Fenestration is a fancy architectural term that means “openings in the outside of the building.” You will see this word a lot when you read ACCA manual J or when you are doing a manual J load calculation. Fenestration loads include heat losses and gain through windows, doors, skylights, etc., and they can make up […]

We have discussed DTD (design temperature difference) quite a bit for air conditioning applications, but what about refrigeration? Let's start by defining our terms again. Suction Saturation Temperature The saturation temperature is the temperature at which the refrigerant will be at a given pressure if it is currently changing state. This change of state would […]

One aspect of motor selection that can get overlooked is motor bearings, and it can have big consequences. Sleeve bearings are most common in residential and light commercial applications because they are less expensive and quieter. They don't have rolling “balls” but rather rely on a thin film of oil on metal sleeves. Sleeve bearings […]