The power supply should not really be a problem. The connections on the 960 in the Akoya are the same and the power consumption of the 1060, which is sold as particularly efficient, is very moderate.
It's hard to say about the space (if you don't have a Medion Akoya), because the dimensions are somewhat different depending on the cooler/manufacturer. If you already have the Medion, it's best to measure it yourself and then compare it with the information here.
Basically, the dimensions of the 1060 will be similar to the 960 already installed.