Energy transfer

Physics

Archaeology

Energy (signal processing)

Air source heat pumps

Defrosting

Mathematics education

Heat pump

Unit (ring theory)

Geography

Procession

Quantum mechanics

Mathematics

Heat transfer

Environmental science

Engineering physics

Air conditioning

Mechanical engineering

Thermodynamics

Heat exchanger

Engineering

Applied Energy

Air source heat pump units have found their wide applications in recent decades due to their high efficiency and low environmental pollution. To solve their undesired frosting problem, reverse cycle defrosting is always employed. As a transient and nonlinear heat and mass transfer procession, defrosting performance directly affects the occupants’ thermal comfort. During defrosting, the metal energy storage values of indoor and outdoor coils are varied as their temperature fluctuations. It is therefore necessary to investigate the energy transfer procession in an air source heat pump unit and the effect of metal energy storage during defrosting. However, scarce of attentions were paid to this fundamental problem. In this study, two experimental cases with two-working-circuit and three-working-circuit outdoor coils were conducted basing on frost evenly accumulated on their surfaces. After four types of energy supply and five types of energy consumption during defrosting were calculated, a qualitative and quanti...

Energy transfer procession in an air source heat pump unit during defrosting