Thermal / Mechanical Energy

[rk27]

I need to know if the following is a valid train of thought. Current philosophy states that in a data center each watt of electricity is converted to a watt of heat. You then use this for load calulations. I have noticed that with the Hitachi Tagmastore there are a lot of hard drives. These drives spin at a high rate. It currently consumes aout 10 kW.

What I need to know is if the power consumption should still be considered a thermal load or should it be derated because the energy is being used for mechanical work?

Thank you in advance for your input.

 

[CESSNA1]

RK27: As long as the entire system is in the environment being cooled, then the total heat load (ie 10 KW) is used. If, for example (and this is a stretch), the drive motor and electonics are in another space than the power they consume/dissippate would not be included in the space under consideration; only the power in the disc drive would be used in the calculation.

Hope this helps
Regards
Dave

http://www.wsec1.com

 

[IRstuff]

The speed of the drive is irrelevant; that only reflects the energy required to get it to speed. The frictional loss in the bearings and inductive losses in the motors and other efficiencies are what generate the heat once the drives reach their correct spin speed.

Since they consume 10 kW, that's essentially all real power.

TTFN