The refrigerant flows through the coils on the back or under the freezer and through an expansion valve to the inside of the freezer. As the refrigerant passes through the expansion valve the pressure drops and hence the temperature also drops.
The noun MM has 1 sense: 1  1. a metric unit of length equal to one thousandth of a meter. 2  Meaning: 3  A metric unit of length equal to one thousandth of a meter. 4  Classified under: 5  Nouns denoting quantities and units of measure. 6  Synonyms: 7  millimeter; millimetre; mm. 8  Hypernyms (mm is a kind of...):
In metric units, M means mega which means million. You may see the notation Nm3/s which is a metric (SI) unit for Normal m3/s. Normal is the same as standard or base, which can be confused with Newton (unit of force) since both have the same abbreviation.