conservation of energy in Computer Rooms

Status
Not open for further replies.
mshields

mshields

Senior Member
Location
Boston, MA
or for that matter in any kind of a room.

I sat through a seminar the other day in which the CRAC unit vendor stated that the amount of electrical energy going into the room in KW is equivalent to the amount of heat that needs to be removed from the room in BTU's (or however you measure it).

I would have thought that the heat generated is associated with the efficiency of the equipment. i.e. if the equipment is 80% efficient then 20 of power going to the unit is converted to heat. The other 80% is used and performs work.

Which is true?

thanks,

Mike
 
Mike,
Electrical efficiency of a server is useful power output divided by the total electrical power consumed. I believe that although the IT guys will not agree, a server has an efficiency pretty close to 0, meaning that it offers no useful power. ;)
The heat output in Watts from the server is essentially the same as electrical power input in Watts.
 
ron said:
Mike,
Electrical efficiency of a server is useful power output divided by the total electrical power consumed. I believe that although the IT guys will not agree, a server has an efficiency pretty close to 0, meaning that it offers no useful power. ;)
The heat output in Watts from the server is essentially the same as electrical power input in Watts.
Click to expand...
Agree 100%. Here is an example of simular equipment. A fiber carrier say an OC-48, the thing that transports all them 1's and 0's consumers about 500 watts. The lazer output on the transmitter is 0 Dbmw or 1 milli-watt.

It is no different than you computer. It consumes 100 to 400 watts at any given moment, but the output power to say your CRT, VDU, or ethernet port is about 1 milli-watt. The output power is meaningless and can be ignored.

Hope that helps.
 
There are some here that will argue that something like a computer server is not even Utilization Equipment (Art. 100 Definition).
ron said:
a server has an efficiency pretty close to 0 . . .
Click to expand...
Now, back in the early '70s I used to do heat lose calculations on dwellings that were applying for a reduced electric rate from the utility. My employer was the utility and I was to lay out the calcs in a way that made electric heat look good. But that is another story.

What I got out of that is that the computer server, to me, looks 100% efficient as an electric heater.

Gosh, then it must be Utilization Equipment. :rolleyes:
 
I kind of thought I'd be all wet on this one

I kind of thought I'd be all wet on this one

now if you're feeing a motor and therefore converting to mechanical power, can I safely assume that is another matter?
 
090501-1341 EST

mshields:

Your post #5 on the electric motor. It depends.

If the motor drives the spindle of a machine cutting metal, and the part cut with all chips are left in the building until they reach ambient temperature, then all energy that went into the motor is dissipated into the building.

If the motor drives a generator and the output wires go to a different building, then only some of the input energy to the motor is dissipated in the building containing the motor.

.
 
gar said:
090501-1341 EST

mshields:

Your post #5 on the electric motor. It depends.

If the motor drives the spindle of a machine cutting metal, and the part cut with all chips are left in the building until they reach ambient temperature, then all energy that went into the motor is dissipated into the building.

If the motor drives a generator and the output wires go to a different building, then only some of the input energy to the motor is dissipated in the building containing the motor.

.
Click to expand...


But a motor could also lift weights up onto a platform in the same room. Then not all the input power is converted to heat, and you have more input power than heat output.
 
This is really a thermodynamics discussion. Energy goes into a system. What are the boundaries of the system, and is it closed or open?

The energy into a box may go in as electricity with a little heat loss from the conductors inside the box, change to magnetism with some heat loss, change to motion with some heat loss, change to heat in the work of cutting, and then stay as heat if the box is closed around the tailings and the work piece (or be stored as potential energy as in the lift example Steve posted).

Now if the box is only big enough to surround the motor, but not the cutting blades, the heat inside the box is the energy "lost" as it goes in as electricity and leaves on the rotating shaft.
 
ELA said:
That was an interesting question that I had not really given much thought to before.
The computers help relieve the heating system burdon in winter right?

http://www.techradar.com/news/computing/idle-computers-don-t-waste-energy-588095
Click to expand...

If we are strictly talking about data centers, the HVAC system is generally always ran in the cooling mode, even when its -10 deg. outside. If heating systems are even provided, they wouldn't run unless almost all the computer equipment shut down.
 
Efficiency can be a relative term. It was stated that the efficiency of servers is near zero. Not if you consider them as a heaters.

My other implied point was that if computer centers were designed to be energy efficient perhaps the building heating burden could be lowered in winter at the same time the cooling requirement was lessened.
 
Think about the mars rover. The electronics inside keep itself from freezing. The electronic keep the inside at 80 degrees so the heat is needed and wanted. Perfectly efficient. They tested this theory in the artic buy putting electronics in side a canvas ball and rolling it across the Artic. The electronics kept the inside of the ball cozy warm despite the sub zero temps outside. The discovery channel had a show on this.
 
Status
Not open for further replies.
Top