[glend (Glen)]

It took awhile to assemble everything, but I managed to get a bench test done today. Started by flushing the radiator with vinegar, because I found some advice online that these small radiators for liquid coolers sometime had manufacturing burrs and rosin inside, and the vinegar is suppose to desolve the rosin, well it must have worked because when I tipped it out it was blue grey. I brought the camera temperature controller in from the observatory and setup all the power connections for the pump (wires everywhere), stuck a small blower fan on aimed at the pump heatsink, and the installed the radiator fan (just reused the old heatsink fan for now). Filled the system with a concentrated anti-scale, biocide, etc fluid mixed with demineralised water.

Test #1. After filling the system and checking for leaks (there were none). I checked the hose vibration at the camera and there was nothing. I started the first test. The ambient room temperature was 25.4C when I started. Turning on the camera controller the temperature started at 25.4C and rapidly (within one minute) dived to single digits. The Set Point was at 1C so I reset it to -10C to see how low it would go. Within a few minutes it dropped below 0C and after about five minutes it got down to -8.0C, which means a Delta T of -33.4C! This is the best result I have achieved with this Jaycar TEC (52 W, 6amp). The previous low temp benchmark on this mono camera was a Delta T of -27C, with a insultated cold finger and it took much longer to achieve that.
I should add that there was no insulation on the cold finger, nor argon bag for this test, and you can see the frost layer in the photos below. So I believe I maybe able to get it to a Delta T of -35C with the cold finger insulated as I normally have it for imaging. The system I have is designed to shed more than 200W of heat, and going by Rowland's 2X rule it should be capable of cooling more powerful TECs, or two stage TEC, if I wanted to go there.

I have attached some photos taken during the test. Fairly pleased with the result. I need to install the larger 120mm fan for the radiator (that's the size its designed for), and install the pump and radiator in the stand I am making for it in the observatory. There is plenty of hose length for my rear camera mount RC but I will need to check on the hose route for the newt. Adding more hose will not affect performance as the head pressure of the pump is over 5m. You will notice in the photos of the camera that it has a much smaller out-hanging cooling arm, and the weight seems a little less than with the heatpipe sink and fan.

Next test will probably be an imaging test.