JP2007187027A - Cogeneration system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cogeneration system performing optimal cooling control. <P>SOLUTION: In this cogeneration system, a motor, a generator driven by the motor, a radiator provided on a circulation path of coolant absorbing heat from the motor, a fan cooling the radiator, and a heat exchanger provided in a position at which coolant flows from the motor to the radiator on the circulation path and supplying a heat utilization device with heat absorbed from the motor by coolant are stored in a storage box including an intake port and an exhaust port, and an inside of the storage box is ventilated by taking fresh air in from the intake port by the fan and exhausting from the exhaust port. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cogeneration system.

In recent years, global environmental problems have been greatly improved, and various technologies for effectively utilizing limited resources and energy have been developed.
In particular, a cogeneration system that collects exhaust heat generated during power generation and effectively uses the heat is drawing attention (see, for example, Patent Document 1).
JP 2005-61344 A

  In the cogeneration system, the heat generated from the generator and the heat generated from the prime mover driving the generator are collected by a heat exchanger, and are effectively utilized by a heat utilization device such as a boiler or a chiller / heater. For this reason, high energy efficiency of about 70% is realized. However, the heat that cannot be recovered is eventually released into the air.

  The cogeneration system is configured by housing various heating elements such as a generator, a prime mover, and a control device in a housing box called an enclosure. Therefore, the temperature inside the enclosure rises due to the heat that cannot be recovered. Therefore, it is necessary to properly ventilate and cool the air inside the enclosure.

  Here, the temperature inside the enclosure is influenced by the output of the prime mover and the generator, the outside air temperature, and the like. For example, when a prime mover or a generator is operated at maximum output under hot summer heat, the inside of the enclosure becomes quite hot. In this case, it is conceivable that the allowable temperature set for the equipment inside the enclosure may be exceeded.

  For this reason, conventional cogeneration systems use the maximum required air volume calculated based on the temperature maintenance level and estimated maximum temperature inside the enclosure, the maximum heat dissipation from the prime mover, and the maximum heat dissipation from the generator. It was taken in by always operating the ventilation fan attached to the to keep the allowable temperature limit of the equipment inside the enclosure.

  However, the outside air temperature may be high or low, and the prime mover or generator is not always operated at the maximum output. For this reason, the inside of the enclosure is often excessively ventilated, which is a factor that hinders the improvement of energy efficiency in the cogeneration system.

  The present invention has been made in view of the above problems, and has as its main object to provide a cogeneration system that performs optimum cooling control.

In order to solve the above-described problems, the present invention provides a motor box, a generator driven by the motor, and a refrigerant circulation path that absorbs heat from the motor in a storage box having an intake port and an exhaust port. A heat radiator that is provided, a fan that cools the radiator, and heat that is provided at a position where the refrigerant flows from the prime mover to the radiator on the circulation path and that supplies heat absorbed by the refrigerant from the prime mover to a heat utilization device The present invention relates to a cogeneration system in which ventilation is performed inside the storage box by storing outside air through the intake port and exhausting the air from the exhaust port by the fan.
According to such an embodiment, since the inside of the storage box (hereinafter also referred to as an enclosure) can be ventilated by a fan (hereinafter also referred to as a radiator fan) that cools the radiator, optimal cooling control is performed. It becomes possible. Moreover, since the ventilation fan conventionally used for ventilation can be made unnecessary, the cost of the ventilation fan can be reduced. In addition, since power for driving the ventilation fan can be eliminated, energy efficiency can be improved.

The cogeneration system includes: an inverter that outputs AC power that drives the fan; and an inverter control device that controls the rotational speed of the fan by controlling the frequency of AC power output from the inverter. It can also be provided.
By such an aspect, it becomes possible to freely control the rotational speed of the radiator fan. For this reason, since the air volume can be arbitrarily adjusted according to the outside air temperature, the prime mover, the amount of heat released from the generator, etc., it is possible to prevent wasteful cooling inside the enclosure and improve the overall thermal efficiency. In addition, since the power for driving the fan can be suppressed to a necessary amount, it is possible to improve the total thermal efficiency.

Further, the inverter control device calculates a sum of a value indicating the amount of heat released from the prime mover into the air per unit time and a value indicating the amount of heat released from the generator into the air per unit time. The rotational speed of the fan may be controlled based on a value obtained by dividing by a value indicating the amount of heat absorbed by air.
In this manner, the amount of air required per unit time to discharge the air inside the enclosure that has absorbed heat from the prime mover and generator is calculated, and the rotation speed of the radiator fan is controlled based on that value. can do. For this reason, it becomes possible to optimally control the amount of air to be ventilated.

Here, the value indicating the amount of heat absorbed by the unit amount of air is calculated based on a value indicating a difference between the allowable temperature of the air inside the storage box and the temperature of the outside air taken from the intake port. You can also
With such an aspect, it is possible to calculate the required air amount according to the temperature difference between the inside and outside of the enclosure. By performing ventilation based on the amount of air thus calculated, it is possible to control the temperature inside the enclosure to be kept constant.

The cogeneration system is provided between the heat exchanger and the radiator on the circulation path, and includes a first port through which refrigerant flows from the heat exchanger, and first refrigerant from which the refrigerant flows out to the radiator. A control valve having a second port and a third port through which refrigerant flows out to the bypass of the radiator, an amount of refrigerant flowing out from the second port of the control valve, and the third port It is also possible to provide a control valve control device that controls the ratio to the amount of refrigerant flowing out.
Such an aspect makes it possible to freely control the amount of refrigerant flowing into the radiator, so that it is possible to cool the refrigerant optimally according to the performance and durability of the prime mover. This also makes it possible to perform optimal cooling control.

Further, the control valve control device controls the ratio based on a value obtained by dividing a value indicating the amount of heat released from the prime mover into the refrigerant by a value indicating the amount of heat absorbed by the unit amount of refrigerant. You can also
According to such an aspect, it is possible to calculate the amount of refrigerant per unit time necessary for cooling the heat absorbed by the refrigerant from the prime mover, and to control the amount of refrigerant flowing to the radiator based on the value. Therefore, it is possible to optimally control the cooling of the refrigerant.

Further, the value indicating the amount of heat absorbed by the unit amount of refrigerant is calculated based on a value indicating a difference between the temperature of the refrigerant flowing into the radiator and the temperature of the refrigerant flowing out of the radiator. You can also.
According to such an aspect, it is possible to calculate the amount of refrigerant that passes through the radiator according to the temperature difference between the refrigerant before and after passing through the radiator. Then, by controlling the control valve based on the amount of refrigerant calculated in this way, it is possible to control the temperature of the refrigerant to be kept constant.

  In addition, the problems disclosed by the present application and the solutions thereof will be clarified by the column of the best mode for carrying out the invention and the drawings.

  A cogeneration system that performs optimum cooling control can be provided.

  FIGS. 3 and 4 are diagrams for explaining the cogeneration system 100 according to the present embodiment in comparison with the conventional cogeneration system 110. FIG. A conventional cogeneration system 110 is shown in FIGS.

  First, a conventional cogeneration system 110 will be described as shown in FIG. A conventional cogeneration system 110 includes an engine 200, a generator 300, a radiator 500, a radiator fan 600, a heat exchanger 800, and a wax valve 710 inside an enclosure 400 having a ventilation fan 630 on the ceiling. And is configured.

The engine 200 is a prime mover for driving the generator 300. For example, it can be a diesel engine or a gas turbine engine. The electric power generated by the generator 300 is used by an external power usage device (not shown).
Exhaust heat from the engine 200 is absorbed by a refrigerant circulating in the circulation path 510 (hereinafter also referred to as engine jacket cooling water) and supplied to a heat utilization device (not shown) by the heat exchanger 800.

  Warm air inside the enclosure 400 is discharged to the outside by a ventilation fan 630 provided on the ceiling of the enclosure 400. The enclosure 400 has an intake port 410 and an exhaust port 420, takes in outside air from the intake port 410, and discharges air inside the enclosure from the exhaust port 420.

The refrigerant that has absorbed the heat from the engine 200 is cooled by the radiator 500 provided on the circulation path 510. In addition, wind is blown from the radiator fan 600 to the radiator 500 so that the refrigerant can be efficiently cooled in the radiator 500. The circulation path 510 is provided with a bypass 511 that bypasses the radiator 500, and a wax valve 710 is provided at a branch point to the bypass 511.
In the wax valve 710, the opening degree of the valve changes according to the temperature of the refrigerant. As a result, the ratio between the amount of refrigerant flowing out to the radiator 500 and the amount of refrigerant flowing out to the detour 511 that bypasses the radiator 500 changes according to the temperature of the refrigerant.

  Radiator fan 600 can be driven by engine 200 as shown in FIG. 1, or can be driven by motor 610 as shown in FIG.

In the conventional cogeneration system 110 as shown in FIG. 1 and FIG. 2, the temperature maintenance control for keeping the allowable temperature limit of the electric product such as a control device and an electric motor provided in the enclosure 400 is controlled by the ventilation fan 630. It corresponds by taking in the outside air by driving.
The amount of air taken in at this time is calculated on the basis of the temperature maintenance level in the enclosure 400, the assumed maximum temperature, the maximum engine heat dissipation, the maximum generator heat dissipation, and the maximum generator heat dissipation (presumed maximum value), which are attached to the motor. This is achieved by operating the ventilation fan 630 at all times.

Also, the temperature of the engine jacket cooling water must be maintained within a certain range from the viewpoint of engine performance and durability, and the engine jacket cooling water is passed through the radiator 500 to drive the shaft end of the engine 200 or the electric motor. This is achieved by air cooling with the radiator fan 600 as the source.
The heat exchange capacity of the radiator 500 and the air blowing amount of the radiator fan 600 are determined based on the maximum jacket exhaust heat amount grasped in advance (assumed maximum value).
The water flow rate adjustment to the radiator 500 uses a thermostat type wax valve 710, and is determined by the expected operation (opening degree) according to the temperature of the engine jacket cooling water.

Further, the intake air amount necessary for maintaining the internal temperature of the enclosure 400 is calculated as follows.
First, when the engine 200 is driven inside the enclosure 400 to obtain a generator output, heat dissipation from the engine 200, the generator 300, the exhaust pipe, the cooling water pipe, etc. (7% to 10% of the engine input heat amount) The temperature inside the enclosure 400 rises. Therefore, assuming that the intake air temperature is high, such as in summer, ventilation necessary to keep the temperature in the enclosure 400 below a predetermined temperature (allowable temperature for use of electrical products such as control devices and electric motors) is performed.

  For this purpose, the amount of intake air is calculated by dividing the amount of heat released from the engine, generator, etc. by the amount of heat processed per cubic meter of air.

Specifically, it is represented by Formula (1).

Here, G is the fuel consumption [kg / h or l / h] at the rated output of the generator, H is the fuel heating value [kcal / kg or kcal / l], and f is the engine heat dissipation rate [ %], P is the generator rated output [kW], η is the generator efficiency [%], 860 is a constant [kcal / kWh] for heat quantity conversion, and Δt is the temperature rise tolerance [C], Cp is the constant-pressure specific heat [kcal / kg] of dry air, and ρ is the air density [kg / m ³ ]. Δt is the difference between the allowable use temperature of the electrical product and the maximum intake air temperature (outside air temperature) assumed.

G × H × f is the amount of heat released from the engine and others, P × (1 ÷ η−1) × 860 is the amount of heat released from the generator 300, and Δt × Cp × ρ is the amount per 1 m ³ of air. The amount of heat for treatment.

  Here, the intake air amount calculated by the equation (1) is set based on the maximum intake air temperature assumed at the time of the generator rated output. If the generator output or the intake air temperature decreases, the intake air is reduced. The amount is excessive. Similarly to the intake air amount, the air flow rate of the radiator fan 600 is set based on the maximum enclosure temperature assumed at the rated output of the generator. If the generator output or intake air temperature decreases, the intake air amount Becomes excessive.

  It can be said that generating these excessive amounts of air constantly consumes excessive electric power or engine power related to the driving of the radiator fan 600.

For example, G = 48.6 [l / h], H = 9320 [kcal / l], f = 7 [%], P = 190 [kW], η = 91 [%], Δt = 15 [° C.] Allowable temperature = 55 ° C, maximum intake air temperature = 40 ° C), Cp = 0.24 [kcal / kg], ρ = 1.24 [kg / m ³ ], intake air amount = 10723 [m ³ / h]. However, if G = 27.6 [l / h], P = 100 [kW], Δt = 35 [° C] (allowable temperature for electrical products = 55 ° C, maximum intake air temperature = 20 ° C), the amount of intake air = 2545 [m ³ / h]. This difference in the intake air amount is excessive.

  In addition, constantly blowing such an excessive amount of air lowers the temperature inside the enclosure 400 more than necessary, and promotes heat dissipation from exhaust heat that should originally be effectively used, resulting in overall thermal efficiency. It will also reduce.

  Further, in the conventional cogeneration system 110, no consideration is given to the advanced use of jacket exhaust heat. That is, the temperature control of the engine jacket cooling water is kept within a certain range (for example, fluctuates with a width of about 80 ° C. to 90 ° C.) by the thermostat type wax valve 710 that operates according to the engine outlet jacket cooling water temperature. However, since it is not a control method that maintains a constant temperature (it cannot stably maintain a high temperature of about 90 ° C), the use of jacket exhaust heat is mostly about using hot water (60 ° C to 70 ° C). As a result, it is impossible to use jacket exhaust heat at a high level (application to an absorption chiller / heater or a waste heat recovery boiler that requires a stable supply of a high temperature).

  Next, the cogeneration system 100 according to the present embodiment will be described with reference to FIGS. 3 and 4 in comparison with the conventional cogeneration system 110.

First, as shown in FIG. 3, the cogeneration system 100 according to the present embodiment does not include the ventilation fan 630. That is, the cogeneration system 100 according to the present embodiment includes an engine 200 (corresponding to a prime mover described in claims) in an enclosure (corresponding to a storage box described in claims), A generator 300 driven by the engine 200, a radiator 500 (corresponding to a radiator according to the claims) provided on a refrigerant circulation path 510 that absorbs heat from the engine 200, and the radiator 500 are cooled. A radiator fan (corresponding to the fan described in claims) 600 and a position where the refrigerant flows from the engine 200 to the radiator 500 on the circulation path 510 and the heat absorbed by the refrigerant from the engine 200 are not shown. And a heat exchanger 800 that supplies the heat utilization device. The enclosure 400 is provided with an intake port 410 and an exhaust port 420, and outside air is taken in from the intake port 410 by the radiator fan 600 and exhausted from the exhaust port 420, thereby ventilating the interior of the enclosure 400.
As described above, by performing ventilation inside the enclosure 400 by the radiator fan 600, it is possible to perform optimum cooling control. It is also possible to reduce auxiliary power and initial cost.

As shown in FIG. 3, the cogeneration system 100 according to the present embodiment may include an inverter 620 and a control device 900 (corresponding to the inverter control device described in the claims). it can. Inverter 620 outputs AC power for driving radiator fan 600. Control device 900 controls the rotational speed of radiator fan 600 by controlling the frequency of the AC power output from inverter 620.
By doing in this way, it becomes possible to perform the rotation speed control by the inverter 620 of the radiator fan 600. As a result, the air volume can be arbitrarily adjusted according to the conditions, the auxiliary power can be reduced, and the overall thermal efficiency can be improved.

Note that the control device 900 includes a CPU (Central Processing Unit) 910, a memory 920, and an I / F 930, as shown in FIG.
The CPU 910 is responsible for overall control of the control device 900, and performs various controls by executing a control program 940 comprising codes for performing various operations according to the present embodiment stored in the memory 920. Execute. In addition to the control program 940, the memory 920 includes a fan rotation speed air volume table 1000, a generator output fuel consumption table 1010, a three-way valve opening water flow table 1020, a generator output jacket exhaust heat table 1030, an exhaust temperature, which will be described later. A coolant temperature table 1040 is stored. The I / F 930 receives input of signals from various sensors in the cogeneration system, and outputs various signals for driving the inverter 620 and a three-way valve 700 described later.

Next, as shown in FIG. 4, cogeneration system 100 according to the present embodiment is provided between heat exchanger 800 and radiator 500 on circulation path 510, and the refrigerant flows from heat exchanger 800. A three-way valve 700 having a first port, a second port through which refrigerant flows out to the radiator 500, and a third port through which refrigerant flows out to the bypass circuit 511 of the radiator 500 (adjustment according to claims) (Corresponding to a valve). A control device 900 (corresponding to the control valve control device described in the claims) 900 according to the present embodiment controls the three-way valve 700.
By doing so, it is possible to adjust the flow rate of the cooling water to be passed through the radiator 500 according to the conditions, not the control of the course using the wax valve 710. Thereby, optimal cooling control becomes possible.

  For example, based on the value obtained by dividing the value indicating the amount of heat released from the engine 200 into the refrigerant by the value indicating the amount of heat absorbed by the unit amount of refrigerant, the amount of refrigerant flowing out of the second port and the third The ratio to the amount of refrigerant flowing out from the other port can be controlled. Thereby, an amount of refrigerant necessary to cool the heat absorbed from engine 200 can be caused to flow into radiator 500.

Here, the value indicating the amount of heat absorbed by the unit amount of refrigerant is calculated based on the value indicating the difference between the temperature of the refrigerant flowing into the radiator 500 and the temperature of the refrigerant flowing out of the radiator 500.
By doing so, the refrigerant flows into the radiator 500 so that the temperature of the refrigerant flowing out of the radiator 500 becomes the target value with respect to the target value of the engine inlet coolant temperature (that is, the temperature of the refrigerant flowing out of the radiator). It becomes possible to control the quantity of the refrigerant | coolant to perform. As a result, the engine outlet coolant temperature can be stably maintained at a high level, so that the jacket exhaust heat can be highly utilized. This makes it possible to supply heat to an absorption chiller / heater or an exhaust heat recovery boiler that desires a stable supply at a high temperature.

=== Details of Cooling Control ===
Next, details of the cooling control in the cogeneration system 100 according to the present embodiment will be described. The cooling control is divided into cooling of the air inside the enclosure 400 and cooling of the refrigerant.

<Cooling the air in the enclosure>
FIG. 5 is a diagram for explaining cooling of the air inside the enclosure 400. The air inside the enclosure 400 is cooled by ventilating the air inside the enclosure 400 with the radiator fan 500. In FIG. 5, two radiators 500 and two radiator fans 600 are shown, but one each may be used. By using a plurality of radiators 500 and radiator fans 600, cooling can be performed more efficiently.

  First, when there is a heat demand by a heat utilization device such as an absorption chiller / heater or an exhaust heat recovery boiler, the jacket exhaust heat, which is the heat absorbed by the refrigerant from the engine 200, is shown in FIG. A heat exchanger 800 supplies the heat utilization device. Therefore, since the temperature of the refrigerant decreases as it passes through the heat exchanger 800, it is not necessary to further cool the refrigerant with the radiator 500. Accordingly, the refrigerant is returned to the engine 200 through the bypass 511.

  On the other hand, the air inside the enclosure 400 is warmed by heat radiation from the engine 200 and the generator 300. For this reason, the radiator fan 600 is controlled to a rotational speed that secures an air volume necessary to ventilate the air inside the enclosure 400 heated by the engine 200 and the generator 300.

  Of course, even if there is a heat demand, if the demand is small, the temperature of the refrigerant that has passed through the heat exchanger 800 may not be greatly reduced. In this case, the control device 900 controls the three-way valve 700 to adjust the ratio of the amount of refrigerant flowing to the radiator 500 and the amount of refrigerant flowing to the bypass 511 so that a part of the refrigerant is cooled by the radiator 500. To.

  On the other hand, when there is no heat demand from the heat utilization device, the temperature of the refrigerant does not decrease even when it passes through the heat exchanger 800 as shown in FIG. Therefore, the three-way valve 700 is controlled so that the refrigerant flows into the radiator 500. Then, the wind from the radiator fan 600 is blown onto the radiator 500, so that the heat from the refrigerant is released into the enclosure 400. That is, the air inside the enclosure 400 is warmed not only by the engine 200 and the generator 300 but also by the radiator 500. For this reason, the radiator fan 600 is controlled to a rotational speed that secures the air volume necessary for ventilating the air inside the enclosure 400 heated by the radiator 500, the engine 200, and the generator 300.

<Cooling of refrigerant>
Next, FIG. 6 is a diagram for explaining the cooling control of the refrigerant. Cooling of the refrigerant is performed by the heat exchanger 800 and the radiator 500. The control device 900 controls the cooling of the refrigerant by controlling the three-way valve 700 and adjusting the ratio of the amount of refrigerant flowing to the radiator 500 and the amount of refrigerant flowing to the bypass 511. In FIG. 6, two radiators 500 and two radiator fans 600 are shown, but one may be used. By using a plurality of radiators 500 and radiator fans 600, cooling can be performed more efficiently.

First, when there is a heat demand from the heat utilization device, the jacket exhaust heat is supplied to the heat utilization device by the heat exchanger 800 as shown in FIG. Therefore, since the temperature of the refrigerant decreases as it passes through the heat exchanger 800, it is not necessary to further cool the refrigerant with the radiator 500. Accordingly, the three-way valve 700 is controlled so that the refrigerant is returned to the engine 200 through the bypass 511.
On the other hand, when there is no heat demand from the heat utilization device, the temperature of the refrigerant does not decrease even when it passes through the heat exchanger 800 as shown in FIG. Therefore, the three-way valve 700 is controlled so that the refrigerant flows into the radiator 500.

<Control when there is heat demand>
Next, the control when there is a heat demand by the heat utilization device will be described in detail. The processing target in this case is only heat radiation from the generator 300 and the engine 200.

  In this case, the amount of intake air is calculated by dividing the amount of heat released from the engine, generator, etc. by the amount of heat processed per cubic meter of air.

Specifically, it is represented by the formula (2).

Here, G is the fuel consumption [kg / h or l / h] according to the generator output, H is the fuel heating value [kcal / kg or kcal / l], and f is the engine heat dissipation rate [% , P is the generator output [kW], η is the generator efficiency [%], 860 is the constant [kcal / kWh] for heat quantity conversion, and Δt is the temperature rise allowable value [° C. Cp is the constant-pressure specific heat [kcal / kg] of dry air, and ρ is the air density [kg / m ³ ]. Δt is the difference between the allowable use temperature of the electrical product and the maximum intake air temperature (outside air temperature) assumed.

  The amount of heat released from the engine 200 (a value indicating the amount of heat released from the prime mover into the air per unit time) is calculated by G × H × f in equation (2). Here, the fuel consumption amount G is a value that depends on the output of the generator 300. The relationship between the fuel consumption amount G and the generator output P is stored in the generator output fuel consumption table 1010 as shown in FIG. Further, the fuel heating value H is a value determined according to the fuel, for example, 9320 [kcal / l] in the case of A heavy oil. The engine heat dissipation rate f can be set to 7%, for example. Therefore, the amount of heat released from the engine 200 can be calculated once the generator output is determined.

  The amount of heat released from the generator 300 (a value indicating the amount of heat released from the generator 300 into the air per unit time) is calculated by P × (1 ÷ η−1) × 860 in Equation (2). The generator efficiency η can be 91%, for example. Therefore, the amount of heat released from the generator 300 can be calculated once the generator output is determined.

  A value obtained by dividing the sum of the heat dissipation amount from the engine 200 and the heat dissipation amount from the generator 300 by the value indicating the amount of heat absorbed by the unit amount of air is necessary to process the total heat dissipation amount. Means the amount of air. Therefore, the required rotational speed of the radiator fan 600 can be obtained based on the amount of air.

The value indicating the amount of heat absorbed by the unit amount of air is Δt × Cp × ρ in equation (2). Δt is a value indicating the difference between the allowable temperature of the air inside the enclosure 400 and the temperature of the outside air taken from the intake port. For example, the allowable temperature of the air inside the enclosure 400 can be set to 55 ° C., which is the allowable temperature of the electrical product. The constant pressure specific heat Cp of the dry air is 0.24 [kcal / kgK], and the air density ρ is 1.24 [kg / m ³ ]. Therefore, if the outside air temperature is determined, Δt × Cp × ρ can be calculated.

  As described above, when the outside air temperature and the generator output are determined, the control device 900 can obtain the optimum air volume that sets the temperature inside the enclosure 400 to 55 ° C., which is the allowable temperature of the electrical product, using Equation (2). it can. Then, the control device 900 can obtain the required rotational speed of the radiator fan 600 based on the relationship between the rotational speed and the air volume of the radiator fan 600 stored in the fan rotational speed air volume table 1000 shown in FIG. Then, the control device 900 outputs a signal from the I / F 930 to the inverter 620 so that AC power having a frequency at which the radiator fan 600 rotates at the rotation speed is output from the inverter 620.

  As described above, in the cogeneration system 100 according to the present embodiment, the internal temperature of the enclosure 400 is set to the target value (for example, 55 ° C.) by controlling the rotational speed of the radiator fan 600 according to the outside air temperature and the generator output. Can be maintained.

<Control when there is no heat demand>
Next, control when there is no heat demand from the heat utilization device will be described. The processing target in this case is heat radiation from the generator 300 and the engine 200 and jacket exhaust heat.

  In this case, the intake air amount is calculated by dividing the heat release amount from the engine, generator, and jacket exhaust heat by the processing heat amount per cubic meter of air.

Specifically, it is represented by Formula (3).

Here, G is the fuel consumption [kg / h or l / h] according to the generator output, H is the fuel heating value [kcal / kg or kcal / l], and f is the engine heat dissipation rate [% , P is the generator output [kW], η is the generator efficiency [%], 860 is a constant [kcal / kWh] for heat quantity conversion, and Q is the jacket exhaust heat [kW] T2 is the exhaust temperature [° C.] from the radiator, t1 is the outside air temperature [° C.], Cp is the constant-pressure specific heat [kcal / kg] of the dry air, and ρ is the air density [kg / m ^3] ].

G × H × f is the amount of heat released from the engine and others, P × (1 ÷ η−1) × 860 is the amount of heat released from the generator 300, Q × 860 is the jacket exhaust heat, t2−t1) × Cp × ρ is the amount of heat processed per 1 m ³ of air (the amount of heat absorbed by a unit amount of air).

  The amount of heat released from engine 200 (a value indicating the amount of heat released from the prime mover into the air per unit time) is calculated by G × H × f in equation (3). Here, the fuel consumption amount G is a value that depends on the output of the generator 300. The relationship between the fuel consumption amount G and the generator output P is stored in the generator output fuel consumption table 1010 as shown in FIG. Further, the fuel heating value H is a value determined according to the fuel, for example, 9320 [kcal / l] in the case of A heavy oil. The engine heat dissipation rate f can be set to 7%, for example. Therefore, the amount of heat released from the engine 200 can be calculated once the generator output is determined.

  Further, the amount of heat released from the generator 300 (a value indicating the amount of heat released from the generator 300 into the air per unit time) is calculated by P × (1 ÷ η−1) × 860 in Equation (3). The generator efficiency η can be 91%, for example. Therefore, the amount of heat released from the generator 300 can be calculated once the generator output is determined.

  The jacket exhaust heat Q is a value that depends on the output of the generator 300. The relationship between the jacket exhaust heat Q and the generator output P is stored in the generator output jacket exhaust heat table 1030 as shown in FIG. Accordingly, the jacket exhaust heat Q can be calculated once the generator output is determined.

  A value obtained by dividing the sum of the heat dissipation amount from the engine 200, the heat dissipation amount from the generator 300, and the jacket exhaust heat by the value indicating the amount of heat absorbed by the unit amount of air is processed as the total heat dissipation amount. Means the amount of air required to Therefore, the required rotational speed of the radiator fan 600 can be obtained based on the amount of air.

  The value indicating the amount of heat absorbed by the unit amount of air is (t2−t1) × Cp × ρ in Equation (3). t2-t1 is a value indicating the difference between the radiator exhaust temperature and the temperature of the outside air taken from the intake port.

  Since the radiator exhaust temperature varies depending on the amount of water flowing through the radiator, it is necessary to set the radiator exhaust temperature in consideration of the relationship between the radiator exhaust temperature and the amount of water through the radiator.

The amount of radiator water flow can be calculated using Equation (4) if the jacket exhaust heat corresponding to conditions such as the outside air temperature and the input heat amount is obtained.

Here, Q is jacket exhaust heat [kW], 860 is a constant [kcal / kWh] for heat quantity conversion, t2 is a radiator outlet cooling water temperature [° C], and t1 is a heat exchanger primary. The side outlet cooling water temperature [° C.], Cw is the specific heat of water [kcal / kgK], and ρ is the density of water [kg / m ³ ].

  And if the radiator water flow amount according to conditions is calculated | required, the opening degree of the three-way valve which can output it can be derived. The relationship between the amount of radiator water flow and the three-way valve opening is stored in the three-way valve opening water flow table 1020 as shown in FIG.

  Furthermore, in order to obtain the radiator water flow rate, it is necessary to set the radiator outlet cooling water temperature, but the radiator outlet cooling water temperature varies depending on the air flow rate, so the relationship between the radiator water flow rate and the air flow rate is taken into account. It is necessary to set the cooling water temperature. That is, it is necessary to grasp in advance the relationship between the radiator exhaust temperature and the radiator outlet cooling water temperature. The relationship between the radiator exhaust temperature and the radiator outlet cooling water temperature is stored in the exhaust temperature cooling water temperature table 1040 as shown in FIG.

  The cogeneration system 100 according to the present embodiment realizes an energy saving effect by reducing fan power by suppressing the number of revolutions of the radiator fan as much as possible.

  If the optimum point that can achieve the state where the radiator fan speed is suppressed as much as possible is found in the relationship between the radiator fan exhaust temperature and the radiator outlet cooling water temperature, the optimum point according to the conditions (radiator fan speed, three-way valve opening degree) ) Can be derived.

  However, it is necessary to know in advance the relationship between the engine inlet cooling water temperature and the radiator water flow rate. Moreover, in order to grasp | ascertain the amount of water flow of a radiator, it is necessary to grasp | ascertain the heat exchanger primary side exit cooling water temperature.

If the jacket exhaust heat according to the conditions (outside air temperature, input heat amount) is obtained, the engine inlet cooling water temperature can be obtained using the equation (5).

  Where Q is jacket exhaust heat [kW], 22 is jacket coolant rated circulation flow rate [t / h], 1000000 is coefficient [g / t], 3600 is coefficient [sec / h] Yes, 1 is the specific heat of water [cal / gK], 1000 is the coefficient [cal / kcal], 4.186 is the coefficient [kW / kcal], 94 is the engine outlet coolant temperature (target value) [℃ ]. The value of the denominator of the equation (5) represents the amount of heat per 1 g of cooling water and 1 ° C. temperature difference.

Moreover, the heat exchanger primary side exit cooling water temperature is calculated | required using Formula (6).

  Where Q is the heat demand [kW], 22 is the jacket cooling water rated circulation flow rate [t / h], 1000000 is the coefficient [g / t], 3600 is the coefficient [sec / h] Yes, 1 is the specific heat of water [cal / gK], 1000 is the coefficient [cal / kcal], 4.186 is the coefficient [kW / kcal], 94 is the engine outlet coolant temperature (target value) [℃ ]. The value of the denominator of Equation (6) represents the amount of heat per 1 g of cooling water mass and 1 ° C. temperature difference. In equation (6), the heat demand Q is 0 when there is no heat demand.

  A sequence diagram for controlling the rotational speed of the radiator fan 600 calculated as described above and a sequence diagram for controlling the opening degree of the three-way valve 700 are shown in FIGS.

  In the sequence diagrams shown in FIGS. 12 and 13, “K” represents setting of constants and ratios. That is, when the input value is x, the output value y is Kx. “FX” represents a function. That is, when the input value is x, the output value y is FX (x). “T” represents signal switching. That is, if the input x is 1, the output c is a, and if the input x is 0, the output c is b. “FG” represents the occurrence of a function. That is, when the input value is x, the output value y is FG (x). “MS” represents a monitor switch. That is, the output y (1 or 0) is output according to the relationship between the input x and a predetermined condition (higher or lower than the threshold value). “Δ” represents subtraction. That is, the output y is input value axa−input value bxb. “F” represents a function. That is, when the input value is x, the output value y is f (x). The input x is selected according to the condition (1 or 0) and the output y is output.

=== Flow of processing ===
Next, an outline of the exhaust heat treatment in the cogeneration system 100 according to the present embodiment will be described with reference to the flowchart shown in FIG.

First, according to the input of the generator output (S1000), the control device 900 calculates device heat dissipation (S1010). The control device 900 also calculates jacket exhaust heat (S1020).
Next, upon receiving the input of the operation state of the pump at the heat demand destination (S1030), the control device 900 performs processing according to the presence or absence of waste heat utilization at the heat demand destination (S1040).
When the exhaust heat is used, the control device 900 calculates the amount of heat processed in the heat exchanger 800 (S1050). In this case, as described above, the amount of heat processed in the heat exchanger 800 is substantially equal to the jacket exhaust heat (S1060). Next, the control device 900 calculates the target processing heat quantity (S1070). In this case, the target processing heat amount is equipment heat dissipation (S1080). Device heat radiation is heat radiation from the engine 200 or the generator 300 to the air.

  On the other hand, if there is no exhaust heat utilization, the control device 900 calculates the amount of heat processed in the heat exchanger 800 (S1090). In this case, the amount of heat processed in the heat exchanger 800 is 0 (S1100). Next, the control device 900 calculates the target processing heat quantity (S1110). In this case, the target processing heat amount is the sum of the device heat dissipation and the jacket exhaust heat (S1120).

Subsequently, the control device 900 calculates the air volume based on the calorific value calculation formula using each value of the outside air temperature and the radiator exhaust temperature (S1150). The calorific value calculation formula is shown by the formula (7).

Q = m * c * (t2-t1) (7)

Here, Q is the amount of heat [kW], m is the mass [g], c is the specific heat [cal / gK], and t1 and t2 are the temperature [° C.].

  When the air volume is calculated (S1160), the control device 900 determines whether or not the air volume is within the range of the blowing capacity corresponding to the inverter output (S1170). If the air volume is not within the range of the blowing capacity corresponding to the inverter output, the process returns to S1140.

  When the air volume is within the range of the blowing capacity according to the inverter output, the control device 900 uses the calorific value calculation formula represented by the above formula (7) based on the target processing heat quantity, the outside air temperature, and the air volume. The enclosure ambient temperature is calculated (S1180). When the enclosure ambient temperature is calculated (S1190), the control device 900 determines whether the enclosure ambient temperature does not exceed the allowable temperature of the electrical product (S1200). If the enclosure ambient temperature exceeds the allowable temperature of the electrical product, the process returns to S1140.

  When the enclosure ambient temperature does not exceed the allowable temperature of the electrical product, the control device 900 calculates the processing heat quantity from the outside air temperature, the radiator exhaust temperature, and the air volume based on the calorific value calculation formula (S1210). When the processing heat amount is calculated (S1220), the control device 900 determines whether or not the processing heat amount exceeds the target processing heat amount (S1230). If the processing heat quantity does not exceed the target processing heat quantity, the process returns to S1140.

  When the processing heat amount exceeds the target processing heat amount, the control device 900 calculates the radiator outlet cooling water temperature based on the relationship between the radiator exhaust temperature and the radiator outlet cooling water temperature in the verification test (S1240, S1250). . Next, the control device calculates the heat exchanger outlet cooling water temperature from the processing heat amount in the heat exchanger 800, the cooling water pump capacity, and the cooling water set temperature based on the calorific value calculation formula (S1260, S1270). And the control apparatus 900 calculates the process calorie | heat amount in the radiator 500 by deducting apparatus heat radiation from the object process calorie | heat amount (S1280, S1290). Subsequently, the control device 900 calculates a radiator water flow rate based on a calorific value calculation formula based on a processing heat amount in the radiator 500, a cooling water pump capacity, and a heat exchanger outlet cooling water temperature (S1300, S1310). If the radiator water flow rate is outside the range of the cooling water pump capacity (S1320), the process returns to S1140.

  When the radiator water flow rate is within the range of the cooling water pump capacity (S1320), the control device 900 calculates the heat exchanger outlet cooling water temperature, the radiator outlet cooling water temperature, and the radiator water flow rate based on the calorific value calculation formula. The amount of heat for treatment is calculated (S1330, S1340). The control device 900 ends the process when the amount of processing heat exceeds the target processing heat amount, and returns to S1140 if it does not exceed the target processing heat amount.

  The cogeneration system 100 according to the present embodiment has been described above. However, according to the cogeneration system 100 according to the present embodiment, optimal cooling control can be performed. Further, since the rotation speed of the radiator fan 600 can be freely controlled using the inverter 620, the air volume can be arbitrarily adjusted according to the outside air temperature, the heat radiation amount from the engine 200, the generator 300, etc. It is possible to prevent unnecessary cooling inside 400 and improve the overall thermal efficiency. In addition, since the power for driving the radiator fan 600 can be suppressed to a necessary amount, the total thermal efficiency can be improved. Further, since the amount of refrigerant flowing into the radiator 500 can be freely controlled by using the three-way valve 700, it is possible to cool the refrigerant optimally according to the performance and durability of the engine 200. Become. This also makes it possible to perform optimal cooling control.

  Although the best mode for carrying out the present invention has been described above, the above embodiment is intended to facilitate understanding of the present invention and is not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes equivalents thereof.

It is a figure which shows an example of the whole structure of a cogeneration system. It is a figure which shows an example of the whole structure of a cogeneration system. It is a figure which shows the cogeneration system which concerns on this Embodiment. It is a figure which shows the cogeneration system which concerns on this Embodiment. It is a figure which shows the cooling control in the cogeneration system which concerns on this Embodiment. It is a figure which shows the cooling control in the cogeneration system which concerns on this Embodiment. It is a figure which shows the fan rotation speed air volume table which concerns on this Embodiment. It is a figure which shows the generator output fuel consumption table which concerns on this Embodiment. It is a figure which shows the three-way valve opening degree water flow rate table which concerns on this Embodiment. It is a figure which shows the generator output jacket waste heat table which concerns on this Embodiment. It is a flowchart which shows the outline | summary of the waste heat processing which concerns on this Embodiment. It is a figure which shows the control block diagram which concerns on this Embodiment. It is a figure which shows the control block diagram which concerns on this Embodiment. It is a figure which shows the structure of the control apparatus which concerns on this Embodiment. It is a figure which shows the exhaust temperature cooling water temperature table which concerns on this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Cogeneration system 200 Engine 300 Generator 400 Enclosure 410 Intake port 420 Exhaust port 500 Radiator 510 Circulation path 511 Detour 600 Radiator fan 610 Motor 620 Inverter 630 Ventilation fan 700 Three-way valve 710 Wax valve 800 Heat exchanger 900 Controller 1000 Fan Rotational speed air volume table 1010 Generator output fuel consumption table 1020 Three-way valve opening water flow rate table 1030 Generator output jacket exhaust heat table 1040 Exhaust temperature Cooling water temperature table

Claims (7)

In a storage box having an inlet and an outlet,
Prime mover,
A generator driven by the prime mover;
A radiator provided on a refrigerant circulation path that absorbs heat from the prime mover;
A fan for cooling the radiator,
A heat exchanger provided at a position where the refrigerant flows from the prime mover to the radiator on the circulation path, and supplying heat absorbed by the refrigerant from the prime mover to a heat utilization device;
Is housed,
A cogeneration system in which outside air is taken in from the intake port by the fan and exhausted from the exhaust port, thereby ventilating the inside of the storage box. An inverter that outputs AC power for driving the fan;
An inverter control device for controlling the rotational speed of the fan by controlling the frequency of the AC power output from the inverter;
The cogeneration system according to claim 1, comprising: The inverter control device calculates a sum of a value indicating the amount of heat released from the prime mover into the air per unit time and a value indicating the amount of heat released from the generator into the air per unit time. The cogeneration system according to claim 2, wherein the rotation speed of the fan is controlled based on a value obtained by dividing by a value indicating the amount of heat absorbed by the fan. The value indicating the amount of heat absorbed by a unit amount of air is calculated based on a value indicating a difference between an allowable temperature of air inside the storage box and a temperature of outside air taken in from the intake port. The cogeneration system according to claim 3. A first port through which a refrigerant flows from the heat exchanger, a second port through which the refrigerant flows out to the radiator, and the heat radiation; A third port through which the refrigerant flows out to the bypass of the vessel,
A regulating valve control device for controlling a ratio between the amount of refrigerant flowing out of the second port of the regulating valve and the amount of refrigerant flowing out of the third port;
The cogeneration system according to claim 1, comprising: The control valve control device controls the ratio based on a value obtained by dividing a value indicating the amount of heat released from the prime mover into the refrigerant by a value indicating the amount of heat absorbed by the unit amount of refrigerant. The cogeneration system according to claim 5. The value indicating the amount of heat absorbed by the unit amount of refrigerant is calculated based on a value indicating a difference between a temperature of the refrigerant flowing into the radiator and a temperature of the refrigerant flowing out of the radiator. The cogeneration system according to claim 6.

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