Definition
A closed-loop refrigeration system that moves heat from one location to another by alternately compressing and expanding a refrigerant. By reversing the direction of refrigerant flow, the same unit can either remove heat from an enclosed space (cooling) or deliver heat into it (heating).
Plain English
A device that moves heat from one place to another using a refrigerant. The same unit can be reversed to either cool a space or warm it.
Context Anchor
Seen in aircraft heating, ventilation, air conditioning, and maintenance descriptions for cabin temperature control.
Derivation
From 'heat' (warmth) and 'pump' (a device that moves a fluid from one place to another). The name reflects the core idea: heat itself is being pumped from one location to another, rather than being generated.
Why Pilots Care
Provides efficient cabin temperature control with lower power consumption than combustion heaters, supporting passenger comfort and electrical system management.
Analogy
Think of it like a refrigerator that can run both ways. One way carries heat out of the cabin; the other way carries heat into the cabin.
Grounding Statement
Even cool air contains some heat, and a heat pump moves some of that heat to where it is useful.
Intuition Check
Do not read “pump” as meaning it pumps air like a fan. A heat pump moves heat, usually by circulating refrigerant through a heating-and-cooling system.
Example Sentence 1
The aircraft's cabin temperature is regulated by a heat pump that can be switched between cooling and heating modes.
Example Sentence 2
During the preflight inspection the mechanic confirmed the heat pump was cycling properly before departure.