Assertion: heat pump's system | /r/CapableOf | use refrigerant
Facets:
value: years ago
type: TEMPORAL
Source sentences:
text: Most residential systems years ago used a refrigerant called Freon-22 that happens to be in this group.
text: In systems using refrigerant, this working fluid can also be used to transfer heat a considerable distance, though this can become impractical because of increased risk of expensive refrigerant leakage.