An outdoor enclosure (L 2.2 m, w 0.75 m & H = 3 m) housing control system hardwa
ID: 2073497 • Letter: A
Question
An outdoor enclosure (L 2.2 m, w 0.75 m & H = 3 m) housing control system hardware and components is to be retrofitted with a cooling system. The customer requires that separate packs of PCBs (w = 0.5 m, L = 0.75 m) be placed in 6 smaller enclosures inside the main enclosure. In order to minimize costs, the customer would prefer not to rearrange the components. However, the customer is open to modifying the outer enclosure to accommodate multiple fans and vents. To begin, you must assess the total heat load, and calculate the required mass flowrate to remove the heat from the enclosure. For the smaller PCBs, you have a choice of several smaller fans whose motors generate 10 W of heat or one larger fan, which has a motor that generates 20 W of heat For the large control panel configuration (L 2 m, H-1 m) at the bottom of the cabinet, the estimated heat generation for its fan motor is about 30 W. Be sure to set the appropriate spacing between the PCBs and control panels as they will impact your design by setting the heat transfer coefficients. Assuming no heat loss to the environment, if the temperature rise of the air is not to exceed 10 degrees C, for both the bundle of control panels and the PCBs in the enclosure. 0 9 Count 6 per/box Q 200W Air Air Exhaust fan Large Control Panel Determine a) The total flow rate that the fans needs to deliver b) The fraction of temperature rise that is due to the heat generated by the fan and its motor c) The highest component surface temperature. d) The highest allowable inlet air temperature if the temperature of the components is not to exceed 70 degrees C. Can this system operate in a region where the average ambient temperature is 120 F? e) For the smaller PCB bundle discuss the design differences and issues concerning single fan vs. multiple fan configurations. f) Can a single fan be used to cool both the large control panels and small PCB bundles simultaneously? Also, explain in detail how you would size a fan/s for this system g) Now consider heat loss to the environment. How does this impact the design?Explanation / Answer
Given that,
Outdoor enclosure , L =2.2 m W = 0.75 m H = 3m
PCB , w = 0.5m L= 0.75m
Largest control panel configuration , L= 2m H = 1m
a) The flow rate of the fans =?
Q = 3.16 x P / ( T1 - T2 )
= 3.16 X 200 / 10
= 63.2
b) The fraction of temperature rise that is due to the heat generated by the fan and its motor:
Temperature rise =?
The temp doesnt increase by 100
if the motor power is 200w then if the motor power is 20 w and if the motor power is 30w
Then the temp will rise 10 times for the 200w comparing to the 20w and 30w power.
The fraction of the rise in temp = 10
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.