Evaporator temperatures below 32° are common and acceptable in refrigeration; that's why there is a defrost sequence. In a heat pump running in heat mode, it's the same; freezing is a part of the process, and defrost is necessary. In comfort cooling, we can't allow the evaporator to get below 32°, or it will freeze. […]

This tip was a COMMENT on the sensible heat ratio tip left by Jim Bergmann. As usual, Jim makes a great point; once you get the “sensible” capacity for a piece of equipment at a set of conditions, you can easily calculate a true target delta T. Another interesting thing you can do is use […]

There's a moral to this story, though it is a bit more of a cautionary tale than most I write. While it doesn't rank with the story of three wise men or even Frank Capra's Christmas classic “It's a Wonderful Life,” you may find some common threads with both learning wisdom and remembering why throwing […]