COOLING OF ELECTRONIC EQUIPMENT

Problems of cooling of electronic equipment:

The causes of printed circuit board failure can generally be linked to two factors

1)Performance problems from environmental stresses
2)performance problems from manufacturing problems

The environmental problem :
1)Occur when printed circuit board is exposed to element or situation affect its performance .
2)Problems will occur usually due to variable like temperature rise.

   High environmental temperatures found on some manufacturing floors will degrade electronic            components.

SO,WE ALREADY FIND THE SOLUTION TO OVERCOME ALL THESE PROBLEMS :) :)

    

   ABSTRACT

Electronic devices generate heat due to current flow through them . High rate of generation result in high operating temperature which leads to device failures . Failures rate of electronic equipment increases exponentially with temperature. Thermal control is important in electronic equipment design as major failures are caused by high thermal stress in the joints of electronic component mounted on circuit board.

WHAT IS PRINTED CIRCUIT BOARD(PCB).

Properly wired plane board made of polymers and glass–epoxy materials on which various electronic components .The PCBs are plane boards, usually 10 cm wide and 15 cm long and only a few millimeters thick, and they are not suitable for heavy components such as transformers. In the thermal design of a PCB, it is important to pay particular attention to the components that are not tolerant of high temperatures, such as certain high-performance capacitors, and to ensure their safe operation.

•A typical electronic system involves layers of PCB .Each PCB has its mot (maximum operating temperature). When circuit is subjected beyond this mot, then risks occurs in the damage of PCB
If one component fails due to high operating temperature, te whole board fails and need to be replace.

The maximum operating temperature for PCB is in between 0- 60 C
we operate the laptop to discover and investigate the arrangement of electronic component for PCB in laptop. This is the video that show we operate the laptop and study about the cooling system in laptop

This is the link of the video  https://www.youtube.com/watch?v=ObhFuMifv8s&feature=youtu.be

WHAT ARE THE SOLUTION?????????

•Method of cooling
i) Using heat frames
ii) Forced convection


     Cooling using heat frames

Cold plate which is a thicker copper plate is used to pass the heat to cooling devices. 

Heat generated first passes through the PCB and then epoxy adhesive and then to heat frame. 

Heat frames provides a low resistance path from PCB to heat sink. The thicker the heat frame , the lower the resistance to heat flow .If heat sources are evenly distributed , temperature variation will be symmetric as the arrows in the figure . 

   Forced convection.

•Simplest system of forced convection is arranging the PCB’s in and airtight enclosure.
A fan is used to force air through the PCB’s . Radiation transfer in these cases will be smaller due to the PCB’s facing each other nearly at the same temperature.

  

  The heat flow can be calculated

The other route for heat flow calculation is the use of convection coefficient 

This is the link our presentation video  https://www.youtube.com/watch?v=dWe06glK8Ts

RECOMMENDATION.

CONCLUSION

Heat transfer along a PCB is complicated in nature because of multidimensional effects and non-uniform heat generation on the surfaces.We can still obtain sufficiently accurate results by thermal resistance network in one or more dimensions.Copper or aluminium cladding, heat frames, or cores are commonly used to enhance heat conduction along the PCBs.The thickness of the copper cladding on the PCB is usually expressed in terms of ounces of copper, which is the thickness of 1-ft2 copper sheet made of one ounce of copper.


REFFERENCES

1.  Retrieved from http://highered.mheducation.com/sites/dl/free/0073398187/835451/Chapter15.pdf
2.  Retrieved from http://www.newagepublishers.com/samplechapter/001151.pdf.