Abstract: The invention is directed to a system and process operating on an air-standard cycle either to cool or heat a room. The system may be advantageously employed to cool or heat relatively small areas or rooms, particularly driver's cabins in locomotives and the like. In cooling operation, outside air is expanded in a turbine, cooled below ambient, and introducted into a heat exchanger. Air from the room to be cooled is introduced into the heat exchanger and heat is removed therefrom. Suitable valves are provided to change the operation of the heat exchanger to that of a regenerator and to direct the flow of air accordingly. Specifically, air heated by compression in the compressor is directly introduced into the room and air leaving the room is passed through the regenerator/heat exchanger and released into the atmosphere.

Abstract: A process and apparatus for regulating the quantity of fresh air in high-speed trains by means of pressure-wave valves. A signal for adjusting a drive unit is determined from the passenger count and outside temperature. This drive unit causes a stop fork to move into a flap stop position of the valve in the "open" operating mode so that the required amount of fresh air can be supplied. The process according to the invention results in a considerable saving on energy, since only the absolutely necessary amount of fresh air need be heated or cooled and the period of time in which ventilation can be used rather than cooling is lengthened.