Why would you want to use LN2 for electronics testing?
In three words: Speed, Capacity, Reliability.
LN2 hands down achieve those goals not to mention that purchase price and overall operating cost are lower in most cases.
LN2 cooled systems easily allow the test equipment to get the parts to temperature quickly saving much money in shortened test times, tech time, and maintenance time as well. They have very simple designs, low maintenance costs, require less lab space, produce less noise and present less load on building HVAC systems.
To some people, LN2 seems exotic, dangerous, and expensive. It is no more any of that than electrical power was in the early days of electrical distribution. Indeed 80% of the air we breathe is Nitrogen so it is not toxic.
The purchase price and maintenance cost are considerably lower.
Speed of cooling translates to faster testing and more completed units per day.
Traditional refrigeration systems are limited to -40°C for useful amounts of heat removal. Very specialized and often troublesome systems are required to remove heat below -40°C.
Very large and expensive refrigeration systems are required for cooling massive or active loads or when speed is needed.
These larger compressor systems use very much power and typically dump the heat into the lab where heating and air conditioning systems must again use more power to remove the heat from the building.
Issues that can be a negative factor in the choice to use Liquid Nitrogen as a coolant are listed here:
Installation of an outdoor tank and distribution system for maximum cost-benefit is very expensive but a good investment for long-term planning. LN2, especially in bulk quantities is fairly cheap when compared with the maintenance and running costs of refrigeration systems during peak utility rates.
Designing a system with an outdoor tank requires a fair amount of planning including future needs and knowledge of overall maximum requirements.
If you aren’t ready to buy an outdoor tank with inside distribution lines, portable tanks are a good choice but it can be considered troublesome to make sure tanks are always kept full enough to complete needed testing and pressure and tank level is always manually/automatically maintained.
Liquid Nitrogen is extremely cold. This is good news and bad news. The bad news part of that is there will always be more losses when trying to insulate plumbing, valves, and fittings due to the large temperature difference. It doesn’t keep indefinitely in storage without some notable loss. Caution must also be used whenever making or removing tank connections such as when changing portable tanks.
In summary, there will likely always be a need for refrigerated temperature test equipment. The simplicity of a self-contained temperature chamber or thermal platform that can be plugged into any laboratory power outlet is balanced against requirements of scalability, speed, capacity, and big picture costs of Liquid Nitrogen v. electricity plus maintenance.