Data center in Yaroslavl: engineering solutions for smooth operation

    The very idea of ​​building a large data center in Yaroslavl caused revival among technical experts. The task is to create an optimal area and the most efficient technical construction.


    DDIBP

    Here are the given parameters:
    • The average annual Power Usage Effectiveness should not exceed 1.3 when consuming one rack about 20 kW;
    • There should be the possibility of phased (modular) construction;
    • Reliability category of power supply according to UPTIME INSTITUTE requirements - TIRE 4 (100% duplication of nodes);
    • The data center should be easy to use.
    Another introduction: the cooling system should continue to work even after turning off the main power, plus the case must be economically feasible. You can read about other conditions in the previous topic about the construction of a data center.

    Decision selection


    We decided to use DDIBP (diesel dynamic uninterruptible power supply), also known as Flywheel UPS or DRUPS, as a source of guaranteed and uninterrupted power supply . The technology was used back in the USSR and was called UGP (installation of guaranteed power). The principle of operation of the machine is based on the rotation of the alternator (synchronous reversible electric machine), which can operate in motor or generator mode.

    The continuity of rotation of the electric machine during problems with external power is provided by the accumulated kinetic energy. A huge flywheel attached to the shaft of a reversible machine is used as a drive of kinetic energy.

    Flywheels as kinetic energy storage devices are used in the DDIBP, limited to a range of 1 MW. In more powerful devices, DDIBPs use so-called kinetic modules. The operation of these devices is based on a combination of mechanical and electrical principles.



    How it works


    If there is a satisfactory external supply (from the city)
    1. Synchronous electric machine (alternator - 3) rotates idling in the mode of an electric motor;
    2. The kinetic module (energy storage - 4) rotates on the same shaft with a synchronous electric machine (alternator);
    3. Diesel (1) with a heated crankcase is in standby mode quick start;
    4. The clutch (2) connecting the diesel engine to electric machines is open;
    5. The inductor (5), using the energy of the alternator “cleans” the power supply and the output produces an almost perfect sine wave.
    6. Bypass circuit breaker (9) is open.
    If external power disappears or becomes unsatisfactory, the
    untwisted flywheel continues to rotate by inertia, giving up the stored kinetic energy to a synchronous electric machine. She, in turn, switches from the electric motor mode to the generator mode and generates electricity to the consumer.
    1. The kinetic module (energy storage - 4) rotates and continues to rotate a synchronous electric machine (alternator - 3);
    2. Diesel (1) receives a start command and spins up to the required speed;
    3. Clutch engages (2), connecting the diesel shaft with the shaft of an electric machine;
    4. The electric machine continues to rotate due to diesel energy;
    5. The kinetic module (energy storage - 4) rotates, accumulating energy.
    Electricity consumers continue to receive electricity without noticing the problem.

    According to the statistics of DDDBP manufacturers, 98% of incidents with external electricity are of a short-term nature, and the autonomy of the DDIBP on the untwisted flywheel is sufficient to eliminate them. Problems that are of a longer nature are accompanied by starting and connecting the diesel engine to electric machines by clutch coupling.

    12 in favor

    1. A single system is able to reserve more power;
    2. Easy to operate (especially important in the regions);
    3. It does not require the installation of air conditioners for cooling (we save on air conditioners and power for them);
    4. Low operational costs for maintenance;
    5. High efficiency with minimal load (almost a linear graph of 40%);
    6. Minimum amount of power electronics .;
    7. High operating time before the overhaul (10 years);
    8. Does not require a power reserve for charging batteries (10-15% of the power consumption of UPS systems);
    9. Resistant to short circuit currents;
    10. At a cost comparable with the classical systems of guaranteed and uninterrupted power used in modern data centers;
    11. It takes up less space than the classic static DDIBP.
    12. It idles as a synchronous compensator.
    The latter will stop a little more. An overexcited synchronous engine idling is used as a reactive power compensator. We get the opportunity not to pay for the reactive component of electric power, compensating for it by using DDIBP.

    What is active and reactive power?


    In most cases, electrical circuits contain both active and reactive resistance. In circuits with active resistance, electrical energy is completely converted into heat, doing useful work. Unit of measure Watt (W). In alternating current circuits, which contain, along with active resistances, inductive and capacitive loads, there is a loss in reactive power due to the presence of magnetic and electric fields in the electrical circuits. Conventionally, this power is not spent on useful work. Unit of measure volt-ampere reactive (var) or kilovolt-ampere reactive (kvar).

    Given that the data center in Yaroslavl is being built, as previously written, near the walls of the Yarpivo brewery, for clarity, you can consider an example on a glass of beer. The glass is filled with a layer of useless foam (reactive power). We pay for it as part of the drunk beer, but only the volume of active liquid (active power) does useful work.



    The sum of active and reactive power is the total power.

    The ratio of the active power of the electric circuit to the full power is usually called the power factor or “cosine phi” (cos φ):

    Power Factor = Active Power / Apparent Power

    Power factor cannot be greater than one. If the active power is equal to the total power, and this indicates the absence of reactive load, cos φ = 1 (unit). For a practical example, - cos φ of the server = 0.95, and cos φ of the air conditioner = 0.7. From here it is already visible how much in percentage we will pay for the foam).

    Practical choice


    When researching the market, we found that there are four leading manufacturers whose equipment is installed in the data center, all located in European countries.
    1. Piller - Germany
    2. Hitec - Holland
    3. Hitzinger - Austria
    4. Evrodisel - Belgium
    All work in large power ranges, have a good production base, all are represented in data centers and have a positive history and feedback. Accordingly, there is a competitive environment.

    Interesting design features


    Hitzinger, Evrodisel, Hitec
    DDIBP of these manufacturers have a classic arrangement of units (coaxial). Dual-kinetic drive. It has a hard connection with an alternator.

    It looks like this:



    Advantages: simplicity and minimal amount of power electronics.

    Piller
    It works on the same principle as the classic DDIBP - but the kinetic energy storage is not placed on the same frame as the other components of the device. The kinetic drive has a vertical arrangement, according to the principle of "spinning top". In these devices, not mechanical coupling of the units is used, but electrical.

    Schematic diagram:



    It looks like this:



    Advantages: the kinetic drive can be installed separately from the power unit itself, the drive is placed in a sealed enclosure filled with gas, thus reducing the resistance, which allows to increase the autonomy time without starting the diesel engine.

    And here are photos of devices in reality (not in our data center):







    PS This topic was promised in the first about the Yaroslavl data center . If you have other questions about the work of the data center - I will try to answer in the comments.

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