Heat Rejection
Heat Rejection
(OP)
Hi,
I am trying to do heat rejection calculations for a few buildings on an ethanol plant that is being started up. I am supposed to just take the light and motor starters into account to calculate the heat rejection. Is there a standard for this and where can I find it? I was told to look through IEEE 141 and could not find anything on this.
Doug
I am trying to do heat rejection calculations for a few buildings on an ethanol plant that is being started up. I am supposed to just take the light and motor starters into account to calculate the heat rejection. Is there a standard for this and where can I find it? I was told to look through IEEE 141 and could not find anything on this.
Doug





RE: Heat Rejection
As far as indoor lighting - every watt will end up as heat.
For motor starters, I know I posted this information here within the last couple of years. Or see MCC technical data from major vendors.
For motors, start with basic motor efficiency to determine heat rejected directly by the motor. Then add in pump/fan losses, then piping heat/friction losses.
What is the purpose of the calculation, exactly?
RE: Heat Rejection
I have been digging through these forums and from what I have found it seems like people just assume that 10% of the power the motor consumes turns into heat. Is this how it is usually calculated?
RE: Heat Rejection
Link above is to an old thread with some typical data.
10% loss in a motor is a reasonable,conservative approximation for what you are doing, but my point was that there are many other sources of heat loss in addition to motors.
RE: Heat Rejection
If the liquid stays in the building 100 % of the pumps
energy input stays there, too.
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