Follow the explanation
Back to the model ↑How the parts work together
Add work at the compressor
Start at the compressor. It takes in low-pressure vapour and pushes it out at higher pressure and temperature. Electrical work makes this sustained circulation possible. The marker follows one parcel; the other components keep operating at the same time.
Release heat into the room
Follow the orange high-pressure line into the condenser. Heat leaves for the surrounding air, and the refrigerant changes from vapour to liquid. This is why the outside heat exchanger feels warm during operation.
Drop the pressure
The high-pressure liquid passes through the narrow capillary tube. Its pressure falls, and part of it flashes into vapour. Follow the change from the orange high-pressure side to the blue low-pressure side.
Take heat from the inside
The cold mixture enters the evaporator. As its liquid evaporates, it absorbs heat from the compartment. Vapour returns to the compressor. Now switch the compressor off: the model stops its driven circulation and active heat-transfer arrows.
The main parts
- Compressor
- An electric motor drives the pump inside this sealed housing. It draws in low-pressure vapour and discharges higher-pressure, hotter vapour. It supplies work to the cooling cycle.
- Condenser · heat out
- The outside heat exchanger transfers heat from the refrigerant to the room. As high-pressure refrigerant gives up heat, it condenses from vapour into liquid. It releases both the absorbed interior heat and the compressor's added energy.
- Capillary tube · pressure drop
- This narrow tube restricts the flow between the high- and low-pressure sides. Across it the pressure drops and some liquid flashes into vapour. The resulting cold liquid-vapour mixture enters the evaporator. The coil is enlarged here so it can be inspected.
- Evaporator · heat in
- Inside the cabinet, low-pressure refrigerant absorbs heat as the remaining liquid evaporates. The refrigerant leaves as vapour and returns to the compressor. Interior air and the refrigerant travel in separate spaces.
- Insulated cabinet
- Insulation slows heat entering from the room. The cutaway opens the front and removes a side panel to reveal the cooling circuit; it is an inspection view, not a simulation of leaving the door open.
Questions worth exploring
Why is the back of a refrigerator warm?
The condenser there is where the heat leaves. Danfoss says the heat given off equals the heat absorbed in the evaporator plus the heat created by compression, so the room gains more heat than the cabinet loses. As it gives up that heat the refrigerant condenses from vapour to liquid. The model shows this with orange for the high-pressure side; the colours are not measured temperatures.
Danfoss · How a refrigerator worksDanfoss · Refrigeration basics, including condenser heat balance
Why does evaporating refrigerant make the inside cold?
A liquid absorbs heat as it evaporates, as you notice when alcohol dries on skin. The evaporator keeps the refrigerant at low pressure, so it boils at a low temperature and pulls heat from the cabinet air. The compressor sucks the vapour away to hold that pressure down. Refrigerant and cabinet air travel in separate spaces, and the model does not calculate temperatures or cooling capacity.
Danfoss · Refrigeration basics, including condenser heat balanceDanfoss · How a refrigerator works
What does the capillary tube do?
It is a thin tube that serves as the expansion device. Liquid refrigerant from the condenser is forced through it and sprayed into the low-pressure evaporator, so its pressure falls and part of it flashes into vapour. Danfoss notes that a capillary tube suits small, simple appliances such as refrigerators but cannot regulate how much liquid enters. In the model the coil is enlarged so you can inspect it.
Danfoss · How a refrigerator worksDanfoss · Refrigeration basics, including condenser heat balance
What does the compressor switch do in this model?
Switching the compressor off stops the driven flow and the heat-transfer arrows, showing that the compressor supplies the work that keeps refrigerant circulating. In a real refrigerator a thermostat turns the compressor on and off to hold the temperature. This model has no thermostat cycling, and real systems keep exchanging heat and equalizing pressure after switch-off.