JPH0788805B2 - Cogeneration system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cogeneration system for efficiently utilizing heat energy and electric power energy.

[0002]

2. Description of the Related Art A cogeneration system is a combined heat and power system that uses an engine, a gas turbine, or the like as a power source to generate electric power, and at the same time uses the exhaust heat thereof to supply hot water, cool air, or heat the air. In such a cogeneration system, for example, a prime mover that is a power source and a generator are one-to-one.
It is common to connect the motors and heat pumps in a one-to-one correspondence, and to install an electric heat pump separately from the exhaust heat utilization system. is there.

[0003]

However, in the conventional system as described above, since the thermoelectric ratio to be supplied is always constant, it is possible to flexibly respond to changes in the heat demand and the electric power demand whose balance changes depending on the season or time zone. I can not cope. In particular,
When the power demand falls below the planned value, the prime mover cannot perform rated operation, and partial load operation will be performed according to the demand. For this reason, the thermal efficiency of the generator and the heat recovery portion is considerably reduced as compared with that during the rated operation, and the target overall thermal efficiency of the cogeneration system, for example, 70 to 80% cannot be achieved. Further, in the conventional type, for example, when there is a small electric power demand and a thermal demand, it is not possible to operate only the heat pump by using the night electric power which is cheap in terms of system configuration. That is, the conventional type has room for improvement in order to obtain high economic efficiency. Further, in the conventional type, since the electric heat pump is provided outside the system, it is not possible to operate with high efficiency in cooperation with the heat pump. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cogeneration system capable of performing flexible system operation according to electric power demand and heat demand and constantly increasing the thermal efficiency by constantly operating the prime mover. And Further, it is an object of the present invention to provide a cogeneration system in which high economic efficiency is obtained by using nighttime electric power and the utility of the system can be expanded by incorporating an electric heat pump.

[0004]

That is, the above object of the present invention is to provide a prime mover, an induction generator connected to and driven by the prime mover via a clutch attached to a switching unit, and a first heat load device, Exhaust heat recovery means for recovering exhaust heat energy of the prime mover, a second heat load device for converting and supplying the recovered exhaust heat energy, a commercial power source for supplying power to the induction generator, the prime mover and the The present invention is achieved by a cogeneration system characterized by comprising a pipe system connecting exhaust heat recovery means and connecting the exhaust heat recovery means and the second heat load device.

[0005]

By adjusting the switching unit according to the electric power demand and the heat demand, the output of the prime mover which is operated at the rated power can be appropriately distributed and supplied to the induction generator and the heat pump serving as the first heat load device. Also, by operating the prime mover at the rated speed, the utilization efficiency of thermal energy can be maximized. Furthermore, by applying a heat storage type heat pump system that uses night power, cold water in the summer and hot water in the winter are efficiently made by the heat pump during the night and stored in a heat storage tank, and the cold water or hot water is used in the daytime. By cooling and heating, it is possible to construct a highly economical system.

[0006]

Embodiments of the cogeneration system of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic system diagram showing an embodiment of the cogeneration system of the present invention. In the figure, this cogeneration system includes a prime mover 1 including a diesel engine,
A switching unit 2 connected to the power shaft 10 of the prime mover 1,
First and second power transmission shafts 11 and 12 provided as outputs of the switching unit 2 and divided into two systems, an induction generator 3 connected to the first power transmission shaft 11, and a second power transmission shaft. A heat pump 4 connected to the power transmission shaft 12 as a first heat load device, a cooling water heat exchanger 5 connected to the prime mover 1 and serving as an exhaust heat recovery means for recovering exhaust heat energy of the prime mover 1, Connected to the prime mover 1 via an exhaust gas pipe 14,
Similarly, the exhaust gas heat exchanger 6 which also serves as exhaust heat recovery means communicates with the cooling water heat exchanger 5 and the exhaust gas heat exchanger 6 via the heating pipe 15, and a heat medium is circulated as a second heat load device. It is composed of an absorption refrigerator 7 and a heat exchanger 8. Although well-known components such as instrumentation, pumps, valve mechanisms, bypass pipes and cooling towers necessary for operation are not shown, they may be provided at appropriate places according to the purpose of use. Of course

To further explain the system configuration, in the prime mover 1, cooling water is circulated by the cooling water heat exchanger 5 and its exhaust gas is supplied to the exhaust gas heat exchanger 6 through the exhaust gas pipe 14. It is configured to be. The switching unit 2 is provided with clutches 16, 17, 18 arranged on the power shaft 10 and the first and second power transmission shafts 11, 12, respectively, and each clutch 16, 17, 18 is connected to each shaft. The drive side and driven side of 10, 11 and 12 can be connected or disconnected respectively. The induction generator 3 is capable of supplying electric power generated according to demand to the electric power supply unit 20 and also capable of supplying a commercial electric power source 9 secured as reserve power via a power supply line 19. . The heat pump 4, for example, pumps heat of low temperature to supply heat energy of high temperature to the cold / hot heat supply unit 21, and in the present embodiment, a vapor compression type is applied to the prime mover 1 as a drive source. However, when the switching unit 2 is switched, the induction generator 3 is used as a motor and driven. The cooling water heat exchanger 5 performs heat exchange on the circulating cooling water of the prime mover 1, and the exhaust gas heat exchanger 6 performs heat exchange on the exhaust gas of the prime mover 1. As the heat load devices 7 and 8, devices such as an absorption refrigerator, a heat exchanger, and a hot water storage tank are used according to the purpose. In the present embodiment, the heat load device 7 is an absorption refrigerator and a heat load device 8 is used. Heat exchangers are respectively applied as heat exchangers, and the heat medium that is circulated is heat-converted by the absorption refrigerator and the heat exchanger, and the cold energy that is heat-converted by the absorption refrigerator is converted to the cold heat supply unit 22 by the heat exchanger. The generated heat energy can be supplied to the heat supply unit 23.

The operation method of the cogeneration system of the present invention will be described below. When performing the same combined heat and power operation as the conventional type, the prime mover 1 is driven and the clutch 16 of the power shaft 10 is connected to transmit the driving force to the switching unit 2. Further, the induction generator 3 is driven by connecting the clutch 17 of the first power transmission shaft 11, and the electric power generated by the induction generator 3 is supplied to the power supply unit 20. On the other hand, in response to heat demand, the circulating cooling water of the prime mover 1 is cooled by the cooling water heat exchanger 5
When the heat medium is cooled to a predetermined temperature by the above, the heat medium that is heat-exchanged with it is further heated in the exhaust gas heat exchanger 6 through the warming pipe 15. The heated heat medium is supplied to the heat load device 7 configured as an absorption chiller and the heat load device 8 configured as a heat exchanger, respectively, and the cold energy converted into heat is supplied to the cold heat supply unit 22 and the heat energy. The converted thermal energy is supplied to the thermal supply unit 23. The above operating method is performed when the demands for electric power and heat as planned are obtained, and by operating the prime mover 1 in a rated manner, the supply of a predetermined amount of electric power and the utilization of exhaust heat energy are maximized. High efficiency can be achieved.

Next, the simultaneous operation method of the induction generator and the heat pump applied when the planned electric power demand is small and the thermal demand is large will be described. In response to such demand, as in the case of combined heat and power supply operation, the prime mover 1 is driven to drive the induction generator 3 to supply the generated power to the power supply unit 20 and the second power transmission shaft 12 The clutch 18 is connected to drive the heat pump 4 to supply cold and hot energy to the cold and hot heat supply unit 21. On the other hand, the exhaust heat utilization system of the prime mover 1 is similar to the case of the combined heat and power supply operation described above. By the above operating method, the driving force of the prime mover 1 is divided and the induction generator 3
The heat pump 4 to supply the reduced power generation amount.
However, cooling and heating energy is added separately from the exhaust heat utilization system, and the system can achieve its operation purpose. That is,
By performing the above operation, even if the power demand is reduced, the prime mover 1 is not subjected to the partial load operation, and the rated operation is performed to achieve high efficiency of the system. In the above operating method, when only the cooling energy is supplied from the first heat load device, the heat pump can be replaced with a refrigerator.

Next, an operation method in the case where there is no electric power demand targeted by the system but only heat demand will be described. In this operating method, the prime mover 1 is driven and the clutch 16 of the power shaft 10 is connected to transmit the driving force to the switching unit 2.
Further, the clutch 18 of the second power transmission shaft 12 is connected to drive the heat pump 4, which is the first heat load device, to supply cold / hot energy to the cold / heat supply unit 21. On the other hand, the exhaust heat utilization system of the prime mover 1 is similar to the case of the combined heat and power supply operation described above. With such an operating method, even if the electric power demand and the thermal demand differ from the plan, it is possible to effectively utilize the prime mover 1 and achieve highly efficient operation as a cogeneration system.

Next, an operation method for driving the heat pump by the commercial power source will be described. This operating method is usually applied when a heat pump is used as an alternative means of the prime mover 1 or inexpensive nighttime electric power is used as a commercial electric power source. That is, in this operating method, the induction generator 3 is used as an electric motor, and is driven by supplying power from the commercial power source 9 via the power supply line 19. that time,
A clutch 16 is disengaged from the power shaft 10, and clutches 17 and 18 are connected to the first and second power transmission shafts 11 and 12. Therefore, the induction generator 3 functioning as an electric motor drives the heat pump 4 via the switching unit 2. As a result, the heat pump 4 can supply cold / hot heat energy to the cold / hot heat supply unit 21. However, since the above operating method uses an expensive commercial power source, it cannot be said that the original purpose of the system is sufficiently satisfied. Therefore, preferably, a heat storage type heat pump system can be adopted. Although not shown, this heat storage heat pump system has a heat storage tank added to the heat pump 4,
During the night, the heat pump is driven by using inexpensive nighttime electric power, and the cold / hot heat energy efficiently produced by the heat pump 4 is stored in the heat storage tank, and the cold / hot heat energy is supplied to the cold / hot heat at the time of daytime heat demand. Supply to part 21. With such a configuration, it is possible to electrically drive the heat pump incorporated in the system to supply cold / hot heat energy without separately installing a heat pump with an electric motor. Moreover, inexpensive nighttime electricity can be used. This operating method can also be applied when the prime mover 1 is stopped due to a failure or maintenance, and can supply cold and hot energy, but an expensive commercial power source is ensured as reserve power.

Finally, a method for starting the prime mover 1 will be described. Normally, the prime mover 1 is started by an attached starter, but in the system of the present invention, the induction generator 3 is used.
Can be done at. That is, in this starting operation method, the induction generator 3 is used as an electric motor, and the commercial power source 9 is used.
Is driven by feeding power via a power feed line 19. At that time, the power shaft 10 and the first power transmission shaft 11 are clutches.
16 and 17 are connected, and the clutch 18 of the second power transmission shaft 12 is disengaged. Therefore, the induction generator 3 functioning as an electric motor can start the prime mover 1 via the switching unit 2. With such a configuration, it is possible to omit a generally provided engine starting device such as a starter motor and a compressor, and to effectively use the system. As described above, the cogeneration system of the present invention is basically operated on the basis of heat demand. However, depending on the situation or when inexpensive fuel can be obtained, electric power is not required. Demand-based operation is also possible. That is, the cogeneration system of the present invention is not only capable of flexibly responding to electric power demand and heat demand as compared with conventional systems, but also can achieve effective use and high operation of equipment, and are economically effective due to use of nighttime electric power. Is also obtained.
It should be noted that the absorption refrigerator and the heat exchanger described as the heat load device in the above embodiments are not limited to those for cold heat or warm heat, and it is a matter of course that those suitable for the purpose are appropriately used. Further, in the above embodiment, the diesel engine is used as the prime mover, but a gas engine, a gas turbine, or the like may be used instead. In particular, when a gas turbine is used as a prime mover, a cooling water heat exchanger is not provided, so that the heat medium is exchanged with the exhaust gas heat exchanger, or the cooling water heat exchanger and the exhaust gas heat exchanger are used respectively. It is also possible to provide an independent heating tube.

[0013]

As described above, according to the cogeneration system of the present invention, not only the prime mover and the generator are connected in a one-to-one correspondence, but also, for example, a plurality of heat load devices are demanded. Since it is configured to be switched and connected, it is possible to perform flexible operation according to the power demand and heat demand as described below, as compared with the conventional one-operation system in which the thermoelectric ratio is constant. In case of combined heat and power operation When power demand and heat demand are balanced as planned, high efficiency operation of the system can be achieved by operating as usual and driving only the generator. Simultaneous operation of generator and heat pump When the power demand is less than planned, the generator and heat pump are operated at the same time, and the exhaust heat energy of the prime mover is used to allow the prime mover to operate at a rated rate for highly efficient system operation. Can be achieved. In the case of engine / heat pump operation When there is no electric power demand and heat demand, only the heat pump is operated using the prime mover as a drive source, and at the same time, exhaust heat energy of the engine is used to achieve high efficiency operation. In case of electric / heat pump operation By operating the heat pump by using the induction generator as an electric motor, it is possible to supply thermal energy even during maintenance or failure of the prime mover. In addition, by adopting the heat storage type heat pump system, it is possible to further increase the economic effect by using the nighttime electric power whose price is cheap. In addition to the above effects, the system of the present invention can simplify the system by eliminating the need for a starter by applying an induction generator used as an electric motor as a starter of a prime mover.

[Brief description of drawings]

FIG. 1 is a schematic system diagram of a cogeneration system according to an embodiment of the present invention.

[Explanation of symbols]

 1 prime mover 2 switching unit 3 induction generator 4 heat pump 5 cooling water heat exchanger 6 exhaust gas heat exchanger 7,8 heat load equipment 10 power shaft 11,12 power transmission shaft 14 exhaust gas pipe 15 heating pipe 16,17,18 clutch 20 Electric power supply unit 21 Cold heat supply unit 22 Cold heat supply unit 23 Hot heat supply unit

Claims (3)

[Claims] 1. A prime mover, an induction generator and a first heat load device connected to the prime mover via a switching unit, and exhaust heat recovery means for recovering exhaust heat energy of the prime mover.
A second heat load device that converts and supplies the recovered exhaust heat energy; and a commercial power source that supplies power to the induction generator,
A cogeneration system comprising: a pipe system that connects the prime mover and the exhaust heat recovery means and that connects the exhaust heat recovery means and the second heat load device. 2. The cogeneration system according to claim 1, wherein a heat pump is applied to the first heat load device, and an absorption refrigerator and a heat exchanger are applied to the second heat load device, respectively. system. 3. The prime mover enables electric power energy and thermal energy to be supplied by the induction generator and the first heat load device, and the exhaust heat energy recovered by the exhaust heat recovery means is transferred to the second heat recovery device. The cogeneration system according to claim 1, wherein the cogeneration system converts the heat energy into heat energy and supplies the heat energy.