# Tag Info

37

When a reactor is shut down the core produces much less heat, but they do still produce heat through a mechanism known as decay heat. The fact that the core is producing less heat means that the coolant temperature is going to drop, but how far that temperature drops depends on the decay heat generation rate. This in turn is based on operating history, or ...

34

Electricity production optimization is a very complex subject. It is also affected by many parameters , which I will try to outline below. TL;DR: Demand is constantly monitored and supply is constantly adjusted TL;DR 2: Lshaver's excellent post is a suggested reading after reading this, because it expands and explains what happens at timescales ranging from ...

19

Actually the turbine method is very efficient. The Turgo turbine is up to 90% efficient at extracting the energy from the water. Large-scale hydro plants using Francis Turbines can be as high as 95% efficient (see here). Electrical generators typically use high RPMs, so you need speed as well as torque to drive it round. Low RPM generators are possible too, ...

18

Timescales on the grid Power demand fluctations can be broken into timescales from micro-seconds to decades. On the "decades" end of the scale, the power industry and utility regulators work together to plan and fund construction of power plants and the associated transmission and distribution infrastructure. When you turn your air conditioner off ...

13

Xenon is a result of the nuclear reaction and a neutron poison. If you don't wait for the xenon to decay, it eats up too many neutrons and you can't go critical. They always say "there are not enough rods to pull." If you have a nice new reactive core, you can get started sooner. If the core is old, you will have to wait a long time before enough xenon (...

13

There are two different ways for the water flow to transmit energy. One is the pressure difference between the water entering and leaving the turbine. The other the kinetic energy change of fast flowing water entering the turbine and slow flowing water leaving it. Your bucket idea seem to be like a http://en.wikipedia.org/wiki/Pelton_wheel which works by ...

10

Yes, they monitor demand and due to differences in how different power stations are controlled they can increase or reduce output to match demand. Some power plants like nuclear run at full output as they are slow to change, but others like Dinorwig (in the UK) can go from standby to max output in 12 seconds and reduce to half quickly. Danish researchers did ...

9

It's not a simple relationship. First let's deal with the kinetic energy of the wind passing through the rotor. The mass of air passing through it in one second, $m$, is equal to the the density of the air ($\rho$), times the surface area of the rotor (${\pi}r^2$), times the velocity of the air ($v$). i.e. ${\rho}{\pi}r^2v$. The kinetic energy of that air ...

9

Does the DC load somehow feedback and lower the resistance of the primary coil so that more power can be drawn? Yes. It would be simpler to analyze an AC load though. The diodes are not central to your question: The impedance of RL is also transformed, so if you have a 10:1 transformer and RL is 2 Ω, the AC source will see the transformer as a 200 Ω ...

7

The answer really boils down to two factors: safety and testing. I'm going to give a generic summary of these two things below, but the real answer is quite complicated. The crux of nuclear plant operation revolves around nuclear safety. I'm not talking about personal safety, which is the purview of the Occupational Safety and Health Administration (OSHA),...

6

Peak Demand One of the biggest issues in the electricity business is managing peak demand. This is the maximum amount of electricity needed at any one time. Typically this will be the middle of the day on the hottest days in the summer, as that combines household usage (everyone is awake), office usage (everyone is at work, or at least before the pandemic...)...

5

Assumptions: The copper side with the traces is modeled as a sheet of copper rather than traces. The body is thin enough that thermal conductivity within the body is unimportant, and the entire device is considered to be at a uniform temperature. Only the two broad surfaces contribute to the heat loss, the sides are neglected. The surroundings, including ...

5

You seem to be asking about using fruit juice as the electrolyte of a battery. Yes, that's possible, but you don't get a lot of power that way. The power also doesn't just come from the fruit juice. That's only one of the chemical reactants. One or both electrodes are the other side of the chemical reactions. The EMF is a function of the battery ...

5

The short answer is these terms are defined by standards organizations based on specific test methods. These methods specify the engine condition, environmental factors, fuel chemistry, inlet and exhaust systems configurations, and the correction factors applied to the measurements. The specific tests and standards used vary by country and by industry. So ...

4

Increasing the insulation between the heat sources there is quite difficult. Instead, you can sink the heat away: Add a full copper fill on the backside of the PCB and connect that into a heat sink that is kept cool externally. Add copper rectangles between the separate heating elements. Connect the rectangles to back side with plenty of vias. This should ...

4

Your "Bonus question" holds the answer here. Assuming that the two trains are perfectly identical, and that the power consumption is identical (which, if you have the same weight, motor, and size, it will be), you are down to transmission loss. The resistance of a conductor is R=L*Rho/A. L=length Rho=resistivity (material property) A=cross sectional area ...

4

It depends a bit on the quality you expect from some of the peripherals and what their qualities are at given clock speeds. Will you want a very high speed SPI interface and can this specific chip support that on the Fast Auxiliary Clock? Or are you going to do 1MHz SPI at most? So also for all the other devices. It's of course a nice boasting thing to be ...

4

Base on a quick calculation using online max current calculator for trace width properties, I believe your traces are undersized for 20A of current. Strip line current calculations (Internal Traces) for 50 mil 4 oz copper is Max Current: 3.76 amps Trace Temperature: 35.0 °C Resistance: 0.0000640 ohms Voltage Drop: 0.000241 volts Power Dissipation: 0....

4

The biggest problem with a "two cylinder" crankshaft is that there is a dead spot in the torque curve whenever either "piston" is at TDC or BDC. When you have your feet directly on the pedals of a conventional circular crank, you actually have the ability to apply force over greater than a 180° arc — by a combination of flexing your ankles and ...

4

Electricity is a convenient way to generate power centrally and distribute it to where it is needed according to demand. Central power generation by technologies like steam and gas turbines means that you can build large power plants with the associated gains in efficiency and economies of scale. Electrical power is also very versatile: Electric motors ...

4

If you get lucky, the power supply will either shut down because it is overloaded, or deliver a very reduced voltage. Either way, the keyboard won't work properly, or won't work at all. If you get unlucky, the power supply will overheat, catch fire, and burn your house down. (I'm not joking - at least about the chance of it catching fire). A "wall wart" ...

4

There are many factors that make BLE low power, and I have attempted to address as many of them as possible. In order to better understand the power consumption differences between Bluetooth classic and BLE, it would helpful to look at some of the differences between the Bluetooth technologies. This would help appreciate the difference in power consumption. ...

4

If you have horizontal water flow (no head) you are extracting its kinetic energy (from its velocity) not its potential energy (from its head). So you need to know the velocity of that flow as well as the flow rate to calculate the energy available. (You can calculate it from the flow rate and channel dimensions) You cannot extract all the available ...

4

Think of it as the volume of water you're displacing per second - the area multiplied by the distance moved. So intuitive I hope I can get away without an equation, but there's some good stuff in the "Power" paragraph here :https://en.wikipedia.org/wiki/Drag_%28physics%29#Drag_at_high_velocity

4

It's a pretty rough approximation, and only holds where skin friction is the dominant source of drag throughout the speed range considered. Skin friction increases about as speed ^2. So for double speed, the resistance force is quadrupled. Plus the rate is doubled. Power is the rate of doing work, so 4 X force and 2 X rate equals 8 X power. This doesn't work ...

4

Batteries can't deliver unlimited current. Internal resistance, and limitations of the chemical reaction within the battery make that it can only deliver so much current. And the more current is drawn, the bigger the voltage drop will be because of above mentioned reasons. Specific power (W/kg) and capacity, specific charge or specific energy(Wh/kg or J/kg) ...

3

Torque is proportional to current. If you can't supply the full current, then the torque will be lower than it would be otherwise. The highest current draw is at startup when the motor is not turning. This means the motor will produce lower than intended torque when it tries to get going. If this torque isn't enough to get the motor moving, then it will ...

3

The word that will unlock your searching is disaggregation - there's quite a lot of research going on right now into energy disaggregation. These generally involve some kind of learning algorithm, and the energy-disaggregation field is quite young, so you won't find a reliable off-the-shelf package. But you will find current research which will help you ...

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