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Understanding Compressor SEER and EER Ratings

jakerbake | Posted in Energy Efficiency and Durability on

I thought the only real major difference between the low temp models and the regular models was the equipment to handle the freezing (e.g. base pan heaters).  But these models also have better cooling ratings (SEER, EER).  Are they overall just more efficient models?  Or are the cooling ratings just a sort of glitch result because they are able to operate for longer in the season?

I don’t technically need hyper-heat, but I get rebates on those models in my state.  So trying to decide if it’s worth it just for efficiency reasons.

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Replies

  1. Craig | | #1

    The simple explanation: Larger components and refrigerant circuit, but rested to a nominally smaller load. IE 5 tons unit is rates at 4 tons, thereby along for greater range of use.

    There's more engineering than that, but that's the simplistic answer. So yes, it will "rate" at a slightly better efficiency, but may not necessarily be more efficient given operating conditions.

  2. Steve Grinwis | | #2

    I might have bits of this wrong. This is not my area of expertise.

    Hyper heat is a combination of a bunch of technologies. Variable refrigerant flow, variable speed compressors, and Flash injection.

    As temperatures get colder outside, you need a lower condensation temperature to get your coolant to condense. In a normal variable compressor system, you end up having to do this by slowing down your compressor, giving the coolant more time at lower pressure to condense. You don't want to send gas back to your evaporator. It'll do you no good there. That's called flash gas.

    This sucks because as it gets colder, your refrigerant flow rate drops, and with it so does your capacity.

    Enter Flash injection. What if you kept your compressor rate high, your mass flow rate high, and put a liquid / gas separator tank into the mix after the condensate coil? That way if you have gas left that hasn't condensed, no problem, just send it back around through the compressor again.

    In the fashion you get better 'reversibility' to your cycle, which improves thermodynamic efficiency, better mass flow rate, better capacity, and you can actually cheat and use this high pressure low temperature gas to help cool the compressor.

    Bonus points all around.

    In short, yes, these units are actually more efficient then their non hyper heat equivalents, while offering better low and high temperature capacity!

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