Question-and-Answer Resource for the Building Energy Modeling Community
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Generally, for smaller DX units, I've never had any luck getting detailed info from manufacturers, and sometimes it's even hard to get design COPs for really small units. Generally, when I have to make assumptions, I stick with 90.1 baseline efficiencies and curves (or just software default curves). That's not quite right of course, but it's a tiny impact.
Heat pumps tend to be more important, so I'll spend more time hunting down performance curves. It's also not as straightforward getting detailed performance curve info especially in the format needed for software (that has been adapted from the polynomial curves method for chillers), but I find it's usually pretty doable to get at least one curve for full load COP by OA temp (or source temp for WWHPs), and also another curve for capacity at those conditions - but not always possible/easy to get the full curve. because of that I'll confirm that there is plenty of capacity in the coldest conditions, and potentially ignore the capacity degradation in the model, while being sure to account for the temp dependency.
