Open air-cycle ventilating heat pump

A climate-control system comprising:

• a first turbomachine fluidly connected with a source of outdoor air and operable in a compressor mode and in an expander mode, wherein the first turbomachine is configured to compress air in the compressor mode and expand air in the expander mode;
• a second turbomachine operable in a compressor mode and in an expander mode, wherein the second turbomachine is configured to compress air in the compressor mode and expand air in the expander mode;
• a first heat exchanger fluidly connected to the first turbomachine and receiving air from the first turbomachine in the compressor mode and in the expander mode;
• a second heat exchanger fluidly connected to the first heat exchanger and the second turbomachine, wherein the second heat exchanger receives air from the first heat exchanger, and wherein the second heat exchanger provides air to the second turbomachine in the compressor mode and in the expander mode;
• and
• one or more fans that force air from the source of outdoor air across an exterior of the first heat exchanger and force indoor return air across an exterior of the second heat exchanger, wherein the air flowing across the exterior of the first heat exchanger is fluidly isolated from air flowing inside of the first heat exchanger, and wherein the return air flowing across the exterior of the second heat exchanger is fluidly isolated from air flowing inside of the second heat exchanger.