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Old 11-19-16, 07:22 AM   #8
jeff5may
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Steve,

Both papers are super useful! I learned new things from both of them. I knew scroll compressors hit the market after recip and rolling piston compressors, but I didn't know it wasn't until the 1980's until they started showing up in manufactured units. The second document is all killer, no filler. The pictures show stuff you never want to see in real life. I just wonder what kind of noises those units made when they failed!

The OEM's are still inventing new applications of the scroll design. The latest innovation is the dual-stage scroll. Basically, the manufacturers have begun to use the intermediate-pressure ports in the scroll in a new way. Instead of simply opening the ports to the suction-side internally to reduce capacity, they have turned the ports into intermediate pressure taps. These ports are piped outside the compressor shell, enabling system designers to use the ports however they see fit.

The new Gree Terra series use the taps to inject cool gas into the compressor, increasing compression ratio while lowering discharge temperature. This enables their air-source outdoor units to dig deeper into cold-climate territory, providing full capacity at temperatures where other units cannot. Xringer installed a shiny new one of these this summer to replace one of his Sanyo units that lost a control board. It will be interesting to find out how the new design performs this winter. It gets pretty cold in Boston, and his 2 Sanyos had trouble keeping his house warm during cold spells without tripping circuit breakers and such.

Marx290,

Please post some words to go with the pictures. For example, what's up with the hourglass-shaped hx? And why did you put so many spacers on the cylindrical one? Are they heat spreaders, or the fasteners for some sort of cover? That's a huge heat exchanger for such a small compressor. Not so much the bulk of it, but the tubing diameter.
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