JPH06176792A - Power storage type heat-electricity combined supply system - Google Patents

Abstract

PURPOSE:To improve system operating efficiency and reliability on a power supply system for a co-generation system installation people. CONSTITUTION:A Na-S battery 2 used as a heat supply unit, for a co-generation system is kept in a consistently operating condition by parting hot gas 11 exhausted from an internal combustion engine 6 and guiding it to a constant- temperature tank 8 in power storage facilities which require heating. At this time, the flow rate of the hot gas is determined by controlling a flow control valve 12 depending on the temperature of the constant-temperature tank 8. Water absorbed by an exhaust heat boiler 1 which is operated by using exhaust heat from the internal combustion engine 1 is heated by a water-water heat exchanger 7 which uses return water of bearing cooling water for the internal combustion engine 1 for heat source and a gas-water heat exchanger 9 which is provided at the gas outlet of the constant-temperature tank 8, and the access of electric power to the Na-S battery 2 as the power supply unit is made through a DC-AC bidirectional convertor 18. In this way, new functions such as extra power adjustment in a power available time zone, reservation in the power supply unit and emergency power supply are added.

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 effectively utilizing energy.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to FIG. In a normal cogeneration system, heat generated from an internal combustion engine is supplied to heat demand, and electric power generated by a generator is supplied to load electric power. Commercial electric power supplements electric power that cannot be covered by a generator. Reverse flow from the generator side to the product system cannot be performed.

[0003]

With the increasing interest in global environmental problems, "shifting from an energy consumption expanding society to an energy saving society" has become a national issue. It is expected that active utilization of cogeneration systems such as highly efficient cogeneration systems will be more effective than ever.

Given this situation, the Ministry of International Trade and Industry has recently
Revised the law on the reverse flow of power generation equipment that generates surplus power. As a result, power can be sold if safety can be secured through discussions between the electric utility and the customer (the owner of the power generation equipment). Under this circumstance, a particular problem is the power sale time zone. In other words, the load demand of the consumer is
Most of the time, the demand for electricity is reduced at night and surplus electricity is generated, so the power selling time is concentrated at night. On the electric power company side, the peak of electric power demand occurs from 1:00 pm to 4:00 pm in the daytime, so the reverse flow from the customer is
This time is the best. Even for consumers, the unit price of electricity sold at night is low (about 1/3 during the day), so it is economically advantageous to sell electricity during the day.

[0005]

In order to solve the above problems, the present invention mainly installs at night by installing an AC / DC bidirectional converter on the output side of the generator and providing a power storage facility on the downstream side. The surplus electric power is stored, discharged during the daytime when the peak load occurs in the commercial grid, and transmitted to the commercial grid through the AC / DC bidirectional converter via the grid connection control panel and reverse power flow to the commercial grid. Devised a system.

Here, the electric power storage equipment uses a high-efficiency Na—S battery which can effectively utilize high temperature exhaust heat from the cogeneration, has a high energy density and can be designed compactly.

With such a system configuration, it can be used not only for adjusting the reverse power flow time zone but also as an emergency power for a power failure of the commercial system, a standby power when the power load abnormally rises, a system and a simultaneous commercial power failure. Is possible.

[0008]

The generator 4 converts the rotational force of the internal combustion engine into electric power, and supplies the generated electric power to the electric power load.

In the storage battery 2 (Na-S battery), when surplus power is generated at night, the surplus power is charged and discharged during a daytime commercial grid peak load period to supply the power to the commercial grid. . It is also used as an emergency power source for blackouts in commercial systems and as a standby power source when using a power load that exceeds the generated power.

The AC / DC bidirectional converter 18 converts AC power into DC when charging the storage battery and converts DC power into AC when discharging.

The system linkage control panel 15 works to supply electric power from the commercial system when the cogeneration system cannot cover the load power, and supplies the electric power to the commercial system when the cogeneration system covers the load and there is surplus power. Work to supply.

On the other hand, in the normal heat supply system, the internal combustion engine 6 gives a rotating force to the generator, but about 60% of the input energy becomes heat and is exhausted.

In the exhaust heat boiler 1 installed in the exhaust system of the internal combustion engine, the exhaust heat gas from the internal combustion engine turns the water supplied to the heat load into hot water or steam.

In the water-water heat exchanger 7, the bearing portion of the internal combustion engine is cooled and the exhaust heat boiler is heated by absorbing water.

The boiler 3 supplies hot water, steam or the like to the heat load.

The header 13 distributes the supplied heat to each heat load.

The Na-S battery must always be kept at a constant temperature (about 350 ° C.) in order to maintain its operating condition. Therefore, a heat supply system is required. Normally, the Na-S battery is heated by an electric heater or the like and is maintained at a constant temperature, so that amount is lost. The present invention utilizes high temperature waste heat from the cogeneration system to achieve high efficiency. The operation of the exhaust heat gas system device for maintaining the Na-S battery at a constant temperature will be described below.

The flow rate control valve 12 is installed in the exhaust heat system of the gas turbine and controls the flow rate of the high temperature exhaust gas supplied to the Na-S battery side.

In the constant temperature bath 8, a constant temperature (about 350 ° C.) is constantly maintained in order to maintain the operating state of the Na--S battery.

The gas-water heat exchanger 9 installed in the exhaust gas system of the constant temperature tank is installed on the exhaust gas outlet side from the constant temperature tank in order to effectively utilize the exhaust heat, and is used for heating absorption water supplied for heat demand. .

[0021]

FIG. 1 shows an embodiment of the present invention. The cogeneration system according to the present invention is roughly divided into a heat supply system, a water absorption heating system of an exhaust heat boiler 1, a Na-S battery 2 heating system, a heat supply system of a boiler 3, a generator 4 as a power supply system, and a Na-S battery. 2, there is a commercial system 5. Here, the structure of the water absorption heating system which is one of the heat supply systems is the gas turbine 6
Water-water heat exchanger 7, Na-S for cooling bearing cooling water such as
It consists of a gas-water heat exchanger 9 installed in an exhaust system of a constant temperature bath 8 that keeps the battery 2 at a constant temperature, and the water absorption 10 is heated by the water-water heat exchanger 7 and the gas-water heat exchanger 9 to exhaust heat. It is supplied to the boiler 1. The Na-S battery 2 heating system is a gas turbine 6
The high temperature exhaust gas 11 of the internal combustion engine, such as the above, is branched at the outlet portion and introduced into the thermostatic bath 8 through the heat insulating pipe to heat the Na—S battery 2 and maintain it at a constant temperature. The exhaust gas from the constant temperature bath 8 transfers heat to the water absorption system in the gas-water heat exchanger 9 to become a low temperature, and is released to the outside air via the flow rate control valve 12. In other words, the system configuration has a high thermal efficiency because it has a system configuration in which the exhaust gas after achieving the purpose of the high temperature gas distributed for the purpose of keeping the Na-S battery 2 at a constant temperature is also effectively used. With such a system, the heated water absorption 10 is heated again by the exhaust heat boiler 1 to become hot water or steam, and is supplied to the heat load 14 via the header 13. When the heat supplied to the load is insufficient in such a system, it is supplemented by the boiler 3. The power supply system is
Switch 1 from generator 4 via system linkage control panel 15
6a, the system directly supplied to the load, the system supplied from the commercial power system to the load 17 directly by the switch 16b via the system coordination control panel 15, the Na-S battery 2 to the DC / AC
Switch 16 converted to AC through bidirectional converter 18
There is a system that is supplied to the load via c, 16a. Here, the Na-S battery 2 is charged with surplus electric power that is often generated at night and the like, and is discharged as necessary to supply electric power. There are the following three operation methods when supplying power.

(1) Power sale to the commercial system When the daytime load power can be covered by the power generated by the generator, the surplus power charged at night is discharged and sold to the commercial system.

(2) Standby power supply When the electric power load exceeds the electric power obtained by adding the generated electric power and the contract electric power of the commercial system, the electric power is discharged to compensate for the surplus electric power.

When the commercial system is out of power, the load power is supplied by the generator output and the discharge power from the battery.

(3) Emergency power supply When the power supply from the commercial system and the generator is stopped,
Discharges from the battery and supplies power to main equipment for a short time.

That is, by using the electric power storage facility together with the cogeneration system, the surplus electric power can be effectively utilized, and the system can be operated with higher efficiency. Furthermore, when using a Na-S battery as power storage equipment,
Since high-temperature exhaust gas can be used as a heat source for preheating, the cost of equipment such as an electric heater which has been conventionally used and the heater power can be saved.

[0027]

According to the present invention, since the electric power storage facility for charging the surplus electric power and discharging the electric power as necessary is installed in order to effectively utilize the generated electric power, the high temperature operation type battery (Na Since the existing high-temperature exhaust gas is used as a heat source for the (-S battery, etc.), the facility cost of the conventionally used electric heater for heating and the heater power are saved.

[Brief description of drawings]

FIG. 1 is a block diagram of a power storage type combined heat and power supply system according to the present invention.

FIG. 2 is a block diagram of a conventional power storage type combined heat and power supply system.

[Explanation of symbols]

1 ... Exhaust heat boiler, 2 ... Storage battery (Na-S battery), 7 ... Water-water heat exchanger, 8 ... Constant temperature bath, 9 ... Gas-water heat exchanger, 1
2 ... Flow control valve, 15 ... System linkage control panel, 18 ... AC /
DC bidirectional converter.

Claims (3)

[Claims] 1. A combined heat and power system having a high temperature exhaust heat, wherein a part of the exhaust heat heats an electric power storage facility to maintain the electric power storage facility in an operating state. system. 2. A power storage type combined heat and power supply system, characterized in that the heat load supply water is heated by the high temperature exhaust gas after heating the power storage equipment. 3. As an operation method of an electric power storage facility for charging surplus electric power, when the daytime load electric power can be covered by the electric power generated by the generator, the surplus electric power charged at night is discharged to sell the electric power to a product system, When the power load exceeds the power generated by adding the generated power and the contract power of the commercial system, discharge the power to compensate for the excess power.If the product system has a power failure, the generator output and the discharged power from the battery An electric power storage type combined heat and power supply system characterized by discharging the battery and supplying electric power to main equipment for a short time when the operation of supplying load electric power, the supply of electric power from a commercial system and a generator is stopped.