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Re: BTU removal

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Posted ByWilliam on October 25, 2002 at 12:11:28:

In Reply to: BTU removal posted byJames Partain on October 23, 2002 at 15:14:30:

: If I have ambient air temperature of 80°F, 80 percent relative humidity and I want to maintain a maximum of 105°F in an enclosure while removing 1783019 BTU's per hour produced by an electric motor, how many CFM's do I need? Enclosure is 3,032 cubic feet ID.

: James Partain

Randy & James; See the following,

Using your numbers, to maintain a 25 degree rise (105-80=25) in temperature the fan would be very very large.

You are neglecting the heat BTU's that is transmitted into the load as brake horsepower (bhp). For instance, if the motor is driving a water pump that requires (at peak) 650 bhp
Then all of the motor heat (650hp doing work) is transmitted into the water.
The heat given off into your room is motor inefficiencies, extra hp (50hp) not used. But its way less than 1783019 BTUH.

William

Edited by EE, Feb 25

Follow Ups

Re: Re: BTU removal Natalie 17:05:35 02/24/03 (0)

Subject: Re: Re: BTU removal

Comments:: : If I have ambient air temperature of 80°F, 80 percent relative humidity and I want to maintain a maximum of 105°F in an enclosure while removing 1783019 BTU's per hour produced by an electric motor, how many CFM's do I need? Enclosure is 3,032 cubic feet ID. : : James Partain : Randy & James; : Using your numbers, to maintain a 25 degree rise (105-80=25) in temperature the fan would be very very large. : You are neglecting the heat BTU's that is transmitted into the load as brake horsepower (bhp). For instance, if the motor is driving a water pump that requires (at peak) 650 bhp : Then all of the motor heat (650hp doing work) is transmitted into the water. : The heat given off into your room is motor inefficiencies, extra hp (50hp) not used. But its way less than 1783019 BTUH. : William

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