First a sonic ice cream cooler was invented... now sound waves can be used to to cool a car's interior. The technology for using sound enable heat transfer to cool an enclosed space has already been developed, (Ben & Jerry's Cooler) but now research is being carried out to re-use automotive exhaust gas to produce acoustic waves which then in turn powers the car's air conditioning. The concept is based on basic physical principles involving refrigeration, but expanding those principles to sound pressure rather than state changes in matter. Really "cool" technology, don't you think?