A vehicle air conditioner has an air conditioning unit and an air conditioning control unit. The method includes: a client adding a chat robot in an IM group satisfying a configured condition; the chat robot automatically obtaining a message and publishing the message in the IM group. The receptacle includes an inner receptacle member and one or more walls extending around the receptacle member, with spaces between adjacent walls being established at descending pressure values outward from the inner receptacle, which is held at a high pressure.