Batteries of various types. How does a pneumatic energy accumulator work Energy capacity of gravitational energy storage devices

A reservoir of air or other gas connected to a duct and equipped with a safety valve regulated to a specified pressure. A pneumatic accumulator is a necessary element of sand blowing and sand-shooting machines for the manufacture of... ... Metallurgical dictionary

pneumatic accumulator- pneumatinis akumuliatorius statusas T sritis Energetika apibrėžtis Suslėgtų dujų arba oro energijos kaupiklis. atitikmenys: engl. pneumatic accumulator vok. Druckluftspeicher, m rus. pneumatic accumulator, m; pneumatic accumulator, m pranc.… … Aiškinamasis šiluminės ir branduolinės technikos terminų žodynas

PNEUMATIC ACCUMULATOR- a tank with air (or other gas), connected to the air duct and equipped with a safety device. valve, which is regulated to a given maximum pressure. Used in complex pneumatic applications. networks for equalizing operating pressure, on wind-electric... ... Big Encyclopedic Polytechnic Dictionary

Battery (disambiguation)- Battery (lat. accumulator collector, from lat. accumulo collect, accumulate) a device for storing energy for the purpose of its subsequent use. Car battery battery used in a car... ... Wikipedia

Battery- This term has other meanings, see Battery (meanings). Battery (lat. accumulator collector, from lat. accumulo collect, accumulate) a device for storing energy for the purpose of its subsequent use, ... ... Wikipedia

BATTERY- (from Latin accumulator collector) a device for storing energy for the purpose of its subsequent use. 1) Electric battery converts electrical energy into chemical energy and, if necessary, provides the reverse conversion;... ... Big Encyclopedic Dictionary

BATTERY Modern encyclopedia

Battery- (from the Latin accumulator collector), a device for storing energy for the purpose of its subsequent use. 1) Electric battery galvanic cell reusable; converts electrical energy into chemical energy and... Illustrated Encyclopedic Dictionary

battery- A; m. A device for storing energy for the purpose of its subsequent use. Thermal, electrical a. Charge a. ◁ Rechargeable, oh, oh. A. tank. And the battery. * * * battery (from Latin accumulator collector), a device for storing... ... encyclopedic Dictionary

Battery- (lat. accumulator collector, from accumulo collect, accumulate) a device for storing energy for the purpose of its subsequent use. Depending on the type of accumulated energy, A. are distinguished: electrical, hydraulic, thermal,... ... Great Soviet Encyclopedia

A cave, a compressor and a gas turbine - this is how a pneumatic energy accumulator works. In the US, the first such device was built in 1991 in McIntosh, Alabama. Its purpose is to smooth out peak loads at power plants.

In the accumulation mode, air is driven by compressors into an underground storage facility (natural salt cave) with a volume of 538 thousand cubic meters. up to a pressure of 77 atm. When power consumption on the grid increases unexpectedly, air escapes and releases power into the system. The time for emptying the tank to a lower operating pressure of 46 atm is 26 hours, during which the station produces 110 MW of power.

The compressed air does not spin the turbine on its own, but enters the gas turbine. Since 2/3 of the power of a gas turbine is usually spent on driving the compressor, which pumps air into it, significant savings are obtained. Before entering the turbine, the air is heated in a heat exchanger (recuperator) with combustion products, which also adds efficiency.

They note a reduction in gas consumption by 60...70% compared to a traditional gas turbine, quick start from a cold state (several minutes) and Good work at low loads.

Construction of the Mcntosh station took 30 months and cost $65 million.

The Alabama project is not unique. Back in 1978, in Huntorf, the Germans launched a 290 MW storage facility (2 hours of operation) in two salt caves at a depth of 600...800 m with a pressure range of 50...70 atm. The storage facility originally served as a hot reserve for industry in northwest Germany and is now used to smooth out production peaks. wind power plants.

They write that in the Donbass during the Soviet era they planned to install a 1050 MW pneumatic battery in the same cave, its fate is unknown.

In 2012, a 500 MWh pneumatic storage facility was opened in Texas next to a 2-megawatt wind farm, but there are few specifics about it.

The chain of the technological cycle of electricity production necessarily includes such a link as a storage device (battery). IN traditional ways In electricity generation, energy reserves are accumulated in a preliminary, “non-electric” form, and this link, the energy storage unit, is located directly in front of the electric generator.

The reservoir of the hydroelectric power station is designed to accumulate potential energy river water in the gravitational field of the Earth, raising it to a certain height with the help of a dam. Thermal power plant accumulates in its storage facilities the reserves of solid or liquid fuel necessary for uninterrupted operation, or supplies it via pipeline natural gas, the calorific value of which guarantees the required energy supply. The reactor rods of nuclear power plants represent a supply of nuclear fuel that has a certain resource of nuclear energy available for use.

Constant power mode is available for all listed types of power generators. The amount of energy produced is regulated by within wide limits depending on the level of immediate energy consumption. Alternative sources (wind, tidal, geothermal, solar energy) cannot provide guaranteed constant power generator at the required this moment level. The storage device, therefore, is not so much a storage of resources as a damping device, making energy consumption less dependent on fluctuations in source power. The energy of the source is accumulated in the storage device, and later consumed, as needed, in the form electrical energy. Moreover, its price largely depends on the cost of the drive.

A characteristic feature of the storage device in alternative energy sources is that the energy accumulated in it can be spent on other purposes. For example, with their help, strong and super-strong magnetic fields can be generated.

The units of energy measurement accepted in physics and energy and the relationships between them: 1 kWh, or 1000 W 3600 s - the same as 3.6 MJ. Accordingly, 1 MJ is equivalent to 1/3.6 kWh, or 0.278 kWh

Some common energy storage devices:

Let's make a reservation right away: this review is not full classification storage devices used in the energy sector, in addition to those discussed here, there are thermal, spring, induction, and various other types of energy storage devices.

1. Capacitor type storage

The energy stored by a 1 F capacitor at a voltage of 220 V is: E = CU2 /2 = 1 2202 /2 kJ = 24 200 J = 0.0242 MJ ~ 6.73 Wh. The weight of one such electrolytic capacitor can reach 120 kg. Per unit mass specific energy turns out to be equal to just over 0.2 kJ/kg. Hourly operation of the drive is possible with a load within 7 W. Electrolytic capacitors can last up to 20 years. Ionistors (supercapacitors) have a high energy and power density (about 13 Wh/l = 46.8 kJ/l and up to 6 kW/l, respectively), with a resource of about 1 million recharging cycles. The undeniable advantage of a capacitor storage device is the ability to use the accumulated energy in a short period of time.

2. Gravity type storage devices

Energy storage devices of the pile driver type store energy when lifting a pile driver weighing 2 tons or more to a height of about 4 m. The movement of the moving part of the pile driver releases the potential energy of the body, imparting it to the electric generator. The amount of energy produced E = mgh in the ideal case (without taking into account friction losses) will be ~ 2000 10 4 kJ = 80 kJ ~ 22.24 Wh. The specific energy per unit mass of a copra woman turns out to be equal to 0.04 kJ/kg. Within an hour, the drive is capable of providing a load of up to 22 W. Expected service life mechanical design exceeds 20 years. The energy accumulated by a body in a gravitational field can also be spent in a short period of time, which is an advantage of this option.

The hydraulic accumulator uses the energy of water (weighing about 8-10 tons) pumped from a well into the tank of a water tower. In reverse motion, under the influence of gravity, the water rotates the turbine of the electric generator. A conventional vacuum pump can easily pump water to a height of up to 10 m. The stored energy is E = mgh ~ 10000 8 10 J = 0.8 MJ = 0.223 kW hour. The specific energy per unit mass turns out to be equal to 0.08 kJ/kg. The load provided by the drive for an hour is within 225 W. The drive can last 20 years or longer. The wind engine can directly drive the pump (without converting energy into electricity, which is associated with certain losses); the water in the tower tank can, if necessary, be used for other needs.

3. Flywheel based storage

The kinetic energy of a rotating flywheel is determined as follows: E = J w2/2, J means the intrinsic moment of inertia of the metal cylinder (since it rotates around the axis of symmetry), w is the angular velocity of rotation.

With radius R and height H, the cylinder has a moment of inertia:

J = M R^2 /2 = pi * p R^4 H/2

where p is the density of the metal - the material of the cylinder, the product pi* R^2 H is its volume.

Maximum possible linear speed points on the cylinder surface Vmax (about 200 m/s for a steel flywheel).

Vmax = wmax*R, whence wmax = Vmax/R

Maximum possible rotation energy Emax = J wmax^2/2 = 0.25 pi*p R2^2 H V2max = 0.25 M Vmax^2

The energy per unit mass is: Emax/M = 0.25 Vmax^2

The specific energy if the cylindrical flywheel is made of steel will be about 10 kJ/kg. A flywheel weighing 200 kg (with linear dimensions H = 0.2 m, R = 0.2 m) stores energy Emax = 0.25 pi 8000 0.22 0.2 2002 ~ 2 MJ ~ 0.556 kWh. The maximum load provided by the flywheel storage device for an hour does not exceed 560 W . The flywheel may well last 20 years or more. Advantages: rapid release of accumulated energy, the possibility of significantly improving characteristics by selecting the material and changing geometric characteristics flywheel.

4. Storage in the form of a chemical battery(lead acid)

A classic rechargeable battery, having a capacity of 190 Ah at an output voltage of 12 V and 50% discharge, is capable of delivering a current of about 10 A for 9 hours. The energy released will be 10 A 12 V 9 h = 1.08 kWh, or approximately 3.9 MJ per cycle. Taking the mass of the battery equal to 65 kg, we have a specific energy of 60 kJ/kg. The maximum load that the battery can provide for an hour does not exceed 1080 W. Guarantee period The service life for a high-quality battery is within 3 - 5 years, depending on the intensity of use. It is possible to directly receive electricity from the battery with an output current reaching thousands of amperes, with an output voltage of 12 V, corresponding to the automotive standard. Many devices designed for a constant voltage of 12 V are compatible with the battery; 12/220 V converters of varying output power are available.

5. Pneumatic type storage

Air pumped into a steel tank with a volume of 1 cubic meter to a pressure of 40 atmospheres performs work under conditions of isothermal expansion. The work A performed by an ideal gas under conditions T=const is determined according to the formula:

A = (M / mu) R T ln (V2 / V1)

Here M is the mass of the gas, mu is the mass of 1 mole of the same gas, R = 8.31 J/(mol K), T is the temperature calculated on the absolute Kelvin scale, V1 and V2 are the initial and final volume occupied by the gas (at this V2 / V1 = 40 when expanded to atmospheric pressure inside the tank). For isothermal expansion, the Boyle-Marriott law is valid: P1V1 = P2 V2. Let's take T = 298 0K (250C) For air M / mu ~ 40: 0.0224 = 1785.6 moles of substance, gas does work A = 1785.6 8.31 298 ln 50 ~ 16 MJ ~ 4.45 kWh per cycle. The walls of the tank, designed for a pressure of 40-50 atmospheres, must have a thickness of at least 5 mm, and therefore the mass of the storage device will be about 250 kg. Stored data pneumatic storage the specific energy will be equal to 64 kJ/kg. The maximum power provided by the pneumatic accumulator during an hour of operation will be 4.5 kW. Guaranteed lifespan, like most performance-based drives mechanical work their structural parts are from 20 years. Advantages of this type of storage: the possibility of locating the tank underground; the tank can be a standard gas cylinder With the use of appropriate equipment, the wind turbine is capable of directly transmitting motion to the compressor pump. In addition, many devices directly use the stored energy of compressed air in a tank.

We present the parameters of the considered types of energy storage devices in a summary table:

Autonomous engineers often wonder how to collect, store and use “extra” energy. There are several reasons for the appearance of under-collected kW - an excessive amount of SB, charging stages that do not use the system 100%, unnecessarily sunny days, absence of owners of the house, etc.
The easiest way is batteries. Depending on religious beliefs, they can be different: lead-acid, alkaline, nickel-cadmium, “lifer”, etc. But in any case, it is the battery part of the battery that accounts for 50% (more likely 60%) of the cost of the final kWh Therefore, all the dances are centered around them, my dear ones.
Somewhere in the section it was noted that the development path of battery technology did not develop according to the scenario that alternatives needed - efficiency with relatively small dimensions. However, in a private house where there are no electrical networks, there is often a lot of land. This idea stems from a simple fact - many people want to escape the hustle and bustle of the city and buy plots often not just far from cities, and beyond the high concentration of people, but also far from civilization as such, where there are no communications, and even electricity. That is why, very often, alternativeists have such a type of resource as space. What traditional battery technologies don't take into account. So you can look for non-traditional ones. AndreyNS, started a couple of threads on this issue and thereby gave me the idea of ​​looking for options.
There are many super alternative ways to save alternative energy not in traditional accounts.
And one of them that I decided to introduce is... a pneumatic accumulator!
The principle is simple - excess electricity during the day is converted into compressed air. Then, as needed, we release it through a pneumatic motor, which rotates a generator that charges the batteries at night, in the case of SB, or in calm conditions, in the case of VG.
It looks something like this:

I think that the principle is clear to most of my colleagues.
The principle is the principle, but I am primarily interested in the economic justification for this type of battery. I wonder how much the energy stored in this way costs, and whether it can compete with traditional methods.
To do this, I did a little research on what it costs in terms of pneumoaccus. For convenience and ease of perception, all prices will be in dollars, and we will also omit some little things such as wires, pipes, etc. However, I included the compressor, air motor and gene in the calculations.
So.
1. The most important thing is capacity. This is the most expensive part of the pneumoacc, but also the most durable and reliable with virtually unlimited engine hours, cycles or years. On the Internet I found a used gas tank of 16 cubic meters. for about $2k.
2. Compressor. There are many options. From automotive ones with lubrication and cooling to semi-industrial ones, so to speak, “for construction”. I chose new head(we have a container), with the characteristics I need - about $80. There is an option with compressors for MAZ-KAMAZ, it is cheaper and more reliable, but they do not provide the required pressure (up to 16 atmospheres).
3. Pneumatic motor. On the Internet I found a ready-made one for 250W with a flow rate of 6.67 l/sec. There is no price for it, so we will operate with prices for pneumatic tools. A new drill or grinder costs about $25.
4. Generator. The most real one is a car from, say, a vase. New $80, used 35. Estimated number of engine hours from 15k.
Brief description of the specific system. The compressor has a capacity of 300-400 l/min, which allows it to pump up the container in 10 hours. The pneumatic motor consumes 6.67 l/sec, or 24 cubic meters. at one o'clock. A 16 cubic meter capacity, pumped up to 16 atm, is enough for 10.7 hours. That is, we have 10.7 hours x 250W = 2.675 kW. This is roughly comparable to a car battery with 225 ah. More precisely, with one, 100% cycle. There is approximately 250 days of excess electricity in my system per year, which means we have 250 cycles per year.
The cost of a normal auto account, minus metal, is about $200. But it can work for a maximum of 250 cycles at 100% discharge.
In other words, this pneumatic storage-generating system replaces 1 car battery per year. Or $200 per year.
Now to our pneumoacc.
1. Capacity. Service life from 50 years. Actually, with regular painting, it takes 500 or 5000 years, but let’s take 50 and not count the paint. This means we divide $2000 (its cost) by 50 and get about $40 per year.
2. Compressor. Let's take the service life to be 10,000 engine hours. Accordingly, we divide 10,000 by 250 cycles and by 10 hours (work in each cycle) we get 4 years. Divide $80 by 4 to get $20 per year.
3. Pneumatic motor. The service life of cheap pneumatic tools from a store cannot be sanely assessed. However, let’s count it as 10,000 engine hours, taking into account the possibility of purchasing good tool used for cheap. Further 10000 / 250 days / 10 hours we get the same 4 years. $25 cannot be divided by four, but we will divide and get $6 per year.
4. Gen. The motor life is about 20k motor-hours (and don’t argue with me!). 20000 / 250 /10 = 8 years or $10 per year.

Total we have:
1. 40$
2. 20$
3. 6$
4. 10$
-
$76 per year.
That is, having such a pneumatic accumulating-generating system is almost 3 times cheaper than buying 1 car battery per year!
And I have not yet added a separate charge to the electric battery, which it undoubtedly needs.
Just like that.
These calculations surprised me, to put it mildly. Of course, there is no efficiency - we pump in 1.5 - 2 kW, we get 200-250, but personally this suits me.
You can try to calculate a little differently: the pneumatic battery generates at night directly on the battery and you can roughly estimate how much the discharge depth will decrease and, accordingly, how much less often you need to change the electric battery, and accordingly, what economic efficiency this idea.
If the system is increased by 2-10 times, the efficiency, in theory, will improve even more.
It looks like it's time to start full-scale experiments. I have almost everything from the set, except for the pneumatic motor, but I’ll either buy it for 50 hryvnia ($6) or, which is more expensive, I’ll ask someone for temporary use.