Blast Auxiliary Portable AC How Does the Blast Auxiliary Portable AC Work? The Blast Auxiliary Portable AC needs only a rechargeable and small lithium battery in order to start. This battery is included in the package together with an USB cable for charging. The battery of this device should be recharged when empty so that it has a longer life. The principle on which the Blast Auxiliary Portable AC functions is the one of thermoelectric cooling, which makes any surroundings cooler. This air conditioning gadget uses DC electric current on a side of its plate and AC current on the other. The side that’s supposed to get heated remains at the room’s temperature, whereas the AC one gets cooler and goes way below the outside temperature. While the air travels through the vent, this effect cools and sends it into the room.