Additional air cooling for car

[Gcc1]

Hi, advice for additional ‘air con’ please - so have a slightly modded 2008 BMW 330i tourer which I love (and so far managed to keep despite pressure….🤣). Only thing is the air con isn’t quite strong enough for my 2 dogs which usually travel in the folded rear seats on our frequent 3-hour run to Dorset. Been looking at small desk-top type rechargeable evaporative air coolers as a supplement (and to avoid using the other half’s Nissan’s Qashqai zzzzzz). Anyone has experience to share eg whether it’s even remotely effective? Understand it’s never going to be as good as another air con and just as a supplement. Cheers