Where Will Your Product End Up Being Used?
When starting a new application, it’s critical that you determine what the environmental conditions range your end device will live in. Your environmental conditions will affect how easily your product might get to your maximum case temperature. Or maybe your user is in contact with your device and you need to design a safe touch temperature.
In many cases, the application is clear on what temperature range your device may be subject to. It may only require simple lab conditions (23-25°C at sea level) to perform well. Other times the application may live in extremes, which will drastically influence the end user’s experience with your product.
Most of the time you, the thermal designer, don’t have the capacity to control what the end user will do. Just think of how you treat your poor smartphone all day; You use it constantly so you generate heat and drain the battery. Then, you shove it back in your pocket next to your own body heat and no airflow to help cool it down. While your product may not have such high demands as your smartphone, the environmental conditions your device will experience is critical to the overall performance and longevity of your end product.
After you have taken a moment to consider what temperature and altitude you expect, you might find that you have a large range of conditions.
Altitude: Ain’t No Mountain High Enough
Altitude is fairly simple to tackle. Most consumer applications will be at sea level. We find that most aerospace and military devices need to withstand higher atmosphere conditions. Maybe if you design equipment for extreme hikers, that may be another time where altitude is an important parameter to consider.
Thermal Range: Hot, Hot, Hot! Or Cold?
Temperature is a bit more tricky to consider, since you may have an upper and lower limit. We’ve seen applications that need to survive from high temperature environments around 100°C, outside in the hot desert at 41°C. and other applications that need to function at -40°C.
Then the next key is to determine what temperature to use in your simulation. We recommend using the highest temperature in your range first. If the simulations determine your heat sink cannot perform well enough in this case, then the heat sink is inadequate for your application.
Trying Out Your Environmental Conditions Range
For more assurance and a better idea of how your heat sink will behave over the environmental temperature range, we recommend 2 other cases. One case should be at room temperature at sea level and another should be at your lowest temperature and highest altitude. Most users will probably be at the former condition and running this case will give you a good idea of what most of your end users should expect. Running the latter case can help give you an indicator of the other extreme your system will experience.
If your system meets your thermals at all three of these cases, it looks like your solution will work well for the environmental conditions range.
What was the hottest application you needed to design for? What was the coldest? Email us as firstname.lastname@example.org!