Hydrogel Coated Heatsinks Significantly Boost Passive CPU Cooling Capabilities
Papers shared on cell report physical science suggests that coating the heatsink with hydrogel provides a ‘significant’ benefit for passive cooling. This paper focuses on testing hydrogel-based moisture thermal batteries (MTB) for passive thermal management of electronic devices such as 100W FETs and 84W Intel Core i5-4690 CPUs. The test results are encouraging, with MTB the electronic components operate about 15°C cooler than with a heatsink alone. Naturally, caveats apply.
In a foreword to a research discussion, scientists from the University of California stated that cooling electronics is a necessary but expensive business, with the main costs being the use of energy and water, and the environmental impact of using those resources. It’s a reminder… Improving passive cooling can be a big boon in reducing this kind of overhead.
A hydrogel coating cools down in the same way animals sweat. Scientists explain that when the electronics are under load, the hydrogel releases water that evaporates and creates a cooling effect. When the electronics are idle, the hydrogel can recharge with moisture and be ready for the next workload.
From this description, you can see that hydrogel cooling is ideal for applications with cyclical workloads. Scientists give examples of his 5G cell towers and data centers where the cycle from high load to low load is his 12 hours.
The tests were completed with the aforementioned 100W FET and 84W Intel CPU, and in both cases the cooling performance of the MTB was “significantly higher than previously reported passive cooling methods”. RH) was performed at 70%. A delta of 15°C seems like a very worthwhile improvement. Humidity helps recharge his MTB during applied heat loads. It is therefore particularly effective in tropical regions such as Florida, Hong Kong, Singapore and Taiwan, where relative humidity can reach 80-90%.
When a MTB alone isn’t enough, it can be combined with heat pipes, vapor chambers or liquid circulation loops for a hybrid solution. However, there are ways to tailor his MTB for specific use cases. For example, MTBs respond positively to having larger surface areas and thinner hydrogel coatings as design constraints permit. Another thing in favor of MTB is that scientists claim it’s a scalable solution at a relatively low price of $12 per bike.
The scientist concludes that the ideal applications for MTBs are in “5G chips, power batteries, servers/data centers, thermal management of optoelectronics.” The use of devices that follow the ideal cyclical nature required for his MTB water recharge from humidity may be compatible with the use of devices such as HTPCs. But this is obviously still in the testing phase.
I wanted to see a graph showing what happens when the workload doesn’t run along a smooth cycle and the hydrogel can’t recharge. It would also be interesting to check the results with power consumption. Will the hydrogels no longer provide a temperature difference of 15°C or will they decompose under long sustained heat loads? It’s a challenge.