Hardware Development And Initial Subassembly Tests Of A Gas-fired Stirling Engine/refrigerant Compressor Assembly

A gas-fired Stirling/Rankine heat pump is being developed at Sunpower. Inc. The free-piston Stirling engine/magnetic coupling/refrigerant compressor (FPSE/ MC/C) assembly used as the power module for this type of heat pump is currently in the test phase. To achieve high efficiency, low cost, and a more durable system, modifications have been made to a previously introduced design. The modifications include changes in material selection, a different displacer drive, and the use of a low-cost and more efficient engine cooler. A commercially available R-22 compressor is employed in the prototype. Low cost iron-neodymium permanent magnets are used to provide an efficient magnetic coupling. To match the engine power to the lead, a double-acting variable gas spring is arranged in parallel with the engine and compressor. After the gas spring was designed and fabricated, it was tested with the compressor. Before system integration and tests, the engine/linear alternator and the compressorlheat pump have been set up and are being tested separately