4890X2 coming

[error8]

So all the electricity gets transformed into heat eventually. Why do some people don't want to admit the truth, is beyond me.

 

[fffblackmage]

Originally posted by: Idontcare
Your car does mechanical work while burning gas, but in the end every BTU of power generated is eventually converted to heat as the entropy of the system seeks to become maximized during the process of equilibration. Whether 90% of it is heat at time-zero and the remaining 10% is mechanical work that devolves into heat or whether 10% of it is heat at time-zero and the remaining 90% is mechanical work that devolves into heat is irrelevant, power-consumption means heat (in the end) and in a confined electrical system such as your computer box all that energy become heat inside your computer box which is why everybody on the planet cares to equate power-consumption with heat. For all practical considerations they are the same, given time, and the time here is mere microseconds.

How does the mechanical work devolve into heat? Even if the brakes heat up, some energy is lost through infrared light energy. Also, some work is done to wear out the brake pads. Not all kinetic energy of the car was turned to heat energy.

The idea that all electrical energy is converted to heat doesn't make sense to me. (or I just haven't been completely convinced yet)

Another example, if you have a light bulb, a lot of electrical energy is turned to heat, but some energy is emitted as light. Conservation of energy holds here because the total energy in the light emitted and heat produced will equal the amount of electrical energy put into the light bulb. However, the amount of heat produced is less than the total energy, because some energy was expressed as light.

Forms of energy "include (but are not limited to) kinetic, potential, thermal, gravitational, sound, light, elastic, and electromagnetic energy"

I am arguing that "heat" is one type of energy, and not everything ends up as heat, because there are other ways for energy to be expressed.

"The increase in the internal energy of a system is equal to the amount of energy added by heating the system, minus the amount lost as a result of the work done by the system on its surroundings."

Therefore, not all electrical energy is converted to heat, because some energy was used to do "work."

I guess you could argue energy will become heat eventually, but then again, that heat energy could also turn to another form of energy as well.

 

[Idontcare]

Originally posted by: fffblackmage
How does the mechanical work devolve into heat? Even if the brakes heat up, some energy is lost through infrared light energy. Also, some work is done to wear out the brake pads. Not all kinetic energy of the car was turned to heat energy.

The idea that all electrical energy is converted to heat doesn't make sense to me. (or I just haven't been completely convinced yet)

Another example, if you have a light bulb, a lot of electrical energy is turned to heat, but some energy is emitted as light. Conservation of energy holds here because the total energy in the light emitted and heat produced will equal the amount of electrical energy put into the light bulb. However, the amount of heat produced is less than the total energy, because some energy was expressed as light.

Forms of energy "include (but are not limited to) kinetic, potential, thermal, gravitational, sound, light, elastic, and electromagnetic energy"

I am arguing that "heat" is one type of energy, and not everything ends up as heat, because there are other ways for energy to be expressed.

"The increase in the internal energy of a system is equal to the amount of energy added by heating the system, minus the amount lost as a result of the work done by the system on its surroundings."

Therefore, not all electrical energy is converted to heat, because some energy was used to do "work."

I guess you could argue energy will become heat eventually, but then again, that heat energy could also turn to another form of energy as well.

These are the kinds of posts that flat out baffle me. You either didn't read my posts or you've read them and elected to discard most of their contents and then restate bits and pieces of it as your own and then repeat it back to me as if I'm the one here that needs an education on partition functions, canonical ensembles and energy manifolds.

Did you click any of the links? Read any of my comments where I stated you guys need to define what you mean by "heat"?

Originally posted by: Idontcare
There does seem to be a bit of misconception in this thread regarding power consumption versus heat.

In my view this misconception stems from the fact no one has defined what they view the term "heat" to mean.

Are you guys defining heat here as infrared photons, phonons, temperature or more precisely as the specific heat capacity?

Once we have an agreed upon metric definition of "heat" then we can have a meaningful discussion on how the energy provided by the PSU is divided up across the varying domains of the energy manifold ( a dynamic process) represented by the GPU "system" and how a significantly large part of the energy comes to occupy the portion of the energy manifold most folks would consider to be "heat".

Electrical Power

And perhaps the next largest communication barrier here is that I see some folks are talking about where the energy is on the energy manifold "at an instantaneous point in time" (the light bulb example) versus some other folks are talking about where the energy eventually ends up at the point of thermodynamic equilibrium for the system.

Excepting for the power consumed by your hard-drive in the semi-permanent storage of bits, all energy consumed by your computer (and light bulb) is eventually converted to heat by way of phonon-phonon coupling and phonon-photon coupling. It all comes down to standard statistical mechanics, if your GPU consumes 180W of power then after some period of time you have 180W of heat to dissipate into the world, conservation of energy combined with energy manifolds and thermodynamics sees to it. (I'm sure some of you can see why you are basically arguing that perpetual motion machines could exist if this weren't true)

Whether this period of time is that of the switching time of the transistor (picoseconds) or that of the refresh rate for the memory on your GPU housing the only "temporary" work created by the consumption of electrical power of your GPU is surely something that can be debated...but in the end if your GPU is consuming 180W of power you can rest assured you are dissipating 180W of heat, the energy has no where else to go in the system but into the lowest energy manifold and that is the phonon manifold we humans characterize as "heat".

 

[fffblackmage]

Originally posted by: Idontcare
These are the kinds of posts that flat out baffle me. You either didn't read my posts or you've read them and elected to discard most of their contents and then restate bits and pieces of it as your own and then repeat it back to me as if I'm the one here that needs an education on partition functions, canonical ensembles and energy manifolds.

Did you click any of the links? Read any of my comments where I stated you guys need to define what you mean by "heat"?

I'm sorry.

I read your posts again, but I still don't know what you specifically defined heat and energy as. I used these definitions:

heat - process of energy transfer from one body or system to another due to a difference in temperature
energy - scalar physical quantity that describes the amount of work that can be performed by a force, including kinetic, potential, etc.

You used a lot of jargon and most of these concepts are difficult to understand quickly. So, I most likely misunderstood something. I didn't take thermodynamics and whatnot, and I'm sure most people didn't either.

I also didn't fully understand what happened to the work done by the car engine example you gave. You said that work devolves into heat, but how did that exactly happen?

 

[Idontcare]

Originally posted by: fffblackmage

Originally posted by: Idontcare
These are the kinds of posts that flat out baffle me. You either didn't read my posts or you've read them and elected to discard most of their contents and then restate bits and pieces of it as your own and then repeat it back to me as if I'm the one here that needs an education on partition functions, canonical ensembles and energy manifolds.

Did you click any of the links? Read any of my comments where I stated you guys need to define what you mean by "heat"?

I'm sorry.

I read your posts again, but I still don't know what you specifically defined heat and energy as. I used these definitions:

heat - process of energy transfer from one body or system to another due to a difference in temperature
energy - scalar physical quantity that describes the amount of work that can be performed by a force, including kinetic, potential, etc.

You used a lot of jargon and most of these concepts are difficult to understand quickly. So, I most likely misunderstood something. I didn't take thermodynamics and whatnot, and I'm sure most people didn't either.

I also didn't fully understand what happened to the work done by the car engine example you gave. You said that work devolves into heat, but how did that exactly happen?

Ah! I see now. Yes, my bad then, I was assuming a working understanding of thermo at a minimum was at play here. Statistical mechanics is a graduate level (PhD) version of thermodynamics and physics...so its pointless me bringing up these concepts then as they add zero value to your understanding of what it is I'm trying to communicate.

Let's start by reading this regarding a working definition of what heat is versus a couple of examples of what it is not.

And I highly recommend reading this brief tutorial on Ohm's law and pay close attention to the section regarding power in electrical circuits.

The example No1 provided in the tutorial is a good starting point to see how a GPU really is to be treated as a resistor in a circuit, and notice the comments:

Generally, power is dissipated in the form of Heat (heaters), Mechanical Work such as motors, etc or Energy in the form of radiated (Lamps) or stored energy (Batteries).

In our case the only thing capable of storing any electrical work performed in our system is the memory...this is where stored energy resides. But on IC's the storage of energy is really poor, and the charge leaks to "ground" quickly, creating more heat in the system in the form of elevated temperature (which itself is simply a higher excited state in phonon modes, or lattice vibrations if you will).

For a light bulb the entire electrical power consumed by the lightbulb is actually first converted to heat, whatever power is consumed by the lightbulb (100W for example) is converted from electrical potential into phonon (vibration) energy in the filament itself. The material comprising the filament has a specific heat, which when combined with a known amount of mass (of the filament in this example) and heat (100% of the power dissipated in this example) gives rise to the temperature of the filament.

It is the temperature of the filament that then gives rise to the thermal radiation, aka blackbody radiation, which generates a spectrum of light (photons) comprising the entire span of the electromagnetic spectrum ranging from visible (sometimes UV) down thru the infrared.

The infrared light is already of the right wavelength for photon-phonon coupling as needed for the transfer of heat from the filament to whatever solid body absorbs these low energy photons.

But the visible light is higher energy photons, and their absorption by surrounding material results in the creation of an electronic excited state whose lifetime is limited to a few nanoseconds. (this is how your eye detects light by the way, molecules in your retina absorb the photon, converting its energy)

The electronic excited state decays by way of two pathways, as described by the Jablonski diagram. Either radiatively (the emission of a photon) or non-radiatively (the creation of excited state vibrations and photons, aka heat). The radiated photons will subsequently be absorbed by material, some converted to heat and some re-emitted as photons, and so on and so on until eventually all the visible photons that were emitted by the light bulb have been converted into heat.

The same is true of the automobile. The engine converts chemical potential into mechanical energy (doing work), heat (temperature of the exhaust), noise (sound waves), etc.

The sound waves reverberate off of surfaces and are slowly absorbed and converted into excited phonons (heat, elevating the temperature of the sound absorbing material). The hot exhaust is dissipated into the surrounding environment, you are familiar with this part of the cycle. And the mechanical energy is (over time) converted into heat by way of friction...the sources of friction are the tires rolling on the ground, the bearings in the drive train, and the brakes. (that is what brakes do, apply an increasing level of friction, converting the translational energy of the car into heat and noise)

In the end, when the car comes to a stop (assuming it made a round-trip and returned to exactly the same location on earth it started from), every last bit of energy that came from that chemical potential has been converted to heat in the surroundings. Work was done, but all the energy became heat in the end. Same as the light bulb.