Find out the model number and the max kw heating it applies then match the chiller with at least the same cooling power. If it heats 4kw you want at least 4kw chilling power. If you upsize some you can blast the roto hotter and faster and the chiller will keep up which will essentially speed up recovery
Chiller capacity is often listed at a couple of temps. The colder you ask them to go, the less cooling power they can provide. asking your rotovap chiller to hold -40C, and running denatured alcohol in it might seem like the right approach, but running water at 4C as your coolant might give you the same thoughput from a less expensive chiller because of the heat capacity difference between water and alcohol.
you can also get models designed to go outside. the advantage being they also dump the heat outside, which is more convenient than into your lab, and as it’s outside, the fire marshal isn’t going to ask if it’s UL listed or explosion proof.
edit: note the “might”. the logic is sound. I haven’t actually bothered with the specific math yet. I probably will if someone doesn’t beat me to it.
4.2J/g.oC vs 2.6J/g.oC & 1g/ml vs 0.8g/ml => -40C vs 4C is probably wrong, but using water as your heat transfer fluid whenever possible is sound…and 4C should be plenty cold for your rotovap
We had to replace this about 6 months ago, luckly we had a spare on the shelf.
The refrigeration unit of the chiller is pretty durable. Worst case scenerio you have a hvac guy look it over. We have a guy here that will service cascade systems as well.