JP2683945B2 - Power and heat output devices for cogeneration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial application field >> The present invention relates to a power / heat output device of a cogeneration device.

<< Prior Art >> An apparatus of this kind is disclosed in Japanese Patent Application Laid-Open No. 63-198759.

This is configured to recover the heat of the engine body and the heat of the exhaust gas into a heat recovery liquid in a hot water tank via a heat exchanger, provide an electric heater in the hot water tank, and use a large amount of heat to store the hot water. When the internal temperature falls below a set value, the entire output power of the generator is supplied to the electric heater.

<< Problems to be Solved by the Invention >> The above-described conventional technique operates as shown in FIG. The lower half of the figure shows the relationship between the external power load W and the engine output P, and the upper half shows the relationship between the external power load W and the heat output Q.

While power is being supplied to the external load, the engine is operating at engine output P ₁ corresponding to the external power load to provide heat output Q ₁ . If the temperature of the heat recovery liquid in the hot water storage tank decreases during the power supply, the power supply to the outside is stopped, and the entire power is supplied to the electric heater. This allows the engine to run at engine power P ₂ corresponding to the electric heater load,
The total heat output Q of the heat output Q ₂ corresponding to the electric heater load and the heater heating amount Q ₃ is supplied.

Therefore, in the conventional technique, there is a problem in that electric power cannot be supplied to the outside when the heat output Q is maximum and the heat output is small when the external power load W is a partial load.

An object of the present invention is to always supply power to an external power load and to increase the heat output when the external power load is a partial load.

<< Means for Solving the Problems >> In order to achieve the above object, the present invention, as shown in FIGS. 1 and 2, for example, removes the heat generated by the engine 2 from the body heat of the engine 2 and the exhaust gas heat. The heat recovery liquid 8 in the hot water storage tank 7 is recovered through a heat exchange device 18 for heat recovery. An electric heater 29 is provided in the hot water storage tank 7, and the electric heater 29 is supplied by a power supply control device 30 for heating. The heating power supply control device 30 is connected to the output circuit 23 of the generator 3 via the adjustment unit 31, and based on the fact that the heating control unit 32 inputs the heating detection signal from the heating detection unit A, generates a heating command signal. In the power / heat output device of the cogeneration device, the heating detection unit A of the heating power supply control device 30 comprises an external power load detection unit 33, The external power load detecting means 33 is connected to the output circuit 2 of the generator 3. 3 is configured to detect the external power load W extracted to the outside, and the heating control unit 32 of the heating power supply control device 30 is a region where the value of the external power load signal input from the external power load detection means 33 is large. In a smaller area, the heater power supply amount H of the power supply controller 31 is adjusted to a larger value, and the heater heating amount Q ₃ of the heat recovery liquid in the hot water storage tank 7 by the electric heater 29 is increased. It is a thing.

<< Operation >> The present invention operates as follows, for example, as shown in FIG.

As shown in the lower half of the figure, the engine output P ₁ corresponding to the external power load W is smaller in the region where the external power load W is smaller than in the region where the external power load W is large.
The heater power supply amount H to 29 is increased to increase the engine output P ₂ corresponding to the electric heater load, and the engine output P is almost 100%. As a result, as shown in the upper half of the figure, the heat output Q corresponding to the external power load W is 100% output, which is the sum of the heat output Q _{1 from the} external power load and the heat output Q _{2 from the} electric motor load. Is a value obtained by adding the heater heating amount Q ₃ of the heat frequency liquid in the hot water storage tank 7 to a value close to.

<< Example >> Hereinafter, an example of the present invention will be described with reference to the drawings.

As shown in the system diagram of FIG. 1, the cogeneration system 1 includes a liquid-cooled gas engine 2, a generator 3, a first circuit 4 for exhaust heat recovery, and a circuit 5 for cooling the engine. By driving the generator 3 by the engine 2, power is generated by the generator 3 and, at the same time, the heat generated by the engine heat of the engine 2 and the exhaust gas heat is transferred through the engine coolant to the first exhaust heat recovery circuit. 4. The waste heat recovery liquid 8 in the hot water storage tank 7 is recovered by the second heat recovery second circuit 6. On the other hand, when the usage amount of the exhaust heat recovery liquid 8 in the hot water storage tank 7 decreases and the amount of heat radiated from the first exhaust heat recovery circuit 4 decreases, and the temperature of the engine coolant rises above a predetermined temperature. The engine coolant is also radiated from the engine cooling circuit 5 to maintain the temperature of the engine coolant within a certain temperature range.

The exhaust heat recovery first circuit 4 connects the outlet of the water jacket 9 of the engine 2 to the engine coolant flow path 10a of the exhaust heat absorption heat exchanger 10 and the engine coolant of the exhaust heat recovery heat exchanger 11. It is connected to the inlet of the water jacket 9 through the flow path 11a and the engine coolant circulation pump 12 in order. The exhaust gas of the engine 2 is supplied to the heat exchanger 10 for absorbing exhaust heat.
From the exhaust gas passage 10b through the muffler 14. The engine coolant whose temperature has risen in the water jacket 9 absorbs exhaust heat while passing through the engine coolant flow passage 10a of the exhaust heat absorbing heat exchanger 10, and further rises in temperature. While passing through the engine coolant flow path 11a of the heat exchanger 11, the heat is radiated to the exhaust heat recovery circulating fluid in the exhaust heat recovery circulating fluid flow path 11b and returned to the water jacket 9. The exhaust heat recovery circulating liquid in the exhaust heat recovery second circuit 6 is circulated by the circulation pump 16 and absorbs heat while passing through the exhaust heat recovery circulating liquid flow passage 11b of the exhaust heat recovery exchanger 11. afterwards,
The heat recovery liquid 8 is heated in the heat radiation path 7a in the hot water storage tank 7. The heat exchanger 11 for recovering exhaust heat and the heat radiation path 7a in the hot water storage tank 7 constitute a heat exchanger 18 for recovering engine exhaust heat.

The engine cooling circuit 5 has an outlet of the water jacket 9 connected to an inlet of the water jacket 9 through the radiator 20 and the engine coolant circulation pump 12 in this order. By controlling the amount of the engine coolant circulating to the radiator 20 by the variable split valve 21, even if the power generation load or the exhaust heat recovery load of the engine 2 fluctuates, the engine coolant flowing through the water jacket 9 is changed. The temperature is kept within a certain range to prevent the engine 2 from burning.

An electric control panel 24 is provided in the output circuit 23 of the generator 3. The induction motor 26 is connected to the output circuit 23a for the induction motor branched from the electric control panel 24 via the motor starting position 25, and the output circuit 23b for the resistance load branched from the electric control panel 24 is connected to the electromagnetic contactor 27. A resistive load 28 such as lighting is connected via the. As the motor starting device 25, it is preferable to employ the type described in Japanese Patent Application No. 62-215962 previously proposed by the present applicant.

In the cogeneration apparatus 1 described above, the electric heater 29 is provided in the hot water storage tank 7. This electric heater 29
The heating value is configured to be able to be adjusted steplessly, and is controlled by the heating power supply control device 30.

The heating power supply control device 30 includes a power supply adjustment unit 31 composed of an electromagnetic contactor, a heating control unit 32, and a heating detection unit A composed of an external power load detection unit 33. Based on the input of the heating detection signal from the detecting means 33, a heating command signal is output and the power supply adjusting section (electromagnetic contactor) 31 is operated to adjust the power supply.

That is, the electric heater 29 is connected to the electric control panel 24 via the power supply adjusting unit 31. The external power load detecting means 33 is constituted by a current detector, and is configured to indirectly detect, as a current value, an external power load taken out of the output circuit 23 of the generator 3 to the outside.

Then, the heating control unit 32 operates as shown in FIG. The lower half of the figure shows the external power load W and the engine output P
The upper half shows the external power load W and the hot water tank 7.
3 shows the relationship with the thermal output Q of FIG.

As shown in the lower half figure, towards the region smaller than the external electric power load W is large area, since the engine output P ₁ corresponding to the external electric power load is low, the heater power supply amount H of that much to the electric heater 29 and many, to increase the engine output P ₂ corresponding to the electric heater load, the engine output P to about 100%. Thus, as shown in the upper half view, thermal power Q corresponding to the external electric power load W, the thermal output Q ₁ by the external electric power load
And the total heat output Q _{2 from the} electric heater load are about 100%
To the value obtained by adding the heater heating amount Q ₃ of the heat recovery liquid in the hot water storage tank 7. That is, in a region where the value of the detection signal of the external power load W input from the external power load detection means 33 is smaller than in a region where the value is large, the heater power supply amount H of the power supply adjusting unit 31 is adjusted to a large value, and the electric power is adjusted. The heater heating amount Q ₃ of the heat recovery liquid in the hot water storage tank 7 by the heater 29 is increased.

As shown in FIG. 1, the temperature of the heat recovery liquid 8 in the hot water storage tank 7 is detected by a temperature detector 34, and the heating controller 32 controls the electric heater 29 through a power supply controller 31. By controlling the power supply, a constant liquid temperature is maintained.

In this embodiment, the heat radiation path 7a is provided in the hot water storage tank 7, but the heat radiation path 7a is omitted, and the heat recovery liquid 8 in the hot water storage tank 7 is directly circulated to the second circuit 6 for exhaust heat recovery. It is also possible to make it.

Further, the engine 2 may be a gasoline engine or a diesel engine instead of the gas engine.

(First Modification) FIG. 3 shows a first modification.

In this configuration, the external power load detection means 33 is composed of a watt hour meter 37 so that the external power load is directly detected.

It should be noted that the external power load detecting means 33 can be changed as follows, instead of the current detector and the watt hour meter.
That is, the engine output is detected by detecting the opening of the throttle valve of the engine 2 with an intake negative pressure sensor or the like, or by detecting the position of the governor actuator, and indirectly connecting the external power load via the engine output. It detects.

(Second Modification) FIG. 4 shows a second modification.

This is to provide a temperature detector 39 at the inlet side of the heat exchanger 11 for heat recovery in the second circuit 6 for heat recovery to control the temperature of the heat recovery liquid 8 in the hot water storage tank 7 to a constant value. It is. Instead of this, as shown in the two-dot chain line diagram in FIG.
A temperature detector 40 may be provided at the exhaust heat recovery heat exchanger 11 outlet side in the second exhaust heat recovery circuit 4.

(Third Modification) FIGS. 5 and 6 show a third modification.

This is, as shown in FIG. 6, a device of a model having an allowable external power load of 15 kW and one heater of 7.5 kW provided. In a region where the external power load W is 7.5 kW or less, the heater is used. It is designed to be used. In the figure, P ₁ is the engine output corresponding to the external power load, P ₂ is the engine output corresponding to the electric heater load (heater power supply amount H), Q ₁ is the heat output by the external power load, and Q ₂ is the heat by the electric heater. On output, Q ₃ is the heater heating.

This is controlled as follows, as shown in FIG. First, it is determined whether the external power load is 7.5 KW or less (S
1) In the case of 7.5KW or less, it is determined whether the heater is ON (S2), and if it is ON, it is determined whether the liquid temperature in the hot water tank is lower than the set temperature (S3), If low, heater is on
(S4), and if it is higher, the heater is turned off (S5).
If the external power load exceeds 7.5 KW in S1, the heater is turned off (S5). Further, in S2, if the heater is not turned on, it is determined whether or not the liquid temperature in the hot water tank is higher than a set temperature (S6). The heater turns on.

(Fourth Modification) FIGS. 7 and 8 show a fourth modification.

This is, as shown in Fig. 8, provided with three 3.75KW heaters in a device of a model with an allowable external power load of 15KW, and three heaters in the area where the external electrode load W is 3.75KW or less. When the external power load W is 3.75 to 7.5 KW, two heaters are turned on, and when the external power load W is 7.5 to 11.25 KW, one heater is turned on. Symbols P ₁ , P ₂ , Q ₁ , Q _2, and Q ₃ indicate the same contents as in FIG.

This is controlled as follows, as shown in FIG. First, it is determined whether the external power load is 11.25 kW or less (S1). In the following cases, the No. 1 heater is turned on (S2),
Next, it is determined whether the external power load W is equal to or less than 7.5 kW (S
3) In the following cases, the two heaters No. 1 and No. 2 are turned on (S4), and then it is determined whether the external electrode load is 3.75KW or less (S5). In case of No.1 to 3 of 3
The two heaters are turned on (S6). In S1, 1
If it exceeds 1.25KW, do not turn on the heater (S7).
In addition, if it exceeds 7.5 KW in S3, it is returned to S1 and S
If it exceeds 3.75KW in 5, it returns to S3.

<< Effects of the Invention >> The present invention has the following effects because it is configured and operates as described above.

The heat output corresponding to the external power load is the sum of the heat output from the external power load and the heat output from the electric heater load, which is 10
It is a value that the heater heating amount of the heat recovery liquid in the hot water storage tank is added to a value close to 0% output. Thereby, while always supplying power to the external power load, the heat output when the external power load is a partial load can be increased.

Moreover, since the engine can be operated in a state of almost full load, it is possible to prevent the adverse effects that occur during low load continuous operation.
That is, seizure of the piston ring and cylinder head due to supercooling of the engine, or corrosion due to exhaust gas condensed water in the exhaust gas heat exchanger can be prevented.

[Brief description of the drawings]

1 to 8 show an embodiment of the present invention. FIG. 1 and FIG. 2 show one embodiment thereof, FIG. 1 is an overall system diagram, and FIG. 2 is a diagram showing each relationship between an external power load, an engine output and a heat output. FIG. 3 shows a first modification and is a partial view corresponding to FIG. FIG. 4 shows a second modification and is a partial view corresponding to FIG. 5 and 6 show a third modified example, FIG. 5 is a flowchart, and FIG. 6 is a diagram corresponding to FIG. 7 and 8 show a fourth modification, FIG. 7 is a flowchart, and FIG. 8 is a diagram corresponding to FIG. FIG. 9 shows a conventional example and is a view corresponding to FIG. 2 ... engine, 3 ... generator, 7 ... hot water tank, 8 ...
Heat recovery liquid, 18 ... Heat exchange device, 23 ... Output circuit of generator 3, 29 ... Electric heater, 30 ... Heating power supply control device, 31
...... Power supply adjusting section, 32 ...... Heating control section, 33 ...... External power load detecting means, A ...... Heating detecting section, H ...... Heater power supply amount,
Q ₃ …… Heater heating amount, W …… External power load.

Claims (1)

(57) [Claims] A heat recovery liquid (8) in a hot water storage tank (7) receives heat generated by an engine between body heat of an engine (2) and exhaust gas heat via a heat exchange device (18) for exhaust heat recovery. ), An electric heater (29) is provided in the hot water storage tank (7), and the electric heater (29) is a power supply adjusting unit (31) of the heating power supply control device (30).
Connected to the output circuit (23) of the generator (3), and the heating power supply control device (30) is configured such that the heating control unit (32) inputs a heating detection signal from the heating detection unit (A). The power / heat output device of the cogeneration device, which is configured to output a heating command signal based on the power supply control unit (31) to perform the power supply adjustment operation, wherein the heating detection unit of the heating power supply control device (30) (A) consists of an external power load detecting means (33), and the external power load detecting means (33) detects an external power load (W) taken out from the output circuit (23) of the generator (3). The heating control unit (32) of the heating power supply control device (30) is configured such that the region where the value of the external power load signal input from the external power load detecting means (33) is smaller than the region where the value is large is larger. , Adjust the heater power supply (H) of the power supply controller (31) to a large value. Save
It is configured to increase the heater heating amount (Q ₃ ) of the heat recovery liquid in the hot water storage tank (7) by the electric heater (29).
Heat output device.