<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>Have looked in to this a bit more.</div><div>An average compression type car air conditioner takes about 3000W </div><div>of power to run. Cooling with peltiers requires 4x this power to get the</div><div>equivalent effect. So 12000W required to keep up with a car air conditioner!</div><div>Peltiers have a typical maximum difference in temperature from one side</div><div>to the other of 70C, but to run at maximum efficiency it is recommended </div><div>to keep the temperature difference at less than 30C. So this would mean</div><div>a peltier rated 72W should be run at around 30W. </div><div>The efficiency also depends on how well you can remove the heat from</div><div>the hot side, as if it gets too hot the heat build up can migrate across to the </div><div>cold side.</div><div>A 1&1/2 x 1&1/2" peltier may be around 72W (12V & 6 A) & cost US $3:61</div><div>Deal Extreme with free shipping....</div><div><a href="http://m.dx.com/p/tec1-12706-semiconductor-thermoelectric-cooler-peltier-white-157283?stiff=99">http://m.dx.com/p/tec1-12706-semiconductor-thermoelectric-cooler-peltier-white-157283?stiff=99</a></div><div>So to get the same cooling as your car air conditioner you need 166 of these </div><div>& that's running them at full power & not the more economical half power.</div><div> I have read that a peltier air conditioner can drop a cars temperature to 20C</div><div>below ambient, but I don't have any specs on the unit they mention.</div><div> I am going to persevere with them as I am building a small one person sub</div><div>& I like that I can make a dehumidifyer, airconditioner & heater all in one & take</div><div>up little room. As discussed, their heating efficiencies are great, so if you look</div><div>at them as a descent heater with the spin off of some cooling benefit then they</div><div>don't look so bad! Battery technology is leaping forward, so I am anticipating that</div><div>their power drain won't be such a big deal by the time I get around to buying</div><div>batteries.</div><div>Cheers Alan</div><div><br></div><div><br><br><div>Sent from my iPad</div></div></body></html>