COOLING by passive water evaporation is a well-known concept in India. Villagers, in remote places, have long used passive water-evaporation systems to keep liquids cold. The summer season in India is always very hot and very dry. Hot, dry winds blow across the plains for months on end. In the absence of electricity, storing drinking water in earthen pitchers is a great idea. A little of the water evaporates from the surface of the pitcher and cools it by ten to fifteen degrees.
Inspired by this, I was looking for ways to cool my laptop this summer. Laptops do not operate well at room temperature in the hot noon of the Indian summer. My last computer’s motherboard fried itself last year, trying to operate at 47 degrees C room temperature. The delicate and compact electronics do not lend themselves to efficient airflow and cooling.
Buying an air-conditioner is the easy way out. An air-conditioner would not only eliminate the heat issues of the laptop, it would probably eliminate all the dust issues as well. However, the cost of operation and acquisition of an air-conditioner was just too high. Furthermore, the peak summer season lasts for about 3 months of the year. Any cooling solution would be useless for the rest of the year. After giving it some thought, I had to drop the idea of acquiring an air-conditioner.
Looking for cheaper alternatives, I came across a whitepaper on Google’s data centers. They have patented their method of cooling motherboards using water. Instead of a simple heat sink near the hot components, they connect cold water pipes to the heat sink. Using water is far more efficient than cold air to cool down the components. Of course, using water to cool computers is not a new concept. Cray supercomputers have used water-cooling for a long time.
A desktop computer can employ a similar cooling mechanism. There are two alternatives here: either connect cold water pipes to the desktop’s electronics or immerse the desktop in a cold-water container.
Connecting pipes to the desktop’s heat generating components would require a water pump. An extra water pump would generate heat and consume electricity. It would also be noisy and would occupy more space. There would be more points of failure due to more moving parts.
An immersion type desktop container would solve the heat problem using passive cooling. To achieve this, the desktop is placed in a double walled metal container. The inner container contains the motherboard and all the heat generating electronics in the usual configuration. The space between the inner and outer walls is then filled with water. The water well is open to the atmosphere and cools down by evaporation. Of course, such a system would not work efficiently when there is high humidity in the air. For such scenarios, the air-cooling would probably suffice.
The above options would not need a lot of investment from a home user. Custom aluminum containers are not very expensive to make. Your friendly neighborhood welder would probably be able to cut and build it for you. The alternative is to use household cooking utensils. The inner container could probably be a large aluminum utensil and the outer container could even be a plastic tub.
Aluminium is written as Aluminum in the US.
The last alternative is to cool the air in the room using passive evaporation. A ceiling fan will greatly accelerate the evaporation process. A cool room will lead to a comfortable user and cooler electronics. Even five degrees of reduction in temperature goes a long way when the shade temperature is at 48 degrees Celsius. It could mean the difference between a working computer and a blown motherboard.