Thermodynamics of Computation Wiki - westurner
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westurner
"Quantum knowledge cools computers: New understanding of entropy" (2011)
[https://www.sciencedaily.com/releases/2011/06/110601134300.h...](https://www.sciencedaily.com/releases/2011/06/110601134300.htm)

> _The new study revisits Landauer 's principle for cases when the values of
> the bits to be deleted may be known. When the memory content is known, it
> should be possible to delete the bits in such a manner that it is
> theoretically possible to re-create them. It has previously been shown that
> such reversible deletion would generate no heat. In the new paper, the
> researchers go a step further. They show that when the bits to be deleted
> are quantum-mechanically entangled with the state of an observer, then the
> observer could even withdraw heat from the system while deleting the bits.
> Entanglement links the observer's state to that of the computer in such a
> way that they know more about the memory than is possible in classical
> physics._

"The thermodynamic meaning of negative entropy" (2011)
[https://www.nature.com/articles/nature10123](https://www.nature.com/articles/nature10123)

Landauer's principle:
[https://en.wikipedia.org/wiki/Landauer%27s_principle](https://en.wikipedia.org/wiki/Landauer%27s_principle)

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westurner
"Thin film converts heat from electronics into energy" (2018)
[http://news.berkeley.edu/2018/04/16/thin-film-converts-
heat-...](http://news.berkeley.edu/2018/04/16/thin-film-converts-heat-from-
electronics-into-energy/)

> _This study reports new records for pyroelectric energy conversion energy
> density (1.06 Joules per cubic centimeter), power density (526 Watts per
> cubic centimeter) and efficiency (19 percent of Carnot efficiency, which is
> the standard unit of measurement for the efficiency of a heat engine)._

"Pyroelectric energy conversion with large energy and power density in relaxor
ferroelectric thin films" (2018)
[https://www.nature.com/articles/s41563-018-0059-8](https://www.nature.com/articles/s41563-018-0059-8)

Carnot heat engine > Carnot cycle, Carnot's theorem, "Real heat engines":
[https://en.wikipedia.org/wiki/Carnot_heat_engine](https://en.wikipedia.org/wiki/Carnot_heat_engine)

Carnot's theorem > Applicability to fuel cells and batteries:
[https://en.wikipedia.org/wiki/Carnot%27s_theorem_(thermodyna...](https://en.wikipedia.org/wiki/Carnot%27s_theorem_\(thermodynamics\))

> _Since fuel cells and batteries can generate useful power when all
> components of the system are at the same temperature [...], they are clearly
> not limited by Carnot 's theorem, which states that no power can be
> generated when [...]. This is because _Carnot's theorem applies to engines
> converting thermal energy to work _, whereas_ fuel cells and batteries
> instead convert chemical energy to work. _[6] Nevertheless, the second law
> of thermodynamics still provides restrictions on fuel cell and battery
> energy conversion_

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westurner
Is there enough heat energy from a datacenter to -- rather than heating oceans
(which can result in tropical storms) -- turn a turbine (to convert heat
energy back into electrical energy)?

~~~
westurner
Is there a statistic which captures the amount of heat energy discharged into
ocean/river/lake water? "100% clean energy with PPAs (Power Purchase
Agreements)" while bleeding energy into the oceans isn't quite representative
of the total system.

"How to Reuse Waste Heat from Data Centers Intelligently" (2016)
[https://www.datacenterknowledge.com/archives/2016/05/10/how-...](https://www.datacenterknowledge.com/archives/2016/05/10/how-
to-reuse-waste-heat-from-data-centers-intelligently)

> _There are two big issues with data center waste heat reuse: the relatively
> low temperatures involved and the difficulty of transporting heat. Many of
> the reuse applications to date have used the low-grade server exhaust heat
> in an application physically adjacent to the data center, such as a
> greenhouse or swimming pool in the building next door. This is reasonable
> given the relatively low temperatures of data center return air, usually
> between 28° and 35°C (80-95°F), and the difficulty in moving heat around.
> Moving heat energy frequently requires insulated ducting or plumbing instead
> of cheap, convenient electrical cables. Trenching and installation to run a
> hot water pipe from a data center to a heat user may cost as much as $600
> per linear foot. Just the piping to share heat with a facility one-quarter
> mile away might add $750,000 or more to a data center construction project.
> There’s currently not much that can be done to reduce this cost._

> _To address the low-temperature issue, some data center operators have
> started using heat pumps to increase the temperature of waste heat, making
> the thermal energy much more valuable, and marketable. Waste heat coming out
> of heat pumps at temperatures in the range of 55° to 70°C (130-160°F) can be
> transferred to a liquid medium for easier transport and can be used in
> district heating, commercial laundry, industrial process heat, and many
> more. There are even High Temperature (HT) and Very High Temperature (VHT)
> heat pumps capable of moving low-grade data center heat up to 140°C._

Heat Pump:
[https://en.wikipedia.org/wiki/Heat_pump](https://en.wikipedia.org/wiki/Heat_pump)

"Data Centers That Recycle Waste Heat"
[https://www.datacenterknowledge.com/data-centers-that-
recycl...](https://www.datacenterknowledge.com/data-centers-that-recycle-
waste-heat/)

