JPH0322557B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The disclosed technology belongs to a technical field in which energy is stored during off-peak usage of energy such as electric power for consumer use and industrial use, and is used when necessary. .

This invention utilizes a compression heat pump cycle that follows the processes of enthalpy, expansion, and endothermic gasification, such as polytropic compression of fluids such as ammonia gas and carbon dioxide gas, and cooling and liquefaction. This invention relates to a storage system, in particular, during off-peak electrical energy use, surplus energy from equipment compared to peak times is converted into low-pressure gas such as ammonia gas, compressed to high pressure using a compressor, etc., and then stored in seawater, etc. It is cooled and liquefied using practically unmanned cold energy and stored as high-pressure liquefied gas. At peak energy usage, the high-pressure liquefied gas is converted into low-temperature, low-pressure liquid through an expansion valve etc. using the Juur-Thomson effect. , and convert it into a gas state, and use the cold energy generated in the process to recover energy by using a freezer, etc., or combine it with a Rankine cycle to use it as a cold energy source for the cooling liquefaction process of the Rankine cycle. The gasified fluid is absorbed or adsorbed onto a gas absorption medium such as an ammonia gas complex to reduce its capacity and then stored again.
The invention relates to a system in which the gas absorbed or adsorbed by the gas absorbing medium is separated at low pressure during the off-peak period, and is fed again to the compressor, etc., and is compressed again to high pressure and repeated. It is.

[Prior art]

As is well known, the use of energy is essential for both civil and industrial activities, but in any case, the demand for energy such as electricity and fuel gas is not constant over time, and major fluctuations are due to seasonal factors. Small fluctuations include peaks and off-peaks due to time factors such as day and night.

However, as a matter of course, on the energy supply side, equipment planning is based on demand during peak periods, and therefore it is necessary to reduce the load or stop operations during off-peak periods to balance supply. However, the unavoidable prerequisites are that the operating efficiency of the equipment is inevitably poor, the energy efficiency of the equipment deteriorates during low-load operation, and furthermore, the investment efficiency is poor.

Such a decline in operation during off-peak hours is extremely negative from the perspective of social capital, and is also extremely unignorable from the perspective of energy economics.

To deal with this, an energy storage system is developed that stores surplus energy during off-peak periods by operating equipment in the same way or similar to that during off-peak periods, and then extracts and uses it as desired during peak periods. has started to be researched and developed.

[Problem that the invention seeks to solve]

For example, a pumping dam uses surplus electricity to pump up water to a dam at night, or a large-capacity underground tank that compresses air by sending it to a surplus expansion turbine at night, and compresses the air during peak hours during the day. A system that uses air to generate power or uses the flywheel's inertia to rotate the flywheel with surplus electricity,
Alternatively, energy storage systems using superconductivity are being researched.

Among these, pumped storage dams and pneumatic power storage have been put into practical use, but only the pumped storage dam method has been commercialized, and the flywheel method and superconducting method are still at the research stage and are unlikely to be put into practical use in the future. It requires a considerable investment over time and a research period of around 20 years, which is too late for actual development.

Both pumping dams and compressed air energy storage have problems due to their location, and are also less efficient.

[Purpose of the invention]

The purpose of the present invention is to alleviate the low-load operation during off-peak hours of energy supply facilities based on the above-mentioned conventional technology, and to achieve average capacity operation of the energy supply facilities. The efficiency of the pump is such that it can be used at different times, and its efficiency allows it to recover and use more cold energy than the energy input during off-peak hours, or when combined with the Rankine cycle, it can be used more efficiently than conventional water pumps. It is possible to recover rotational energy with higher efficiency compared to other methods, and in addition, because it requires small-scale equipment, there are almost no restrictions on plant location, and it can be performed at low cost. It is an object of the present invention to provide an excellent cold energy storage system that can be fully utilized and thus benefit economic applications in the energy industry.

[Means and actions to solve the problem]

In accordance with the above-mentioned object and the gist of the above-mentioned patent claims, the structure of the present invention is designed to solve the above-mentioned problems. By inputting surplus energy during off-peak hours into the motor of a compressor such as a compressor, the fluid low-pressure gas such as ammonia gas is compressed to high temperature and high pressure, and then the temperature of the high temperature and high pressure gas is substantially reduced. Using unlimited available seawater and the cold energy released from LNG, it is cooled and liquefied and stored as high-pressure liquefied gas in high-pressure tanks, etc. During peak energy demand, the high-temperature, high-pressure liquefied gas is pumped through expansion valves, etc. The high-pressure liquefied gas can be stored as energy by converting it into a low-temperature, low-pressure liquid and gas due to the Joel-Thomson effect, and utilizing the cold energy during the transition from the low-temperature, low-pressure liquid-gas state to low-pressure gas to external facilities such as freezers. In this process, the enthalpy is increased and the gasified fluid is transferred to a gas absorbing medium such as an ammonia complex whose temperature and pressure are increased by pressure and temperature manipulation, and to a refrigerant such as seawater or the atmosphere while heat is radiated. The gas absorption medium, which has absorbed ammonia gas, etc., is brought to a low temperature and low pressure state by an expansion valve during off-peak periods, and the gas absorption medium is stored after reducing the volume that has once increased through gasification. Compression heat pumps efficiently separate and extract absorbed ammonia gas, etc. by heating with seawater, the atmosphere, solar heat, industrial waste heat, steam, etc., and guide it to the compressor mentioned above to raise the temperature and pressure again. It takes technical measures to effectively reuse energy stored during peak periods by following the cycle.

[Example - Configuration]

Next, embodiments of the present invention will be described below with reference to the drawings.

In the embodiment shown in FIGS. 1 and 2, A is a cold energy storage system that is the gist of the present invention, and as shown in FIG. 1, it is closed by a piping system, and the closed system is as shown in FIG. The working fluid follows the well-known compression heat pump cycles A, B, C, D, and H with enthalpy i on the horizontal axis and pressure P on the vertical axis, and the gas of the working fluid is uses ammonia (NH ₃ ), and as mentioned above, for example,
During off-peak energy such as electricity,
As described later, ammonia gas (a) is separated from the gas absorbing medium in a low temperature and low pressure state in a gas discharger.
The gas passes through a predetermined cleaner 1 and is compressed and pressurized to a high temperature by a compressor 2 in which excess energy during off-peak hours is input and operated, and becomes a high-temperature, high-pressure gas (b).

At this time, the ammonia gas supplied to the compressor 2 is, for example, 10°C and the pressure is 1Kg/cm ²
G gas, and when heated to high temperature and pressure by compressor 2, the pressure is 15Kg/cm ² G at over 150℃.
gas.

In addition, in this embodiment, the compressor 2 is
As shown in the figure below, the design depends on the conditions, for example,
If the output pressure of the compressor 2 is low in one stage, the air may be passed through a multi-stage compressor using appropriate means such as an intercooler or a pre-cooler.

The high-temperature, high-pressure ammonia gas thus obtained is then cooled and liquefied in a condenser (heat exchanger) 3 using seawater, the atmosphere, etc., which can be used virtually without limit.

The gas liquefied by cooling by the condenser 3 is a liquid (c) at a temperature of 35° C. and a pressure of 15 kg/cm ² G.

The ammonia gas thus liquefied under high pressure is stored in the storage tank 4 in a high-pressure manner.

Therefore, in this embodiment, the storage tank 4
As mentioned above, the energy storage mode is room temperature and high pressure storage, so stable storage over time can be achieved without being affected by time, days, months, years, etc. However, depending on the type of fluid, high temperature and high pressure storage,
Alternatively, there is also a mode of low-temperature and high-pressure storage, which requires a high-pressure tank with specified insulation. Of course, the storage is done during off-peak hours.

Therefore, during peak power usage, the storage tank 4
Ammonia gas (c), a liquefied gas stored in
is expanded through the expansion valve 5 to form a low temperature and low pressure liquid,
Alternatively, it becomes ammonia gas (d) in a mixed phase of liquid and gas, and the cold energy is supplied to the cold heat recovery and utilization device 6 until the entire amount of the low-temperature, low-pressure liquid or liquid and gas is vaporized into low-pressure gas (e). In the cold energy recovery and utilization device 6, for example, the cold energy is supplied to the freezer by exchanging heat with the working fluid gas of the freezer, etc., and the surplus energy during off-peak hours stored in the storage tank 4 is effectively used for the first time. This results in effective reuse of surplus energy input.

The ammonia gas (d), which has been made low-temperature and low-pressure by the expansion valve 5, has a temperature of -9°C and a pressure of 2 kg/cm ^{2 .}
Ammonia gas (E), which is the liquid and gas of G, and which supplied cold energy in the cold energy recovery and utilization device 6.
The temperature is raised to 0°C to 10°C, and the pressure is low-pressure ammonia gas of 2Kg/cm ² G. Therefore, in terms of enthalpy, the cold energy from -9°C to 0°C to 10°C, which corresponds to the enthalpy change from D to E in Figure 2, was recovered by being effectively used in freezers, etc. It turns out.

As mentioned above, the cold energy recovered by the cold heat recovery and utilization device 6 can be used directly in a freezer or the like, or it can be put into the low-temperature side of a thermoelectric power generation element and taken out in the form of energy such as electricity or work as appropriate. It is possible.

Therefore, the liquefied ammonia gas stored in the storage tank 4 as an energy storage mode returns to a low-pressure gas body of 0°C to 10°C after passing through the cold heat recovery and utilization equipment 6. In the case of the ammonia of this example, the volume of ammonia gas from the liquefied state to the gasified state is increased by 300 to 400 times, making it unsuitable for handling as a working fluid. Therefore, to deal with this, in the present invention, the low-pressure ammonia gas (e) from the cold heat recovery and utilization equipment 6 is absorbed into a gas absorption medium and liquefied, thereby reducing its volume and making it possible to store it. It is made to be.

That is, in general, as a gas absorption medium for the gaseous fluid in the gasified state, an ammonia complex is used for ammonia, and an aqueous gas absorption medium (hydrate, hydroxide, etc.) is used for propane, butane, freon, carbon dioxide, etc. There are liquid and slurry forms such as potassium carbonate and potassium carbonate.

The above-mentioned low-pressure ammonia gas (e) is supplied to a gas absorption tank 7 containing a gas absorption medium, and to the gas absorption tank 7, a liquid ammonia complex (such as ammonium thiocyanate) in the gas absorption medium storage facility 13 described below is supplied. A liquid whose pressure and temperature have been raised through pressure and temperature manipulation is fed into the absorption tank 7, and low-pressure ammonia is absorbed by the shower of the gas absorption medium inside the absorption tank 7. .

The liquid ammonia complex absorbs low-pressure ammonia gas and becomes a liquid state while dissipating heat to a cold heat source at an almost constant temperature and constant pressure. The target cooling source may have a relatively high temperature, such as seawater or air. In addition, since the pressure is raised in advance by pressure manipulation, the amount of ammonia gas absorbed is greater than in the case of low pressure. ) can be absorbed and liquefied. At this time, low pressure ammonia gas
In order to harmonize the pressure levels of (e) and the liquid ammonia complex, a compressor 2a may be interposed between the cold heat recovery and utilization device 6 and the gas absorption tank 7.

Therefore, the ammonia gas whose volume has been reduced by being absorbed by the gas absorption medium in the gas absorption tank 7 has been changed into a form that is advantageous for storage and pipe transportation.

The ammonia gas absorbed by the gas absorption medium in the gas absorption tank 7 is sent to the heat exchanger 16 via the pump 8, and is sent from the gas absorption medium storage facility 13 to the gas absorption tank 7 as described later. The gas absorbing medium exchanges heat with the gas absorbing medium to raise its temperature, is cooled down, and is then sent to the gas absorbing medium storage facility 9 to be stored as a storage body in preparation for the next off-peak period.

In this way, from the state in which the surplus energy stored in advance is recovered as cold energy during peak power usage, when power usage shifts to the next off-peak, the gas that has absorbed the ammonia stored in the gas absorption medium storage equipment 9 The absorption medium is appropriately supplied to the gas release tank 11 by a pump or the like.
At this time, the pressure is made low by the expansion valve 10 before the gas release tank 11 to partially release the absorbed ammonia gas and lower the temperature. It is heated by a heat source and releases ammonia gas (a).

Since the gas absorption medium is previously lowered to a low temperature by pressure operation by the expansion valve 11, the external heat source for heating may be a relatively low temperature source, and there is a wide range of choices, such as inexpensive seawater, air, solar heat, factory waste heat, etc. It becomes wider.

The generated ammonia gas (a) passes through the splash cleaner 1 and is again supplied to the compressor 2, which generates a compression heat pump cycle as shown in FIG.
You will follow B, H, D, and H.

Thus, the gas absorption medium such as ammonia complex separated in the gas release tank 11 is transferred to the absorption medium storage facility 13 after gas separation via the pump 12.
The gas absorbing medium is stored in the storage area and prepared for cold heat recovery during the next power peak period, but at the time of the next cold heat recovery, the pressure of the gas absorption medium is increased to a predetermined pressure by the pump 14 as a pressure control, and the gas is supplied to the heat exchanger 16 as a temperature control. After raising the temperature to the same temperature, the gas is fed into the gas absorption tank 7 again in the form of a shower, and as mentioned above, low pressure ammonia gas (Ho) is fed into the gas absorption tank 7.
absorb.

In this case, instead of providing the heat exchanger 16, a heat exchange tube is built into either the gas absorbing medium storage equipment 9 or 13, and the gas absorbing medium on either the outbound or return trip and the gas being stored are Heat exchange with a medium may also be performed.

Furthermore, by connecting the heating equipment of the gas discharge tank 11 with the endothermic device of the gas absorption tank 7 through the piping 15, the energy used in the equipment can be economized by performing some reforming and offsetting the equipment. can be achieved. Therefore, in the above-described embodiment, the operating rate of the power plant (not shown), etc. can be uniformly and effectively operated in terms of total energy.

In the above embodiment, in order to reduce the volume of the low-pressure ammonia gas from the cold heat recovery and utilization device 6, a liquefied ammonia complex is used as a gas absorption medium, and this is stored in a pressurized state in the gas absorption medium storage facility 9. As shown in FIG. The function of the medium storage facility 13 may also be used.

As shown in FIGS. 1 and 3, the heat exchanger 16
A heat exchanger 16a using seawater or the atmosphere may be further provided between the gas absorbing tank 7 and the gas absorbing tank 7 to heat the gas absorbing medium showered in the gas absorbing tank 7. In addition, a compressor 2a is disposed in the conduit between the cold heat recovery and utilization device 6 and the gas absorption tank 7, as shown by the imaginary line, and the cold heat recovery and utilization device 6
It is also possible to compress the low-pressure ammonia gas from the tank and send the compressed volume of the low-pressure ammonia gas to the gas absorption tank 7 in order to improve the efficiency of absorption into the gas absorption medium.

Furthermore, as the working fluid in the compression heat pump cycle, not only the ammonia gas used in the above-mentioned embodiments but also various fluids such as carbon dioxide gas and propane gas can be employed. Further, the system of the present invention does not necessarily need to be installed at an energy supply facility, but may be installed in a distributed manner at an energy consumption facility.

Next, the embodiment shown in FIGS. 4 and 5 will be described. In the embodiment shown in FIGS. 1 and 3 above, in the gas absorption tank 7, the gas absorption medium that has absorbed the gas that has passed through the cold heat recovery and utilization device 6 is fed and stored by the pump 8 to the gas absorption medium storage facility 9. A heat exchanger 16 is provided in the middle of the line to exchange heat between the gas absorption medium and the gas absorption medium fed from the absorption medium storage facility 13 to the gas absorption tank 7. In the embodiment shown in FIGS. 4 and 5, the gas absorption medium in the absorption medium storage facility 13 is pressurized and heated to a high temperature by the boost pump 14 without installing this heat exchanger 16. A heat exchanger 1 using seawater, the atmosphere, or a heat medium existing around the equipment is installed in the line feeding the gas absorption tank 7.
7 is provided to cool the gas absorption medium from the gas absorption tank 7 to the gas absorption medium storage facility 9, that is,
It is designed so that it can be stored in a high pressure state without lowering the temperature, and depending on the cooling design, a heat exchanger 18 may be installed in the line from the gas absorption tank 7 to the gas absorption medium storage equipment 9. Since the other configurations are the same as those of the embodiments shown in FIGS. 1 and 3, detailed explanation will be omitted.

〔Effect of the invention〕

As described above, according to the configuration of the present invention, the following effects can be obtained.

(a) Basically, the operation of equipment, whether for civil or industrial use, involves load fluctuations during peak and off-peak times, but energy use is required in energy supply facilities such as power plants that must constantly supply energy. In order to respond to the peak load of workers, their operating capacity is designed for peak hours.
Off-peak availability is reduced, resulting in significant waste. On the other hand, in the system according to the present invention, excess energy is supplied to the fluid flowing through the compression heat pump cycle during off-peak hours to create an energy storage system, and this is recovered as cold energy during peak hours for effective use. Regardless of the circumstances, it will be possible to contribute to the leveling of power demand, etc.

(b) The gas whose cold energy is recovered and utilized by the cold energy recovery and utilization device is efficiently absorbed by the gas absorption medium whose pressure and temperature are raised in the gas absorption tank, and is also absorbed by easily available refrigerants such as seawater and air. There is an economic advantage to storing a cooled, essentially gaseous fluid in a liquid state in a small volume.

(c) The low-temperature, high-pressure gas absorption medium that has absorbed gas is expanded and cooled and sent to the gas release tank via an expansion valve during off-peak hours, so the gas absorption medium in this gas release tank is easily available. Gas that is effectively heated by a heating medium such as seawater or the atmosphere and absorbed by a gas absorption medium can be easily released using an inexpensive heating medium, resulting in great economic effects.

[Brief explanation of the drawing]

Figure 1 is a schematic system diagram of the embodiment, Figure 2 is a graph of the compression heat pump cycle, Figure 3 is a schematic system diagram from the embodiment in Figure 1 with the gas absorption medium storage equipment omitted, and Figure 4 is a separate diagram. Schematic system diagram of the embodiment. FIG. 5 is a schematic system diagram of the embodiment shown in FIG. 4, with the gas absorption medium storage equipment omitted. A... Cold energy storage system, 2... Compressor, 3... Condenser, 4... Storage tank, 5... Expansion valve, 6... Cold energy recovery and utilization device, 7
... Gas absorption tank, 8 ... Pump, 9 ... Gas absorption medium storage equipment, 10 ... Expansion valve, 11 ... Gas release tank, 12 ... Pump, 13 ... Absorption medium storage equipment, 14 ... Pressure increase Pump, 16, 16a, 17...
…Heat exchanger.

Claims (1)

[Claims] 1. (a) In an energy storage system that utilizes a compression heat pump cycle, (b) Using rotational energy obtained from surplus electricity during off-peak hours, low-pressure gas is compressed and the gas is heated to a high temperature. After increasing the pressure, the high-temperature, high-pressure gas is cooled and stored in a low-temperature liquid state, and (c) at peak times, the low-temperature, high-pressure liquefied gas is reduced to a low temperature and low pressure through an expansion valve, and the resulting cold energy is utilized. (d) The gas whose enthalpy has been increased by recovering and using the cold energy is transferred to a gas absorbing medium (chemical heat storage material, etc.) whose temperature and pressure have been increased by pressure and temperature manipulation, and to easily available sources such as seawater and the atmosphere. (e) during off-peak hours, the high-pressure gas-absorbing medium is passed through an expansion valve to a gas discharger in a low-temperature, low-pressure state; The absorbing gas is heated in the gas emitting device using an easily available heat medium such as seawater, air, or solar heat, and the absorbed gas is released, and this low-pressure gas is compressed and pressurized again.The cycle is repeated. A cold energy storage system characterized by: