JPH0786329B2 - Combined heat and power equipment - Google Patents

Description

The present invention relates to a combined heat and power supply system for supplying electric power, steam and hot water, and more particularly to an exhaust gas generating hot water by exhaust heat of an internal combustion engine. The present invention relates to a combined heat and power supply device that eliminates a secondary delay on the secondary side (heat receiving side) of a heat heat exchanger.

(Prior Art) In general, a combined heat and power device cools an internal combustion engine that drives a generator with cold water of an exhaust heat heat exchanger, and at the same time, converts cold water heated by the exhaust heat into hot water. The exhaust gas heat exchanger further heats the exhaust gas from the internal combustion engine to convert it into steam, and these hot water and steam are stored in a hot water storage tank and a heat storage tank, respectively, and are supplied to the hot water and steam load by a heat load device. ing.

Then, as the heat storage control of the conventional combined heat and power device, so that the pressure of the steam stored in the heat storage tank is constant, based on the detected value of the steam pressure on the outlet side of the exhaust gas heat exchanger,
The flow rate of hot water supplied to the heat receiving side inlet of the exhaust gas heat exchanger is controlled.

Further, in the conventional hot water load control, the hot water from the exhaust heat heat exchanger and the exhaust gas heat exchanger are adjusted so that the temperature of the hot water supplied from the hot water heat exchanger and the hot water storage tank to the hot water load becomes constant. Based on the detected temperature value in the hot water header distributed to the heat exchanger, the flow rate of chilled water supplied to the heat receiving side (secondary side) inlet of the exhaust heat heat exchanger is controlled to be constant at the set value. There is.

Further, the hot water supply flow rate supplied to the hot water load is controlled by each water supply valve and the hot water valve so that the exhaust heat becomes constant based on the detected temperature value in the hot water storage tank.

(Problems to be Solved by the Invention) However, in such a conventional combined heat and power device, when the load of the internal combustion engine changes, the exhaust gas flow rate of the primary system changes and the steam pressure at the exhaust gas heat exchanger outlet varies. By controlling the opening degree of the hot water flow rate adjusting valve based on this, the heat exchange efficiency of the exhaust heat heat exchanger is reduced, and the heat exchange amount is reduced.

In addition, the exhaust heat exchanger that cools the internal combustion engine is also electrically,
There is a problem that the heat exchange heat quantity is reduced due to the secondary delay with respect to the heat load fluctuation.

Further, the hot water supplied to the hot water header fluctuates as the flow rate of cold water in the exhaust heat exchanger that cools the internal combustion engine fluctuates as the load on the internal combustion engine fluctuates, causing heat exchange due to the secondary delay of the exhaust heat heat exchanger. The amount is reduced substantially, and the heat receiving side (secondary side) of the exhaust heat exchanger
The temperature of the hot water header to which hot water is supplied from the outlet fluctuates with respect to the set value, and the hot water is due to the secondary delay cause of the exhaust heat heat exchanger due to the fluctuation of the exhaust gas flow rate of the primary system.
Similarly, there is a problem that the heat exchange heat quantity is substantially reduced, and the fluctuation range of the steam pressure at the exhaust gas heat exchanger outlet becomes large with respect to the set value.

Further, in the heat load following operation, there is a problem that the fluctuation of the heat exchange amount due to the secondary delay of each of the exhaust heat and exhaust gas heat exchangers becomes larger than the set value.

Therefore, the present invention has been made in consideration of the above circumstances, and its purpose is to reduce exhaust heat at the time of load fluctuation of the internal combustion engine, reduce secondary delay of the exhaust gas heat exchanger, and prevent deterioration of the heat exchange efficiency. An object of the present invention is to provide a combined heat and power supply device.

[Structure of Invention]

(Means for Solving the Problems) The present invention relates to a switcher for selecting one of the operation modes of electric load following operation and thermal load following operation, and a correction amount for calculating a correction amount for correcting the load fluctuation of the internal combustion engine. An arithmetic circuit is mainly provided.

That is, the present invention relates to an internal combustion engine that drives a generator, a fuel flow rate detector and a fuel flow rate adjusting valve that detect and adjust the supply flow rate of fuel supplied to the internal combustion engine, and cold water due to exhaust heat from the internal combustion engine. Exhaust heat heat exchanger that heats the water to generate hot water, a cold water temperature detector that detects the temperature of the cold water supplied to the heat receiving side of the exhaust heat heat exchanger, and a cold water flow rate adjustment that adjusts the cold water supply flow rate A valve, a heat storage tank for storing the steam generated by further heating hot water from the heat receiving side of the exhaust heat heat exchanger in the exhaust gas heat exchanger with the exhaust gas from the internal combustion engine, and the exhaust heat heat exchanger First hot water flow rate adjusting valve for adjusting the flow rate of hot water supplied from the heat receiving side of the hot water heat exchanger to the hot side of the hot water heat exchanger, and the hot water heat exchanger from the hot side to the hot side of the hot water storage tank Second hot water for adjusting the supply flow rate of hot water A quantity control valve, first and second hot water flow rate detectors for respectively detecting hot water supply flow rates supplied to the hot water load from the heat receiving sides of the hot water heat exchanger and the hot water storage tank, and a steam load from the heat storage tank. In the combined heat and power supply device having a steam flow rate detector for detecting the supply flow rate of the steam supplied to, an output estimation circuit for estimating the output of the generator by the detection value detected by the fuel flow rate detector, and this output A comparator that compares the estimated output estimated by the estimation circuit with a power setting value and outputs a deviation;
From the power load output calculation circuit for converting the detected value of the hot water supply flow rate detected by the second warm water flow rate detector and the detected value of the steam supply flow rate detected by the steam flow rate detector into electric power, and from this power load output calculation circuit The power conversion signal and the deviation signal from the comparator are switchably output according to the operation mode, and a part of the output signal from this switch is adjusted to the opening of the fuel flow control valve to adjust the fuel. The load fluctuation of the internal combustion engine is corrected based on the controller provided to the flow rate adjusting valve, a part of the output signal from the switch, and the temperature difference of the cold water at the heat receiving side outlet and inlet of the exhaust heat heat exchanger. And a correction amount calculation circuit for adjusting the valve opening degree by applying the correction signal as a bias signal to the cold water flow rate adjusting valve and the first and second hot water flow rate adjusting valves, respectively. And wherein the digit.

(Operation) First, when performing the electric load following operation of the combined heat and power supply device, the operation mode of the switch is selected as the electric load following operation mode.

Then, the opening of the fuel flow rate adjusting valve that adjusts the supply amount of the fuel supplied to the internal combustion engine is set so that the deviation between the detected value of the fuel flow rate detector that detects the fuel supply flow rate and the power setting value becomes zero. And the electric load following operation is performed.

That is, the fuel supply flow rate detection value detected by the fuel flow rate detector is estimated as the electric output of the generator by the output estimation circuit, and is compared with the power set value by the comparator to calculate the deviation.

This deviation signal is selectively output by the switcher that has been switched to the electric load following operation mode, and is given to the controller and the correction amount calculation circuit, respectively, and in the controller, the fuel is adjusted so that this deviation becomes zero. It is adjusted to the opening of the flow rate adjusting valve and given to the fuel flow rate adjusting valve.

Therefore, the opening of the fuel flow rate adjusting valve is controlled so as to be constant at the power setting value, so that the electric output of the generator driven by the internal combustion engine is constantly controlled at the power setting value.

On the other hand, a part of the output signal from the switch, which is given to the correction amount calculation circuit, is based on the temperature signal indicating the temperature difference between the cold water at the heat receiving side outlet and the heat receiving side outlet of the exhaust heat exchanger. A correction amount for correcting the load variation of the internal combustion engine is calculated, and the correction amount is given to the cold water flow rate adjusting valve and the first and second hot water flow rate adjusting valves as bias signals.

That is, according to the present invention, since the correction signal for correcting the fluctuation of the load of the internal combustion engine is given as a bias signal to the cold water flow rate adjusting valve and the first and second hot water flow rate adjusting valves respectively in advance, the internal combustion engine It is possible to prevent a decrease in the heat exchange efficiency of the exhaust heat exchanger due to the load change of the secondary system and to control the secondary system heat load change so that the set value is set in advance. it can.

On the other hand, when performing the heat load following operation of the combined heat and power supply device, the operation mode of the switch is selected as the heat load following operation mode.

Then, the opening degree of the fuel flow rate adjusting valve that controls the supply flow rate of the fuel supplied to the internal combustion engine is controlled by following the fluctuations of the heat load of the steam load and the hot water load.

That is, the detected values of the steam flow rate detector and the first and second hot water flow rate detectors that detect the steam supply flow rate and the hot water supply flow rate supplied to the steam load and the hot water load, respectively, of the heat load are the power load output. Converted to electric power by the circuit.

This electric power conversion signal is selectively output by the switch and given to the controller, where it is adjusted to the required operation signal and given to the fuel flow rate adjusting valve, and its opening is controlled according to the fluctuation of the heat load. Then, the internal combustion engine is operated following the heat load.

Further, also in the heat load following operation, as in the electric load following operation, the correction amount for correcting the load fluctuation of the internal combustion engine is calculated by the correction amount calculating circuit, and as a bias signal, the chilled water flow rate adjusting valve and the first and second To the hot water flow rate adjusting valves, and their valve openings are adjusted.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 2 is a system diagram showing an overall configuration of an embodiment of the present invention. In the figure, the flow rate of fuel supplied to the internal combustion engine 2 that drives the generator 1 depends on the opening degree of the fuel flow rate adjusting valve 3. It is controlled and detected by the fuel flow rate detector 4.

The internal combustion engine 2 is cooled by an exhaust heat heat exchanger 5 such as a water jacket, and is provided with an exhaust gas heat exchanger 6 for passing exhaust gas into the heating side body.

The cold water inlet on the heat receiving side (secondary side) of the exhaust heat exchanger 5 is connected to the heating side outlet of the hot water storage tank 7 via the cold water pipe 5a, and the cold water pipe 5a is connected from the upstream side to the downstream side. Toward the hot water tank three-way valve (second hot water flow rate adjusting valve) 8, cold water header 9 connected to a cold water source (not shown), cold water pump 10, cold water flow rate adjusting valve 1
1. A cold water temperature detector 12 for detecting the cold water temperature is sequentially installed, and cold water is supplied to the heat receiving side inlet of the exhaust heat heat exchanger 5.

The outlet on the heat receiving side of the exhaust heat exchanger 5 is connected to the inlet on the heating side of the hot water heat exchanger 14 via the hot water pipe 13, and the hot water header 15 is interposed in the middle of the hot water pipe 13 and the hot water header 15 Is equipped with a header temperature detector 15a for detecting the internal temperature.

One outlet end of the hot water header 15 is connected to the heating side inlet of the exhaust gas heat exchanger 6 via a pipe 16, and a hot water pump 17 and a flow rate adjusting valve 18 are interposed in the pipe 16 from the upstream side to the downstream side. Therefore, the hot water supplied to the exhaust gas heat exchanger 6 by the hot water pump 17 is heated by the exhaust gas from the internal combustion engine 2 to generate steam.

The heat receiving side outlet of the exhaust gas heat exchanger 6 is connected to a steam load 20 via a steam pipe 19, a heat storage tank 21 is interposed in the middle of the steam pipe 19, and steam pressure detection is performed before and after the heat storage tank 21. A vessel 22 and a vapor flow rate detector 23 are installed.

A cold water supply pipe 24 for supplying cold water is connected to a heat receiving side inlet of the hot water heat exchanger 14, while a heat receiving side outlet is connected to a first warm water load 26 via a first warm water supplying pipe 25. , First
A first hot water temperature detector 27 and a first hot water flow rate detector 28 are installed in the middle of the hot water supply pipe 25.

On the other hand, the body on the heat receiving side of the hot water storage tank 7 is connected to the second hot water load 30 via the second hot water supply pipe 29, and the second hot water supply pipe
A second hot water temperature detector 31 and a second hot water flow rate detector 32 are installed in the middle of 29.

One end of the hot water tank three-way valve 8 is provided with a hot water heat exchanger via a connecting pipe 33.
The hot water heat exchange three-way valve (second hot water flow rate adjusting valve) 34 is interposed in the middle of the connecting pipe 33, and one end of this hot water heat exchange three-way valve 34 is connected to the heating water outlet of the hot water pipe 13. There is communication on the way.

The control device 35 includes a fuel flow rate adjusting valve 3, a fuel flow rate detector 4, a hot water tank three-way valve (second hot water flow rate adjusting valve) 8, a cold water flow rate adjusting valve 11, a cold water temperature detector 12, and a hot water header temperature detector.
15a, flow rate adjusting valve 18, steam pressure detector 22, steam flow rate detector 23, first hot water temperature detector 27, first hot water flow rate adjusting valve
28, second hot water temperature detector 31, second hot water flow rate detector 32
And a hot water heat exchange three-way valve (first hot water flow rate adjusting valve 34) are electrically connected by a signal line indicated by a broken line in the figure, and control the opening degree of each adjusting valve in response to detection values from various detectors. It is like this.

The control device 35 is configured as shown in FIG. 1, and the fuel flow rate detector 4 is provided with the fuel supply flow rate detection value supplied to the internal combustion engine 2 detected by the fuel flow rate detector 4 as an electric output of the generator 1. An output estimation circuit 36 for converting to and estimating the output, and a power comparator 3 for comparing the output from the output estimation circuit 36 with a power set value.
7. Switch 38 for switching between the operation mode of electric load following operation and heat load following operation, controller consisting of PID (proportional integral derivative) controller 39 and electric air converter 40, fuel flow rate adjusting valve 1
Are sequentially electrically connected in series in this order.

That is, the deviation between the detection value detected by the fuel flow rate detector 4 and the power setting value is calculated by the power comparator 37,
The opening of the fuel flow rate adjusting valve 3 that makes this deviation zero is adjusted by a controller, and this adjustment signal is converted into a required air pressure by the electric air converter 40, and the fuel flow rate adjusting valve including a diaphragm valve or the like. 3 to control the opening degree.

A power load output calculation circuit is provided at the other switching end c of the switching device 38.
41 via the steam flow rate detector 23, the first hot water flow rate detector 28
And a second hot water flow rate detector 32 are electrically connected to each other, and the detected values of these detectors 23, 28, 32 are calculated as power load output calculation circuits.
It is designed to be converted to electric power at 41.

Further, one output end of the switch 38 is connected to one input end of a correction amount calculation circuit 42 for calculating a correction amount for correcting the load fluctuation of the internal combustion engine 2 for driving the generator 1 shown in FIG. .

Through the adder 43 to the other input end of the correction amount calculation circuit 42,
Connected to the cold water temperature detector 12 and the hot water header temperature detector 15a, respectively, which are provided with the temperature / current converters 44 and 45,
The temperature difference detected by both the temperature detectors 12 and 15a, that is, the temperature difference between the outlet side and the inlet side of the cold water passing through the heat receiving side of the exhaust heat exchanger 5 is calculated by the adder / subtractor 43. Has become.

The output end of the temperature / current converter 44 of the cold water temperature detector 12 is connected to the adder / subtractor 48 via the temperature comparator 46 and the PID controller 47, and the load of the internal combustion engine 1 calculated by the correction amount calculation circuit 42. The correction amount for correcting the fluctuation is added as a bias signal to the adjustment signal of the detected value from the cold water temperature detector 12 by the adder / subtractor 48, converted into the required air pressure by the electric air converter 49, and the diaphragm valve The opening degree of the cold water flow rate adjusting valve 11 is controlled.

The first hot water temperature detector 27 includes a temperature / current converter 50, a temperature comparator 51, a PID controller 52, an adder / subtractor 53, an electric air converter 54, a hot water heat exchange three-way valve (a first hot water flow rate adjusting valve). ) 34 in series and the output end of the correction amount calculation circuit 42 is connected to one input end of the adder / subtractor 53, and the correction signal from the correction amount calculation circuit 42 is applied to the hot water heat exchange three-way valve 34 as a bias signal. It is designed to be used.

Further, the second hot water temperature detector 31 is also a temperature / current converter 55, a temperature comparator 56, a PID controller 57, an adder / subtractor 58, an electric air converter 59, a hot water tank three-way valve (second hot water flow rate adjusting valve). 8 is sequentially connected in series, the output end of the correction amount calculation circuit 42 is connected to one input end of the adder / subtractor 58, and the correction signal from the correction amount calculation circuit 42 is applied to the hot water tank three-way valve 8 as a bias signal. It is like this.

Next, the operation of this embodiment will be described.

First, when performing the electric load following operation on the combined heat and power supply device, the operation mode of the switch 38 is switched to the electric load following operation mode, and the opening degree of the fuel flow rate adjusting valve 3 is based on the detection value of the fuel flow rate detector 4. It is controlled and the electric load following operation is performed.

That is, the detected value of the fuel flow rate detector 4 is the output estimation circuit 36.
Is estimated and converted into the electric output of the generator 1 by the electric power comparator
At 37, it is compared with the power set value and the deviation is output.

Since the operation mode of the switch 38 is switched to the electric load following operation mode, this deviation signal flows from the terminal a to the terminal b and is given to the PID controller 39 and the correction amount calculation circuit 42, respectively.

The deviation signal given to the PID controller 39 is PID (proportional-integral-derivative) controlled here and adjusted to the opening degree of the fuel flow rate adjusting valve 3 so as to make the deviation zero, and then to the electric air converter 40. Then, the air pressure is converted into a required pressure, which is supplied to the fuel flow rate adjusting valve 3 to control the opening thereof.

Therefore, the fuel flow rate for operating the internal combustion engine 2 so that the electric output of the generator 1 is kept constant at the power set value is given through the fuel flow rate adjusting valve 3.

On the other hand, in the correction amount calculation circuit 42, the load fluctuation amount of the internal combustion engine 1 is calculated based on the deviation signal from the switch 38 and the temperature difference between the detected values of the cold water temperature detector 12 and the hot water header temperature detector 15a. Detect the correction amount to be corrected.

This correction amount is applied to the adders / subtractors 48, 53, 58 as bias signals, and then the cold water flow control valve 11, the hot water heat exchange three-way valve first hot water flow rate adjusting valve 34, and the hot water tank three-way valve (second hot water flow control valve). Each of the hot water flow rate adjusting valves 8 is provided to control the opening of these valves.

That is, since the load variation of the internal combustion engine 2 is given to each of the valves 11, 34, 8 as a bias signal in advance, the secondary delay of the exhaust heat heat exchanger 5 is prevented, and the heat exchange efficiency is not lowered. It can be prevented.

On the other hand, when performing the heat load follow-up operation for the combined heat and power supply device, the operation mode of the switch 38 is switched to the heat load follow-up operation, and the opening of the fuel flow rate adjusting valve 3 changes the steam flow rate detector 23 and the first hot water flow rate. The heat load following operation is performed by controlling based on the detection values of the detector 28 and the second hot water flow rate detector 32.

That is, the steam flow rate detector 23 and the first hot water flow rate detector 2
8. Each detected value of the second hot water flow rate detector 32 is converted into a power load by the power load output calculation circuit 41, and flows from the c terminal to the b terminal through the switch 38 which is switched to the thermal load following operation mode. Are supplied to the controller including the PID controller 39 and the electro-pneumatic converter 40, and the correction amount calculation circuit 42, respectively, and are supplied from the controller to the fuel flow rate adjusting valve 3 to control the opening degree thereof and the heat load. Follow-up operation is performed.

In the correction amount calculation circuit 42, the load fluctuation amount of the internal combustion engine 2 is calculated based on the power conversion signal from the switch 38 and the temperature difference between the re-detection values of the cold water temperature detector 12 and the hot water header temperature detector 15a. A correction amount that corrects is detected.

This correction amount is applied as a bias signal to the adders / subtractors 48, 53, 58, respectively, and then given to the cold water flow control valve 11, the hot water heat exchange three-way valve 34, and the hot water tank three-way valve 8, respectively, and the opening degrees of these valves are adjusted. Controlled.

That is, since the load variation of the internal combustion engine 2 is given to each of the valves 11, 34, 8 as a bias signal in advance, the secondary delay of the exhaust heat heat exchanger 5 is prevented, and the heat exchange efficiency is not lowered. It can be prevented.

Therefore, according to the present embodiment, it is possible to prevent the secondary delay of the exhaust heat exchanger 5 in both the electric load following operation and the heat load following operation, and prevent the heat exchange efficiency from decreasing.

〔The invention's effect〕

As described above, the present invention can switch the operation mode between the electric load following operation and the thermal load following operation by the switching operation of the changer, and moreover, the load fluctuation of the internal combustion engine that drives the generator can be changed. A correction amount to be corrected is calculated by a correction amount calculation circuit, and the correction amount is given as a bias signal to the steam flow rate adjusting valve and the first and second hot water flow rate adjusting valves, respectively, and the opening degree thereof precedes the load fluctuation. Therefore, it is possible to prevent the secondary delay of the exhaust heat heat exchanger that uses the exhaust heat of the internal combustion engine as a heat source, and prevent the heat exchange efficiency from decreasing.

[Brief description of drawings]

FIG. 1 is a block diagram of an essential part of an embodiment of the combined heat and power supply apparatus according to the present invention, and FIG. 2 is a block diagram showing the overall configuration of the combined heat and power supply apparatus including the control device shown in FIG. 1 ... Generator, 2 ... Internal combustion engine, 3 ... Fuel flow rate adjusting valve, 4 ... Fuel flow rate detector, 5 ... Exhaust heat heat exchanger, 7 ...
… Hot water storage tank, 8 …… Hot water storage tank three-way valve (second hot water flow control valve), 11 …… Cold water flow control valve, 12 …… Cold water temperature detector,
14 …… Hot water heat exchanger, 15 …… Hot water header, 15a …… Hot water header temperature detector, 20 …… Steam load, 21 …… Heat storage tank, 23 …… Steam flow rate detector, 26 …… First hot water Load, 27
...... First hot water temperature detector, 28 ...... First hot water flow rate detector, 31 ...... Second hot water temperature detector, 32 ...... Second hot water flow rate detector, 34 ...... Hot water heat exchange three-way Valve (first hot water flow rate adjusting valve), 35 ... control device, 36 ... output estimation circuit, 38 ... comparator, 41 ... power load output calculation circuit, 42 ... correction amount calculation circuit.

Claims (1)

[Claims] 1. An internal heat engine for driving a generator, a fuel flow rate detector and a fuel flow rate adjusting valve for detecting and adjusting a supply flow rate of fuel supplied to the internal combustion engine, and exhaust heat from the internal combustion engine. An exhaust heat heat exchanger that heats cold water to generate hot water, a cold water temperature detector that detects the temperature of the cold water supplied to the heat receiving side of this exhaust heat heat exchanger, and a cold water flow rate that adjusts this cold water supply flow rate. A regulating valve, a heat storage tank for storing the steam generated by further heating the hot water from the heat receiving side of the exhaust heat heat exchanger in the exhaust gas heat exchanger with the exhaust gas from the internal combustion engine, and the exhaust heat heat exchange A first hot water flow rate adjusting valve for adjusting the supply flow rate of hot water supplied from the heat receiving side of the water heater to the hot side of the hot water heat exchanger, and from the hot side of the hot water heat exchanger to the hot side of the hot water storage tank Second hot water flow rate adjustment to adjust the flow rate of hot water to be supplied A valve, first and second hot water flow rate detectors for detecting the supply flow rates of the hot water supplied to the hot water load from the heat receiving sides of the hot water heat exchanger and the hot water storage tank, respectively, and to the steam load from the heat storage tank. In a combined heat and power device having a steam flow rate detector that detects the supply flow rate of steam to be supplied, an output estimation circuit that estimates the output of the generator based on the detection value detected by the fuel flow rate detector, and this output estimation A comparator that compares the estimated output estimated by the circuit with a power setting value and outputs a deviation, a hot water supply flow rate detection value detected by the first and second hot water flow rate detectors, and a steam flow rate detector An electric power load output calculation circuit for converting the detected steam supply flow rate detected value into electric power;
A switch that outputs the power conversion signal from the power load output calculation circuit and the deviation signal from the comparator in a switchable manner in accordance with the operation mode, and a part of the output signal from the switch of the fuel flow control valve. Based on the controller that adjusts the opening degree and gives it to the fuel flow rate adjusting valve, a part of the output signal from the switch and the temperature difference of the cold water at the heat receiving side outlet and inlet of the exhaust heat heat exchanger. A correction amount for correcting the load fluctuation of the internal combustion engine is calculated, and the correction signal is applied as a bias signal to the cold water flow rate adjusting valve and the first and second hot water flow rate adjusting valves to adjust the opening degrees of these valves. A combined heat and power supply device comprising a correction amount calculation circuit.