Login-Verarbeitung ...

Trial ends in Request Full Access Tell Your Colleague About Jove

21.5: Refrigerators and Heat Pumps

JoVE Core

Ein Abonnement für JoVE ist erforderlich, um diesen Inhalt ansehen zu können. Melden Sie sich an oder starten Sie Ihre kostenlose Testversion.

Refrigerators and Heat Pumps

21.5: Refrigerators and Heat Pumps

Refrigerators or heat pumps are heat engines operating in a reverse direction. For a refrigerator, the focus is on removing heat from a specific area, whereas, for a heat pump, the focus is on dumping heat into one particular area. A refrigerator (or heat pump) absorbs heat Qc from the cold reservoir at Kelvin temperature Tc and discards heat Qh to the hot reservoir at Kelvin temperature Th, while work W is done on the engine’s working substance.

A household refrigerator removes heat from the food while exhausting heat to the surrounding air. The required work is performed by the motor using electricity, which moves a coolant through the coils. A coolant with a boiling temperature below the freezing point of water is sent through the cycle. The coolant extracts heat from the refrigerator at the evaporator, causing the coolant to vaporize. It is then compressed and sent through the condenser, where it exhausts heat to the outside.

The effectiveness or coefficient of performance KR of a refrigerator is measured by the heat removed from the cold reservoir divided by the work done by the working substance cycle by cycle. Conversely, the coefficient of performance KP of a heat pump is measured by the heat dumped to the hot reservoir divided by the work done to the engine on the working substance cycle by cycle.

Suggested Reading


Keywords: Refrigerators Heat Pumps Heat Engines Heat Removal Heat Dumping Cold Reservoir Hot Reservoir Work Coefficient Of Performance Coolant Evaporator Condenser Vaporization Compression

Get cutting-edge science videos from JoVE sent straight to your inbox every month.

Waiting X
Simple Hit Counter