You are probably correct in thinking that the 「内外」refers to inside and outside equipment of an air conditioner. The control unit (i.e., thermostat) of the air conditioner needs to communicate with both the outside and inside devices and usually this communication is hardwired with electrical cables. However, this new air conditioner uses Bluetooth or some other method to enable wireless communication, therefore this new system is now wireless. So, the phrase in question can be simplified to say "the development of wireless cooling controls for the New iVRV" or something like that.