I was under the assumption that DC devices pulled amps, so your peltier will pull as much as it can given the voltage it is running. That 172W pelt is rated at 11.3A@24V, so you'll only get in trouble when you start powering it with more voltage, not more amperage. Anyways, what CPU are you cooling? AMD/Intel? They do make pelts with lower wattages that won't cool as well as a 172/226, but run on less AMPs, which will lower your PSU bill. 182 is a bit much for a PSU, especially since it's 24V, and therefore only good for running your Pelt.
If you have to have 40mm, then 131W is your best alternative, but I'm afraid that you'll be wanting something more.
www.tetech.com is a good place to go and look for pelts. DangerDen actually gets theirs from there anyways. Oh, well, hope I haven't completely crapped your day.