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I previously worked on Virtual Reality and other hardware at Valve.  I currently work at Google[x].

Prior to starting at Valve, I built computer peripherals such as keyboards, mice, and joysticks that were designed to be used inside MRI machines.  My company, Mag Design and Engineering, sold these devices directly to researchers at academic institutions who used them to publish scientific papers in peer-reviewed journals.

After work, I spend time on many different types of projects that usually involve circuit design, machining, material selection, and general fabrication/hacking.  My favorite place to be is my home workshop.

ben dot krasnow at gmail




Sunday, April 19, 2009

DIY aquarium chiller is a success

Today was the first warm day of the season here in Sunnyvale, CA. In my living room, the air temperature was close to 90*F

The aquarium temperature was a steady 80*F throughout the day.
The temperature controller claimed to be using only 10-15% of the chiller's capacity, but I think this might be misleading because of the way the system is setup. The chiller (water cooler) has its own thermostat, and attempts to keep its water temperature around 45*F. The fishtank's temperature controller turns a pump on and off that pushes the chilled water through a heat exchanger with the aquarium water. The amount of time that the pump is running is the "percentage of capacity" that I have been listing here and in other posts. I am sure the system has a non-linear response such that the amount of cooling delivered at %100 would not be ten times the cooling delivered at %10. This is because the chiller's water temperature would be rising (making it less effective at cooling the tank) as the pump runs more often. Nonetheless, I think the chiller system has plenty of headroom, and it only rarely gets hotter than 90*F in my house, so I am feeling pretty good about the project.

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