A system includes a primary heat exchanger with a first passage connected to a hot fluid source, a second passage connected to the first passage, and a third passage connected to the second passage and an outlet line. A compressor inlet is connected to the outlet line. A secondary heat exchanger is connected to a compressor outlet. First and second turbines are connected to an outlet of the secondary heat exchanger. A first load heat exchanger is connected to the first turbine. A second load heat exchanger is between the second turbine and a system outlet. A first valve connects the hot fluid source to the second and third passages. A second valve connects the first and second passages with the outlet line. A third valve is between the secondary heat exchanger and the second turbine. A fourth valve is between the first load heat exchanger and the system outlet.