In South Carolina, in the summer, the daytime temperature can get very hot and this can linger well into the nighttime hours, cooling off very slowly. My SBIG cameras struggle to get to -15C on warm nights and sometimes don't make it. This means I have to take yet another set of dark and bias frames and add them to my master library. Keeping the camera temperature at a single setpoint really simplifies data acquisition and master library frames. Since I standardize on -25C for all my late fall, winter, and early spring exposures, it would be nice to keep that setpoint year round. About the only way to reach that setpoint in the summer is to use water cooling. This can get you an extra 8-10 degrees cooling, but usually I need more to reach my -25C target. Colder water is the next logical step, but the camera heat transferring to your water cooling warms the water and reduces the cooling available to the camera. When I was cooling with a 5 gallon bucket and plenty of ice, I could reach the -20C, but that was it. When you cool with ice, you have to buy it and add it, and do this all over again the next imaging night and every night you want to image. Solution .... a water chiller that replaces the ice :-))) and maintains the water at a temperature low enough to allow me to reach my setpoint in a closed system.
This system is an adaptation from the chiller system built by Joe Mize found here : Water Cooling System
With the system being a "closed" system, I no longer need to haul water or ice out to the observatory. The pumps and the chiller are connected to two outlets on my Web Power switch. This lets me cut either the pumps on without the chiller or with it. I chose the standard model Chiller as its specs said it could drop an 80 gallon tank by 10 degrees F. With only 4 gallons of water in my entire system, it can cool the water to 50F even when the outside temp is 86F. My initial testing shows that I can get the camera to a lower temp by turning off the fan since this is just moving hotter air across the heat sink in the camera. All my STL cameras have the 3 heaters for the front camera window installed and they are running whenever the cameras are powered up. Since having them installed by SBIG, I have never experienced a damp camera window even on nights when I run in 90+% humidity. The main three components were purchased from BE Cooling and a Grand total spent on this project : Chiller $350.00, ViaAqua filter $65.00, MaxiJet Reservoir $49.99, Insulation $20.00....... Total invested = $484.99 not bad to be able to cool to -25C in the dead of the summer !!!!!!!