Hey dude.

With regards to your parallel compressor plan, noone has disputed its use for energy efficiency, it can and has been used to great success. What EvoCarlos pointed out was... You said that if one compressor failed then the system could carry on running with reduced efficiency. If you did run your unit in this state, various nasty gack from the burnt out compressor would be pumped through your system, potentially clogging a cap tube or other metering device, which could lead to a dangerous situation pressure wise.

I really and truley hope you build this and that it works well for you as it would open up new avenues for cooling. If it doesnt work, at least you'll have learnt alot in the process.