increase or decrease from the difference. That is, in step S107 or S113, the control device 4 calculates the amount of increase or decrease in power generation based on the temperature of the heat medium supplied to the heat load Y and the required temperature required by the heat load Y, and the calculation result The power generation amount of the power generator 1 is controlled based on the above. Thereby, temperature adjustment with higher accuracy becomes possible.

  Further, the control device 4 may mainly control the power generation device 1, and the control of the boiler 3 may be only prohibited in the heat main operation mode. That is, the control device 4 only needs to stop and prohibit at least the operation of the boiler 3 with respect to the boiler 3, and other control of the boiler 3 may be left to another control device (for example, the control device of the boiler 3 itself). .

  Further, in the heat main operation mode, the heat medium temperature may be adjusted only by exhaust heat without using the heater 5 by utilizing the increase in the exhaust heat amount of the engine 11 accompanying the increase in the power generation amount. Further, the fuel of the engine 11 is not limited to gas, but may be liquid fuel such as gasoline, kerosene, or light oil. The power generation device 1 may be a power generation device using a fuel cell. In this case, in the power generation system, the exhaust heat of the fuel cell corresponds to the exhaust heat of the engine 11. That is, the power generation system of the present invention may be an engine-driven cogeneration device or a fuel cell cogeneration device.

1: power generator, 11: engine, 12: generator, 13: inverter,
2: heat exchanger, 3: boiler, 4: control device, 5: heater, Y: heat load

Claims (4)

A power generator, a heat exchanger through which a heat medium that receives exhaust heat of the power generator flows, a boiler that adjusts the temperature of the heat medium, and the power generator and the boiler according to a power load situation and a heat load situation A power generation system comprising:
The control device includes a heat main operation mode in which the combustion of the boiler is stopped as an operation mode, and the temperature of the heat medium is adjusted by controlling the power generation amount of the power generation device according to a heat load situation. Power generation system. In claim 1,
In the heat main operation mode, the control device controls a power generation amount of the power generation device based on a temperature of the heat medium supplied to a heat load and a required temperature of the heat load. In claim 1 or 2,
A heater for heating the heat medium;
The heater is a power generation system that is driven by the generated power of the power generation device increased by the control of the control device when the control device is in the heat main operation mode. In any one of Claims 1-3,
The control device calculates a power generation amount to be increased or decreased based on a temperature of the heat medium supplied to the heat load and a required temperature of the heat load in the heat main operation mode, and based on the calculation result A power generation system for controlling the power generation amount of the power generation device.

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