On 18 Dec 2019, at 15:57, Rod Beck <rod.beck@unitedcablecompany.com> wrote:

Energy efficiency is a hobby of mine and most of my properties embody Passive House Technology. This led me to wonder what is the inefficiency of these servers in data centers. Every time I am in a data center I am impressed by how much heat comes off these semiconductor chips. Looks to me may be 60% of the electricity ends up as heat.

Less than a 100.000th of the energy in a data center is used to run the applications in a datacenter as summarised in this graph: The full talk by Amory Lovins of the Rocky Mountain View: https://youtu.be/wY_js13AuRk?t=1343 <https://youtu.be/wY_js13AuRk?t=1343> My research group has come up with supporting evidence for these claims. Our Wafer Scale Integration and new operating system software can actually achieve these savings. Merik Voswinkel Metamorph research institute

On 2019-12-18 15:57, Rod Beck wrote:

This led me to wonder what is the inefficiency of these servers in data> centers. Every time I am in a data center I am impressed by how much> heat comes off these semiconductor chips. Looks to me may be 60% of the> electricity ends up as heat. What are you expecting the remaining 40% of the electricity ends up as?

In reality, at least 99% of the electricity input to a datacenter ends up as heat within the DC. The remaining <1% turns into things like: - electricity and light leaving the DC in network cables (but will turn into heat in the cable and at the receiving end) - sound energy (noise) that escapes the DC building (but will turn into heat later on as the sound attenuates) - electric and magnetic potential energy in the form of stored bits on flash memory, hard disks and tapes (but that will turn into heat as you store new bits over the old bits) (I'm saying <1%, but I'm actually expecting it to be *much* less than one percent.) This is basic physics. First law of thermodynamics: you can't destroy (or create) energy, just convert it. Second law: all energy turns into heat energy in the end. :-) You are really asking the wrong question. Efficiency is not measured in how little of the input energy is turned into heat, but in how much *utility* you get out of a certain amount of input energy. In case of a datacenter, utility might be measured in number of database transac- tions performed, floating point operations executed, scientific articles published in Nature (by academic researchers using your HPC datacenter), or advertisments pushed to the users of your search engine. There is another efficiency number that many datacenters look at, which is PUE, Power Usage Effectiveness. That is a measure of the total energy used by the DC compared to the energy used for "IT load". The differece being in cooling/ventilation, UPS:es, lighting, and similar stuff. However, there are several deficiencies with this metric, for example: - IT load is just watts (or joules) pushed into your servers, and does not account for if you are using old, inefficient Cray 1 machines or modern AMD EPYC / Intel Skylake PCs. - Replace fans in servers with larger, more efficient fans in the rack doors, and the IT load decreases while the DC "losses" increase, leading to higher (worse) PUE, even though you might have lowered your total energy usage. - Get your cooling water as district cooling instead of running your own chillers, and you are no longer using electricity for the chillers, improving your PUE. There are still chillers run, using energy, but that energy does not show up on your DC's electricity bill... This doesn't mean that the PUE value is *entirely* worthless. It did help in putting efficiency into focus. There used to be datacenters that had PUE numbers close to, or even over, 2.0, due to having horribly inefficient cooling systems, UPS:es and so on. But once you get down to the 1.2-1.3 range or below, you really need to look at the details of *how* the DC achieved the PUE number; a single number doesn't capture the nuances. /Bellman

The laws of thermodynamics dictate that near 100% of the electricity consumed by a piece of equipment (let's use a high powered 2RU size router as an example) comes off as heat. Unless it's doing mechanical physical work like lifting a load or spinning a fan. Some infinitesimal portion leaves as photons down the fiber. On Wed, Dec 18, 2019 at 6:58 AM Rod Beck <rod.beck@unitedcablecompany.com> wrote:

Energy efficiency is a hobby of mine and most of my properties embody Passive House Technology. This led me to wonder what is the inefficiency of these servers in data centers. Every time I am in a data center I am impressed by how much heat comes off these semiconductor chips. Looks to me may be 60% of the electricity ends up as heat.

Regards,

Roderick.

Roderick Beck VP of Business Development

United Cable Company

www.unitedcablecompany.com

New York City & Budapest

rod.beck@unitedcablecompany.com

36-70-605-5144

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