Patent attributes
A carbon dioxide vapor compression system including a compressor, a first heat exchanger, an expansion device arrangement, and a second heat exchanger connected in a closed loop. The expansion device arrangement includes an inlet line disposed between the first heat exchanger and the expansion devices and an outlet line disposed between the expansion devices and the second heat exchanger. The expansion device arrangement includes at least three expansion devices with a fixed and variable expansion device being in parallel arrangement and another fixed expansion device being arranged in series with the parallel fixed and variable expansion devices. The expansion device arrangement may also include a flow path that extends from the inlet line to the outlet line and which includes only fixed expansion devices to provide a functional flow path through the expansion device arrangement if the variable expansion device fails.
